Literature Supporting Claims Regarding the Environmental Benefits of Plants

Listed in chronological order

Zinia, N. J. and P. McShane (2018). "Ecosystem services management: An evaluation of green adaptations for urban development in Dhaka, Bangladesh." Landscape and Urban Planning 173: 23-32. We evaluated green adaptation strategies (parks, gardens, green roof, rainwater harvest, green façades/wall, porous pavement, and green and blue belts) in the context of urban development and potential climate change impacts for the city of Dhaka, Bangladesh. Our review of relevant literature revealed substantial environmental (cooler and cleaner environment), economic (reduced energy demand, avoided cost of drainage maintenance, increased land values) and social (higher social interaction, improved mental and physical health) benefits arising from the maintenance and development of ecosystem services in major cities. Our evaluation of green adaptation strategies was undertaken with household surveys in three wards of Dhaka, expert interviews, and our personal experiences. Rooftop gardens/agriculture had very high social acceptance (85%) and economic feasibility and was commonly practiced in Dhaka, particularly among house owners. Pocket park, green roof, rainwater harvest, green façades/wall, porous pavement, and community garden were all considered to be highly feasible for implementation with collective efforts but had lower social acceptance. Many respondents were unwilling to pay for green adaptation strategies even knowing their benefits. Our research revealed that successful implementation of beneficial green adaptation will require public participation at all stages supported through awareness raising campaigns. Enforcement of laws and strong commitment from the government was also considered to be beneficial. However, more transparent cost-benefit analyses promoting the conservation of ecosystem services is required, particularly for resource-poor Dhaka. Green adaptations make cities more resilient to pressures from demographic change and climate change increasingly relevant in the developing world.

Simon, H., et al. (2018). "Modeling transpiration and leaf temperature of urban trees–A case study evaluating the microclimate model ENVI-met against measurement data." Landscape and Urban Planning 174: 33-40. Increasing vegetation cover in cities is a key approach to mitigating urban heat excess. However, both the effect of vegetation on microclimate and the plants’ vitality need to be assessed to support and quantify the effects of such strategies. One way to assess the interactions between vegetation and the urban environment is through microclimate models that can simulate the effects of vegetation onto the urban microclimate as well as effects of urban environments onto vegetation. To provide reliable estimates microclimate models need to be parameterized based on empirically obtained data. In this paper we compare modeled transpiration rates and leaf temperatures of a leading microclimate model, ENVI-met V4, with in-situ measured stem sap flow and leaf temperatures of two different trees in an urban courtyard. The vegetation model of ENVI-met is evaluated considering four synoptic situations including varying cloud covers ranging from fully cloudy to clear sky. The comparison of simulation results with empirical data reveals a high agreement. The model is capable of capturing the magnitude as well as short-term variations in transpiration caused by microclimatic changes. However, substantial deviations were found in situations with low photosynthetic active radiation. Modeled and observed diurnal tree transpiration and leaf temperature showed good agreement. These findings indicate that ENVI-met is capable of simulating transpiration rates and leaf temperatures of trees in complex urban environments.

Tigges, J., et al. (2017). "Modeling above-ground carbon storage: a remote sensing approach to derive individual tree species information in urban settings." Urban Ecosystems 20(1): 97-111. Vegetation has gained importance in respective debates about climate change mitigation and adaptation in cities. Although recently developed remote sensing techniques provide necessary city-wide information, a sufficient and consistent city-wide information of relevant urban ecosystem services, such as carbon emissions offset, does not exist. This study uses city- wide, high-resolution, and remotely sensed data to derive individual tree species information and to estimate the above-ground carbon storage of urban forests in Berlin, Germany. The variance of tree biomass was estimated using allometric equations that contained different levels of detail regarding the tree species found in this study of 700 km2, which had a tree canopy of 213 km2. The average tree density was 65 trees/ha per unit of tree cover and a range from 10 to 40 trees/ha for densely urban land cover. City-wide estimates of the above-ground carbon storage ranged between 6.34 and 7.69 tC/ha per unit of land cover, depending on the level of tree species information used. Equations that did not use individually localized tree species information undervalued the total amount of urban forest carbon storage by up to 15 %. Equations using a generalized estimate of dominant tree species information provided rather precise city-wide carbon estimates. Concerning differences within a densely built area per unit of land cover approaches using individually localized tree species information prevented underestimation of mid-range carbon density areas (10–20 tC/ha), which were actually up to 8.4 % higher, and prevented overestimation of very low carbon density areas (0–5 tC/ha), which were actually up to 11.4 % lower. Park-like areas showed 10 to 30 tC/ha, whereas land cover of very high carbon density (40–80 tC/ha) mostly consisted of mixed peri-urban forest stands. Thus, this approach, which uses widely accessible and remotely sensed data, can help to improve the consistency of forest carbon estimates in cities.

Threlfall, C. G., et al. (2017). "Increasing biodiversity in urban green spaces through simple vegetation interventions." Journal of Applied Ecology. Cities are rapidly expanding world-wide and there is an increasing urgency to protect urban biodiversity, principally through the provision of suitable habitat, most of which is in urban green spaces. Despite this, clear guidelines of how to reverse biodiversity loss or increase it within a given urban green space is lacking. We examined the taxa- and species-specific responses of five taxonomically and functionally diverse animal groups to three key attributes of urban green space vegetation that drive habitat quality and can be manipulated over time: the density of large native trees, volume of understorey vegetation and percentage of native vegetation. Using multi-species occupancy-detection models, we found marked differences in the effect of these vegetation attributes on bats, birds, bees, beetles and bugs. At the taxa-level, increasing the volume of understorey vegetation and percentage of native vegetation had uniformly positive effects. We found 30–120% higher occupancy for bats, native birds, beetles and bugs with an increase in understorey volume from 10% to 30%, and 10–140% higher occupancy across all native taxa with an increase in the proportion of native vegetation from 10% to 30%. However, increasing the density of large native trees had a mostly neutral effect. At the species-specific level, the majority of native species responded strongly and positively to increasing understorey volume and native vegetation, whereas exotic bird species had a neutral response. Synthesis and applications. We found the probability of occupancy of most species examined was substantially reduced in urban green spaces with sparse understorey vegetation and few native plants. Our findings provide evidence that increasing understorey cover and native plantings in urban green spaces can improve biodiversity outcomes. Redressing the dominance of simplified and exotic vegetation present in urban landscapes with an increase in understorey vegetation volume and percentage of native vegetation will benefit a broad array of biodiversity.

Park, J., et al. (2017). "The influence of small green space type and structure at the street level on urban heat island mitigation." Urban Forestry & Urban Greening 21: 203-212. The purpose of this study was to determine the types and structures of small green spaces (SGs) that effectively reduce air temperature in urban blocks. Six highly developed blocks in Seoul, South Korea served as the research sites for this study. Air temperature was measured at the street level with mobile loggers on clear summer days from August to September in 2012. The measurements were repeated three times a day for three days. By analyzing the spatial characteristics, SGs within the six blocks were categorized into the four major types: polygonal, linear, single, and mixed. The result revealed that the polygonal and mixed types of SGs showed simple linear regression at a significant level (p < 0.01). It indicated that the blocks’ urban heat island (UHI) mitigation (ΔTRmn) increased in a linear fashion when the area and volume of these two types of green spaces increased. The area and volume of a polygonal SG with mixed vegetation, over 300 m2 and 2300 m3, respectively, lowered the ΔTRmn by 1 °C; SG with an area and volume of larger than 650 m2 and 5000 m3, respectively, lowered the ΔTRmn by 2 °C. The results of this study will be useful to urban planners and designers for determine the types and structures of urban green spaces to optimize the cooling effect, as well as how such green spaces should be designed and distributed.

Ow, L. F. and S. Ghosh (2017). "Urban cities and road traffic noise: Reduction through vegetation." Applied Acoustics 120: 15-20. This study was carried out to determine the effect of roadside vegetation on the reduction of road traffic noise under varying planting intensities. Roadside vegetation ranging from minimal planting through to moderate and dense plantings were used. The results showed that the traffic noise was reduced by 50% when vegetation was enhanced from a minimal to moderate planting intensity, and no enhancement in noise reduction was observed as vegetation was further increased to a dense intensity. A 5 m depth of vegetation barrier was found to be an ideal depth for traffic noise reduction. Without the vegetative barrier, the observed mean noise levels were 78 dB. On average, vegetative barriers (moderate to dense) were able to reduce traffic noise by 9–11 dB. Trunk size was found to be linearly related to traffic noise abatement and synthetic barriers were found to be inferior to tree belts both psychologically and in absolute values of noise. This report also investigated the effectiveness associated with setbacks where it was found that the greater the setback distance, the higher the level of noise amelioration and a 10 m depth was identified as the threshold for an effective tree belt.

Margaritis, E. and J. Kang (2017). "Relationship between green space-related morphology and noise pollution." Ecological Indicators 72: 921-933. Green spaces have been proved to have a positive effect on traffic noise pollution in the local scale; however their effects have not been explored on the urban level. This paper investigates the effects of green space-related parameters from a land cover viewpoint on traffic noise pollution in order to understand to what extent greener cities can also be quieter. A triple level analysis was conducted in the agglomeration, urban and kernel level including various case study cities across Europe. The green space parameters were calculated based on land cover data available in a European scale, while traffic noise data were extracted from online noise maps and configured in noise indices. In the first level 25 agglomerations were investigated, six of which were further analyzed in the urban and kernel levels. It was found that the effect of green spaces on traffic noise pollution varies according to the scale of analysis. In the agglomeration level, there was no significant difference in the cluster of the higher green space index and the percentage of people exposed in the lowest (55–59 dB(A)) or the highest noise band of more than 70 dB(A). In the urban level it was found that lower noise levels can possibly be achieved in cities with a higher extent of porosity and green space coverage. Finally, in the kernel level a Geographically Weighted Regression (GWR) analysis was conducted for the identification of correlations between noise and green. Strong correlations were identified between 60% and 79%, while a further cluster analysis combined with land cover data revealed that lower noise levels were detected in the cluster with higher green space coverage. At last, all cities were ranked according to the calculated noise index.

Jayasooriya, V. M., et al. (2017). "Green infrastructure practices for improvement of urban air quality." Urban Forestry & Urban Greening 21: 34-47. Green Infrastructure (GI) practices have shown to be promising in mitigating the air pollution in urban areas of several cities across the world. GI practices such as trees, green roofs and green walls are widely used in United States and Europe to mitigate the air pollution. However, there is yet limited knowledge available in identifying the most suitable GI strategy for an urban area in improving the air quality. Furthermore, it is evident that Australia is still lagging behind in adapting GI to mitigate air pollution, compared with US and Europe. Therefore, this study analyzed the air quality improvement through several GI scenarios consisting of trees, green roofs and green walls considering a case study area in Melbourne, Australia by using the i- Tree Eco software. The results were compared with case studies in different cities across the world. The results showed that the i-Tree Eco software can be successfully applied to an Australian case study area to quantify the air quality improvement benefits of GI. The results were further assessed with several environmental, economic and social indicators to identify the most suitable GI scenarios for the study area. These indicators were quantified using different methods, to assess the effectiveness of different GI scenarios. The results showed that, trees provided the highest air pollution removal capability among the different GI considered for the study area. Combination of different GI such as green roofs and green walls with trees did not provide a significant increment of air quality improvement however, has provided more local benefits such as building energy savings. The results obtained from this study were also beneficial in developing policies related to future GI applications in major cities of Australia for the air quality improvement.

Helen P. King, J. M., Anil Graves, Richard B. Bradbury, James McGinlay, James M. Bullock (2017). "Biodiversity and cultural ecosystem benefits in lowland landscapes in southern England." Journal of Environmental Psychology 53: 185-197. Evidence of the link between biodiversity and cultural ecosystem benefits (CEB) is scarce. Participatory workshops were used to explore perceptions of CEB attributable to biodiversity in lowland arable and semi-natural grassland landscapes in southern England. Increased biodiversity was found to be associated with greater perceived benefit, mainly at the habitat and landscape scale. It was, however, difficult to separate the effects of biodiversity from those of abiotic and human-made features, all of which combined to provide an important sense of place. Furthermore, CEB were strongly linked with supporting infrastructure, notably public access. It was observed that CEB were generated through socio-psychological 'pathways' as people interacted with environmental settings, such as acquiring knowledge, feeling regenerated and communicating with others. CEB were also attributed to provisioning and regulatory services, questioning the validity of partitioning cultural services. The findings have implications for practitioners designing programmes to enhance nature's contribution to people.

Englund, O., et al. (2017). "How to analyse ecosystem services in landscapes—A systematic review." Ecological Indicators 73: 492-504. Ecosystem services (ES) is a significant research topic with diverse modelling and mapping approaches. However, the variety of approaches—along with an inconsistent terminology—cause uncertainties concerning the choice of methods. This paper identifies and qualitatively assesses methods for mapping ES in terrestrial landscapes, based on a systematic review of the scientific literature. It further aims to clarify the associated terminology, in particular the concept of landscape and landscape scale. In total, 347 cases of ES mapping were identified in the reviewed papers. Regulating and maintenance services were most commonly mapped (165), followed by cultural (85), and provisioning services (73). For individual ES, a large variation in number of mapping cases was found. This variation may either reflect the perceived importance of the ES, or that different ES can be more or less easily mapped. Overall, Logical models and Empirical models were most commonly used, followed by Extrapolation, Simulation/Process models, Data integration, and Direct mapping. Only twelve percent of all ES mapping cases were validated with empirical data. The review revealed highly diverging views on the spatial extent of landscapes in studies of ES, and that the term landscape is sometimes used rather arbitrarily.

Zölch, T., et al. (2016). "Using green infrastructure for urban climate-proofing: An evaluation of heat mitigation measures at the micro-scale." Urban Forestry & Urban Greening 20: 305-316. Urban green infrastructure (UGI) has been increasingly promoted as a key measure to mitigate heat stress in cities caused by the urban heat island effect and climate change impacts, including climate variability and extremes. However, comparable information concerning the performance of different UGI types to moderate such impacts is mostly lacking. This creates serious challenges for urban planners who need to decide on the most effective measures while considering spatial and administrative constraints. This study investigates how different types and quantities of UGI, i.e. trees, green roofs, and green facades, affect pedestrian thermal comfort. The study was applied to high-density residential areas under current and future climatic conditions. Climate change will on average increase afternoon Physiological Equivalent Temperature (PET) values by 2.4 K; however, this could be vastly reduced by different UGI scenarios. Planting trees had the strongest impact with an average PET reduction of 13% compared with existing vegetation. Trees shade open spaces and provide evapotranspirative cooling. Another valuable adaptation option is green facades, which have mitigating effects of 5%–10%. In contrast, the effects of green roofs were negligible. Our results indicate that increasing the share of green cover did not directly correspond to the magnitude of the PET reduction. Placing vegetation strategically in heat-exposed areas is more effective than just aiming at a high percentage of green cover. We conclude that our extensive comparative analysis provides empirical evidence to support UGI on the micro-scale and assists planners and decision- makers to effectively select and prioritise concrete measures to adapt to climate change.

Van Renterghem, T. and D. Botteldooren (2016). "View on outdoor vegetation reduces noise annoyance for dwellers near busy roads." Landscape and Urban Planning 148: 203- 215. The effect of outdoor vegetation, as seen from the living room's window facing an inner- city ring road, on the self-reported noise annoyance, was studied. Face-to-face surveys were taken at 105 participants at their homes in the city of Ghent (Belgium). The living room window, facing the road, was in all cases highly exposed to road traffic noise and characterized by Lden levels between 65 and 80 dBA, as taken from the official European Environmental Noise Directive's city road traffic noise map. All houses were selected to have a pronounced front-back level difference to rule out this effect. The self-reported extent to which vegetation is visible through the living room window was shown to be a strong and statistically significant predictor of the self-reported noise annoyance. The complete absence of view on vegetation results in a 34% chance of being at least moderately annoyed by noise, while this chance reduced to 8% for respondents answering to have a very pronounced vegetation view, notwithstanding median Lden levels of 73 dBA at the street-facing facade of the dwelling. Real vision on outdoor vegetation was shown to be essential - living room (indoor) plants and the mere presence of vegetation in the neighborhood is insufficient. Road traffic noise facade insulation, measured in- situ at each dwelling, could not be linked to the self-reported noise annoyance.

Tong, Z., et al. (2016). "Roadside vegetation barrier designs to mitigate near-road air pollution impacts." Science of The Total Environment 541: 920-927. With increasing evidence that exposures to air pollution near large roadways increases risks of a number of adverse human health effects, identifying methods to reduce these exposures has become a public health priority. Roadside vegetation barriers have shown the potential to reduce near-road air pollution concentrations; however, the characteristics of these barriers needed to ensure pollution reductions are not well understood. Designing vegetation barriers to mitigate near-road air pollution requires a mechanistic understanding of how barrier configurations affect the transport of traffic-related air pollutants. We first evaluated the performance of the Comprehensive Turbulent Aerosol Dynamics and Gas Chemistry (CTAG) model with Large Eddy Simulation (LES) to capture the effects of vegetation barriers on near- road air quality, compared against field data. Next, CTAG with LES was employed to explore the effects of six conceptual roadside vegetation/solid barrier configurations on near-road size- resolved particle concentrations, governed by dispersion and deposition. Two potentially viable design options are revealed: a) a wide vegetation barrier with high Leaf Area Density (LAD), and b) vegetation–solid barrier combinations, i.e., planting trees next to a solid barrier. Both designs reduce downwind particle concentrations significantly. The findings presented in the study will assist urban planning and forestry organizations with evaluating different green infrastructure design options.

Sjöman, H., et al. (2016). "Diversification of the urban forest—Can we afford to exclude exotic tree species?" Urban Forestry & Urban Greening 18: 237-241. Introduced tree species represent a substantial component of urban forests in cities all over the world. Yet there is controversy about the further use of introduced tree species. Many practice orientated publications, research papers and governmental websites in the fields of urban planning, urban forestry, and urban ecology argue for planting native species and avoiding introduced species. Such arguments for native-only species selection are also touted by environmental groups and the media. Consequently, the debate has sometimes spiralled away from a sensible and rational platform where invasion risks and biodiversity loss are discussed, to a groundless and unreasonable argument where exotic species are generally considered incapable of providing ecosystem services. From a European perspective, we here aim to curate a set of necessary considerations for current and future discussions on native and non-native plant material in sustainable urban development. Using examples from Northern and Central Europe we illustrate that in some regions the catalogue of native tree species may be too limited to fulfil ecosystem services and resilience in harsh urban environments. A main message from our line of arguments is that we cannot afford to generally exclude non-native tree species from urban greening. If “native-only” approaches become incorporated in regional, national or international policy documents or legislation there is a risk that urban ecosystem resilience will be compromised, particularly in regions with extreme environmental conditions. Since both invasion risks and sizes of native species pools vary conspicuously at regional to continental scales we also argue to adapt urban policies on using non-native trees to regional contexts.

Salmond, J. A., et al. (2016). "Health and climate related ecosystem services provided by street trees in the urban environment." Environmental Health 15(1): S36. Urban tree planting initiatives are being actively promoted as a planning tool to enable urban areas to adapt to and mitigate against climate change, enhance urban sustainability and improve human health and well-being. However, opportunities for creating new areas of green space within cities are often limited and tree planting initiatives may be constrained to kerbside locations. At this scale, the net impact of trees on human health and the local environment is less clear, and generalised approaches for evaluating their impact are not well developed. In this review, we use an urban ecosystems services framework to evaluate the direct, and locally-generated, ecosystems services and disservices provided by street trees. We focus our review on the services of major importance to human health and well-being which include ‘climate regulation’, ‘air quality regulation’ and ‘aesthetics and cultural services’. These are themes that are commonly used to justify new street tree or street tree retention initiatives. We argue that current scientific understanding of the impact of street trees on human health and the urban environment has been limited by predominantly regional-scale reductionist approaches which consider vegetation generally and/or single out individual services or impacts without considering the wider synergistic impacts of street trees on urban ecosystems. This can lead planners and policymakers towards decision making based on single parameter optimisation strategies which may be problematic when a single intervention offers different outcomes and has multiple effects and potential trade-offs in different places. We suggest that a holistic approach is required to evaluate the services and disservices provided by street trees at different scales. We provide information to guide decision makers and planners in their attempts to evaluate the value of vegetation in their local setting. We show that by ensuring that the specific aim of the intervention, the scale of the desired biophysical effect and an awareness of a range of impacts guide the choice of i) tree species, ii) location and iii) density of tree placement, street trees can be an important tool for urban planners and designers in developing resilient and resourceful cities in an era of climatic change.

Razzaghmanesh, M., et al. (2016). "The role of green roofs in mitigating Urban Heat Island effects in the metropolitan area of Adelaide, South Australia." Urban Forestry & Urban Greening 15: 89-102. Changing an urban environment and replacing vegetated surfaces with low albedo materials is one of the reasons for increasing temperatures in an urban environment and consequently also one of the key causes of urban heat island effects. In this study, an experimental investigation at the micro-scale and also a numerical simulation at the macro-scale of a typical urban environment in Adelaide were conducted to estimate the potential for mitigating the UHI effect. The results showed that existing low albedo materials such as asphalt, metal roofs and brick pavements contribute to the heat island potential. Also, urban development and a lack of natural vegetation contribute to increased temperatures in cities. The ability of two types of extensive and intensive green roofs to reduce the surrounding micro-climate temperature were monitored. The results showed that they have significant cooling effects in summer time and could behave as an insulation layer to keep buildings warmer in the winter. Furthermore, different scenarios of adding green roofs to the Adelaide urban environment were investigated using the Envi–MET model. The scenario modelling of adding green roofs in a typical urban area in Adelaide, Australia, supported the hypothesis that this can lead to reductions in energy consumption in the Adelaide urban environment. Also an increased use of other water sensitive urban design technologies such as green walls and street trees together with the adoption of high albedo materials is recommended for achieving the optimum efficiency in terms of reducing urban temperatures and mitigating urban heat island effects.

Rai, P. K. (2016). "Biodiversity of roadside plants and their response to air pollution in an Indo-Burma hotspot region: implications for urban ecosystem restoration." Journal of Asia-Pacific Biodiversity 9(1): 47-55. In recent Anthropocene, biodiversity of urban roadside plants is now increasingly being realized as an eco-sustainable tool for monitoring and mitigation of air pollution. The present study aimed to investigate the impact of particulate matter (PM) pollutants on leaf morphology (stomata), biochemical (heavy metals, protein, and sugars) parameters and enzyme activity (peroxidase and catalase) of 12 common roadside plant species, growing at two different sites of Aizawl City, i.e. the Ramrikawn (RKN-Med; polluted peri-urban) site and the Mizoram University (MZU-Low; less polluted rural) site. The highest dust deposition was noted for the RKN-Med site on Ficus benghalensis and the lowest in Bauhinia variegate. The plant species growing at the RKN-Med site showed significant decreases in stomatal size and stomatal index (p ˂ 0.05). Further, increased concentration of heavy metals (Fe, Cu, and Zn) was recorded at the RKN-Med site. Moreover, tolerant roadside plants find their suitability for plantation in ecologically sensitive regions, having implications for urban ecosystem restoration.

Pulighe, G., et al. (2016). "Insights and opportunities from mapping ecosystem services of urban green spaces and potentials in planning." Ecosystem Services 22, Part A: 1-10. Urbanization and rapid population growth pose the cities in front of massive challenges in terms of environmental impacts. This paper explores recent progresses in mapping ecosystem services provided by urban green infrastructures (GI) and discuss how GI can contribute to promoting cohesion, resilience and livability toward sustainable and green cities. It also investigates the interlinkages between ecosystem services paradigm, mapping approaches at urban level and benefits provided for human well-being. A literature study focusing on recent research papers is conducted, highlighting new trends on methods and data, unexplored developments and opportunities on literature regarding mapping green infrastructures with respect to planning, management and ecosystem services’ provision. Additionally, an in-depth analysis of selected case studies synthesizes and discusses key insights of quantitative results related to key ecosystem services mapping approaches. The results indicate that mapping efforts integrates multiple disciplines, combining advanced technology and sophisticated models and methods. We argue that mapping ecosystem services would allow urban designers and planning practitioners to help and inform policymakers during the decision process and management of urban landscapes.

Pinho, P., et al. (2016). "Evaluating green infrastructure in urban environments using a multi-taxa and functional diversity approach." Environmental Research 147: 601-610. Forested areas within cities host a large number of species, responsible for many ecosystem services in urban areas. The biodiversity in these areas is influenced by human disturbances such as atmospheric pollution and urban heat island effect. To ameliorate the effects of these factors, an increase in urban green areas is often considered sufficient. However, this approach assumes that all types of green cover have the same importance for species. Our aim was to show that not all forested green areas are equal in importance for species, but that based on a multi-taxa and functional diversity approach it is possible to value green infrastructure in urban environments. After evaluating the diversity of lichens, butterflies and other-arthropods, birds and mammals in 31 Mediterranean urban forests in south-west Europe (Almada, Portugal), bird and lichen functional groups responsive to urbanization were found. A community shift (tolerant species replacing sensitive ones) along the urbanization gradient was found, and this must be considered when using these groups as indicators of the effect of urbanization. Bird and lichen functional groups were then analyzed together with the characteristics of the forests and their surroundings. Our results showed that, contrary to previous assumptions, vegetation density and more importantly the amount of urban areas around the forest (matrix), are more important for biodiversity than forest quantity alone. This indicated that not all types of forested green areas have the same importance for biodiversity. An index of forest functional diversity was then calculated for all sampled forests of the area. This could help decision-makers to improve the management of urban green infrastructures with the goal of increasing functionality and ultimately ecosystem services in urban areas.

Pena, J., et al. (2016). "The green infrastructure of a highly-urbanized neotropical city: the role of the urban vegetation in preserving native biodiversity." Capa 11(4): 66-78. The composition of the urban vegetation that comprises the green infrastructure of a highly urbanized Neotropical city was mapped and described in order to assess how it can be used to preserve and maintain urban biodiversity. Supervised classification was used, followed by Map Algebra methodology, to identify the elements that comprise the green infrastructure of the southern region of Belo Horizonte (Minas Gerais, Brazil). Species composition of the street trees community was also assessed. Almost half of the study area is occupied by 12 types of woody and herbaceous vegetation, composed mostly by urban parks and gardens. Forty-one percent of the almost 90,000 street trees is composed by 10 species from which only four are native. These results show that the green infrastructure of this urban landscape is comprised by a large amount of different types of green elements, and has a great potential for biodiversity conservation. However, management strategies are needed such as better planning of the urban afforestation process, increasing street tree species richness. This study is the first step towards a better understanding of how such urban landscape influences local biodiversity.

Okunlola, A. I., et al. (2016). "Air Pollution Tolerance Index (APTI) and carbon sequestration of selected trees and shrubs for urban development in Akure Ondo State, Southwest Nigeria." Brazilian Journal of Biological Sciences 3(6): 395-405. Urban green space is a collection of trees and shrubs growing in urban area. Green plants are well known for their abilities to reduce air and noise pollution. It is important that plants used for the development of urban landscaping must be tolerant to air pollutants. There must be some criteria to select tolerant plants for urban landscaping design and for that two indices viz. Air Pollution Tolerance Index (APTI) and carbon sequestration can be a good tool. Thus this study was carried out to assess the efficiency of urban trees (Tabebuia rosea, Polyalthia longifolia, Delonix regia and Raphia farinifera) and shrubs (Ficus spp) to tolerate air pollution and potential for carbon sequestration in Akure, Ondo State, Nigeria in 2015. The sites were sampled from Akure City Major Road, from Oloko Junction to Oba-Ile. The plant species identified at the sample area were Ficus spp, Tabebuia rosea, Polyalthia longifolia, Delonix regia and Raphia farinifera. The assessment of the ascorbic acid, pH, relative water content and total chlorophyll content of the leaves of the identified plant species was done to determine the APTI. The APTI of the plant ranged from 5.11 to 9.31 with Tabebuia rosea having the highest value which indicates it’s high tolerance of air pollutants from the assessment and Raffia farinifera with the lowest value and least tolerant. The biomass of the trees species were estimated for the quantification of the amount of carbon sequestered and the absorbed CO2 in the plant. Tabebuia rosea also had the highest carbon sequestered (10,074 kg) and Delonix regia having the lowest of 4,702.50 kg.

Nowak, D. J., et al. (2016). "Urban forest structure, ecosystem services and change in Syracuse, NY." Urban Ecosystems 19(4): 1455-1477. The tree population within the City of Syracuse was assessed using a random sampling of plots in 1999, 2001 and 2009 to determine how the population and the ecosystem services these trees provide have changed over time. Ecosystem services and values for carbon sequestration, air pollution removal and changes in building energy use were derived using the i-Tree Eco model. In addition, photo interpretation of aerial images was used to determine changes in tree cover between the mid-1990s and 2009. Between the mid-1990s and 2003, tree cover in Syracuse exhibited a decline from 27.5 to 25.9 %, but subsequently increased to 26.9 % by 2009. The total tree population exhibited a similar pattern, dropping from 881,000 trees in 1999 to 862,000 in 2001, and then increasing to 1,087,000 trees in 2009. Most of this increase in the urban tree population is due to invasive or pioneer trees species, particularly Rhamnus cathartica, which has more than tripled in population between 2001 and 2009. Insects such as gypsy moth and emerald ash borer pose a substantial risk to altering future urban forest composition. The annual ecosystem services provided by the urban forest in relation to carbon sequestration, air pollution removal and reduction in building energy use are estimated at about $2.4 million per year. An improved understanding of urban forests and how they are changing can facilitate better management plans to sustain ecosystem services and desired forest structure for future generations.

Nash, C., et al. (2016). "Initial insights on the biodiversity potential of biosolar roofs: a London Olympic Park green roof case study." Israel Journal of Ecology & Evolution 62(1- 2): 74-87. Cities dominated by impervious artificial surfaces can experience a multitude of negative environmental impacts. Restoration of green infrastructure has been identified as a mechanism for increasing urban resilience, enabling cities to transition towards sustainable futures in the face of climate-driven change. Building rooftops represent a viable space for integrating new green infrastructure into high-density urban areas. Urban rooftops also provide prime locations for photovoltaic (PV) systems. There is an increasing recognition that these two technologies can be combined to deliver reciprocal benefits in terms of energy efficiency and biodiversity targets. Scarcity of scientific evaluation of the interaction between PVs and green roofs means that the potential benefits are currently poorly understood. This study documents evidence from a biodiversity monitoring study of a substantial biosolar roof installed in the Queen Elizabeth Olympic Park. Vegetation and invertebrate communities were sampled and habitat structure measured in relation to habitat niches on the roof, including PV panels. Ninety-two plant species were recorded on the roof and variation in vegetation structure associated with proximity to PV panels was identified. Almost 50% of target invertebrate species collected were designated of conservation importance. Arthropod distribution varied in relation to habitat niches on the roof. The overall aim of the Main Press Centre building green roof design was to create a mosaic of habitats to enhance biodiversity, and the results of the study suggest that PV panels can contribute to niche diversity on a green roof. Further detailed study is required to fully characterise the effects of PV panel density on biodiversity.

Mguni, P., et al. (2016). "Sustainable urban drainage systems: examining the potential for green infrastructure-based stormwater management for Sub-Saharan cities." Natural Hazards 82(2): 241-257. Green infrastructure (GI)-based approaches to urban drainage such as sustainable urban drainage systems (SUDS) could provide Sub-Saharan cities with an opportunity to address projected climate change impacts and existing deficits in their drainage infrastructure, even more so due to the synergies between an enhanced green infrastructure stock and sustainable urban development. The objective of this paper was to assess the theoretical value of using green infrastructure for stormwater management as an alternative and supplement to conventional pipe- based stormwater management systems. A SWOT analysis is performed to assess the potential that SUDS hold if adopted and implemented in Sub-Saharan cities. This analysis is based on a review of sustainable stormwater management as well as urban planning and governance literature. Results show that despite seemingly significant barriers to the adoption of SUDS in Sub-Saharan cities such as low prioritization on the urban agenda and lack of data among others, the concept may hold valuable potential for flood risk reduction, even more so due to its multi- functionality and synergies with urban agriculture, amenity and water supply. In the light of the existing threats and weaknesses, it is recommended that GI-based SUDS may be best approached initially as experiments at a local community scale.

Mensah, C. A., et al. (2016). "Enhancing quality of life through the lens of green spaces: A systematic review approach." International Journal of Wellbeing 6(1). Improvingcitizens’qualityoflifeisastatedpriorityofmanygovernmentsinboththe global north and south. However, efforts to achieve this often focus on socio-economic measures, with limited attention to the contributions of environmental variables such as green spaces. This paper sought to bridge this knowledge gap by tracing the linkages between green spaces and quality of life, and how these connections can inform policy development in order to assist governments to achieve positive outcomes for quality of life. The paper took a theoretical approach by utilising the systematic review method. In all, 452 publications were included in this review, and rigorous content analysis was employed to retrieve relevant data. Green spaces were found to provide various social, economic, and environmental benefits, which in turn improve physical, psychological, emotional, social, and material wellbeing of individuals and thus enhance quality of life. It is therefore strongly recommended that conservation of green spaces should be integrated into national health, environmental and socio-economic policies in order to promote effective utilisation of green spaces to enhance citizens’ overall quality of life.

McPherson, E. G., et al. (2016). "Structure, function and value of street trees in California, USA." Urban Forestry & Urban Greening 17: 104-115. This study compiled recent inventory data from 929,823 street trees in 50 cities to determine trends in tree number and density, identify priority investments and create baseline data against which the efficacy of future practices can be evaluated. The number of street trees increased from 5.9 million in 1988 to 9.1 million in 2014, about one for every four residents. Street tree density declined from 65.6 to 46.6 trees per km, nearly a 30% drop. City streets are at 36.3% of full stocking. State-wide, only London planetree (Platanus × hispanica) comprises over 10% of the total, suggesting good state-wide species diversity. However, at the city scale, 39 communities were overly reliant on a single species. The state’s street trees remove 567,748 t CO2 (92,253 t se) annually, equivalent to taking 120,000 cars off the road. Their asset value is $2.49 billion ($75.1 million se). The annual value (USD) of all ecosystem services is $1.0 billion ($58.3 million se), or $110.63 per tree ($29.17 per capita). Given an average annual per tree management cost of $19.00, $5.82 in benefit is returned for every $1 spent. Management implications could include establishing an aggressive program to plant the 16 million vacant sites and replace removed trees, while restricting planting of overabundant species. Given the tree population’s youth there is likely need to invest in pruning young trees for structure and form, which can reduce subsequent costs for treating defects in mature trees.

McDonald, R., et al. (2016). Planting healthy air: a global analysis of the role of urban trees in addressing particulate matter pollution and extreme heat. Arlington, The Nature Conservancy. Heatwaves are one of the world's most underestimated threats, killing more than 12,000 people every year around the world - more than any other weather-related event. And heat is especially dangerous in cities, which tend to be much warmer than surrounding less-developed areas. On top of that, cities tend to have higher levels of air pollution, which contribute to more than 3 million deaths every year. With 70 percent of the world's population predicted to live in cities by 2050, heat and air pollution constitute a major public health concern. One relatively simple solution to this problem, plant more trees in cities. Trees cool the air by casting shade and releasing water vapor, and their leaves can filter out fine particulate matter (PM) - one of the most dangerous forms of air pollution, generated from burning biomass and fossil fuels. The Nature Conservancy has studied the effects of trees on air quality in 245 of the world's largest cities and documented the findings in the Planting Healthy Air report. The Planting Healthy Air report documents which cities stand to benefit most from tree plantings, in terms of both heat and PM reduction, and how much investment would be required to achieve meaningful benefits. The analysis found that investing just US$4 per resident in each of these cities in tree planting efforts could improve the health of millions of people, and that trees are as cost-effective as many other common solutions. Most of the cooling and filtering effects created by trees are fairly localized, so densely populated cities - as well as those with higher overall pollution levels - tend to see the highest overall return on investment (ROI) from tree plantings. The localized nature of trees' effects, however, means that particular neighborhoods in virtually any city could benefit from plantings. City planners can even target plantings to protect areas with especially vulnerable populations - such as near schools and hospitals - or use trees as a screen against PM coming from highways and industrial areas. While trees alone can't solve the entirely of cities' air and heat problems, they are a critical piece of the puzzle. The report shows that even a conservative global investment in urban trees can save tens of thousands of lives.

Livesley, S. J., et al. (2016). "The Urban Forest and Ecosystem Services: Impacts on Urban Water, Heat, and Pollution Cycles at the Tree, Street, and City Scale." Journal of Environmental Quality 45(1): 119-124. Many environmental challenges are exacerbated within the urban landscape, such as stormwater runoff and flood risk, chemical and particulate pollution of urban air, soil and water, the urban heat island, and summer heat waves. Urban trees, and the urban forest as a whole, can be managed to have an impact on the urban water, heat, carbon and pollution cycles. However, there is an increasing need for empirical evidence as to the magnitude of the impacts, both beneficial and adverse, that urban trees can provide and the role that climatic region and built landscape circumstance play in modifying those impacts. This special section presents new research that advances our knowledge of the ecological and environmental services provided by the urban forest. The 14 studies included provide a global perspective on the role of trees in towns and cities from five continents. Some studies provide evidence for the cooling benefit of the local microclimate in urban green space with and without trees. Other studies focus solely on the cooling benefit of urban tree transpiration at a mesoscale or on cooling from canopy shade at a street and pedestrian scale. Other studies are concerned with tree species differences in canopy interception of rainfall, water uptake from biofilter systems, and water quality improvements through nutrient uptake from stormwater runoff. Research reported here also considers both the positive and the negative impacts of trees on air quality, through the role of trees in removing air pollutants such as ozone as well as in releasing potentially harmful volatile organic compounds and allergenic particulates. A transdisciplinary framework to support future urban forest research is proposed to better understand and communicate the role of urban trees in urban biogeochemical cycles that are highly disturbed, highly managed, and of paramount importance to human health and well-being.

Lin, M.-Y., et al. (2016). "The effects of vegetation barriers on near-road ultrafine particle number and carbon monoxide concentrations." Science of The Total Environment 553: 372-379. Numerous studies have shown that people living in near-roadway communities (within 100 m of the road) are exposed to high ultrafine particle (UFP) number concentrations, which may be associated with adverse health effects. Vegetation barriers have been shown to affect pollutant transport via particle deposition to leaves and altering the dispersion of emission plumes, which in turn would modify the exposure of near-roadway communities to traffic-related UFPs. In this study, both stationary (equipped with a Scanning Mobility Particle Sizer, SMPS) and mobile (equipped with Fast Mobility Particle Sizer, FMPS) measurements were conducted to investigate the effects of vegetation barriers on downwind UFP (particle diameters ranging from 14 to 102 nm) concentrations at two sites in North Carolina, USA. One site had mainly deciduous vegetation while the other was primarily coniferous; both sites have a nearby open field without the vegetation barriers along the same stretch of limited access road, which served as a reference. During downwind conditions (traffic emissions transported towards the vegetation barrier) and when the wind speed was above or equal to 0.5 m/s, field measurements indicated that vegetation barriers with full foliage reduced UFP and CO concentrations by 37.7–63.6% and 23.6–56.1%, respectively. When the test was repeated at the same sites during winter periods when deciduous foliage was reduced, the deciduous barrier during winter showed no significant change in UFP concentration before and after the barrier. Results from the stationary (using SMPS) and mobile (using FMPS) measurements for UFP total number concentrations generally agreed to within 20%.

Li, X.-B., et al. (2016). "The impacts of roadside vegetation barriers on the dispersion of gaseous traffic pollution in urban street canyons." Urban Forestry & Urban Greening 17: 80-91. Vegetation barriers have been widely applied along urban streets to improve roadside air quality. For a deep investigation of their influences, field measurements and numerical simulations are performed in this study. Carbon monoxide (CO) is selected as a representative of gaseous traffic emissions for both field observations and numerical models. Computational Fluid Dynamics (CFD) models of the standard k-ε turbulent model and Eulerian approach for species transport are solved by FLUENT solver. Results obtained from numerical simulations show a good agreement with field observations on the distribution of roadside CO. In perpendicular wind conditions, both field observations and numerical simulations present a prominent CO reduction over the slow lanes (footpath and bikeway) when vegetation barriers exist. To effectively mitigate roadside air pollution, numerical simulations also provide the optimal heights for roadside vegetation barriers in the given street canyons. For street canyons with an aspect ratio (the ratio of building height to street width) ranging from 0.3 to 1.67, 1.1 m can be used as an optimal height, and 2.0 m could serve as an alternative if tall vegetation barriers are considered. For street canyons with an aspect ratio of lower than 0.3, 0.9 m to 2.5 m can be considered as the optimal heights for roadside vegetation barriers. According to sensitivity analysis, the optimal heights for vegetation barriers are largely insensitive to wind velocities in the given street canyons. In the more complicated urban street canyons and complex meteorological conditions, the optimal heights can be determined by specific numerical simulations. These findings are expected to provide important insights into alleviation of gaseous mobile emissions in terms of vegetation barrier design in urban streets.

La Rosa, D., et al. (2016). "Indicators of Cultural Ecosystem Services for urban planning: A review." Ecological Indicators 61, Part 1: 74-89. The concept of Ecosystem Services has gained traction on the scientific agenda and has found its way into research on urban environments. Cities and towns, like any other ecosystem, provide specific services to their inhabitants and communities and they are benefited by surrounding ecosystems as well. Among the different categories, typical Ecosystem Services categories such as food production and erosion control usually have a lesser importance within urban contexts. However, the very diverse range of land uses and ecosystems in urban contexts provide specific Cultural Ecosystem Services including recreational, cultural and educational values. However, to date only limited attention has been given to the provision of Cultural Ecosystem Services (CES), especially considering the relevant benefits that communities and urban planning processes can derive from them. In this document we review existing approaches for the assessment of CES in urban contexts and provide a critical overview of how indicators are used to assess and measure CES. We first conduct a literature review on the indicators used for CES in urban contexts then the paper addresses some specific issues with reference to both operability and benefits of the use of CES indicators for urban planning and management. Our results show that existing CES indicators have limited usability for urban planning and management. Moreover a lack of appropriate data use is a significant obstacle for proper CES assessment. This impacts the potential for sustainable decision-making concerning CES in urban contexts. These issues, together with fact that most identified indicators are proxy ones, identify an urgent need to develop proper assessment indicators for CES.

Kim, H. W. and Y. Park (2016). "Urban green infrastructure and local flooding: The impact of landscape patterns on peak runoff in four Texas MSAs." Applied Geography 77: 72-81. Even though there is a general acknowledgement that green infrastructure can have a positive role in reducing stormwater runoff, few studies have explored how specific spatial configurations of landscape—one of the critical components of green infrastructure—could influence runoff generation. This study attempts to address this gap by examining the landscape patterns in terms of size, shape, isolation, and connectivity across the four largest metropolitan areas in Texas, using landscape ecology metrics. The outcomes indicate that larger, less fragmented, and more connected landscape patterns are likely to mediate the mean annual peak runoff. In contrast, larger developments of complex shapes with more edges, clustered, and connected are likely to augment the peak runoff. The findings of this paper provide empirical evidences for policy makers to further the importance of interconnection and clusters of green infrastructure and plan strategic green hubs and corridors to more effectively manage stormwater runoff.

Hosseini, S. A. O., et al. (2016). "Effects of geometric design of forest road and roadside vegetation on traffic noise reduction." Journal of Forestry Research 27(2): 463-468. Geometric design of forest roads and design of their landscapes can reduce noise pollution and its harmful effects on human health. We investigated the effects of technical and biological parameters such as geometric road design and various roadside tree stands on reducing noise pollution according to the tree density and distance from roadway in Darabkola Forests, Sari, Iran. We recorded the noise generated by a car (Land Rover) relative to changes in longitudinal slope, horizontal curve radius and type of road pavement. We also measured noise levels according to roadside tree density and stand type (coniferous and hardwood) in 40 rectangular plots of three widths (25, 100 and 300 m) and 50 m length that were randomly demarcated along forest roads. The changes in noise level were recorded using a decibel meter with an accuracy of ±1.5 dB and resolution of 0.1 dB. Noise levels were higher alongside unpaved roads than alongside paved roads. There was an inverse relationship between the measured noise level and horizontal curve radius. The rate of noise level on horizontal curve with a radius less than 30, 30–45 m and more than 45 m were 64.8, 70.8 and 75.9 dB, respectively. The noise level increased with the increasing longitudinal slope of the road. There was a significant difference between the noise level on slopes less than 3 % (67 dB) and 3–8 % (71.2 dB) in comparison with slopes greater than 8 % (77.8 dB), (p < 0.05). Pinus brutia L. reduced the noise level more (about 6 dB) in stands of 1/3 density of mixed hardwoods within 25 m from middle of the road. Careful design of geometric properties of forest roads as well as planting coniferous trees with hardwoods is a suitable solution for reducing noise pollution.

Hoang, L. and R. A. Fenner (2016). "System interactions of stormwater management using sustainable urban drainage systems and green infrastructure." Urban Water Journal 13(7): 739-758. This study explores system interactions of stormwater management solutions using Sustainable Urban Drainage System (SuDS) and Green Infrastructure (GI) within the wider urban landscape. A series of interdependencies between urban components relating to stormwater management are identified. These include physical interdependency, geographical interdependency, cyber interdependency and logical interdependency, as defined by Peerenboom (2001). Stormwater management using SuDS/GI are viewed according to their Hydrological, Ecological and the Built Environment functions during events up to the design rain (non-flood condition) and during controlled exceedance and uncontrolled inundation (flood condition). The inclusion of SuDS/GI into the urban fabric is shown to modify urban functional and relational interdependencies under both these conditions. Within the context of the UK, there are fragmented responsibilities across planning scales created by SuDS/GI solutions which have not addressed the relational complexities that exist between agencies and competent authorities. The paper identifies the key barriers towards effective adoption of SuDS/GI within the context of the UK as physical barriers, perception/information barriers and organisational barriers.

Grote, R., et al. (2016). "Functional traits of urban trees: air pollution mitigation potential." Frontiers in Ecology and the Environment 14(10): 543-550. In an increasingly urbanized world, air pollution mitigation is considered one of most important issues in city planning. Urban trees help to improve air quality by facilitating widespread deposition of various gases and particles through the provision of large surface areas as well as through their influence on microclimate and air turbulence. However, many of these trees produce wind-dispersed pollen (a known allergen) and emit a range of gaseous substances that take part in photochemical reactions – all of which can negatively affect air quality. The degree to which these air-quality impacts are manifested depends on species-specific tree properties: that is, their “traits”. We summarize and discuss the current knowledge on how such traits affect urban air pollution. We also present aggregated traits of some of the most common tree species in Europe, which can be used as a decision-support tool for city planning and for improving urban air-quality models.

Gromke, C., et al. (2016). "Influence of roadside hedgerows on air quality in urban street canyons." Atmospheric Environment 139: 75-86. Understanding pollutant dispersion in the urban environment is an important aspect of providing solutions to reduce personal exposure to vehicle emissions. To this end, the dispersion of gaseous traffic pollutants in urban street canyons with roadside hedges was investigated. The study was performed in an atmospheric boundary layer wind tunnel using a reduced-scale (M = 1:150) canyon model with a street-width-to-building-height ratio of W/H = 2 and a street- length-to-building-height ratio of L/H = 10. Various hedge configurations of differing height, permeability and longitudinal segmentation (continuous over street length L or discontinuous with clearings) were investigated. Two arrangements were examined: (i) two eccentric hedgerows sidewise of the main traffic lanes and (ii) one central hedgerow between the main traffic lanes. In addition, selected configurations of low boundary walls, i.e. solid barriers, were examined. For a perpendicular approach wind and in the presence of continuous hedgerows, improvements in air quality in the center area of the street canyon were found in comparison to the hedge-free reference scenario. The pollutant reductions were greater for the central hedge arrangements than for the sidewise arrangements. Area-averaged reductions between 46 and 61% were observed at pedestrian head height level on the leeward side in front of the building for the centrally arranged hedges and between 18 and 39% for the two hedges arranged sidewise. Corresponding area-averaged reductions ranging from 39 to 55% and from 1 to 20% were found at the bottom of the building facades on the leeward side. Improvements were also found in the areas at the lateral canyon ends next to the crossings for the central hedge arrangements. For the sidewise arrangements, increases in traffic pollutants were generally observed. However, since the concentrations in the end areas were considerably lower compared to those in the center area, an overall improvement remained for the street canyon. The configuration of a sidewise arranged discontinuous hedgerow resulted in general in area-averaged increases in concentrations in the range of 3–19%. For a parallel approach wind, reduced concentrations of up to 30% at the facades and up to 60% at pedestrian level were measured with a sidewise continuous hedgerow arrangement. It is concluded that continuous hedgerows can effectively be employed to control concentrations of traffic pollutants in urban street canyons. They can advantageously affect the air quality at street level and can be a significant remedy to the pedestrians’ and residents’ exposure in the most polluted center area of a street canyon.

Green, T. L., et al. (2016). "Insurance Value of Green Infrastructure in and Around Cities." Ecosystems 19(6): 1051-1063. The combination of climate change and urbanization projected to occur until 2050 poses new challenges for land-use planning, not least in terms of reducing urban vulnerability to hazards from projected increases in the frequency and intensity of climate extremes. Interest in investments in green infrastructure (interconnected systems of parks, wetlands, gardens and other green spaces), as well as in restoration of urban ecosystems as part of such adaptation strategies, is growing worldwide. Previous research has highlighted the insurance value of ecosystems in securing the supply of ecosystem services in the face of disturbance and change, yet this literature neglects urban areas even though urban populations are often highly vulnerable. We revisit the insurance value literature to examine the applicability of the concept in urban contexts, illustrating it with two case studies: watersheds providing drinking water for residents of Vancouver, Canada; and private gardens ensuring connectedness between other parts of urban green infrastructure in London, UK. Our research supports the notion that investments in green infrastructure can enhance insurance value, reducing vulnerability and the costs of adaptation to climate change and other environmental change. Although we recommend that urban authorities consider the insurance value of ecosystems in their decision-making matrix, we advise caution in relying upon monetary evaluations of insurance value. We conclude by identifying actions and management strategies oriented to maintain or enhance the insurance value of urban ecosystems. Ecosystems that are themselves resilient to external disturbances are better able to provide insurance for broader social–ecological systems.

Fulcher, A., et al. (2016). "The next ten years: Strategic vision of water resources for nursery producers." HortTechnology 26(2): 121-132. Nursery and greenhouse producers, research and extension faculty, and representatives from allied fields collaborated to formulate a renewed vision to address water issues affecting growers over the next 10 years. The authors maintained the original container irrigation perspective published in “Strategic vision of container nursery irrigation in the next ten years,” yet broadened the perspective to include additional challenges that face nursery crop producers today and in the future. Water availability, quality, and related issues continue to garner widespread attention. Irrigation practices remain largely unchanged due to existing irrigation system infrastructure and minimal changes in state and federal regulations. Recent concerns over urbanization and population growth, increased climate variability, and advancements in state and federal regulations, including new groundwater withdrawal limitations, have provided an inducement for growers to adopt efficient and innovative practices. Information in support of the overarching issues and projected outcomes are discussed within.

Edmondson, J. L., et al. (2016). "Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs." Scientific Reports 6. Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are ampli ed by the microclimatological e ects of buildings and grey infrastructure through the urban heat island (UHI) e ect. Urban greenspaces may be important in reducing surface temperature extremes, but their e ects have not been investigated at a city-wide scale. Across a mid- sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratied by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less e ective at reducing summer soil surface temperatures. Our findings reveal that the UHI e ects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health.

Ziter, C. (2015). "The biodiversity–ecosystem service relationship in urban areas: a quantitative review." Oikos. By 2050, up to 75% of people globally will live in cities. Despite the potential ramifications of this urbanization for ecosystem services (ES), and the importance of locally produced ES for the health and wellbeing of urban residents, syntheses addressing the underlying ecology of ES provision rarely include urban areas. Here, I conduct a quantitative review of urban ES studies in the ecological literature, synthesizing trends across the discipline. I also quantify the extent to which this work considers the organisms and ecosystem components responsible for ES provision using two approaches: assessment of biodiversity–ES relationships, and an adaptation of the service provider concept. The majority of urban ES studies were conducted in western, developed countries, and typically assessed a single service in a single city – largely ignoring ES synergies and tradeoffs, and cross-city comparisons. While several different ES are studied in urban ecosystems, the field is dominated by weather and climate- related regulating services, with assessments of cultural services particularly lacking. Most studies described a habitat type as the service provider; however, studies that considered the biodiversity–ES relationship were more likely to identify a specific functional group, community, or population as the key provider of an ES. The biodiversity–ES relationship itself was most frequently characterized as dependent on the composition of species, functional traits, or structures, rather than correlated with the magnitude of any specific biodiversity metric. While the study of ES in urban ecosystems is increasing, there exists considerable room for further research. Future studies would benefit by expanding the number and categories of ES assessed within and across cities, as well as broadening the geographical scope of urban ES research. Biodiversity–ES assessments in urban ecosystems would also benefit from an expansion of the biodiversity types considered, particularly regarding non-species based approaches, and consideration of non-native and invasive species.

Yang, J., et al. (2015). "Ranking the suitability of common urban tree species for controlling PM2.5 pollution." Atmospheric Pollution Research 6(2): 267-277. Pollution caused by particles with aerodynamic diameters less than 2.5 μm (PM2.5) is now a major environmental problem in many Asian cities. Planting more trees has been suggested as an unconventional approach to alleviate the problem. In this study, we developed a ranking approach to evaluate the PM2.5 removal efficiency, negative impacts on air quality, and the suitability to urban environments of commonly occurring urban tree species. The results showed that the most frequently occurring tree species in global cities were not the best performers in removing PM2.5. Among the ten most frequently occurring tree species, only London plane (Platanus acerifolia (Aiton) Wild.), silver maple (Acer saccharinum L.) and honey locust (Gleditsia triacanthos L.) were ranked above average. However, there is great potential for improving the removal of PM2.5 from urban air by using species that have high PM2.5 removal efficiency, especially conifer species. Use of conifer species requires choosing the correct gender and matching trees with appropriate sites. The results from this study can assist environmental management agencies in the selection of tree species for urban greening projects focusing on PM2.5 control.

Voskamp, I. M. and F. H. M. Van de Ven (2015). "Planning support system for climate adaptation: Composing effective sets of blue-green measures to reduce urban vulnerability to extreme weather events." Building and Environment 83: 159-167. The risk of pluvial flooding, heat stress and drought is increasing due to climate change. To increase urban resilience to extreme weather events, it is essential to combine green and blue infrastructure and link enhanced storage capacity in periods of water surplus with moments of water shortage as well as water availability with heat stress. ‘Blue-green measures’ is a collective term for sustainable green and blue infrastructure that utilises underlying ecosystem functions to deliver multiple benefits: for example, cooling via evapotranspiration, water storage for heavy rainfall events, discharge peak attenuation, seasonal water storage, and groundwater recharge. Measures contribute most to climate adaptation when implemented in combinations. Such packages of blue-green measures capitalize upon the synergistic interactions between ecosystem functions and hence enhance multiple vulnerability reduction capacities. Moreover, combining blue-green measures enables using their unique potential at different spatial scales and establishing hydrologic connectivity. This paper proposes a framework for a planning support system and a tool to select adaptation measures to support urban planners in collaboratively finding site-specific sets of blue-green measures for a particular urban reconstruction project. With the proposed framework users can evaluate appropriateness of specific adaptation measures for a particular location and compose effective packages of blue-green measures to handle flooding, drought and heat stress. It is concluded that the framework: 1) enables incorporating knowledge on urban climate adaptation and ecosystem services in a communicative urban planning process, 2) guides the selection of a coherent and effective package of blue-green adaptation measures.

Van Renterghem, T., et al. (2015). "Using natural means to reduce surface transport noise during propagation outdoors." Applied Acoustics 92: 86-101. This paper reviews ways of reducing surface transport noise by natural means. The noise abatement solutions of interest can be easily (visually) incorporated in the landscape or help with greening the (sub)urban environment. They include vegetated surfaces (applied to faces or tops of noise walls and on buildings’ façades and roofs), caged piles of stones (gabions), vegetation belts (tree belts, shrub zones and hedges), earth berms and various ways of exploiting ground- surface-related effects. The ideas presented in this overview have been tested in the laboratory and/or numerically evaluated in order to assess or enhance the noise abatement they could provide. Some in-situ experiments are discussed as well. When well designed, such natural devices have the potential to abate surface transport noise, possibly by complementing and sometimes improving common (non-natural) noise reducing devices or measures. Their applicability strongly depends on the available space reserved for the noise abatement and the receiver position.

Tóth, A., et al. (2015). "Green infrastructure: a strategic tool for climate change mitigation in urban environments." Ecology & Safety 9: 132-138. The changing climate has a significant negative impact on urban environments, influencing thereby the quality of life of urban residents and causing a range of problems in urban areas worldwide. There is a need for efficient urban planning and design tools, which can mitigate these negative effects. Green infrastructure represents a tool to create more resilient and sustainable urban environments by greening open spaces in our cities. Green structures and greenery elements improve the urban microclimate and reduce noise, dustiness, the heat island effect and help to manage urban stormwater. Therefore, it is crucial to protect and improve existing green spaces, enhance their connectedness and utilise unconventional areas for creating new green spaces which would improve the health of urban landscapes. Here, greening of roofs, walls, brownfields and other empty spaces comes into play. They still represent an unutilised potential of contemporary urban landscapes. Landscape Architecture as a field of research and design practice plays a crucial role in developing innovative tools, planning and designing green infrastructure which will contribute to creation of sustainable and multifunctional urban landscapes of the future.

Tong, Z., et al. (2015). "Quantifying the effect of vegetation on near-road air quality using brief campaigns." Environ Pollut 201. Many reports of trees' impacts on urban air quality neglect pattern and process at the landscape scale. Here, we describe brief campaigns to quantify the effect of trees on the dispersion of airborne particu- lates using high time resolution measurements along short transects away from roads. Campaigns near major highways in Queens, NY showed frequent, stochastic spikes in PM2.5. The polydisperse PM2.5 class poorly represented the behavior of discrete classes. A transect across a lawn with trees had fewer spikes in PM2.5 concentration but decreased more gradually than a transect crossing a treeless lawn. This coincided with decreased Turbulence Kinetic Energy downwind of trees, indicating recirculation, longer residence times and decreased dispersion. Simply planting trees can increase local pollution concen- trations, which is a special concern if the intent is to protect vulnerable populations. Emphasizing deposition to leaf surfaces obscures the dominant impact of aerodynamics on local concentration.

Sonntag-Ostrom, E., et al. (2015). "Can rehabilitation in boreal forests help recovery from exhaustion disorder? The randomised clinical trial ForRest." Scandinavian Journal of Forest Research 30(8): 732-748. Modern society is faced with increasing incidence of mental and behavioural disorders. The objective of this study was to evaluate whether visits to boreal forests can be utilised for rehabilitation from exhaustion disorder (ED). This randomised controlled trial comprised of a forest rehabilitation group (n = 35) and a waiting list group (control group) (n = 43) with subsequent cognitive behavioural rehabilitation (CBR) for all participants in both groups. The recovery from ED was compared between the forest rehabilitation and the control group at baseline, after the forest rehabilitation (3 months), and at the end of the CBR (1 year). Both groups had enhanced recovery from ED after the 3-month intervention period and at the end of the CBR (1 year), and there were no significant differences between the groups in terms of psychological health measures. Mental state, attention capacity and preferences for different forest environments were studied during the forest visits. Mental state was improved, but it showed some seasonal differences. A significant effect on attention capacity was found for single forest visits, but there was no effect found for the rehabilitation period as a whole. The most popular forest environments contained easily accessible, open and bright settings with visible water and/or shelter. Forest rehabilitation did not enhance the recovery from ED compared to the control group, but the participants' well-being was improved after single forest visits.

Song, C., et al. (2015). "Elucidation of a physiological adjustment effect in a forest environment: A pilot study." International Journal of Environmental Research and Public Health 12(4): 4247-4255. There is a significant positive relationship between exposure to forest environments and physical and mental health. However, there are individual differences within these responses, and this phenomenon has posed questions in various fields. Here, we show that the physiological effect of a forest environment can differ depending on a subject’s initial values and that forests have a physiological adjustment effect close to an appropriate level. Subjects with high initial blood pressure and pulse rate showed a decrease in these values after walking in a forested area, whereas those with low initial values showed an increase. There was no physiological adjustment effect observed in an urban area; thus, these effects are specific to a forest environment.

Siņicina, N., et al. (2015). "Amount of Air Ions Depending on Indoor Plant Activity." Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 2: 267. Literature sources and earlier researches state that plants may be able to produce a variety of air ions, including negative light ions. In this article, the regularity of influence of plants on the number of ions in the room is being proved, basing on a series of experiments performed with the following plants: Spathiphyllum, Scindapsus, Strobilanthes, Chlorophytum and Pinus mugo. It was concluded that plants, in general, are able to stabilize the indoor ion concentration and reduce its fluctuations. The plants help to increase the concentrations of negative ions and decrease the concentration of positive ones, however the optimal and “healthy” ion concentration was not reached. Plants without artificial illumination work more as ion reducers, not producers.

Sgrigna, G., et al. (2015). "Particulate Matter deposition on Quercus ilex leaves in an industrial city of central Italy." Environmental Pollution 197: 187-194. A number of studies have focused on urban trees to understand their mitigation capacity of air pollution. In this study particulate matter (PM) deposition on Quercus ilex leaves was quantitatively analyzed in four districts of the City of Terni (Italy) for three periods of the year. Fine (between 0.2 and 2.5 μm) and Large (between 2.5 and 10 μm) PM fractions were analyzed. Mean PM deposition value on Quercus ilex leaves was 20.6 μg cm−2. Variations in PM deposition correlated with distance to main roads and downwind position relatively to industrial area. Epicuticular waxes were measured and related to accumulated PM. For Fine PM deposited in waxes we observed a higher value (40% of total Fine PM) than Large PM (4% of total Large PM). Results from this study allow to increase our understanding about air pollution interactions with urban vegetation and could be hopefully taken into account when guidelines for local urban green management are realized.

Parmar, R. N., et al. (2015). "Assessment of Status and Carbon Sequestration Potential of Green Cover in the Major Urban Development Authorities of Gujarat." Innovative Energy Technology Systems and Environmental Concerns. A Sustainable Approach: 197-206. Urban forest and tree cover play a fundamentally important role in improving the environmental quality, energy efficiency, aesthetic appeal, biodiversity, and regulating the climatic hazards. The study area encompasses the 8 major urban development authorities of Gujarat which has observed a population increase from 0.59 crore in 1981 to 1.66 crore in 2011, which is projected to increase to 2.01 crores as of 2021. The per capita CO2 emission was recorded to be 1.6 tons/annum in 2011 and is expected to rise to 2-2.5 tons/annum by 2021. The average rate of conversion of land in Gujarat for non-agricultural and non-forestry uses is about 4,000 ha per year leading to the severe defacement of the green cover. In this study, an assessment and evaluation of the area under the urban forest & tree cover and its respective carbon sequestration potential is done for the base year (2011) and an attempt is being made to calculate it for the year 2021 using the standard protocols. As of 2011, about 64.31 lakh trees of about 230 species above 10 cm girth at breast height was enumerated in the study area. The study highlights that the green cover inclusive city planning, stakeholder’s coordination, use of native tree species, compensatory afforestation mechanism, protection of the existing green areas, and employment generation through GIM and MNERGA schemes in the social and agro forestry plantations can enhance the overall green cover in the urban agglomerations of Gujarat. As a result, the total tree number in the study area can be increased from 64.13 lakhs (2011) to 143.7 lakhs (2021) and the carbon stock can be enhanced from 12.86 lakh tonnes of carbon in 2011 to 28.74 lakh tonnes till 2021. For achieving the desired targets, the land under the plantation has to be increased from 23,760 ha in 2011 to 55,158 ha till 2021. Hence, enhancing urban tree and forest cover can give plausible solutions to the infinite woes of socio-economic, ecological, and environmental sustainability of the urban areas of Gujarat.

Pakzad, P., et al. (2015). Review of tools for quantifying the contribution of green infrastructure to carbon performance. Proc. ICUC9-9th International Conference on Urban Climate jointly with 12th Symposium on the Urban Environment, Toulouse. The exchange of carbon between the atmosphere and biosphere is an important factor in global climate regulation. Consequently, it is important to examine how carbon flows and cycles between different pools and how carbon stocks change in response to afforestation, reforestation, deforestation, and other land-cover and land-use activities. Eco-cities and green-cities are emerging concepts for the retrofitting of our urban areas and important component in the creation of more sustainable development towards climate change adaptation and mitigation. Green infrastructure as a key part of eco-cities and green-cities contributes as a major carbon pool for. The term ‘green infrastructure’ refers to an interconnected network of landscape assets that are intertwined with engineered (grey) infrastructure and buildings. The ability to assess the performance of green infrastructure, based on measurable criteria at a variety of temporal and spatial scales, is critical for defining the difference between effective and non-effective scenarios for sustainable urban development. This paper aims to identify the most relevant and applicable evaluation tools, applications and methods for quantifying the carbon performance of green infrastructure in Australia. The existing quantitative tools used to measure green infrastructure sustainability performance are varied in terms of the scale, components and input. This study has identified and tabulated the most relevant tools for quantifying the features and carbon services of green infrastructure. The aim is to help policymakers, environmental groups and researchers to choose the most appropriate tool(s) for the intended context and it will lead them to a more useful and accurate carbon foot printing assessment outcome.

Önder, S. and A. Akay (2015). "Reduction of Traffic Noise Pollution Effects by Using Vegetation." Journal of Engineering and Economic Development 2(2): 23. It is a well-known fact in all societies worldwide that noise is a serious environmental pollutant. In this paper, negative effects resulting from exposure to noise pollution on people’s well-being is reviewed in the light of the previous published studies. First, noise is generally defined, subsequently, in order to clarify the subject, noise pollution types, negative effects of noise on human’s health and attenuation methods of noise pollution are discussed. In conclusion previous studies about the topic of ‘the mitigation of the noise pollution effects by using vegetation’ in Turkey are reviewed to explain the reduction methods of the noise pollution by vegetation and to refer to its aesthetical, ecological, etc. advantages, excluding its noise barrier function. Considering the negative effects of the noise pollution, the findings of this study are important at both individual and social level and could be helpful as a guidance for planning of the areas which have the potential of the noise pollution effects.

Norton, B. A., et al. (2015). "Planning for cooler cities: A framework to prioritise green infrastructure to mitigate high temperatures in urban landscapes." Landscape and Urban Planning 134: 127-138. Warming associated with urban development will be exacerbated in future years by temperature increases due to climate change. The strategic implementation of urban green infrastructure (UGI) e.g. street trees, parks, green roofs and facades can help achieve temperature reductions in urban areas while delivering diverse additional benefits such as pollution reduction and biodiversity habitat. Although the greatest thermal benefits of UGI are achieved in climates with hot, dry summers, there is comparatively little information available for land managers to determine an appropriate strategy for UGI implementation under these climatic conditions. We present a framework for prioritisation and selection of UGI for cooling. The framework is supported by a review of the scientific literature examining the relationships between urban geometry, UGI and temperature mitigation which we used to develop guidelines for UGI implementation that maximises urban surface temperature cooling. We focus particularly on quantifying the cooling benefits of four types of UGI: green open spaces (primarily public parks), shade trees, green roofs, and vertical greening systems (green walls and facades) and demonstrate how the framework can be applied using a case study from Melbourne, Australia.

Nasiri, M., et al. (2015). "The Effects of tree species on reduction of the rate of noise pollution at the edge of Hyrcanian forest roads." Environ Eng Manag J 14(5): 1021-1026. Plants have an effective role in reducing noise pollution. The aim of this study was to evaluate the impact of broad-leaved and coniferous species on reducing noise pollution according to the distance from the sound source and the tree species type. For this purpose, 25 plots for coniferous species and 25 plots for the broadleaved species was selected. The decibel- meter (Casella Enhances CEL-630) and the trumpet (FIAMM) of machine were used to measure the sound level. Results indicated that the tree at the edge of the forest roads causes to decrease noise pollution. As, there was a significant difference between the distance of 300 meter as compared with the distances of 20 meter and 100 meter for the broadleaved species (P<0.05). We also found an inverse relationship between frequency of broadleaved and coniferous trees and the rate of sound level (R2 = 0.94 for coniferous; R2 = 0.89 for hardwood). In plots consist of broadleaved species, the sound level at the distances of 20, 100 and 300 meter have been reduced 10.6, 14.5 and 19.4 dB, respectively. This difference with considering these distances was respectively 10.4, 14.3 and 16.8 dB for coniferous species. It is suggested that the species with low H:D ratio (Height of tree: DBH) and wide crown used to decrease noise pollution. The coniferous species which is grown dense can be used to provide aesthetic quality and increase number of stories.

Mullaney, J., et al. (2015). "A review of benefits and challenges in growing street trees in paved urban environments." Landscape and Urban Planning 134(0): 157-166. Street trees are an integral element of urban life. They provide a vast range of benefits in residential and commercial precincts, and they support healthy communities by providing environmental, economic and social benefits. However, increasing areas of impermeable surface can increase the stresses placed upon urban ecosystems and urban forests. These stresses often lead tree roots to proliferate in sites that provide more-favourable conditions for growth, but where they cause infrastructure damage and pavement uplift. This damage is costly and a variety of preventative measures has been tested to sustain tree health and reduce pavement damage. This review explores a wide range of literature spanning 30 years that demonstrates the benefits provided by street trees, the perceptions of street trees conveyed by urban residents, the costs of pavement damage by tree roots, and some tried and tested measures for preventing pavement damage and improving tree growth.

Middel, A., et al. (2015). "Urban forestry and cool roofs: Assessment of heat mitigation strategies in Phoenix residential neighborhoods." Urban Forestry & Urban Greening 14(1): 178-186. The City of Phoenix (Arizona, USA) developed a Tree and Shade Master Plan and a Cool Roofs initiative to ameliorate extreme heat during the summer months in their arid city. This study investigates the impact of the City's heat mitigation strategies on daytime microclimate for a pre-monsoon summer day under current climate conditions and two climate change scenarios. We assessed the cooling effect of trees and cool roofs in a Phoenix residential neighborhood using the microclimate model ENVI-met. First, using xeric landscaping as a base, we created eight tree planting scenarios (from 0% canopy cover to 30% canopy cover) for the neighborhood to characterize the relationship between canopy cover and daytime cooling benefit of trees. In a second set of simulations, we ran ENVI-met for nine combined tree planting and landscaping scenarios (mesic, oasis, and xeric) with regular roofs and cool roofs under current climate conditions and two climate change projections. For each of the 54 scenarios, we compared average neighborhood mid-afternoon air temperatures and assessed the benefits of each heat mitigation measure under current and projected climate conditions. Findings suggest that the relationship between percent canopy cover and air temperature reduction is linear, with 0.14 °C cooling per percent increase in tree cover for the neighborhood under investigation. An increase in tree canopy cover from the current 10% to a targeted 25% resulted in an average daytime cooling benefit of up to 2.0 °C in residential neighborhoods at the local scale. Cool roofs reduced neighborhood air temperatures by 0.3 °C when implemented on residential homes. The results from this city-specific mitigation project will inform messaging campaigns aimed at engaging the city decision makers, industry, and the public in the green building and urban forestry initiatives.

Mahnert, A., et al. (2015). "Microbiome interplay: plants alter microbial abundance and diversity within the built environment." Frontiers in Microbiology 6(887). The built indoor microbiome has importance for human health. Residents leave their microbial fingerprint but nothing is known about the transfer from plants. Our hypothesis that indoor plants contribute substantially to the microbial abundance and diversity in the built environment was experimentally confirmed as proof of principle by analyzing the microbiome of the spider plant Chlorophytum comosum in relation to their surroundings. The abundance of Archaea, Bacteria and Eukaryota (fungi) increased on surrounding floor and wall surfaces within six months of plant isolation in a cleaned indoor environment, whereas the microbial abundance on plant leaves and indoor air remained stable. We observed a microbiome shift: the bacterial diversity on surfaces increased significantly but fungal diversity decreased. The majority of cells were intact at the time of samplings and thus most probably alive including diverse Archaea as yet unknown phyllosphere inhabitants. LEfSe and network analysis showed that most microbes were dispersed from plant leaves to the surrounding surfaces. This led to an increase of specific taxa including spore-forming fungi with potential allergic potential but also beneficial plant- associated bacteria, e.g. Paenibacillus. This study demonstrates for the first time that plants can alter the microbiome of a built environment, which supports the significance of plants and provides insights into the complex interplay of plants, microbiomes and human beings.

Luederitz, C., et al. (2015). "A review of urban ecosystem services: six key challenges for future research." Ecosystem Services 14: 98-112. Global urbanization creates opportunities and challenges for human well-being and transition towards sustainability. Urban areas are human-environment systems that depend fundamentally on ecosystems, and thus require an understanding of the management of urban ecosystem services to ensure sustainable urban planning. The purpose of this study is to provide a systematic review of urban ecosystems services research, which addresses the combined domain of ecosystem services and urban development. We examined emerging trends and gaps in how urban ecosystem services are conceptualized in peer-reviewed case study literature, including the geographical distribution of research, the development and use of the urban ecosystem services concept, and the involvement of stakeholders. We highlight six challenges aimed at strengthening the concept's potential to facilitate meaningful inter- and transdisciplinary work for ecosystem services research and planning. Achieving a cohesive conceptual approach in the research field will address (i) the need for more extensive spatial and contextual coverage, (ii) continual clarification of definitions, (iii) recognition of limited data transferability, (iv) more comprehensive stakeholder involvement, (v) more integrated research efforts, and (vi) translation of scientific findings into actionable knowledge, feeding information back into planning and management. We conclude with recommendations for conducting further research while incorporating these challenges.

Lin, W., et al. (2015). "Calculating cooling extents of green parks using remote sensing: Method and test." Landscape and Urban Planning 134: 66-75. A green park can be an effective contributor to the reduction of higher temperatures caused by urban heat island effects. A park's cooling effect extends beyond its boundary into the surrounding streets and buildings. Up to now, the measurement of the extent of the cooling effect beyond the park has relied mainly on on-site observations. An alternative method is to calculate the extent of cooling using remote sensing. The principle of the method is that the cooling effect will decline from the boundary into the surrounding areas to a distance at which the effect is longer felt. Analysis of Landsat TM/ETM+ images of Beijing revealed that cooling effects extend as much as 840 m away from the park in cone case, but as little as 35 m in another. While related in part to park size, the extent of the cooling effect is also influenced by the character of the area around each park. Remote sensing provides a viable alternative to ground temperature measurements, but attention has to be paid to the actual cityscape and characteristics of each park as well as to the resolution of the imagery.

Kronenberg, J. (2015). "Why not to green a city? Institutional barriers to preserving urban ecosystem services." Ecosystem Services 12: 218-227. This article investigates the institutional context of urban greening, with a particular capacity to provide urban inhabitants ׳focus on institutional failures that hinder urban ecosystems with services. It is based on a literature review and a study of expert opinions carried out in Poland (with 103 experts involved in the management of urban trees as respondents). The institutional failures covered by this article include government and social empowerment failures. The most important government failures include insufficient funds and various problems related to unprofessional maintenance of trees and its supervision. The most important social empowerment failures include lack of mobilization, related to under-appreciation of the importance of trees and disservices related to trees. While the current discourse on ecosystem services focuses on raising awareness of the benefits that nature provides, this study capacity to provide us with such services requires ׳demonstrates that protecting urban ecosystems a broad institutional reform. This need is particularly relevant in post-socialist, post-transition countries, such as Poland.

Ko, Y., et al. (2015). "Long-term monitoring of Sacramento Shade program trees: Tree survival, growth and energy-saving performance." Landscape and Urban Planning 143: 183-191. Long-term survival and growth of urban forests are critical to achieve the targeted benefits of urban tree planting programs, such as building energy savings from tree shade. However, little is known about how trees perform in the long-term, especially in residential areas. Given this gap in the literature, we monitored 22-years of post-planting survival, growth, and energy saving performance of shade trees in Sacramento, California. Using field surveys, aerial photo interpretation and survival analysis, we calculated cumulative survivorship and compared measured with projected tree growth. Using Shadow Pattern Simulator and Micropas (building energy simulation), combined with survival and growth observations, we modeled the current energy savings produced by the program trees and then compared this result with initial projections from the early years of the program. The 22-year post planting survivorship was 42.4%, considerably less than the initial projection. On average, measured growth rates were within expected ranges to provide shading benefits; 22-year old trees reached 74.6% and 68.8% of the projected 30-year mature size for tree heights and crown diameters, respectively. Annual energy savings were 107 kW h per property and 80 kW h per tree, which were 23% and 52% of the initial projection, respectively. Lower survivorship was the primary factor influencing lower cooling savings. Medium-sized trees had higher survivorship and growth attainment compared to other trees. This study contributes to more accurate quantification of urban greening performance, helping urban forest managers make data-driven decisions.

Janhäll, S. (2015). "Review on urban vegetation and particle air pollution – Deposition and dispersion." Atmospheric Environment 105: 130-137. Urban vegetation affects air quality through influencing pollutant deposition and dispersion. Both processes are described by many existing models and experiments, on-site and in wind tunnels, focusing e.g. on urban street canyons and crossings or vegetation barriers adjacent to traffic sources. There is an urgent need for well-structured experimental data, including detailed empirical descriptions of parameters that are not the explicit focus of the study. This review revealed that design and choice of urban vegetation is crucial when using vegetation as an ecosystem service for air quality improvements. The reduced mixing in trafficked street canyons on adding large trees increases local air pollution levels, while low vegetation close to sources can improve air quality by increasing deposition. Filtration vegetation barriers have to be dense enough to offer large deposition surface area and porous enough to allow penetration, instead of deflection of the air stream above the barrier. The choice between tall or short and dense or sparse vegetation determines the effect on air pollution from different sources and different particle sizes.

James Barth, B., et al. (2015). "New urban developments that retain more remnant trees have greater bird diversity." Landscape and Urban Planning 136: 122-129. The rapid expansion of urban landscapes has significant consequences for wildlife. Habitat loss and fragmentation cause significant loss of species richness. While remnant fragments of habitat are important areas for conservation, the urban matrix between fragments is also critical. Increasing the suitability of the matrix for wildlife can increase the diversity of wildlife that utilise urban landscapes and increases the potential for dispersal among fragments. We investigated the effectiveness of retaining remnant trees during for increasing the species richness and abundance of birds in new urban housing developments. We measured species richness and abundance in four habitat types: non-vegetated streets, vegetated streets, recreational parks and bush sites. We discovered that the number of bird species observed was lowest on the non-vegetated streets and highest within the bush fragments. Species richness on vegetated streets was intermediate between non-vegetated streets and parks. The abundance of birds was highest within recreational parks and we observed significantly more birds on vegetated streets than non-vegetated streets. Additionally, we found the number of species and total abundance of birds was positively associated with the total number of retained mature trees within a vegetated street. The dominant feeding guild and species composition varied between the different habitat types. Our findings suggest that increasing the number of retained mature trees in new housing developments may be an effective means of increasing the number of bird species that utilise the urban matrix.

Irga, P. J., et al. (2015). "Does urban forestry have a quantitative effect on ambient air quality in an urban environment?" Atmospheric Environment 120: 173-181. Increasing urban greenspace has been proposed as a means of reducing airborne pollutant concentrations; however limited studies provide experimental data, as opposed to model estimates, of its ability to do so. The current project examined whether higher concentrations of urban forestry might be associated with quantifiable effects on ambient air pollutant levels, whilst accounting for the predominant source of localized spatial variations in pollutant concentrations, namely vehicular traffic. Monthly air samples for one year were taken from eleven sites in central Sydney, Australia. The sample sites exhibited a range of different traffic density, population usage, and greenspace/urban forest density conditions. Carbon dioxide (CO2), carbon monoxide (CO), total volatile organic compounds (TVOCs), nitric oxide (NO), nitrogen dioxide (NO2), sulfur dioxide (SO2), total suspended particulate matter (TSP), suspended particles <10 μm in diameter (PM10) and particulate matter <2.5 μm (PM2.5), were recorded, using portable devices. It was found that air samples taken from sites with less greenspace frequently had high concentrations of all fractions of aerosolized particulates than other sites, whilst sites with high proximal greenspace had lower particulates, even when vehicular traffic was taken into account. No observable trends in concentrations of NO, TVOC and SO2 were observed, as recorded levels were generally very low across all sampled areas. The findings indicate, first, that within the urban areas of a city, localized differences in air pollutant loads occur. Secondly, we conclude that urban areas with proportionally higher concentrations of urban forestry may experience better air quality with regards to reduced ambient particulate matter; however conclusions about other air pollutants are yet to be elucidated.

Heaviside, C., et al. (2015). "The effects of horizontal advection on the urban heat island in Birmingham and the West Midlands, United Kingdom during a heatwave." Q J Roy Meteorol Soc 141. Birmingham is the second most populous city in the United Kingdom and observations indicate that it has a pronounced urban heat island (UHI), i.e. higher ambient temperatures in the city centre compared with surrounding suburban and rural areas, particularly at night. The effects of UHIs are often amplified during anticyclonic summer weather conditions, which can cause or exacerbate heatwaves. Enhanced temperatures in highly populated regions can mean that significant numbers of people are at risk from heat-related illness during hot weather. Climate change projections often do not include the effects of the UHI, which can mean that assessments of heat-related health effects using these projections underestimate the actual magnitude of future health impacts. We present numerical simulations of the UHI in Birmingham and the West Midlands Metropolitan region during the heatwave of August 2003 using the high-resolution, regional meteorological Weather Research and Forecasting (WRF) model, with an urban canopy scheme. We evaluated the model using local air-temperature observations, and found good model performance in capturing the temporal and spatial signature of the UHI. We performed a sensitivity test, replacing urban land categories with rural ones, and found that the difference in temperature between the two model runs throughout the heatwave period (2–11 August 2003) was around 3°C on average, and reached a maximum of 7°C. Finally, we present a novel generic methodology to enable the examination of the extent of horizontal advection of warm air downwind of the conurbation area. We found that during the heatwave, temperatures downwind of Birmingham were up to 2.5°C warmer than those upwind. This methodology has the potential for improvements to, or parametrizations for, diagnostic models that do not explicitly include dynamics and where local conditions are driven largely by land-surface type.

Hashemi, S. S. G., et al. (2015). "Performance of green roofs with respect to water quality and reduction of energy consumption in tropics: A review." Renewable and Sustainable Energy Reviews 52: 669-679. Green roofs are an increasingly important component of water-sensitive urban design systems that can potentially improve the quality of urban runoff, reduce the energy consumption of buildings, and add esthetic value to the environment. The most important green roof abilities, which appear as a key feature in urban catchments are the ability of rainwater detention and retention and reduction in energy consumption. This paper aims to provide an overview of the effects of the application of the green roof strategy on the quality of runoff water and the reduction of energy consumption. The components of a green roof are discussed, and the advantages and disadvantages of different types of green roofs are assessed. In addition, the origins and concentrations of the main pollutants are discussed, moreover environmental cost- benefits of green roofs are also considered. In addition, the main factors that affect the quality of green roof runoff water, e.g., plant species, fertilization, pH, growth media as well as how green roofs could reduce energy consumption are discussed. Green roofs are considered as sustainable approach for runoff management with achieved aesthetical values and in combination with energy saving on heating/cooling. Hence, green roof causes a sufficient decrease in energy consumption and consequently in the related energy costs. It can help to improve the micro climate around the buildings and save money and also improve water quality. Therefore, green roofs may turn into a profitable investment. Some recommendations for future study also are proposed.

Hansen, R., et al. (2015). "The uptake of the ecosystem services concept in planning discourses of European and American cities." Ecosystem Serv 12. Ecosystem services (ES) are gaining increasing attention as a promising concept to more actively consider and plan for the varied benefits of the urban environment. Yet, to have an impact on decision- making, the concept must spread from academia to practice. To understand how ES have been taken up in planning discourses we conducted a cross-case comparison of planning documents in Berlin, New York, Salzburg, Seattle and Stockholm. We found: (1) explicit references to the ES concept were primarily in documents from Stockholm and New York, two cities in countries that entered into ES discourses early. (2) Implicit references and thus potential linkages between the ES concept and planning discourses were found frequently among all cities, especially in Seattle. (3) The thematic scope, represented by 21 different ES, is comparably broad among the cases, while cultural services and habitat provision are most frequently emphasized. (4) High-level policies were shown to promote the adoption of the ES concept in planning. We find that the ES concept holds potential to strengthen a holistic consideration of urban nature and its benefits in planning. We also revealed potential for further development of ES approaches with regard to mitigation of environmental impacts and improving urban resilience.

Gromke, C. and B. Blocken (2015). "Influence of avenue-trees on air quality at the urban neighborhood scale. Part II: Traffic pollutant concentrations at pedestrian level." Environ Pollut 196. Flow and dispersion of traffic‐emitted pollutants were studied in a generic urban neighborhood for various avenue‐tree layouts by employing 3D steady RANS simulations with the realizable k‐ε turbulence model. In comparison to the tree‐free situation quantitative and qualitative changes with flow reversal in the wind field were observed. Low to moderate increases (<13.2%) in the neighborhood‐averaged pollutant concentration were found at pedestrian level. An approximately 1% increase in the neighborhood‐averaged concentration was obtained with each percent of the street canyon volumes being occupied by vegetation for occupation fractions between 4 and 14%. The overall pattern of concentration changes relative to the tree‐free situation was similar for all avenue‐tree layouts. However, pronounced locally restricted decreases or increases in concentration (‐87 to +1378%) occurred. The results indicate the necessity to account for existing or planned avenue‐trees in neighborhood scale dispersion studies. Their consideration is prerequisite for reliable urban air quality assessment.

Gorzelak, M. A., et al. (2015). "Inter-plant communication through mycorrhizal networks mediates complex adaptive behaviour in plant communities." AoB Plants 7. Adaptive behaviour of plants, including rapid changes in physiology, gene regulation and defence response, can be altered when linked to neighbouring plants by a mycorrhizal network (MN). Mechanisms underlying the behavioural changes include mycorrhizal fungal colonization by the MN or interplant communication via transfer of nutrients, defence signals or allelochemicals. We focus this review on our new findings in ectomycorrhizal ecosystems, and also review recent advances in arbuscular mycorrhizal systems. We have found that the behavioural changes in ectomycorrhizal plants depend on environmental cues, the identity of the plant neighbour and the characteristics of the MN. The hierarchical integration of this phenomenon with other biological networks at broader scales in forest ecosystems, and the consequences we have observed when it is interrupted, indicate that underground 'tree talk' is a foundational process in the complex adaptive nature of forest ecosystems.

Gasparrini, A., et al. (2015). "Mortality risk attributable to high and low ambient temperature: a multicountry observational study." Lancet 386. Background Although studies have provided estimates of premature deaths attributable to either heat or cold in selected countries, none has so far offered a systematic assessment across the whole temperature range in populations exposed to different climates. We aimed to quantify the total mortality burden attributable to non-optimum ambient temperature, and the relative contributions from heat and cold and from moderate and extreme temperatures. Methods We collected data for 384 locations in Australia, Brazil, Canada, China, Italy, Japan, South Korea, Spain, Sweden, Taiwan, Thailand, UK, and USA. We fitted a standard time-series Poisson model for each location, controlling for trends and day of the week. We estimated temperature–mortality associations with a distributed lag non-linear model with 21 days of lag, and then pooled them in a multivariate metaregression that included country indicators and temperature average and range. We calculated attributable deaths for heat and cold, defined as temperatures above and below the optimum temperature, which corresponded to the point of minimum mortality, and for moderate and extreme temperatures, defined using cutoffs at the 2·5th and 97·5th temperature percentiles. Findings We analysed 74 225 200 deaths in various periods between 1985 and 2012. In total, 7·71% (95% empirical CI 7·43–7·91) of mortality was attributable to non-optimum temperature in the selected countries within the study period, with substantial differences between countries, ranging from 3·37% (3·06 to 3·63) in Thailand to 11·00% (9·29 to 12·47) in China. The temperature percentile of minimum mortality varied from roughly the 60th percentile in tropical areas to about the 80–90th percentile in temperate regions. More temperature- attributable deaths were caused by cold (7·29%, 7·02–7·49) than by heat (0·42%, 0·39–0·44). Extreme cold and hot temperatures were responsible for 0·86% (0·84–0·87) of total mortality. Interpretation Most of the temperature-related mortality burden was attributable to the contribution of cold. The effect of days of extreme temperature was substantially less than that attributable to milder but non-optimum weather. This evidence has important implications for the planning of public-health interventions to minimise the health consequences of adverse temperatures, and for predictions of future effect in climate-change scenarios.

Gallagher, J., et al. (2015). "Passive methods for improving air quality in the built environment: A review of porous and solid barriers." Atmospheric Environment 120: 61- 70. Protecting the health of growing urban populations from air pollution remains a challenge for planners and requires detailed understanding of air flow and pollutant transport in the built environment. In recent years, the work undertaken on passive methods of reducing air pollution has been examined to address the question: “how can the built environment work to alter natural dispersion patterns to improve air quality for nearby populations?” This review brings together a collective of methods that have demonstrated an ability to influence air flow patterns to reduce personal exposure in the built environment. A number of passive methods exists but, in the context of this paper, are split into two distinct categories: porous and solid barriers. These methods include trees and vegetation (porous) as well as noise barriers, low boundary walls and parked cars (solid); all of which have gained different levels of research momentum over the past decade. Experimental and modelling studies have provided an understanding of the potential for these barriers to improve air quality under varying urban geometrical and meteorological conditions. However, differences in results between these studies and real-world measurements demonstrate the challenges and complexities of simulating pollutant transport in urban areas. These methods provide additional benefits to improving air quality through altering dispersion patterns; avenue trees and vegetation are aesthetically pleasing and provides cooling and shade from direct sunlight. Additionally, real-world case studies are considered an important direction for further verification of these methods in the built environment. Developing design guidelines is an important next stage in promoting passive methods for reducing air pollution and ensuring their integration into future urban planning strategies. In addition, developing channels of communication with urban planners will enhance the development and uptake of design guidelines to improve air quality in the built environment.

Fantozzi, F., et al. (2015). "Spatio-temporal variations of ozone and nitrogen dioxide concentrations under urban trees and in a nearby open area." Urban Climate 12. The evergreen Quercus ilex L. is one of the most common trees in Italian urban environments and is considered effective in the uptake of particulate and gaseous atmospheric pollutants. Howev- er, the few available estimates on O3 and NO2 removal by urban Q. ilex originate from model-based studies (which indicate NO2/O3 removal capacity of Q. ilex) and not from direct measurements of air pollutant concentrations. Thus, in the urban area of Siena (cen- tral Italy) we began long-term monitoring of O3/NO2 concentrations using passive samplers at a distance of 1, 5, 10 m from a busy road, under the canopies of Q. ilex and in a nearby open-field. Measure- ments performed in the period June 2011–October 2013 showed always a greater decrease of NO2 concentrations under the Q. ilex canopy than in the open-field transect. Conversely, a decrease of average O3 concentrations under the tree canopy was found only in autumn after the typical Mediterranean post-summer rainfalls. Our results indicate that interactions between O3/NO2 concentra- tions and trees in Mediterranean urban ecosystems are affected by temporal variations in climatic conditions. We argue therefore that the direct measurement of atmospheric pollutant concentra- tions should be chosen to describe local changes of aerial pollution.

Fan, C., et al. (2015). "Measuring the spatial arrangement of urban vegetation and its impacts on seasonal surface temperatures." Progress in Physical Geography 39(2): 199- 219. Urban forestry is an important component of the urban ecosystem that can effectively ameliorate temperatures by providing shade and through evapotranspiration. While it is well known that vegetation abundance is negatively correlated to land surface temperature, the impacts of the spatial arrangement (e.g. clustered or dispersed) of vegetation cover on the urban thermal environment requires further investigation. In this study, we coupled remote sensing techniques with spatial statistics to quantify the configuration of vegetation cover and its variable influences on seasonal surface temperatures in central Phoenix. The objectives of this study are to: (1) determine spatial arrangement of green vegetation cover using continuous spatial autocorrelation indices combined with high-resolution remotely-sensed data; (2) examine the role of grass and trees, especially their spatial patterns on seasonal and diurnal land surface temperatures by controlling the effects of vegetation abundance; (3) investigate the sensitivity of the vegetation–temperature relationship at varying geographical scales. The spatial pattern of urban vegetation was measured using a local spatial autocorrelation index—the local Moran’s Iv. Results show that clustered or less fragmented patterns of green vegetation lower surface temperature more effectively than dispersed patterns. The relationships between the local Moran’s Iv and surface temperature are evidenced to be strongest during summer daytime and lowest during winter nighttime. Results of multiple regression analyses demonstrate significant impacts of spatial arrangement of vegetation on seasonal surface temperatures. Our analyses of vegetation spatial patterns at varying geographical scales suggest that an area extent of ˜200 m is optimal for examining the vegetation–temperature relationship. We provide a methodological framework to quantify the spatial pattern of urban features and to examine their impacts on the biophysical characteristics of the urban environment. The insights gained from our study results have significant implications for sustainable urban development and resource management.

Derkzen, M. L., et al. (2015). "REVIEW: Quantifying urban ecosystem services based on high‐resolution data of urban green space: an assessment for Rotterdam, the Netherlands." Journal of Applied Ecology 52(4): 1020-1032. The urban dimension of ecosystem services (ES) is underexposed, while the importance of ES for human well-being is nowhere as evident as in cities. Urban challenges such as air pol- lution, noise and heat can be moderated by urban green space (UGS), simultaneously provid- ing multiple other services. However, available methods to quantify ES cannot typically deal with the high spatial and thematic resolution land cover data that are needed to better under- stand ES supply in the urban context. This study derives methods to quantify and map a bundle of six ES as supplied by UGS, using land cover data with high spatial and thematic resolution, and applies these to the city of Rotterdam, the Netherlands. Land cover data comprise eight classes of UGS. Methods are derived from an evidence base on the importance of UGS types for the supply of each of the six ES that was built using literature review. The evidence base reveals that UGS types differ in their contribution to various ES, although the strength of the evidence varies. However, existing indicators for urban ES often do not discriminate between UGS types. To derive UGS-specific indicators, we combined methods and evidence from different research contexts (ES, non-ES, urban, non-urban). Rotterdam shows high spatial variation in the amount of UGS present, and accounting for this in ES supply reveals that ES bundles depend on UGS composition and configuration. While the contribution of UGS types to ES supply differed markedly with UGS type and ES considered, we demonstrate that synergies rather than trade-offs exist among the ES analysed. Synthesis and applications. Our findings underline the importance of a careful design of urban green space (UGS) in city planning for ecosystem services (ES) provision. Based on the latest insights on how different UGS provide ES, the methods presented in this study enable a more detailed quantification and mapping of the supply of ES in cities, allowing assess- ments of current supply of key urban ES and alternative urban designs. Such knowledge is indispensable in the quest for designing healthier and climate-resilient cities.

Dadvand, P., et al. (2015). "The association between greenness and traffic-related air pollution at schools." Science of The Total Environment 523: 59-63. Greenness has been reported to improve mental and physical health. Reduction in exposure to air pollution has been suggested to underlie the health benefits of greenness; however, the available evidence on the mitigating effect of greenness on air pollution remains limited and inconsistent. We investigated the association between greenness within and surrounding school boundaries and monitored indoor and outdoor levels of traffic-related air pollutants (TRAPs) including NO2, ultrafine particles, black carbon, and traffic-related PM2.5 at 39 schools across Barcelona, Spain, in 2012. TRAP levels at schools were measured twice during two one-week campaigns separated by 6 months. Greenness within and surrounding school boundaries was measured as the average of satellite-derived normalized difference vegetation index (NDVI) within boundaries of school and a 50 m buffer around the school, respectively. Mixed effects models were used to quantify the associations between school greenness and TRAP levels, adjusted for relevant covariates. Higher greenness within and surrounding school boundaries was consistently associated with lower indoor and outdoor TRAP levels. Reduction in indoor TRAP levels was partly mediated by the reduction in outdoor TRAP levels. We also observed some suggestions for stronger associations between school surrounding greenness and outdoor TRAP levels for schools with higher number of trees around them. Our observed reduction of TRAP levels at schools associated with school greenness can be of public importance, considering the burden of health effects of exposure to TRAPs in schoolchildren.

Coutts AM, W. E., Tapper NJ, Beringer J, Livesley SJ (2015). Temperature and human thermal comfort effects of street trees across three contrasting street canyon environments. Theor Appl Climatol. Urban street trees provide many environmental, social, and economic benefits for our cities. This research explored the role of street trees in Melbourne, Australia, in cooling the urban microclimate and improving human thermal comfort (HTC). Three east–west (E–W) oriented streets were studied in two contrasting street canyon forms (deep and shallow) and between contrasting tree canopy covers (high and low). These streets were instrumented with multiple microclimate monitoring stations to continuously measure air temperature, humidity, solar radiation, wind speed and mean radiant temperature so as to calculate the Universal Thermal Climate Index (UTCI) from May 2011 to June 2013, focusing on summertime conditions and heat events. Street trees supported average daytime cooling during heat events in the shallow canyon by around 0.2 to 0.6 °C and up to 0.9 °C during mid-morning (9:00–10:00). Maximum daytime cooling reached 1.5 °C in the shallow canyon. The influence of street tree canopies in the deep canyon was masked by the shading effect of the tall buildings. Trees were very effective at reducing daytime UTCI in summer largely through a reduction in mean radiant temperature from shade, lowering thermal stress from very strong (UTCI > 38 °C) down to strong (UTCI > 32 °C). The influence of street trees on canyon air temperature and HTC was highly localized and variable, depending on tree cover, geometry, and prevailing meteorological conditions. The cooling benefit of street tree canopies increases as street canyon geometry shallows and broadens. This should be recognized in the strategic placement, density of planting, and species selection of street trees.

Churkina, G., et al. (2015). "Natural selection? Picking the right trees for urban greening." Environmental Science & Policy 47: 12-17. Fast-track programs to plant millions of trees in cities around the world aim at the reduction of summer temperatures, increase carbon storage, storm water control, provision of space for recreation, as well as poverty alleviation. Although these multiple benefits speak positively for urban greening programs, the programs do not take into account the drastic differences between urban and natural systems. Elevated temperatures together with anthropogenic emissions of air and water pollutants distinguish the urban system. Although the potential for emissions of volatile organic compounds from urban vegetation combined with anthropogenic emissions to produce ozone has long been recognized, the municipalities actively enlarging their green spaces still generally either overlook or ignore this fact. Here we assess the scientific evidence of biogenic induction of ground-level ozone concentrations in urban and sub- urban areas and argue that it is feasible and beneficial to implement measures necessary to limit biogenic contributions to air pollution. With the example of biogenic induction of ground level ozone concentrations we demonstrate that interactions between plants and urban ambient conditions have to be taken into account in all efforts of creating “naturopolises”. We explore the mechanisms behind these interactions and propose a pathway to improve our understanding of these interactions.

Chen, W. Y. (2015). "The role of urban green infrastructure in offsetting carbon emissions in 35 major Chinese cities: A nationwide estimate." Cities 44: 112-120. The carbon balance in urban areas has become a major research challenge and a principal policy concern in efforts to address anthropogenic climate change. Rapid urbanization and industrialization in China urge the search for integrated strategies to mitigate and adapt to climate change, which not only limit to traditional infrastructure sectors, but also cover urban green infrastructure, because plants and soils function as carbon sinks through biotic sequestration. This study presents a nationwide study about how urban green infrastructure could contribute to the carbon balance in 35 major Chinese cities. By the end of 2010, the total area of urban green spaces (the dominant components of urban green infrastructure) accounts for 6.38% of the total land area of these cities and represented 51.7% of the total urban green spaces of all 657 cities in China. Based on empirical data from the literature, the total amount of carbon stored in the vegetation of the urban green infrastructure of 35 cities was estimated at 18.7 million tons, with an average carbon density of 21.34 t/ha. In 2010, the amount of carbon sequestration totaled 1.90 million tons with an average carbon sequestration rate of 2.16 t/ha/year. Collectively, only 0.33% of the carbon emissions from fossil fuel combustion can be offset, ranging from 0.01% in Hohhot to 22.45% in Haikou. Nevertheless, the dominance of young vegetation stands in Chinese urban green infrastructure suggests this small carbon sequestration efficiency could become substantial in the near future, given that appropriate policies and management practices are adopted to promote urban green infrastructure for climate change mitigation and adaptation.

Caruso, G., et al. (2015). "Greener and larger neighbourhoods make cities more sustainable! A 2D urban economics perspective." Computers, Environment and Urban Systems 54: 82-94. We analyse urban growth forms by means of a 2D microeconomic model where households value green space at neighbourhood scale. We analytically demonstrate that cities can grow more densely when households have the possibility to enlarge the neighbourhood in which they value green space, thus emphasizing the importance of neighbourhood planning in particular for facilitating short trips and views of green amenities. We also show by simulation that the size and form of the city, relative to the size and form of neighbourhoods, impact on the decision of households to leapfrog land or not, thus impacting on the emergence of scattered urbanisation patterns. We conclude that carefully addressing the spatial arrangement of green space and buildings and facilitating trips within neighbourhood units constitute an effective policy lever and an attractive way to deliver more sustainable cities. We further argue that our theoretical experiment with complementary analytical and computer-based simulation provides micro-economic reasoning to the main elements of the Garden City and neighbourhood unit planning concepts.

Calfapietra, C., et al. (2015). "Urban plant physiology: adaptation-mitigation strategies under permanent stress." Trends in Plant Science 20(2): 72-75. Urban environments that are stressful for plant function and growth will become increasingly widespread in future. In this opinion article, we define the concept of ‘urban plant physiology’, which focuses on plant responses and long term adaptations to urban conditions and on the capacity of urban vegetation to mitigate environmental hazards in urbanized settings such as air and soil pollution. Use of appropriate control treatments would allow for studies in urban environments to be comparable to expensive manipulative experiments. In this opinion article, we propose to couple two approaches, based either on environmental gradients or manipulated gradients, to develop the concept of urban plant physiology for assessing how single or multiple environmental factors affect the key environmental services provided by urban forests.

Cahill, J. F. (2015). "Introduction to the Special Issue: Beyond traits: integrating behaviour into plant ecology and biology." AoB Plants 7. The way that plants are conceptualized in the context of ecological understanding is changing. In one direction, a reductionist school is pulling plants apart into a list of measured 'traits', from which ecological function and outcomes of species interactions may be inferred. This special issue offers an alternative, and more holistic, view: that the ecological functions performed by a plant will be a consequence not only of their complement of traits but also of the ways in which their component parts are used in response to environmental and social conditions. This is the realm of behavioural ecology, a field that has greatly advanced our understanding of animal biology, ecology and evolution. Included in this special issue are 10 articles focussing not on the tried and true metaphor that plant growth is similar to animal movement, but instead on how application of principles from animal behaviour can improve our ability to understand plant biology and ecology. The goals are not to draw false parallels, nor to anthropomorphize plant biology, but instead to demonstrate how existing and robust theory based on fundamental principles can provide novel understanding for plants. Key to this approach is the recognition that behaviour and intelligence are not the same. Many organisms display complex behaviours despite a lack of cognition (as it is traditionally understood) or any hint of a nervous system. The applicability of behavioural concepts to plants is further enhanced with the realization that all organisms face the same harsh forces of natural selection in the context of finding resources, mates and coping with neighbours. As these ecological realities are often highly variable in space and time, it is not surprising that all organisms-even plants-exhibit complex behaviours to handle this variability. The articles included here address diverse topics in behavioural ecology, as applied to plants: general conceptual understanding, plant nutrient foraging, root-root interactions, and using and helping others. As a group, the articles in this special issue demonstrate how plant ecological understanding can be enhanced through incorporation of behavioural ideas and set the stage for future research in the emerging discipline of plant behavioural ecology.

Bottalico, F., et al. (2015). Urban forest and air pollutants removal: a matter of quality of life. 10th SISEF National Congress “Sostenere il pianeta, boschi per la vita-Ricerca e innovazione per la tutela e la valorizzazione delle risorse forestali”, SISEF Societa'Italiana di Selvicoltura ed Ecolo. Cities are major actors in climate change: although they cover less than 2% of the Earth’s surface, urban areas produce more than 60% of global carbon dioxide and significant amounts of other greenhouse gas emissions. But cities are ecosystems: they are open and dynamic systems which consume, transform and release materials and energy; they develop and adapt; and they interact with humans and with other systemic components. Green Infrastructure is a relatively new approach towards strengthening the interconnection among the different ecological components played at landscape level. Green infrastructure does not concern just cities but is foreseen as a powerful planning tool to bridge the gap between urban/rural areas. A green infrastructure approach to land use and territorial planning promotes the widest range of functions that can be performed by the same asset, thereby unlocking the greatest number of ecosystem services. Urban and Periurban forests constitute the backbone of Green Infrastructure. So far, ecosystem services provided by urban forests are decisive for the future of a highly urbanized planet. Air quality is one of the most relevant factors influencing both human and environmental health and, definitively, the quality of life. Urban forest ecosystems provide a range of goods and services important for human well-being, commonly classified as provisioning, regulating, cultural, and supporting services. Among them, the regulating service of air quality improvement by air pollutants removal is a crucial one for the present and future health of our cities. The research deals with the understanding of the urban forest component of the green infrastructure by scaling different datasets provided by remote and on-field investigation in order to highlight the potential performance of air pollution removal by the green infrastructure itself. The case study of the city of Florence was investigated by scaling the spatial distribution of urban forests mapped by remote sensing methods. A spatial model using vegetation indices, the Leaf Area Index (LAI), re-fined by on-field LAI survey in different structural types of urban forests, and pollution concentration data was applied to estimate PM10 and O3 removal potential. The results are discussed to predict the role of urban forests in improving air quality in the city of Florence and to identify the opportunities and threats of using a green infrastructure approach along strategic planning and management of urban areas and city regions.

Andersson-Sköld, Y., et al. (2015). "An integrated method for assessing climate-related risks and adaptation alternatives in urban areas." Climate Risk Manage 7. The urban environment is a complex structure with interlinked social, ecological and techni- cal structures. Global warming is expected to have a broad variety of impacts, which will add to the complexity. Climate changes will force adaptation, to reduce climate-related risks. Adaptation measures can address one aspect at the time, or aim for a holistic approach to avoid maladaptation. This paper presents a systematic, integrated approach for assessing alternatives for reducing the risks of heat waves, flooding and air pollution in urban settings, with the aim of reducing the risk of maladaptation. The study includes strategies covering different spatial scales, and both the current climate situation and the climate predicted under climate change scenarios. The adaptation strategies investigated included increasing vegetation; selecting density, height and colour of buildings; and retreat or resist (defend) against sea-level rise. Their effectiveness was assessed with regard to not only flooding, heat stress and air quality but also with regard to resource use, emissions to air (incl. GHG), soil and water, and people’s perceptions and vulnerability. The effectiveness of the strategies were ranked on a common scale (from 3 to 3) in an integrated assessment. Integrated assessments are recommended, as they help identify the most sustainable solutions, but to reduce the risk of maladaptation they require experts from a variety of disciplines. The most generally applicable recommendation, derived from the integrated assessment here, taking into account both expertise from different municipal departments, literature surveys, life cycle assessments and publics perceptions, is to increase the urban greenery, as it contributes to several positive aspects such as heat stress mitigation, air quality improvement, effective storm-water and flood-risk management, and it has several positive social impacts. The most favourable alternative was compact, mid-rise, light coloured building design with large parks/green areas and trees near buildings.

Demuzere M, C. A., Göhler M, Broadbent AM, Wouters H, van Lipzig, NPM, et al. (2014a). The implementation of biofiltration systems, rainwater tanks and urban irrigation in a single-layer urban canopy model. Urban Climate. Urban vegetation is generally considered as a key tool to modify the urban energy balance through enhanced evapotranspiration (ET). Given that vegetation is most effective when it is healthy, stormwater harvesting and retention strategies (such as water sensitive urban design) could be used to support vegetation and promote ET. This study presents the implementation of a vegetated lined bio-filtration system (BFS) combined with a rainwater tank (RWT) and urban irrigation system in the single-layer urban canopy model Community Land Model-Urban. Runoff from roof and impervious road surface fractions is harvested and used to support an adequate soil moisture level for vegetation in the BFS. In a first stage, modelled soil moisture dynamics are evaluated and found reliable compared to observed soil moisture levels from biofiltration pits in Smith Street, Melbourne (Australia). Secondly, the impact of BFS, RWT and urban irrigation on ET is illustrated for a two-month period in 2012 using varying characteristics for all components. Results indicate that (i) a large amount of stormwater is potentially available for indoor and outdoor water demands, including irrigation of urban vegetation, (ii) ET from the BFS is an order of magnitude larger compared to the contributions from the impervious surfaces, even though the former only covers 10% of the surface fraction and (iii) attention should be paid to the cover fraction and soil texture of the BFS, size of the RWT and the surface fractions contributing to the collection of water in the RWT. Overall, this study reveals that this model development can effectuate future research with state-of-the-art urban climate models to further explore the benefits of vegetated biofiltration systems as a water sensitive urban design tool optimised with an urban irrigation system to maintain healthy vegetation.

Wu, J. (2014). "Urban ecology and sustainability: The state-of-the-science and future directions." Landscape and Urban Planning 125(0): 209-221. Ecosystems and landscapes around the world have become increasingly domesticated through urbanization. Cities have been the engines of socioeconomic development but also the centers of major environmental problems since the industrial revolution. Numerous studies have shown that our urban ecosystems and landscapes are on an unsustainable trajectory. Global sustainability depends critically on cities, and urban ecology can – and needs to – play a key role in the transition toward sustainability. In this paper, I review different definitions and perspectives of urban ecology, discuss major advances and key issues, and propose a framework to help move the field forward. After almost 90 years of development, urban ecology has evolved into a truly transdisciplinary enterprise that integrates ecological, geographical, planning, and social sciences. The most salient thrust of current research activities in the field is the emerging urban sustainability paradigm which focuses on urban ecosystem services and their relations to human well-being. While urbanization is complex in many ways, we do know a lot about its patterns, processes, and effects. More specifically, we know a great deal about urban growth patterns in space and time, the underlying drivers and mechanisms, and myriad effects of urbanization on biodiversity, ecological processes, and ecosystem services. Compared to their ancient counterparts, contemporary cities tend to be bigger in physical size and ecological footprint, faster in growth rate in terms of both population and urbanized land, and more irregular in landscape composition and configuration. As coevolving human-environment systems, cities are spatially heterogeneous, complex adaptive systems. As such, the dynamic trajectory of cities can never be fully predicted or controlled, but can and should be influenced or guided in more desirable directions through planning and design activities that are based on urban ecological knowledge and sustainability principles.

Weber, F., et al. (2014). "A walk on the wild side: Perceptions of roadside vegetation beyond trees." Urban Forestry & Urban Greening 13(2): 205-212. Urban nature is of vital importance for human well-being in an increasingly urbanized world. Despite the wide variety of urban greenspaces, previous research has mostly focussed on parks and in particular presence of trees. Although streets are fundamental urban structures and offer an array of green elements beyond trees, the perception and valuation of other kinds of roadside vegetation by urban residents is understudied so far. This study explores the range of roadside vegetation and associated ecosystem services perceived by city dwellers in densely populated inner city districts of two German cities. Further, we explored how wild-grown roadside vegetation is valued by interviewees. Results confirmed the important role of trees but also demonstrated that city dwellers perceive a variety of cultivated and “wild” green components other than trees. Respondents attached a wide range of meanings and values to roadside greenery and showed a surprisingly high awareness of associated ecosystem services. Wild urban roadside vegetation met with high approval, although planted and maintained vegetation was preferred. Our study illustrated that trees and other elements of roadside vegetation fulfil important functions in the view of the public. For many respondents, ecological and economical functions of roadside vegetation were more important than orderliness. This indicates opportunities for enhancing the biodiversity of urban streetscapes. As public green spaces are in short supply in many cities, enhancing cultivated and wild roadside vegetation could help to deliver ecosystem services in the areas near where people move and live.

Weber, F., et al. (2014). "Herbaceous plants as filters: Immobilization of particulates along urban street corridors." Environmental Pollution 186: 234-240. Among air pollutants, particulate matter (PM) is considered to be the most serious threat to human health. Plants provide ecosystem services in urban areas, including reducing levels of PM by providing a surface for deposition and immobilization. While previous studies have mostly addressed woody species, we focus on herbaceous roadside vegetation and assess the role of species traits such as leaf surface roughness or hairiness for the immobilization of PM. We found that PM deposition patterns on plant surfaces reflect site-specific traffic densities and that strong differences in particulate deposition are present among species. The amount of immobilized PM differed according to particle type and size and was related to specific plant species traits. Our study suggests that herbaceous vegetation immobilizes a significant amount of the air pollutants relevant to human health and that increasing biodiversity of roadside vegetation supports air filtration and thus healthier conditions along street corridors.

Vico, G., et al. (2014). "Ecohydrology of street trees: design and irrigation requirements for sustainable water use." Ecohydrology 7. Whereas the beneficial effects of urban vegetation have long been recognized, growing conditions in urban environments, especially for street trees, are typically harsh and limited by low water availability. Supplemental irrigation may be used to preserve aesthetic quality and ability to provide ecosystem services of urban vegetation but requires careful management of available economic and water resources to reduce urban water footprint. To this purpose, decision makers need quantitative tools, requiring few, physically based parameters and accounting for the uncertainties and future scenarios of the hydroclimatic forcing. Focusing on in-row and isolated trees, a minimalist description of street tree water balance is proposed here, including rainfed and irrigated conditions, and explicitly accounting for tree water requirements, growing conditions (in terms of soil properties and extension of bare soil, permeable and impervious pavements surrounding the tree) and rainfall unpredictability. The proposed model allows the quantification of tree cooling capacity, water stress occurrence and irrigation requirements, as a function of soil, plant and climate characteristics, thus providing indications regarding the tree ability to provide ecosystem services and management costs. In particular, an analysis of different planting designs suggests that a balanced design consisting in bare soil and permeable pavement with size equal to the lateral canopy extension is optimal for water conservation, tree cooling capacity and health. The proposed model provides useful indications towards the definition of site-specific guidelines for species selection and planting design, for sustainable urban vegetation.

Van Renterghem, T. (2014). "Guidelines for optimizing road traffic noise shielding by non- deep tree belts." Ecological Engineering 69: 276-286. This paper discusses that a non-deep tree belt along a road can be an interesting solution to achieve road traffic noise reduction. Noise shielding is mainly obtained as a combination of multiple scattering in the tree trunk layer and due to the presence of an acoustically soft soil. A large dataset of full-wave and highly detailed numerical simulations, based as much as possible on measured input data, shows that high biomass density should be strived for as a general rule. This conflicts, however, with practical limitations regarding access to light, nutrients and water for the trees. Some interesting approaches have been identified to relax the need for high biomass density, without affecting noise shielding to an important extent. Rectangular planting schemes, where the spacing orthogonal to the road can be increased, omitting full rows parallel to the road length axis, and thinning inside the belt are examples of such measures. It is discussed that the specific choice of a planting scheme could make a tree belt along a road an efficient noise reducing measure or not.

Van den Berg, A. E., et al. (2014). "Evaluating restoration in urban green spaces: Does setting type make a difference?" Landscape and Urban Planning 127: 173-181. A growing body of research suggests that natural settings are more effective in providing restoration from depleted emotional and cognitive resources than built settings. However, there is a lack of evidence-based guidelines on which options for urban green space design and management are most effective in providing restoration. To address this need, the present study examined the restorative impacts of urban public spaces differing in naturalness. After having been pre-stressed by watching a scary movie, 102 participants were randomly assigned to viewing one of four photo/video presentations depicting an urban street, parkland, tended woodland, or wild woods. Self-reported mood and restorative state were measured at baseline, after the stressor and after viewing the environment. After controlling for stress reactivity, participants in the natural conditions showed stronger recovery on all dependent measures than those in the urban street condition. Differences in recovery among the natural settings did not reach significance. Keyword analysis revealed that the wild woods were described as more arousing than the parkland and tended woodland. There was substantial variation in recovery of vitality within natural conditions, which was related to perceptions of naturalness. In general, the findings suggest that restoration in urban public spaces depends on individual perceptions and needs as well as physical characteristics of the setting.

Torpy, F. R., et al. (2014). "Profiling indoor plants for the amelioration of high CO2 concentrations." Urban Forestry & Urban Greening 13(2): 227-233. Research over the last three decades has shown that indoor plants can reduce most types of urban air pollutants, however there has been limited investigation of their capacity to mitigate elevated levels of CO2. This study profiled the CO2 removal potential of eight common indoor plant species, acclimatised to both indoor and glasshouse lighting levels, to develop baseline data to facilitate the development of indoor plant installations to improve indoor air quality by reducing excess CO2 concentrations. The results indicate that, with the appropriate choice of indoor plant species and a targeted increase in plant specific lighting, plantscape installations could be developed to remove a proportion of indoor CO2. Further horticultural research and development will be required to develop optimum systems for such installations, which could potentially reduce the load on ventilation systems.

Takayama, N., et al. (2014). "Emotional, Restorative and Vitalizing Effects of Forest and Urban Environments at Four Sites in Japan." International Journal of Environmental Research and Public Health 11(7): 7207-7230. The present study investigated the well-being effects of short-term forest walking and viewing ("forest bathing"). The hypothesis in our study was that both environment (forest vs. urban) and activity (walking and viewing) would influence psychological outcomes. An additional aim was to enhance basic research using several psychological methods. We conducted the experiments using 45 respondents in four areas of Japan from August to September, 2011. The hypothesis in our study was supported, because significant interaction terms between the environment and activity were confirmed regarding the Profile of Mood States (POMS) indexes, Restorative Outcome Scale (ROS) and Subjective Vitality Scale (SVS). No statistical differences between the two experimental groups in any of the ten scales were found before the experiment. However, feelings of vigor and positive effects, as well as feelings of subjective recovery and vitality were stronger in the forest environment than in the urban environment.

Sriprapat, W., et al. (2014). "Uptake of toluene and ethylbenzene by plants: removal of volatile indoor air contaminants." Ecotoxicol Environ Saf 102: 147-151. Air borne uptake of toluene and ethylbenzene by twelve plant species was examined. Of the twelve plant species examined, the highest toluene removal was found in Sansevieria trifasciata, while the ethylbenzene removal from air was with Chlorophytum comosum. Toluene and ethylbenzene can penetrate the plants cuticle. However, the removal rates do not appear to be correlated with numbers of stomata per plant. It was found that wax of S. trifasciata and Sansevieria hyacinthoides had greater absorption of toluene and ethylbenzene, and it contained high hexadecanoic acid. Hexadecanoic acid might be involved in toluene and ethylbenzene adsorption by cuticles wax of plants. Chlorophyll fluorescence analysis or the potential quantum yield of PSII (Fv/Fm) in toluene exposed plants showed no significant differences between the control and the treated plants, whereas plants exposed to ethylbenzene showed significant differences or those parameters, specifically in Dracaena deremensis (Lemon lime), Dracaena sanderiana, Kalanchoe blossfeldiana, and Cordyline fruticosa. The Fv/Fm ratio can give insight into the ability of plants to tolerate (indoor) air pollution by volatile organic chemicals (VOC). This index can be used for identification of suitable plants for treating/sequestering VOCs in contaminated air.

Skoulika, F., et al. (2014). "On the thermal characteristics and the mitigation potential of a medium size urban park in Athens, Greece." Landscape and Urban Planning 123: 73-86. The urban heat island (UHI) is one of the most studied phenomena of urban climate. It deals with the increased ambient temperatures in the cities’ central areas compared to their suburban or rural surroundings (Santamouris, 2001). Significant research has been carried out by various researchers all over the world in order to understand the phenomenon’s characteristics and document its magnitude (Arnfield, 2003; Ghiaus, Allard, Santamouris, Georgakis, & Nicol, 2006; Oke, 1982). Measurements have been performed during summer in and around a medium size urban park located in the western part of Athens, Greece. Additional temperature data from 15 urban and suburban stations are used to perform comparative analysis at the city level. The park presents an important temperature inhomogeneity during both day and night. Average nocturnal cool island intensities against the reference urban stations varied between −0.7 K and −2.8 K, while during the daytime the average maximum cool island intensity (CII) was between −0.2 K and −2.6 K. A statistical significant correlation between the CII and the population density is found for both day and night. The park was warmer than the urban stations for ambient temperatures lower than 34◦C, while for higher urban temperatures the park was cooler and the absolute CII increased as a function of the ambient temperature. An important correlation with the wind speed is observed for wind speeds higher than 6 m/s. The mitigation potential of the park was assessed by performing three types of traverses around the park. The park cooling intensity was varying between 3.3 and 3.8 K, while the temperature gradient along the traverses changes as a function of the thermal properties of the urban areas and was between 0.2 and 1.4 K/100 m. The park cooling intensity presents a strong correlation with the wind speed for values higher than 5 m/s. The climatic influence of the park was extended up to 300 m from the borders of the park.

Pearce, M., et al. (2014). "Who children spend time with after school: associations with objectively recorded indoor and outdoor physical activity." International Journal of Behavioral Nutrition and Physical Activity 11(1): 45. Background: Understanding how the determinants of behaviour vary by context may support the design of interventions aiming to increase physical activity. Such factors include independent mobility, time outdoors and the availability of other children. At present little is known about who children spend their time with after school, how this relates to time spent indoors or outdoors and activity in these locations. This study aimed to quantify who children spend their time with when indoors or outdoors and associations with moderate to vigorous physical activity (MVPA). Methods: Participants were 427 children aged 10–11 from Bristol, UK. Physical activity was recorded using an accelerometer (Actigraph GT1M) and matched to Global Positioning System receiver (Garmin Foretrex 201) data to differentiate indoor and outdoor location. Children self-reported who they spent time with after school until bed-time using a diary. Each 10 second epoch was coded as indoors or outdoors and for ‘who with’ (alone, friend, brother/sister, mum/dad, other grown-up) creating 10 possible physical activity contexts. Time spent and MVPA were summarised for each context. Associations between time spent in the different contexts and MVPA were examined using multiple linear regression adjusting for daylight, age, deprivation and standardised body mass index. Results: During the after school period, children were most often with their mum/dad or alone, especially when indoors. When outdoors more time was spent with friends (girls: 32.1%; boys: 28.6%) than other people or alone. Regression analyses suggested hours outdoors with friends were positively associated with minutes of MVPA for girls (beta-coefficient [95% CI]: 17.4 [4.47, 30.24]) and boys (17.53 [2.76, 32.31]). Being outdoors with brother/sister was associated with MVPA for girls (21.2 [14.17, 28.25]) but not boys. Weaker associations were observed for time indoors with friends (girls: 4.61 [1.37, 7.85]; boys: (7.42 [2.99, 11.85]) and other adults (girls: 5.33 [2.95, 7.71]; boys: (4.44 [1.98, 6.90]). Time spent alone was not associated with MVPA regardless of gender or indoor/outdoor location. Conclusions: Time spent outdoors with other children is an important source of MVPA after school. Interventions to increase physical activity may benefit from fostering friendship groups and limiting the time children spend alone.

Pandit, R., et al. (2014). "Valuing public and private urban tree canopy cover." Australian Journal of Agricultural and Resource Economics 58(3): 453-470. In this paper, we estimate the effect of tree canopy cover on sales price of urban residential properties in Perth, Western Australia. Using a data set of 5606 single family homes sold in 2009 and a spatial hedonic model with three spatial effects – spatial-temporal lag on dependent variable, spatial error, and spatially lagged independent variables – we estimated the location-specific effect of tree canopy cover. Tree canopy cover increases the property value when located on adjacent public space, but decreases the value when it is on own property and on the adjacent property within 20 m of property boundary. The results are suggestive that council urban tree planting programs provide significant private benefits to homeowners.

Neema, M. N. and J. Jahan (2014). "An innovative approach to mitigate vehicular emission through roadside greeneries: A case study on arterial roads of Dhaka city." Journal of Data Analysis and Information Processing 2014. With the surge of human population, the need for transportation of goods and people also concomitantly increases, resulting in urban air pollution through emission from motorized traffic especially in developing countries. The extent of environmental pollution in an urban setting is significantly influenced by the pollutants of vehicular fuel combustion. Many effective measures are required in cities to sequester carbon thereby helping to reduce automobile pollution. Roadside greeneries can serve as ecological elements which reduce the concentration of pollutants from vehicular emissions by their direct involvement in absorbing vehicular emitted carbon. In this context, in this study an attempt has been taken to assess contribution of roadside greeneries in absorbing vehicular carbon dioxide emission. A case study has been conducted on arterial roads of mega city Dhaka to quantify the vehicular carbon emission and correlate it with roadside trees to absorb the emitted carbon dioxide. It is noted that in Dhaka city, carbon dioxide is accounted for more than ninety percent of air pollution. To achieve our goals, two busiest arterial roads (namely Mirpur Road and Rokeya Shoroni Road) were taken into account to quantify vehicular carbon emission as well as assess carbon absorption by roadside greeneries. Carbon ab- sorption by different sizes of trees has been quantified using the amount of woody biomass. In addition, absorption by grass-shrubs-herbs has been quantified by the area they cover. The results thus obtained show that in- deed the road with more side greeneries absorbs more vehicular emitted carbon dioxide. It is therefore evident that plantation of more roadside trees is an effective measure of reducing air pollution and consequently turning a city to become healthier and more suitable for living.

Mavrogianni, A., et al. (2014). "The impact of occupancy patterns, occupant-controlled ventilation and shading on indoor overheating risk in domestic environments." Build Environ 78. It is widely recognised that a major source of uncertainty in building performance simulation relates to occupancy and behavioural assumptions. This paper aims to assess the relative impact of lifestyle patterns, occupant-controlled window opening and shading use on indoor overheating risk levels in dwellings. The indoor thermal environment of a set of broadly representative archetypes of the London housing stock was simulated using dynamic thermal modelling. Two lifestyle patterns and four scenarios of window opening and shading use schedules were combined with multiple other varying parameters (building geometry and orientation, insulation levels, level of overshadowing by adjacent buildings), leading to a total of 27,648 modelled dwelling variants. It was found that the rankings obtained for dwellings occupied by a family with children at school and dwellings occupied by pensioners were broadly similar for all combinations of behaviour and the majority of overheating metrics. Lower ranking correlations were, however, observed between simple temperature-dependent window opening scenarios and a more sophisticated scenario of combined shading and night ventilation. This is an indication that shading and/or night cooling could modify indoor overheating risk significantly. The findings of the study add to a growing body of literature suggesting that the way inhabitants occupy and operate a building has a measurable impact on thermal discomfort and potentially the health risks associated with their exposure to high indoor temperatures. This should be taken into consideration in the design of retrofit interventions and public health strategies aiming to minimise such risks.

Madre, F., et al. (2014). "Green roofs as habitats for wild plant species in urban landscapes: First insights from a large-scale sampling." Landscape and Urban Planning 122: 100-107. The urban landscape is known to form a hostile matrix for wild plant communities because of its sealed infrastructure surfaces. However, green roofs can reduce this hostility by providing new spaces for wildlife directly on buildings. In this extensive study of 115 green roofs in northern France, we focused on wild plant communities and the variables that shaped their diversity and their taxonomic and functional compositions. A total of 176 colonizing vascular plant species were identified; 86% were natives, demonstrating that green roofs can serve as habitats for wild biodiversity despite their isolation in an urban landscape in three dimensions. Nonetheless, all types of green roofs were not equal, with the substrate depth playing a major role in the wild plant diversity. The taxonomic and functional compositions of the colonizing plant communities were also shaped by the substrate depth, green roof age, surface area, and height and maintenance intensity at the building scale. We did not detect any effect of the surrounding potential habitats at the landscape scale. The study of functional traits revealed that the wild plant communities are adapted to open xero-thermophilous conditions. This study led us to consider an ecological typology for green roofs referred to as stratum classification, which is based on the vegetal structures living and colonizing these anthropo- ecosystems. Wild roofs adapted to receive spontaneous species could play an interesting role in urban biodiversity dynamics if they continue to be developed at large scales in cities.

Li, Y. and R. W. Babcock (2014). "Green roofs against pollution and climate change. A review." Agronomy for Sustainable Development 34(4): 695-705. Green roofs recover green spaces in urban areas and benefit the public, farmers, and wildlife by providing many environmental, ecological, and economic advantages. Green roofs reduce stormwater runoff, mitigate urban heat island effects, absorb dust and smog, sequester carbon dioxide, produce oxygen, create space for food production, and provide natural habitat for animals and plants. Here, we studied the environmental impact of green roofs in terms of runoff quality and greenhouse gas CO2 sequestration. We screened more than 650 scientific papers and we reviewed detailed findings from 52 publications. There are two major points: (1) Concerning pollution, the concentrations of minor pollutants, such as heavy metals, biochemical oxygen demand (BOD), total suspended solids (TSS), and turbidity, are small and thus do not pose an immediate threat to the environment. However, the concentrations of major pollutants, such as nitrogen of 0.49–9.01 mg/l and phosphorus of 0.04–25 mg/l, vary highly for different green roofs and can adversely affect runoff quality. Nutrient leaching may be controllable through proper mitigation measures including better design and system management which require further research. According to both laboratory experiments and field monitoring data, the main factors affecting runoff quality are precipitation properties, growth media composition and depth, plant species, and maintenance protocols. Research gaps exist in quantifying how these factors affect leachate pollutant load. Systematic studies are needed for improving green roof designs to reduce adverse impacts. (2) Concerning CO2 sequestration, studies reveal that green roofs directly sequester substantial amounts of carbon in plants and soils through photosynthesis. Green roofs reduce ambient CO2 concentrations in the vicinities. Green roofs also indirectly reduce CO2 releases from power plants and furnaces by reducing demand for heating and cooling, suggesting long-term economic and environmental benefits of green roofs.

Lennon, M., et al. (2014). "Urban Design and Adapting to Flood Risk: The Role of Green Infrastructure." Journal of Urban Design 19(5): 745-758. This Practice Paper identifies and critically examines three alternative approaches and associated design philosophies in response to the problem of urban flooding. It traces the reasons why these three approaches have emerged and discusses the attributes of each. Following this, it examines the potential of the green infrastructure approach as a means to realize evolutionary resilience? in designing urban environments for enhanced drainage management. The paper then contrasts the three alternative approaches to flood risk management and identifies some implications of advancing the green infrastructure concept in urban design activities.

Jin, S. J., et al. (2014). "Evaluation of impacts of trees on PM2.5 dispersion in urban streets." Atmos Environ 99. Reducing airborne particulate matter (PM), especially PM2.5 (PM with aerodynamic diameters of 2.5 mm or less), in urban street canyons is critical to the health of central city population. Tree-planting in urban street canyons is a double-edged sword, providing landscape benefits while inevitably resulting in PM2.5 concentrating at street level, thus showing negative environmental effects. Thereby, it is necessary to quantify the impact of trees on PM2.5 dispersion and obtain the optimum structure of street trees for minimizing the PM2.5 concentration in street canyons. However, most of the previous findings in this field were derived from wind tunnel or numerical simulation rather than on-site measuring data. In this study, a seasonal investigation was performed in six typical street canyons in the residential area of central Shanghai, which has been suffering from haze pollution while having large numbers of green streets. We monitored and measured PM2.5 concentrations at five heights, structural parameters of street trees and weather. For tree-free street canyons, declining PM2.5 concentrations were found with increasing height. However, in presence of trees the reduction rate of PM2.5 concentrations was less pronounced, and for some cases, the concentrations even increased at the top of street canyons, indi- cating tree canopies are trapping PM2.5. To quantify the decrease of PM2.5 reduction rate, we developed the attenuation coefficient of PM2.5 (PMAC). The wind speed was significantly lower in street canyons with trees than in tree-free ones. A mixed-effects model indicated that canopy density (CD), leaf area index (LAI), rate of change of wind speed were the most significant predictors influencing PMAC. Further regression analysis showed that in order to balance both environmental and landscape benefits of green streets, the optimum range of CD and LAI was 50%e60% and 1.5e2.0 respectively. We concluded by suggesting an optimized tree-planting pattern and discussing strategies for a better green streets planning and pruning.

Hykš, O. and K. Neubergová (2014). "Mature Vegetation along Roads." Transactions on Transport Sciences: 117. The article deals with the issue of vegetation, particularly mature vegetation, along transport routes. Since rather heated discussions on this topic have recently appeared, particularly in relation to road safety, the authors of this article decided to present this issue in wider context and from various viewpoints. The starting point for this issue is mentioned in the introduction. The next part deals with the history of planting tree alleys in the Czech Republic. Subsequently, a brief summary of advantages and drawbacks of mature vegetation along transport routes is presented. The next part of the article discusses the environmental bases and, last but not least, the article deals with the impact of mature vegetation on road safety.

Hilde, T. and R. Paterson (2014). "Integrating ecosystem services analysis into scenario planning practice: Accounting for street tree benefits with i-Tree valuation in Central Texas." Journal of Environmental Management 146: 524-534. Scenario planning continues to gain momentum in the United States as an effective process for building consensus on long-range community plans and creating regional visions for the future. However, efforts to integrate more sophisticated information into the analytical framework to help identify important ecosystem services have lagged in practice. This is problematic because understanding the tradeoffs of land consumption patterns on ecological integrity is central to mitigating the environmental degradation caused by land use change and new development. In this paper we describe how an ecosystem services valuation model, i-Tree, was integrated into a mainstream scenario planning software tool, Envision Tomorrow, to assess the benefits of public street trees for alternative future development scenarios. The tool is then applied to development scenarios from the City of Hutto, TX, a Central Texas Sustainable Places Project demonstration community. The integrated tool represents a methodological improvement for scenario planning practice, offers a way to incorporate ecosystem services analysis into mainstream planning processes, and serves as an example of how open source software tools can expand the range of issues available for community and regional planning consideration, even in cases where community resources are limited. The tool also offers room for future improvements; feasible options include canopy analysis of various future land use typologies, as well as a generalized street tree model for broader U.S. application.

Haase, D., et al. (2014). "A Quantitative Review of Urban Ecosystem Service Assessments: Concepts, Models, and Implementation." AMBIO 43(4): 413-433. Although a number of comprehensive reviews have examined global ecosystem services (ES), few have focused on studies that assess urban ecosystem services (UES). Given that more than half of the world’s population lives in cities, understanding the dualism of the provision of and need for UES is of critical importance. Which UES are the focus of research, and what types of urban land use are examined? Are models or decision support systems used to assess the provision of UES? Are trade-offs considered? Do studies of UES engage stakeholders? To address these questions, we analyzed 217 papers derived from an ISI Web of Knowledge search using a set of standardized criteria. The results indicate that most UES studies have been undertaken in Europe, North America, and China, at city scale. Assessment methods involve bio- physical models, Geographical Information Systems, and valuation, but few study findings have been implemented as land use policy.

Feyisa, G. L., et al. (2014). "Efficiency of parks in mitigating urban heat island effect: An example from Addis Ababa." Landscape and Urban Planning 123: 87-95. Urban green infrastructure can to a certain extent mitigate urban warming. However, the cooling effect of plants varies with space, time and plant-specific properties. To contribute to our understanding of the cooling effect of vegetation on urban surface and air temperature, 21 parks in Addis Ababa were studied. Air temperature and humidity were measured for 60 plots in nine of the parks for 15 days. Furthermore, the thermal band of Landsat ETM+ was used to examine the cooling impact of all 21 parks on a larger spatial scale. Linear mixed-effects models were used to examine the relationship between characteristics of the vegetation and observed temperature. It emerged that Eucalyptus sp. had a significantly higher cooling effect than any other species group (P < 0.05) and the species with the least effect on temperature were Grevillea and Cupressus. On a larger spatial scale, the cooling effect of parks on their surroundings (Park Cooling Intensity, PCI) was positively related to the NDVI and area of parks (P < 0.01). A negative relationship was observed between PCI and park shape index (SI). The range within which the cooling effect could be observed (Park Cooling Distance, PCD) was positively related to SI and park area. The maximum PCI was 6.72 °C and the maximum PCD was estimated at 240 m. We conclude that the cooling effect is mainly determined by species group, canopy cover, size and shape of parks. Thus, the study provides insights regarding the importance of species choice and spatial design of green spaces in cooling the environment.

Ferrini, F., et al. (2014). "Trees in the urban environment: Response mechanisms and benefits for the ecosystem should guide plant selection for future plantings." Agrochimica 58. It is well known that, at present, more than a half of the world population live in the built-up areas (in Europe almost 80%) and the urbanization trend will continue as the population increases and more people will live in large cities. In this scenario arboriculture and urban forestry should have a main role in the effort to manage urbanization and to create livable cities and it is certain that all green areas, starting from the single tree specimens to periurban forests which, in some way, recall the "concept of nature", can fulfil a paramount function in improving life quality and in reaching the minimal threshold for human well-being. What is going to happen next - over 10-15 years - will obviously be of the greatest interest to all people concerned with urban environment. This latter poses some constraints to tree growth and survival: drought, poor soil quality and compaction, pollutants, salinity, pathogens, light heterogeneity, and conflicts with human activities often cause premature plant death or limit plant growth, thus reducing the net benefit by urban green areas. It is therefore important to better understand the dynamics leading to tree decline in the urban environment, and to develop strategies and techniques aimed at improving the horticultural tolerance (i.e. the capacity to provide benefits, not only to survive, under stressful conditions) of urban trees. These include nursery pre-conditioning techniques and post-planting management techniques, but a key role is played by species selection. Hundreds of species are used in the urban environment, but selection criteria are frequently based upon aesthetics and whether the species are native or not, rather than on the tolerance to typical stresses imposed by the built environment and on the capacity to provide substantial benefits therein.

Edmondson, J. L., et al. (2014). "Urban tree effects on soil organic carbon." PLoS ONE 9(7): e101872. Urban trees sequester carbon into biomass and provide many ecosystem service benefits aboveground leading to worldwide tree planting schemes. Since soils hold ,75% of ecosystem organic carbon, understanding the effect of urban trees on soil organic carbon (SOC) and soil properties that underpin belowground ecosystem services is vital. We use an observational study to investigate effects of three important tree genera and mixed-species woodlands on soil properties (to 1 m depth) compared to adjacent urban grasslands. Aboveground biomass and belowground ecosystem service provision by urban trees are found not to be directly coupled. Indeed, SOC enhancement relative to urban grasslands is genus-specific being highest under Fraxinus excelsior and Acer spp., but similar to grasslands under Quercus robur and mixed woodland. Tree cover type does not influence soil bulk density or C:N ratio, properties which indicate the ability of soils to provide regulating ecosystem services such as nutrient cycling and flood mitigation. The trends observed in this study suggest that genus selection is important to maximise long-term SOC storage under urban trees, but emerging threats from genus-specific pathogens must also be considered.

Dobbs, C., et al. (2014). "Multiple ecosystem services and disservices of the urban forest establishing their connections with landscape structure and sociodemographics." Ecological Indicators 43: 44-55. The promotion of sustainable cities is critical under future environmental change and population growth. Cities in the present and future can ensure the provision of ecosystem services to their urban inhabitants. The urban forest is one of the main suppliers of ecosystem services in urban areas, and can provide the base information to quantify ecosystem services and disservices, detecting the areas were low provision of those occur. In this study multiple ecosystem services and disservices were quantified using transferable indicators in order to detect areas for environmental improvement. The set of spatially explicit indicators enables the detection of areas of low and high provision of ecosystem services. The analysis showed synergies existing among regulating, provisioning and supporting services, while trade-offs were found with cultural services and regulating, provisioning and supporting services. Ecosystem services provision was positively related to the amount of vegetation and negatively related to its degree of fragmentation. A high provision of ecosystem services was found in less populated areas, with more educated and affluent people, highlighting the strong relations existing between social vulnerabilities and areas of low provision of services. Results from this research provide insights on the role of policy makers on better distributed supply of ecosystem services and on how the landscape structure can be modified to plan for sustainable cities.

Demuzere, M., et al. (2014). "Mitigating and adapting to climate change: Multi-functional and multi-scale assessment of green urban infrastructure." Journal of Environmental Management 146: 107-115. In order to develop climate resilient urban areas and reduce emissions, several opportunities exist starting from conscious planning and design of green (and blue) spaces in these landscapes. Green urban infrastructure has been regarded as beneficial, e.g. by balancing water flows, providing thermal comfort. This article explores the existing evidence on the contribution of green spaces to climate change mitigation and adaptation services. We suggest a framework of ecosystem services for systematizing the evidence on the provision of bio-physical benefits (e.g. CO2 sequestration) as well as social and psychological benefits (e.g. improved health) that enable coping with (adaptation) or reducing the adverse effects (mitigation) of climate change. The multi-functional and multi-scale nature of green urban infrastructure complicates the categorization of services and benefits, since in reality the interactions between various benefits are manifold and appear on different scales. We will show the relevance of the benefits from green urban infrastructures on three spatial scales (i.e. city, neighborhood and site specific scales). We will further report on co-benefits and trade-offs between the various services indicating that a benefit could in turn be detrimental in relation to other functions. The manuscript identifies avenues for further research on the role of green urban infrastructure, in different types of cities, climates and social contexts. Our systematic understanding of the bio- physical and social processes defining various services allows targeting stressors that may hamper the provision of green urban infrastructure services in individual behavior as well as in wider planning and environmental management in urban areas.

Dela Cruz, M., et al. (2014). "Can ornamental potted plants remove volatile organic compounds from indoor air? A review." Environ Sci Pollut Res Int 21(24): 13909-13928. Volatile organic compounds (VOCs) are found in indoor air, and many of these can affect human health (e.g. formaldehyde and benzene are carcinogenic). Plants affect the levels of VOCs in indoor environments, thus they represent a potential green solution for improving indoor air quality that at the same time can improve human health. This article reviews scientific studies of plants' ability to remove VOCs from indoor air. The focus of the review is on pathways of VOC removal by the plants and factors affecting the efficiency and rate of VOC removal by plants. Laboratory based studies indicate that plant induced removal of VOCs is a combination of direct (e.g. absorption) and indirect (e.g. biotransformation by microorganisms) mechanisms. They also demonstrate that plants' rate of reducing the level of VOCs is influenced by a number of factors such as plant species, light intensity and VOC concentration. For instance, an increase in light intensity has in some studies been shown to lead to an increase in removal of a pollutant. Studies conducted in real-life settings such as offices and homes are few and show mixed results.

Curtis, A. J., et al. (2014). "Biogenic volatile organic compound emissions from nine tree species used in an urban tree-planting program." Atmos Environ 95. The biogenic volatile organic compound (BVOC) emissions of nine urban tree species were studied to assess the air quality impacts from planting a large quantity of these trees in the City and County of Denver, Colorado, through the Mile High Million tree-planting initiative. The deciduous tree species studied were Sugar maple, Ohio buckeye, northern hackberry, Turkish hazelnut, London planetree, American basswood, Littleleaf linden, Valley Forge elm, and Japanese zelkova. These tree species were selected using the i-Tree Species Selector (itreetools.org). BVOC emissions from the selected tree species were investigated to evaluate the Species Selector data under the Colorado climate and environmental growing conditions. Individual tree species were subjected to branch enclosure experiments in which foliar emissions of BVOC were collected onto solid adsorbent cartridges. The cartridge samples were analyzed for monoterpenes (MT), sesquiterpenes (SQT), and other C10–C15 BVOC using thermal desorption-gas chromatography–flame ionization detection/mass spectroscopy (GC–FID/MS). Individual compounds and their emission rates (ER) were identified. MT were observed in all tree species, exhibiting the following total MT basal emission rates (BER; with a 1−σ lower bound, upper bound uncertainty window): Sugar maple, 0.07 (0.02, 0.11) μg g−1 h−1; London planetree, 0.15 (0.02, 0.27) μg g−1 h−1; northern hackberry, 0.33 (0.09, 0.57) μg g−1 h−1; Japanese zelkova, 0.42 (0.26, 0.58) μg g−1 h−1; Littleleaf linden, 0.71 (0.33, 1.09) μg g−1 h−1; Valley Forge elm, 0.96 (0.01, 1.92) μg g−1 h−1; Turkish hazelnut, 1.30 (0.32, 2.23) μg g−1 h−1; American basswood, 1.50 (0.40, 2.70) μg g−1 h−1; and Ohio buckeye, 6.61 (1.76, 11.47) μg g−1 h−1. SQT emissions were seen in five tree species with total SQT BER of: London planetree, 0.11 (0.01, 0.20) μg g−1 h−1; Japanese zelkova, 0.11 (0.05, 0.16) μg g−1 h−1; Littleleaf linden, 0.13 (0.06, 0.21) μg g−1 h−1; northern hackberry, 0.20 (0.11, 0.30) μg g−1 h−1; and Ohio buckeye, 0.44 (0.06, 0.83) μg g−1 h−1. The following trees exhibited emissions of other C10– C15 volatile organic compounds (VOC): Littleleaf linden, 0.15 (0.10, 0.20) μg g−1 h−1; Ohio buckeye, 0.39 (0.14, 0.65) μg g−1 h−1; and Turkish hazelnut, 0.72 (0.49, 0.95) μg g−1 h−1. All tree species studied in this experiment were confirmed to be low isoprene emitters. Compared to many other potential urban tree species, the selected trees can be considered low to moderate BVOC emitters under Colorado growing conditions, with total emission rates one-tenth to one- hundredth the rates of potential high-BVOC emitting trees. The emissions data were used to estimate the impact of this targeted tree planting on the urban BVOC flux and atmospheric VOC burden. Selecting the low-emitting tree species over known high BVOC emitters is equivalent to avoiding VOC emissions from nearly 500,000 cars from the inner city traffic.

Cuinica, L. G., et al. (2014). "Effect of air pollutant NO2 on Betula pendula, Ostrya carpinifolia and Carpinus betulus pollen fertility and human allergenicity." Environ Pollut 186. Pollen of Betula pendula, Ostrya carpinifolia and Carpinus betulus was exposed in vitro to two levels of NO2 (about 0.034 and 0.067 ppm) – both below current atmospheric hour-limit value acceptable for human health protection in Europe (0.11 ppm for NO2). Experiments were performed under artificial solar light with temperature and relative humidity continuously monitored. The viability, germination and total soluble proteins of all the pollen samples exposed to NO2 decreased significantly when compared with the non-exposed. The polypeptide profiles of all the pollen samples showed bands between 15 and 70 kDa and the exposure to NO2 did not produce any detectable changes in these profiles. However, the immunodetection assays indicated higher IgE recognition by patient sera sensitized to the pollen extracts from all exposed samples in comparison to the non-exposed samples. The common reactive bands to the three pollen samples correspond to 58 and 17 kDa proteins.

Copeland, C. (2014). "Green Infrastructure and issues in managing urban stormwater." Congressional Research Service, Washington, DC. For decades, stormwater, or runoff, was considered largely a problem of excess rainwater or snowmelt impacting communities. Prevailing engineering practices were to move stormwater away from cities as rapidly as possible to avoid potential damages from flooding. More recently, these practices have evolved and come to recognize stormwater as a resource that, managed properly within communities, has multiple benefits. Stormwater problems occur because rainwater that once soaked into the ground now runs off hard surfaces like rooftops, parking lots, and streets in excessive amounts. This runoff flows into storm drains and ultimately into lakes and streams, carrying pollutants that are harmful to aquatic life and public health. Traditional approaches to managing urban stormwater have utilized so-called “gray infrastructure,” including pipes, gutters, ditches, and storm sewers. More recently, interest has grown in “green infrastructure” technologies and practices in place of or in combination with gray infrastructure. Green infrastructure systems use or mimic natural processes to infiltrate, evapotranspire, or reuse stormwater runoff on the site where it is generated. These practices keep rainwater out of the sewer system, thus preventing sewer overflows and also reducing the amount of untreated runoff discharged to surface waters. Cities’ adoption of green technologies and practices has increased, motivated by several factors. One motivation is environmental and resource benefits. Advocates, including environmental groups, landscape architects, and urban planners, have drawn attention to these practices. But an equally important motivation, perhaps larger than environmental benefits, is cost-saving opportunities for cities that face enormous costs of stormwater infrastructure projects to meet requirements of the Clean Water Act. Other potential benefits include reduced flood damages, improved air quality, and improved urban aesthetics. At the same time, barriers to implementing green infrastructure include lack of information on performance and cost- effectiveness and uncertainty whether the practices will contribute to achieving water quality improvements. Another key barrier is lack of funding. At the federal level, there is no single source of dedicated federal funding to design and implement green infrastructure solutions. Without assistance, communities take several approaches to financing wastewater and stormwater projects; the most frequently used tool is issuance of municipal bonds. As a dedicated funding source for projects, the number of local stormwater utilities that charge fees has grown in recent years. Many municipalities try to encourage homeowners and developers to incorporate green infrastructure practices by offering incentives. The most common types of local incentive mechanisms are stormwater fee discounts or credits, development incentives, rebates or financing for installation of specific practices, and award and recognition programs. The Environmental Protection Agency’s (EPA’s) interest in and support for green infrastructure has grown since the 1990s. The agency has provided technical assistance and information and developed policies to facilitate and encourage green infrastructure solutions and incorporation in Clean Water Act permits. Pressed by municipalities about the challenges and costs that they face in addressing needs for wastewater and stormwater projects, in 2012 EPA issued an integrated permitting and planning framework for water infrastructure projects. The intention of the framework document is to provide communities with flexibility to prioritize needed water infrastructure investments. One component of the framework is identifying green infrastructure opportunities. EPA also is working with communities to refine how the agency determines when an infrastructure project is affordable for individual communities.

Cohen, P., et al. (2014). "The impact of an urban park on air pollution and noise levels in the Mediterranean city of Tel-Aviv, Israel." Environmental Pollution 195: 73-83. This study examines the influence of urban parks on air quality and noise in the city of Tel-Aviv, Israel, by investigation of an urban park, an urban square and a street canyon. Simultaneous monitoring of several air pollutants and noise levels were conducted. The results showed that urban parks can reduce NOx, CO and PM10 and increase O3 concentrations and that park's mitigation effect is greater at higher NOx and PM10 levels. During extreme events, mean values of 413ppb NOx and 80 μG/m3 PM10 were measured in the street while mean values of 89ppb NOx and 24 μG/m3 PM10 were measured in the park. Whereas summer highest O3 values of 84ppb were measured in the street, 94ppb were measured in the park. The benefit of the urban park in reducing NOx and PM10 concentrations is more significant than the disadvantage of increased O3 levels. Furthermore, urban parks can reduce noise by ∼5 dB(A).

Clapp, J. C., et al. (2014). "Rationale for the increased use of conifers as functional green infrastructure: A literature review and synthesis." Arboricultural Journal 36(3): 161-178. Green infrastructure is the aggregate of plants and green spaces in the urban landscape. This infrastructure provides many benefits that are becoming increasingly valuable as municipalities strive for urban sustainability. The value of the urban forest is an integral part of securing funding and support for urban forestry initiatives: the higher the value the more support is gained, and benefits accrued. According to available data from street tree inventories, most species that make up street trees in urban forests in the United States and Canada are broadleaf, deciduous species. Since many urban tree benefits are attributed to the tree canopies, benefits effectively drop to negligible levels during the leaf-off period. When a rain event occurs during this season, the canopy cover afforded by evergreen tree species, in concert with the canopy architecture and density of evergreen conifers will help to maintain canopy-dependent benefits. This paper investigates the role that conifers play in increasing the canopy-dependent ecosystem services of an urban forest and the unique role they play in increasing the stability of the urban forest through diversification.

Chong, K. Y., et al. (2014). "Not all green is as good: Different effects of the natural and cultivated components of urban vegetation on bird and butterfly diversity." Biological Conservation 171: 299-309. It has been suggested that provision of greenery can ameliorate the hostility of the urban environment for wildlife, but greenery can either be in the form of regenerating or remnant patches of natural vegetation, or as cultivated tree, shrub, and ground cover. We test if natural and cultivated greenery differed in their effects on bird and butterfly diversity in the tropical city- state of Singapore, while accounting for the effects of traffic density. Natural vegetation cover was positively correlated to both bird and butterfly species richness. Cultivated tree cover was positively correlated to bird species richness. Meanwhile, ground cover was weakly negatively correlated to bird species richness and overall cultivated greenery cover was weakly positively correlated to butterfly species richness. Increasing road lane density also negatively impacted both bird and butterfly species richness, while there was substantial evidence for an interaction effect between road lane density and cultivated tree cover on bird species richness. Cultivated and natural forms of greenery favoured different assemblages of bird and butterfly species. After controlling for the confounding effects of alpha diversity on community dissimilarity, cultivated greenery was found to produce homogeneous bird and butterfly communities in the urban landscape. Therefore, not all forms of greenery benefit urban biodiversity to the same extent. Management of urban areas to support bird and butterfly wildlife would need to maximise natural or semi-natural cover and only resort to highly-manicured, artificial greenery as a second option, while planning road networks carefully to optimize road lane density.

Brantley, H. L., et al. (2014). "Field assessment of the effects of roadside vegetation on near-road black carbon and particulate matter." Sci Total Environ 468. One proposed method for reducing exposure to mobile source air pollution is the construction or preservation of vegetation barriers between major roads and nearby populations. This study combined stationary and mobile monitoring approaches to determine the effects of an existing, mixed-species tree stand on near-road black carbon (BC) and particulate matter concentrations. Results indicated that wind direction and time of day significantly affected pollutant concentrations behind the tree stand. Continuous sampling revealed reductions in BC behind the barrier, relative to a clearing, during downwind (12.4% lower) and parallel (7.8% lower) wind conditions, with maximum reductions of 22% during the late afternoon when winds were from the road. Particle counts in the fine and coarse particle size range (0.5–10 μm aerodynamic diameter) did not show change. Mobile sampling revealed BC concentration attenuation, a result of the natural dilution and mixing that occur with transport from the road, was more gradual behind the vegetation barrier than in unobstructed areas. These findings suggest that a mature tree stand can modestly improve traffic-related air pollution in areas located adjacent to the road; however, the configuration of the tree stand can influence the likelihood and extent of pollutant reductions.

Berland, A. and M. E. Hopton (2014). "Comparing street tree assemblages and associated stormwater benefits among communities in metropolitan Cincinnati, Ohio, USA." Urban Forestry & Urban Greening 13(4): 734-741. Green infrastructure approaches leverage vegetation and soil to improve environmental quality. Municipal street trees are crucial components of urban green infrastructure because they provide stormwater interception benefits and other ecosystem services. Thus, it is important to understand the patterns and drivers of structural heterogeneity in urban street tree assemblages. In this study, we compared the forest structure of street trees across nine communities along both geographic and demographic gradients in metropolitan Cincinnati, Ohio, USA. Specifically, we used a two-part statistical model to compare both the proportion of sampled street segments containing zero trees, and basal area magnitude for street segments with trees. We made community-scale comparisons based on street tree management, socioeconomics, and geographic setting. Then, using modeled stormwater interception estimates from i-Tree Streets, we investigated the implications of heterogeneity in street tree assemblages for stormwater interception benefits. The forest structure of street trees varied across communities in relation to management practices, namely participation in the Tree City USA program. As a consequence of this structural difference, we observed a stark discrepancy in estimated stormwater interception between Tree City USA participants (128.7 m3/km street length) and non-participants (59.2 m3/km street length). While street tree assemblages did not vary by community poverty status, we did find differences according to community racial composition. In contrast to previous research, basal area was greater in predominantly black (i.e., African American) and racially mixed communities than in predominantly white communities. We did not observe structural differences across geographic strata. This research underscores the importance of proactive management practices for increasing the forest structure of street trees. Our findings regarding socioeconomics and geographic setting contrast previous studies, suggesting the need for continued research into the drivers of structural heterogeneity in street tree assemblages.

Berardi, U., et al. (2014). "State-of-the-art analysis of the environmental benefits of green roofs." Applied Energy 115: 411-428. Green roofs have been proposed for sustainable buildings in many countries with different climatic conditions. A state-of-the-art review of green roofs emphasizing current implementations, technologies, and benefits is presented in this paper. Technical and construction aspects of green roofs are used to classify different systems. Environmental benefits are then discussed mainly by examining measured performances. By reviewing the benefits related to the reduction of building energy consumption, mitigation of urban heat island effect, improvement of air pollution, water management, increase of sound insulation, and ecological preservation, this paper shows how green roofs may contribute to more sustainable buildings and cities. However, an efficient integration of green roofs needs to take into account both the specific climatic conditions and the characteristics of the buildings. Economic considerations related to the life-cycle cost of green roofs are presented together with policies promoting green roofs worldwide. Findings indicate the undeniable environmental benefits of green roofs and their economic feasibility. Likewise, new policies for promoting green roofs show the necessity for incentivizing programs. Future research lines are recommended and the necessity of cross- disciplinary studies is stressed.

Baró, F., et al. (2014). "Contribution of Ecosystem Services to Air Quality and Climate Change Mitigation Policies: The Case of Urban Forests in Barcelona, Spain." AMBIO 43(4): 466-479. Mounting research highlights the contribution of ecosystem services provided by urban forests to quality of life in cities, yet these services are rarely explicitly considered in environmental policy targets. We quantify regulating services provided by urban forests and evaluate their contribution to comply with policy targets of air quality and climate change mitigation in the municipality of Barcelona, Spain. We apply the i-Tree Eco model to quantify in biophysical and monetary terms the ecosystem services “air purification,” “global climate regulation,” and the ecosystem disservice “air pollution” associated with biogenic emissions. Our results show that the contribution of urban forests regulating services to abate pollution is substantial in absolute terms, yet modest when compared to overall city levels of air pollution and GHG emissions. We conclude that in order to be effective, green infrastructure-based efforts to offset urban pollution at the municipal level have to be coordinated with territorial policies at broader spatial scales.

Baldauf, R. and D. Nowak (2014). Vegetation and Other Development Options for Mitigating Urban Air Pollution Impacts. Global Environmental Change. B. Freedman. Dordrecht, Springer Netherlands: 479-485. Emission control techniques and programs that reduce air pollution are an important component of air quality management strategies; however, options that directly remove pollution or reduce exposures also exist that can further mitigate the impacts of air pollution in urban areas. These methods can complement existing pollution control programs or provide measures to minimize impacts from sources difficult to mitigate. Since air pollution control techniques, emission standards, and urban planning strategies to reduce urban air pollution impacts are discussed in other sections of this handbook, this section focuses on options that developers, transportation designers, and urban planners can implement to reduce concentra- tions and population exposures to harmful air contaminants.

Andersson, E., et al. (2014). "Reconnecting Cities to the Biosphere: Stewardship of Green Infrastructure and Urban Ecosystem Services." AMBIO 43(4): 445-453. Within-city green infrastructure can offer opportunities and new contexts for people to become stewards of ecosystem services. We analyze cities as social–ecological systems, synthesize the literature, and provide examples from more than 15 years of research in the Stockholm urban region, Sweden. The social–ecological approach spans from investigating ecosystem properties to the social frameworks and personal values that drive and shape human interactions with nature. Key findings demonstrate that urban ecosystem services are generated by social–ecological systems and that local stewards are critically important. However, land-use planning and management seldom account for their role in the generation of urban ecosystem services. While the small scale patchwork of land uses in cities stimulates intense interactions across borders much focus is still on individual patches. The results highlight the importance and complexity of stewardship of urban biodiversity and ecosystem services and of the planning and governance of urban green infrastructure.

Zhang, H., et al. (2013). "Isolation and Identification of Toluene-Metabolizing Bacteria from Rhizospheres of Two Indoor Plants." Water, Air, & Soil Pollution 224(9). The role of the rhizosphere microbial commu- nity in removing volatile organic compounds has not been well investigated. In this study, two species of indoor foliage plants, Fittonia verschaffeltii var. argyroneura and Hoya carnosa, were primed with toluene exposure for 2 months, followed by isolation and identification of the rhizosphere bacteria that were demonstrated to metab- olize toluene. A total of 42 bacterial isolates were obtained. The number of bacterial isolates was narrowed down to 23, which had banding pattern similarities of 80 % or less, using BOX-polymerase chain reaction (PCR) fingerprint- ing technique. The 23 isolates were further characterized by sequencing part of their 16S rDNA after PCR. Their identities were examined using Basic Local Alignment Search Tool (BLAST), resulting in the isolates having the highest sequence similarities (97–100 %) to eight known bacteria strains, none of which had been previously report- ed to be capable of degrading toluene. The bacterial iso- lates were positive for toluene monooxygenase gene, confirming their genetic potential to metabolize toluene. Five of the isolates were further tested with 14C-labeled toluene to directly show their ability to metabolize toluene. Isolate type did not significantly affect the percent of toluene mineralized over 2 weeks' time. However, the iso- lates had differing response to varying toluene concentra- tions. Under low (0.05) and high (0.2 μCi/mL) concentra- tions, they mineralized 43 and 49 % of toluene, respec- tively. The isolation and characterization of toluene- metabolizing bacteria corroborates previous speculation that the rhizosphere microbial community contributes to the phytoremediation potential of indoor foliage plants.

Yang, B. and S. Li (2013). "Green infrastructure design for stormwater runoff and water quality: Empirical evidence from large watershed-scale community developments." Water 5(4): 2038-2057. Green infrastructure (GI) design is advocated as a new paradigm for stormwater management, whereas current knowledge of GI design is mostly based on isolated design strategies used at small-scale sites. This study presents empirical findings from two watershed- scale community projects (89.4 km2 and 55.7 km2) in suburban Houston, Texas. The GI development integrates a suite of on-site, infiltration-based stormwater management designs, and an adjacent community development follows conventional drainage design. Parcel data were used to estimate the site impervious cover area. Observed streamflow and water quality data (i.e., NO3-N, NH3-N, and TP) were correlated with the site imperviousness. Results show that, as of 2009, the impervious cover percentage in the GI site (32.3%) is more than twice that of the conventional site (13.7%). However, the GI site’s precipitation-streamflow ratio maintains a steady, low range, whereas this ratio fluctuates substantially in the conventional site, suggesting a “flashy” stream condition. Furthermore, in the conventional site, annual nutrient loadings are significantly correlated with its impervious cover percentage (p < 0.01), whereas in the GI site there is little correlation. The study concludes that integrated GI design can be effective in stormwater runoff reduction and water quality enhancement at watershed-scale community development.

Wen, M., et al. (2013). "Spatial Disparities in the Distribution of Parks and Green Spaces in the USA." Annals of Behavioral Medicine 45(1): 18-27. Background: Little national evidence is available on spatial disparities in distributions of parks and green spaces in the USA. Purpose: This study examines ecological associations of spatial access to parks and green spaces with percentages of black, Hispanic, and low-income residents across the urban–rural continuum in the conterminous USA. Methods: Census tract-level park and green space data were linked with data from the 2010 U.S. Census and 2006–2010 American Community Surveys. Linear mixed regression models were performed to examine these associations. Results: Poverty levels were negatively associated with distances to parks and percentages of green spaces in urban/suburban areas while positively associated in rural areas. Percentages of blacks and Hispanics were in general negatively linked to distances to parks and green space coverage along the urban–rural spectrum. Conclusions: Place-based race–ethnicity and poverty are important correlates of spatial access to parks and green spaces, but the associations vary across the urbanization levels.

Vos, P. E. J., et al. (2013). "Improving local air quality in cities: To tree or not to tree?" Environ Pollut 183. Vegetation is often quoted as an effective measure to mitigate urban air quality problems. In this work we demonstrate by the use of computer models that the air quality effect of urban vegetation is more complex than implied by such general assumptions. By modelling a variety of real-life examples we show that roadside urban vegetation rather leads to increased pollutant concentrations than it improves the air quality, at least locally. This can be explained by the fact that trees and other types of vegetation reduce the ventilation that is responsible for diluting the traffic emitted pollutants. This aerodynamic effect is shown to be much stronger than the pollutant removal capacity of vegetation. Although the modelling results may be subject to a certain level of uncertainty, our results strongly indicate that the use of urban vegetation for alleviating a local air pollution hotspot is not expected to be a viable solution.

Valderrama, A., et al. (2013). "Creating Clean Water Cash Flows Developing Private Markets for Green Stormwater Infrastructure in Philadelphia." Natural Resources Defense Council. Philadelphia, Pennsylvania. When rainwater rushes off Philadelphia’s buildings and other impervious structures, it strains the city’s combined sewer system, causing approximately 13 billion gallons of untreated sewage mixed with polluted runoff to over ow into city waterways each year. Philadelphia’s expansive stormwater runoff problem is no anomaly. It is one of nearly 800 communities nationwide that are required by the Clean Water Act to reduce raw sewage over ows from combined sewer systems, and thousands more have obligations to reduce pollution from separate storm sewer systems. Philadelphia is also one of many cities nationwide that is increasingly turning to green infrastructure solutions as a key part of the stormwater runoff solution. Green infrastructure includes installations such as rain gardens, swales, and green roofs, which capture runoff from impervious cover before it reaches overburdened sewer systems.

Vailshery, L. S., et al. (2013). "Effect of street trees on microclimate and air pollution in a tropical city." Urban Forestry Urban Greening 12. One of the fastest growing cities in India, Bangalore is facing challenges of urban microclimate change and increasing levels of air pollution. This paper assesses the impact of street trees in mitigating these issues. At twenty locations in the city, we compare segments of roads with and without trees, assessing the relationship of environmental differences with the presence or absence of street tree cover. Street segments with trees had on average lower temperature, humidity and pollution, with afternoon ambient air temperatures lower by as much as 5.6 °C, road surface temperatures lower by as much as 27.5 °C, and SO2 levels reduced by as much as 65%. Suspended Particulate Matter (SPM) levels were very high on exposed roads, with 50% of the roads showing levels approaching twice the permissible limits, while 80% of the street segments with trees had SPM levels within prescribed limits. In an era of exacerbated urbanization and climate change, tropical cities such as Bangalore will have to face some of the worst impacts including air pollution and microclimatic alterations. The information generated in this study can help appropriately assess the environmental benefits provided by urban trees, providing useful inputs for urban planners.

Terzaghi, E., et al. (2013). "Forest Filter Effect: Role of leaves in capturing/releasing air particulate matter and its associated PAHs." Atmospheric Environment 74: 378-384. Plants play a key role in removing particulate matter and their associated Semi-volatile Organic Compounds (SVOCs) from the atmosphere. Understanding the processes involved in particle capture by vegetation is essential to understand the interactions between SVOCs, particles and plants. In the present study Two Photon Excitation Microscopy (TPEM) was used to visualise particle matter uptake and encapsulation, together with its distribution on leaf/needle surface of different broadleaf (cornel and maple) and conifer species (stone pine). Phenanthrene accumulation, the number of particles associated with this compound and its migration from particles into the leaf cuticle was also identified and quantified. Species-specific deposition velocities were estimated to model temporal PM10 leaf/needle accumulation and to investigate the role of Planet Boundary Layer (PBL) height variation in influencing PM10 flux to plants. Particles at the leaf/needle surface were visualised to range in size from 0.2 to 70.4 μm, but cuticular encapsulation was negligible for particles larger than 10.6 μm, which were removed by a washing procedure. Phenanthrene concentration varied between ≈5 and ≈10 ng g−1 dw according to plant species and between ≈10 and ≈200 ng g−1 dw depending on needle age; this compound was visualized to migrate from particles into the adjacent leaf cuticle. Species- specific deposition velocity range between 0.57 and 1.28 m h−1 and preliminary simulations showed that the diel variability of PBL structure influenced the temporal PM10 flux and leaf/needle concentration, e.g. during daytime hours characterized by high PBL height, PM10 accumulated on cornel leaves was about 65% lower than the amount accumulated during night time. The capability of vegetation to capture particles from the atmosphere, retain, encapsulate them into the cuticle and release them to soil and/or lower biomass, highlighted the value of vegetation in removing pollutants from the atmosphere and influencing their environmental fate.

Strohbach, M. W., et al. (2013). "Are small greening areas enhancing bird diversity? Insights from community-driven greening projects in Boston." Landscape and Urban Planning 114: 69-79. Green space is an important component of the urban landscape, providing ecosystem services for city dwellers and supporting biodiversity. In many cities, green space is concentrated in large areas, while the rest is dispersed in small patches like pocket parks, gardens or street trees. Such small-scale green space is often the target of greening initiatives but little is known about their value for supporting and conserving biodiversity. To assess the value of such initiatives for biodiversity, we used birds as an indicator. We examined bird communities at small greening projects (n = 12), nearby randomly chosen urban sites (n = 12), and large parks (n = 6) in Boston, MA, in relationship to underlying landscape patterns. Our results show that large parks harbor a distinct and rich bird community. The other sites, regardless of the presence of greening projects, were very similar to each other. However, most sites with greening projects had higher species richness than the random urban site in their vicinity. The main factor associated with this appears to be the patch size of green space and to a lesser extent, tree cavities. Even small increases of a few hundred square meters were associated with an increase in bird richness. Having more trees with cavities was also beneficial for species richness. Small greening projects appear to be most valuable for urban biodiversity if they target preserving, increasing and connecting existing green space. This may represent a tradeoff with environmental justice criteria for new green space.

Soreanu, G., et al. (2013). "Botanical biofiltration of indoor gaseous pollutants – A mini- review." Chemical Engineering Journal 229: 585-594. In the last decade, indoor air pollution has been unanimously recognised as a public health hazard worldwide, both in developed and developing countries. Accumulation of indoor air pollutants appears to significantly contribute to “sick building syndrome” (SBS) and other reported diseases in affected spaces. Botanical biofiltration has received a great deal of attention in the past decade, likely due its economical, environmental and social benefits, including its potential in the near future to be incorporated in both traditional and the new trend of sustainable zero-emission green buildings. This paper focuses on the potential and challenges of using botanical biofiltration for reducing the impact of gaseous pollutants in indoor environments. It is aimed at reviewing the current state of the art and the future research needs.

Sinicina, N., et al. (2013). "Impact of microclimate and indoor plants on air ion concentration." Vide. Tehnologija. Resursi - Environment, Technology, Resources 1: 66-72. Saturation of air ions is essentially important for all living beings, especially for human health. Existing sanitary norms provide that concentration of small ions has to be in range of 400-50000 ions cm-3 and unipolarity coefficient 0.4 ≤ K ≤ 1.0. Many species of indoor plants emit organic volatile compounds and air ions, therefore they could be used for improving the quality of indoor air. The results show that ionization level of indoor air is significantly insufficient and selected species of indoor plants are not able to improve it. They serve rather as supplementary surfaces for ion absorption. Possible interaction between microclimate, ion concentration and indoor plants in different times of the day is analyzed.

Silvera Seamans, G. (2013). "Mainstreaming the environmental benefits of street trees." Urban Forestry & Urban Greening 12(1): 2-11. Over the course of the last three decades the role of the street tree in planning and policy arenas has transitioned from one primarily of beautification and ornamentation to one more inclusive of environmental services provision in numerous U.S. cities. This phenomenon was examined in the northern California cities of Palo Alto, Sacramento, and San Francisco. Analysis of policy documents, non-profit newsletters, field work, and interviews revealed that claims about the environmental values of street trees have been championed by municipal and non- profit actors and have been legitimized by the production and dissemination of urban forest science.

Schubert, S. and S. Grossman-Clarke (2013). "The influence of green areas and roof albedos on air temperatures during Extreme Heat Events in Berlin, Germany." Meteorologische Zeitschrift 22. The mesoscale atmospheric model COSMO-CLM (CCLM) with the Double Canyon Effect Parametrization Scheme (DCEP) is applied to investigate possible adaption measures to extreme heat events (EHEs) for the city of Berlin, Germany. The emphasis is on the effects of a modified urban vegetation cover and roof albedo on near-surface air temperatures. Five EHEs with a duration of 5 days or more are identified for the period 2000 to 2009. A reference simulation is carried out for each EHE with current vegetation cover, roof albedo and urban canopy parameters (UCPs), and is evaluated with temperature observations from weather stations in Berlin and its surroundings. The derivation of the UCPs from an impervious surface map and a 3-D building data set is detailed. Characteristics of the simulated urban heat island for each EHE are analysed in terms of these UCPs. In addition, six sensitivity runs are examined with a modified vegetation cover of each urban grid cell by –25%, 5% and 15%, with a roof albedo increased to 0.40 and 0.65, and with a combination of the largest vegetation cover and roof albedo, respectively. At the weather stations' grid cells, the results show a maximum of the average diurnal change in air temperature during each EHE of 0.82 K and –0.48 K for the –25% and 15% vegetation covers, –0.50 K for the roof albedos of 0.65, and –0.63 K for the combined vegetation and albedo case. The largest effects on the air temperature are detected during midday.

Sawka, M., et al. (2013). "Growing summer energy conservation through residential tree planting." Landscape and Urban Planning 113(0): 1-9. Energy conservation strategies are now at the forefront of electrical utility demand-side management planning. Residential shade trees extenuate the heating of buildings in the summertime by intercepting insolation and by evapotranspirative cooling of their immediate surroundings. By modifying location-specific climate data and tree growth characteristics, we adapt the Sacramento Municipal Utility District's (SMUD) Tree Benefits Estimator for application in Toronto, Canada. We then use our tool to model the air conditioning energy conservation savings delivered by 577 trees planted in Toronto backyards between 1997 and 2000. In urban residential neighbourhoods, where houses are closely spaced, the energy conservation benefits of planting a tree depend on species, on pre-existing canopy, and on placement of the tree with respect to distance and orientation from buildings. Study trees contributed 77,140 kWh (167 kWh/tree) of electricity savings as of 2009, 54.4% of which was due to shading of neighbouring houses. Twenty-five years following planting, we estimate that each study tree will have delivered, on average, between 435 and 483 kWh in energy conservation benefit. Our findings indicate that residential tree-planting programmes in densely settled urban areas should not focus exclusively on location-driven strategic planting to yield large energy conservation benefits. Instead, we argue that priority should be given to selecting planting locations that will maximize tree survival as neighbourhood energy conservation benefits of a tree that achieves mature stature often outweigh the homeowner-specific benefits of a strategically planted tree.

Salmond JA, W. D., Laing G, Kingham S, Dirks KN, Longley I, et al. (2013). The influence of vegetation on the horizontal and vertical distribution of pollutants in a street canyon. Space constraints in cities mean that there are only limited opportunities for increasing tree density within existing urban fabric and it is unclear whether the net effect of increased vegetation in street canyons is beneficial or detrimental to urban air quality at local scales. This paper presents data from a field study undertaken in Auckland, New Zealand designed to determine the local impact of a deciduous tree canopy on the distribution of the oxides of nitrogen within a street canyon. The results showed that the presence of leaves on the trees had a marked impact on the transport of pollutants and led to a net accumulation of pollutants in the canyon below the tree tops. The incidence and magnitude of temporally localised spikes in pollutant concentration were reduced within the tree canopy itself. A significant difference in pollutant concentrations with height was not observed when leaves were absent. Analysis of the trends in concentration associated with different wind directions showed a smaller difference between windward and leeward sides when leaves were on the trees. A small relative increase in concentrations on the leeward side was observed during leaf-on relative to leaf-off conditions as predicted by previous modelling studies. However the expected reduction in concentrations on the windward side was not observed. The results suggest that the presence of leaves on the trees reduces the upwards transport of fresh vehicle emissions, increases the storage of pollutants within the canopy space and reduces the penetration of clean air downwards from aloft. Differences observed between NO and NO2 concentrations could not be accounted for by dispersion processes alone, suggesting that there may also be some changes in the chemistry of the atmosphere associated with the presence of leaves on the trees.

Rouse, D. C. and I. F. Bunster-Ossa (2013). Green infrastructure: a landscape approach. This report provides an overview of green infrastructure and the role of landscape in urban planning and design. Case studies from around the U.S. provide examples of integrating green infrastructure with traditional urban infrastructure and best management practices. The appendix includes a model regulatory framework.

Radford, K. G. and P. James (2013). "Changes in the value of ecosystem services along a rural–urban gradient: A case study of Greater Manchester, UK." Landscape and Urban Planning 109(1): 117-127. The degradation and loss of vital ecosystem functions and services have been an uncontested result of urbanisation. An understanding of how ecosystem services are provided along rural–urban gradients is crucial in the task of conserving and enhancing vital services in urban environments, increasing the quality of life of urban dwellers, and working towards a sustainable future. Focusing on nine ecosystem services – aesthetic, spiritual, recreation, water flow regulation, carbon sequestration, climate change adaptation, pollination, biodiversity potential, and noise attenuation – regarded as important to urban areas the authors detail the changes in the values of these services along a gradient comprising four categories of urbanisation: urban, suburban, peri-urban and rural, in Greater Manchester, UK. The data on which the discussion is based are derived from an interdisciplinary assessment tool, developed from a selection of previously used assessment methods including the Residential Environment Assessment Tool and the Green Flag Award. Based on a mixture of a field and desktop study, the new tool assigns non-economic values of 0–10 to the selected services, allowing for evaluation of quality between, as well as within, each category of ecosystem service. Trends in the results are discussed, as are drivers for the changes in values along the rural–urban gradient. It is foreseen that this new body of knowledge will allow both practitioners and academics to gain further insight into the provision of ecosystem services along a rural–urban gradient to allow them to tackle the problems associated with them and to optimise open space planning.

Pincetl, S., et al. (2013). "Urban tree planting programs, function or fashion? Los Angeles and urban tree planting campaigns." GeoJournal 78(3): 475-493. Tree planting programs are being implemented in many US cities (most notably New York, Los Angeles, and Chicago) on the basis of the multiple environmental and health benefits they may provide. However, the magnitude and even the direction of the impacts of trees on specific urban environments have seldom been directly measured. In addition, there has been little research on the historical, cultural, political or institutional origins of such programs, or on their implementation process. Pending questions include the degree to which these programs are integrated in the existing frameworks of city government and infrastructure management, how they are paid for, and the kinds of collaborations between nonprofit organizations, the public, and public agencies at all levels they may require in order to succeed. This paper reports on an interdisciplinary research project examining the Million Tree Program of the City of Los Angeles.

Peschardt, K. and U. Stigsdotter (2013). "Associations between park characteristics and perceived restorativeness of small public urban green spaces." Landscape and Urban Planning 112: 26-39. Urban green space in dense city areas is a limited resource. However, previous research indicates that such areas have a positive influence on mental restoration. As stress is a common problem in cities, we test to see whether park characteristics are associated with the perceived restorativeness of nine small public urban green spaces (SPUGS) in the dense city of Copenhagen. Furthermore, we investigate whether there is a difference in preferences for park characteristics amongst average users and the most stressed users of SPUGS. We conducted an on-site questionnaire survey where respondents answered the perceived restorativeness scale (PRS). All SPUGS were analysed using the eight perceived sensory dimensions (PSDs) which describe different park characteristics. The analyses were conducted to see whether the PSDs were present or not and to determine how strong or weak they were. For the first time the PRS and the PSDs have been combined to see whether significant associations can be found between park characteristics and the users' perceived restorativeness. First, seven of the eight PSDs could be used in the study. Second, the PSDs 'social' and 'serene' were significantly associated with average users' perceived restorativeness. And third, a difference between the users is that the PSD 'nature' becomes important for the most stressed individuals. The results indicate that the PSDs can be useful for the future analysis and design processes of SPUGS with the potential for mental restoration. However, the PSDs need to be developed further to make them useful to practitioners.

Peckham, S. C., et al. (2013). "Urban forest values in Canada: views of citizens in Calgary and Halifax." Urban Forestry Urban Greening 12. A significant component of the urban ecosystem is the urban forest. It is also the quintessential meeting point of culture and nature, so it is critical to incorporate values-based approaches to managing them. The values that really count are those of urban citizens. A novel qualitative method was used to determine what qualities of the urban forest are valued by citizens of Calgary, Alberta, and Halifax, Nova Scotia, Canada. These values were compared with those reported in the literature to reveal that citizens value the urban forests mostly for their non-material benefits. Specifically, urban forests contribute to human emotional, intellectual, and moral fulfilment.

O’Donoghue, A. and C. M. Shackleton (2013). "Current and potential carbon stocks of trees in urban parking lots in towns of the Eastern Cape, South Africa." Urban Forestry & Urban Greening 12(4): 443-449. Greening of shopping centre parking lots is a potentially important strategy that can contribute to urban carbon mitigation efforts, improve aesthetics and the shopping experience of consumers, whilst adding to urban biodiversity. Twenty-eight shopping centre parking lots in six Eastern Cape urban centres, South Africa, were sampled to determine tree species composition, density and annual carbon sequestration potential. The best case parking lot found during the study was used as a benchmark to display the difference between current tree density and above- ground carbon stocks relative to the potential optimum. The highest tree density was 66 trees ha−1, whereas the average density across all sampled parking lots was less than half that (27.2 ± 22.6 trees ha−1). The average annual carbon sequestration potential per parking lot was 1390 ± 2503 kg ha−1. Planting density was positively related to annual sequestration rates, whilst parking lot age and the mean annual rainfall of the town had no influence. Mean tree species richness per parking lot was 2.3 ± 1.8 species, with a positive relationship to parking lot size, but not to mean annual rainfall of the site. The majority of trees (62.5%) in parking lots were alien species, although newer parking lots had significantly greater proportions of indigenous species. There was no difference in mean annual carbon sequestration rate per tree between indigenous and alien trees species. Low tree densities and small parking lot areas constrained the potential for earning carbon credits from trees in parking lots. Nonetheless, planners and designers need to be more aware of the potential contribution of trees towards urban sustainability.

McPherson, E. G., et al. (2013). "A new approach to quantify and map carbon stored, sequestered and emissions avoided by urban forests." Landscape and Urban Planning 120: 70-84. This paper describes the use of field surveys, biometric information for urban tree species and remote sensing to quantify and map carbon (C) storage, sequestration and avoided emissions from energy savings. Its primary contribution is methodological; the derivation and application of urban tree canopy (UTC) based transfer functions (t C ha−1 UTC). Findings for Los Angeles and Sacramento illustrate the complex role of regional and local determinants. Although average tree density and size were substantially greater in Los Angeles, the mean C storage density (8.15 t ha−1) was 53 percent of Sacramento's (15.4 t ha−1). In Sacramento, native oaks with very high wood densities (815 kg m−3) accounted for 30 percent of total basal area. In Los Angeles, the most dominant taxa had relatively low wood densities (350-550 kg m−3). The inclusion of relatively more wooded land in the Sacramento study area may partially explain higher C storage levels. In Los Angeles, where development is relatively dense, 14 percent of all trees surveyed shaded more than one building compared to only 2 percent in Sacramento. Consequently, the transfer function for avoided emissions in Los Angeles (2.77 t ha−1 UTC yr−1) exceeded Sacramento (2.72 t ha−1 UTC yr−1). The approach described here improves C estimates and increases the resolution at which C can be mapped across a region. It can be used to map baseline C storage levels for climate action planning, identify conservation areas where UTC densities are highest and determine where opportunities for expanding UTC are greatest.

Maher, B. A., et al. (2013). "Impact of roadside tree lines on indoor concentrations of traffic-derived particulate matter." Environmental Science & Technology 47(23): 13737- 13744. Exposure to airborne particulate pollution is associated with premature mortality and a range of inflammatory illnesses, linked to toxic components within the particulate matter (PM) assemblage. The effectiveness of trees in reducing urban PM10 concentrations is intensely debated. Modeling studies indicate PM10 reductions from as low as 1% to as high as ∼60%. Empirical data, especially at the local scale, are rare. Here, we use conventional PM10 monitoring along with novel, inexpensive magnetic measurements of television screen swabs to measure changes in PM10 concentrations inside a row of roadside houses, after temporarily installing a curbside line of young birch trees. Independently, the two approaches identify >50% reductions in measured PM levels inside those houses screened by the temporary tree line. Electron microscopy analyses show that leaf- captured PM is concentrated in agglomerations around leaf hairs and within the leaf microtopography. Iron-rich, ultrafine, spherical particles, probably combustion-derived, are abundant, form a particular hazard to health, and likely contribute much of the measured magnetic remanences. Leaf magnetic measurements show that PM capture occurs on both the road-proximal and -distal sides of the trees. The efficacy of roadside trees for mitigation of PM health hazard might be seriously underestimated in some current atmospheric models.

Kessler, R. (2013). "Green walls could cut street-canyon air pollution." Environ Health Perspect 121. Rows of tall buildings can create a unique urban habitat known as a street canyon. These canyons trap traffic pollutants, limiting their dispersal into the atmospheric boundary layer that extends as high as 2,000 meters above the ground. A new study suggests that vegetation in street canyons may reduce air-pollutant concentrations much more than previously reported and suggests innovative planting configurations to improve city pollution hot spots. Outdoor air pollution is believed to cause an estimated 1.3 million annual deaths worldwide,2 as well as an increased risk of respiratory and cardiovascular diseases.3 Plantings are often promoted as a partial solution, because leaves absorb gaseous pollutants through their pores and capture particulate matter on their surfaces.4,5,6,7,8,9,10,11 Yet modeling studies of the vegetation across entire cities have estimated that existing green cover reduces air pollution concentrations by less than 1.5%.

Keeley, M., et al. (2013). "Perspectives on the Use of Green Infrastructure for Stormwater Management in Cleveland and Milwaukee." Environmental Management 51(6): 1093-1108. Green infrastructure is a general term referring to the management of landscapes in ways that generate human and ecosystem benefits. Many municipalities have begun to utilize green infrastructure in efforts to meet stormwater management goals. This study examines challenges to integrating gray and green infrastructure for stormwater management, informed by interviews with practitioners in Cleveland, OH and Milwaukee WI. Green infrastructure in these cities is utilized under conditions of extreme fiscal austerity and its use presents opportunities to connect stormwater management with urban revitalization and economic recovery while planning for the effects of negative- or zero-population growth. In this context, specific challenges in capturing the multiple benefits of green infrastructure exist because the projects required to meet federally mandated stormwater management targets and the needs of urban redevelopment frequently differ in scale and location.

Jones, R. E., et al. (2013). "The Value of Trees." Environment and Behavior 45(5): 650-676. The article discusses the value and importance of urban trees and factors that significantly influence public support for protecting them. These factors were identified by examining mail survey data obtained from a representative sample of 800 homeowners living in a rapidly urbanizing area within Southern Appalachia. A series of multiple regression analysis tested an Integrated Model of Urban Tree Support that combines measures of attitudes, beliefs, values, and sociodemographic variables to predict homeowner support for local urban tree protection. The findings lend support to many features of the model and revealed that homeowners who have stronger protree attitudes, have greater environmental concerns, place more importance on trees when looking for a new place to live, attribute symbolic value and meaning to them are more supportive. Women and Democrats are also more supportive. Recommendations are offered for future research and policy.

Irga, P. J., et al. (2013). "Can hydroculture be used to enhance the performance of indoor plants for the removal of air pollutants?" Atmospheric Environment 77: 267-271. The indoor plant, Syngonium podophyllum, grown in both conventional potting mix and hydroculture, was investigated for its capacity to reduce two components of indoor air pollution; volatile organic compounds (VOCs) and CO2. It was found that, with a moderate increase in indoor light intensity, this species removed significant amounts of CO2 from test chambers, removing up to 61% ± 2.2 of 1000 ppmv over a 40 min period. It was also found that the hydroculture growth medium facilitated increased CO2 removal over potting mix. The VOC removing potential of hydroculture plants was also demonstrated. Whilst the rate of VOC (benzene) removal was slightly lower for hydroculture-grown plants than those grown in potting mix, both removed 25 ppmv from the test chambers within 7 days. The effect of benzene on the community level physiological profiles of rhizospheric bacteria was also assessed. There was less variability in the carbon substrate utilisation profile of the bacterial community from the rhizosphere of hydroculture plants compared to potting mix, however the species present encompassed at least those involved with VOC removal. Overall, we propose that plants grown in hydroculture can simultaneously deplete CO2 and VOCs, and thus may have potential for improving indoor air quality.

Hubacek, K. and J. Kronenberg (2013). "Synthesizing different perspectives on the value of urban ecosystem services." Landscape and Urban Planning 109(1): 1-6. Since 2008 more than half of the world population lives in cities and within the next 40 years the share of urban dwellers is estimated to increase to 70%. Urban populations do not only use ecosystem services from outside urban boundaries (clearly their ecological footprints are much larger than their physical areas) but, often unknowingly, they also rely on urban ecosystems. While researchers primarily focus on distant ecosystems, crucial for the preservation of life on the planet, most local ecosystems in and around urban areas suffer from an increasing pressure from further urbanization and growing consumption within cities. Important urban ecosystem services are often being neglected without the understanding of their importance and value. Meanwhile, they are crucial for the sustainability of life and the wellbeing of residents in urban areas. Attempts have been made to highlight the value of urban ecosystem services, especially with reference to urban greenery, water and allotment gardens. Different perspectives on the value of urban ecosystem services have been revealed, including economic (benefits and savings), socio-ecological (resilience), psychological (well-being), cultural (e.g. inspiration), and philosophical or ethical. On the one hand, such a multitude of perspectives suggests that at least some of these perspectives should be meaningful to different groups of stakeholders. On the other hand, ultimately, this variety might weaken the message delivered to decision-makers who often only follow narrow economic reasoning. The objective of this seminar and the special issue of Landscape and Urban Planning that follows is to bring together the various perspectives on the value of urban ecosystem services and discuss the potential of merging and synthesizing these perspectives. Ultimately, this should lay foundations for a more sustainable management of ecosystem services in urban areas.

Haviland-Jones, J., et al. (2013). "The emotional air in your space: Scrubbed, wild or cultivated?" Emotion, Space and Society 6: 91-99. The space around or in our buildings is not empty but is full of air. This air naturally contains some potential toxins but also useful biochemicals that we are not aware of; t however, our olfactory system has evolved to detect some of them subliminally. Conscious preferences for or against types of air may be insufficient for decisions about the desirability of natural, green air. It is a 21st challenge to “green technology” to extend and incorporate behavioral science approaches to understanding influential subliminal processes. We argue that these decisions require an experimental approach because the olfactory system is not easily accessible to conscious analysis. The subliminal effects of “something in the air” are illustrated first in a case study to show the surprising range of emotional effects from natural human mood odors. Then in a controlled study we show some similar subliminal effects from natural plant odors. Here “wild” local air is contrasted with two types of “cultivated” air, either with undetected (a) flower ingredients or (b) perfume ingredients. The subliminal effect of the floral additive led to more positive emotional thought and supported social approach behavior. This implies air management has the potential to provide an invisible support system inside and around buildings just as carefully designed and maintained parks provide a larger support to communities.

Gómez-Baggethun, E., et al. (2013). Urban ecosystem services. Urbanization, biodiversity and ecosystem services: challenges and opportunities: a global assessment. T. Elmqvist, M. Fragkias, J. Goodness et al. Dordretch, Springer. We explore the potential of urban ecosystem services for improving resilience and quality of life in cities. First, we classify and categorize important ecosystem services and disservices in urban areas. Second, we describe a range of valuation approaches (cultural values, health benefits, economic costs, and resilience) for capturing the importance of urban ecosystem service multiple values. Finally, we analyze how ecosystem service assessment may inform urban planning and governance and provide practical examples from cities in Africa, Europe, and America. From our review, we find that many urban ecosystem services have already been identified, characterized and valued, and have been found to be of great value and importance for human well-being and urban resilience. We conclude that the use of the concept of urban ecosystem services can play a critical role in reconnecting cities to the biosphere, and reducing the ecological footprint and ecological debt of cities while enhancing resilience, health, and quality of life of their inhabitants.

Gago, E. J., et al. (2013). "The city and urban heat islands: A review of strategies to mitigate adverse effects." Renewable and Sustainable Energy Reviews 25: 749-758. Cities occupy 2% of the earth's surface but their inhabitants consume 75% of the world's energy resources. Under certain conditions, the heat from solar radiation and different urban activities can make city temperatures rise in certain areas, simply because of the way in which a city is structured. This effect is known as the urban heat island (UHI). This article provides a review of recent research on the urban heat island as well as of the strategies that can be applied to mitigate its adverse effects. Such strategies can be applied in the project design phase of urban planning and thus directly affect city temperatures on a local scale. The elements analyzed in this paper include green spaces, trees, albedo, pavement surfaces, vegetation, as well as building types and materials. The discussion of this research clearly reflects the impact of urban morphology on local temperatures and how urban design can be modified to reduce energy consumption and CO2 emissions into the atmosphere. This study is useful for professionals who are responsible for decision-making during the design phase of urban planning.

Farrugia, S., et al. (2013). "An evaluation of flood control and urban cooling ecosystem services delivered by urban green infrastructure." International Journal of Biodiversity Science, Ecosystem Services & Management 9(2): 136-145. To inform planning decisions and address climate change impacts in expanding cities, it is desirable to quantify urban ecosystem services like flood control and urban cooling. By comparing with a purpose-built habitat map, this study ground-truthed a method to assess flood control, which was developed by Southampton City Council from surface maps. It was confirmed that infiltration capacity is a good proxy for flood control, leaf area index could represent urban cooling, and thereby both could be used to score urban surface types. A two- tiered system was proposed so that surface maps would be used for city-wide scale, and as they produce similar results that are more accurate at fine scales, habitat maps are used at site level. These surrogates were integrated to produce a Green Space Factor for flood control and urban cooling, wherein a combined score can be generated for particular locations. This could be extended further to include other ecosystem services. The new integrated multi-scale ecosystem service quantification tool could be used by developers and policy-makers to identify target areas in their projects and policies that could benefit from enhanced green infrastructure.

Farmer, M. C., et al. (2013). "Bird diversity indicates ecological value in urban home prices." Urban Ecosystems 16(1): 131-144. It is known that public greenspaces contribute positively to urban home prices; yet urban ecologists also have known that not all greenspaces are equally valuable. Also some ecologically valuable space appears on private residences, not only public spaces. This work examines directly whether using a variable derived from bird species richness and relative abundance adds new information regarding ecological value and if high values of that variable significantly improve urban housing prices. We collected information on approximately 368 home sales in Lubbock, TX from 2008 to 2009 from the Multiple Listing Service: Sale Price, Square Footage, Lot Size and Age in 17 neighborhoods identified by the Lubbock Realtor Association. We conducted bird counts in the vicinity of each home sale and recorded both the total numbers of birds and the number of bird species identified in a particular class—less ubiquitous bird species. Finally, we used GIS to record the percentage of tree cover in the immediate area surrounding each sale. We constructed a predictive model for a bird relative abundance and species richness variable (Bird) from AICc statistics. Home price for each sale then was regressed against the predicted value of ‘Bird’ from the selected model and regressed against home price along with other attributes from the Multiple Listing Service. The predicted value for Bird finds that the addition of another desirable, less ubiquitous bird species improves mean home price by $32,028, likely due to the human created landscapes on private properties immediately surrounding a home sale. Curiously, the presence of a nearby park neither explained variation in the ecological indicator nor contributed to home price elevation. This deliberately simple and inexpensive indicator helped to direct attention to the composition of local landscapes in specific areas to assess joint ecological and economic gains rather than presume a priori that open greenspace jointly satisfies these dual objectives.

Ernstson, H. (2013). "The social production of ecosystem services: A framework for studying environmental justice and ecological complexity in urbanized landscapes." Landscape and Urban Planning 109(1): 7-17. A framework is constructed for how to relate ecosystem services to environmental justice. The benefits humans and society can derive from biophysical processes cannot be viewed as objectively existing “out there”, but as entangled in social and political processes. This is unpacked through the analytical moments of generation, distribution and articulation of ecosystem services. Social practice moderates the generation of benefits from biophysical processes (through urban development patterns and day-to-day management of urban ecosystems), but also who in society that benefits from them, i.e. the distribution of ecosystem services (viewed here as the temporal and spatial scales at which it is possible for humans to benefit from biophysical processes). Moreover, for biophysical processes to attain value in decision-making, a social practice of value articulation is needed. The framework then moves between two levels of analysis. At the city-wide level, an ecological network translates how urban ‘green’ areas, viewed as nodes, are interconnected by ecological flows (water, species movement, etc.) where nodes have different protective and management capacities. The network captures spatial complexity—what happens in one location, can have effects elsewhere. At the local level, urban struggles over land-use are studied to trace how actors utilize artifacts and social arenas to articulate how certain biophysical processes are of value. Competing networks of value articulation strive to influence land-use, and multiple local studies bring understanding of how power operates locally, informing city-wide analyses. Empirical studies from Stockholm, Cape Town and other cities inform the framework.

Ellis, J. B. (2013). "Sustainable surface water management and green infrastructure in UK urban catchment planning." Journal of Environmental Planning and Management 56(1): 24-41. Based on the analysis of impervious surface cover and water balance studies, it is argued that conventional, separately-sewered first-generation and alternative second-generation sustainable drainage systems (SUDS) cannot provide a fully sustainable surface water management approach for urban catchment planning. An extended approach based on the introduction of micro-and meso-vegetative SUDS systems into a wider green infrastructure (GI) framework is advocated to effectively address on-site and catchment urban surface water issues. The approach is based on the integrated planning implementation of street ?greening?, with optimisation of existing biofiltration SUDS solutions, together with green roofs, downspout disconnection and sub-catchment riparian corridors to achieve a minimum 25?30% canopy cover level. A leaf-out inventory procedure using GIS and satellite imagery can be employed to assess potential vegetative SUDS locations and types, and their likely impact upon the urban water cycle and receiving water health. However, there is a need to ensure that GI elements are incorporated into planning approaches and protocols for urban drainage infrastructure provision.

De Kluizenaar, Y., et al. (2013). "Road traffic noise, air pollution components and cardiovascular events." Noise and Health 15(67): 388. Traffic noise and air pollution have been associated with cardiovascular health effects. Until date, only a limited amount of prospective epidemiological studies is available on long- term effects of road traffic noise and combustion related air pollution. This study investigates the relationship between road traffic noise and air pollution and hospital admissions for ischemic heart disease (IHD: International Classification of Diseases (ICD9) 410-414) or cerebrovascular disease (cerebrovascular event [CVE]: ICD9 430-438). We linked baseline questionnaire data to 13 years of follow-up on hospital admissions and road traffic noise and air pollution exposure, for a large random sample (N = 18,213) of inhabitants of the Eindhoven region, Netherlands. Subjects with cardiovascular event during follow-up on average had higher road traffic noise day, evening, night level (L den) and air pollution exposure at the home. After adjustment for confounders (age, sex, body mass index, smoking, education, exercise, marital status, alcohol use, work situation, financial difficulties), increased exposure did not exert a significant increased risk of hospital admission for IHD or cerebrovascular disease. Relative risks (RRs) for a 5 th to 95 th percentile interval increase were 1.03 (0.88-1.20) for L den; 1.04 (0.90-1.21) for particulate matter (PM 10); 1.05 (0.91-1.20) for elemental carbon (EC); and 1.12 (096-1.32) for nitrogen dioxide (NO 2 ) in the full model. While the risk estimate seemed highest for NO 2 , for a 5 th to 95 th percentile interval increase, expressed as RRs per 1 μg/m 3 increases, hazard ratios seemed highest for EC (RR 1.04 [0.92-1.18]). In the subgroup of study participants with a history of cardiovascular disease, RR estimates seemed highest for noise exposure (1.19 [0.87- 1.64] for L den); in the subgroup of elderly RR seemed highest for air pollution exposure (RR 1.24 [0.93-1.66] for NO2).

Clowney, D. (2013). "Biophilia as an Environmental Virtue." Journal of Agricultural & Environmental Ethics 26(5): 999-1014. Beginning with E. O. Wilson’s notion of biophilia, our “innate tendency to focus on life and life-like processes,” I construct an environmental virtue with the same name that meets certain criteria an environmental virtue should meet. I argue that this virtue can have its status as a virtue by its contribution to human flourishing, while having care for live nature as its target, and care about live nature as its affective content. I explore its characteristics as both an individual and a collective virtue, and finally show how cultivation of it might serve to unite various communities in the cause of preserving biodiversity.

Calfapietra, C., et al. (2013). "Role of Biogenic Volatile Organic Compounds (BVOC) emitted by urban trees on ozone concentration in cities: A review." Environ Pollut 183. Biogenic Volatile Organic Compounds (BVOC) play a critical role in biosphere/atmosphere interactions and are key factors of the physical and chemical properties of the atmosphere and climate. However, few studies have been carried out at urban level to investigate the interactions between BVOC emissions and ozone (O3) concentration. The contribution of urban vegetation to the load of BVOCs in the air and the interactions between biogenic emissions and urban pollution, including the likely formation of O3, needs to be investigated, but also the effects of O3 on the biochemical reactions and physiological conditions leading to BVOC emissions are largely unknown. The effect of BVOC emission on the O3 uptake by the trees is further complicating the interactions BVOCeO3, thus making challenging the estimation of the calculation of BVOC effect on O3 concentration at urban level.

Berry, R., et al. (2013). "Tree canopy shade impacts on solar irradiance received by building walls and their surface temperature." Building and Environment 69: 91-100. Shading coefficients are used to predict the seasonal and diurnal benefit of architectural shading devices. It is more difficult to model the impact of tree shade on building thermal performance, and data is rare and varies greatly with species and season. We established a range of tree shade amounts and shade qualities from which to develop simple, robust models that predict external wall surface temperatures. We measured percentage shade cover, solar irradiance and external surface temperature on north and west sun-bearing walls of three identical buildings in spring and summer 2010/11. One building was shaded by tall Angophora trees, another by smaller Fraxinus trees and one was unshaded. Tree shade reduced wall surface temperatures by up to 9C and external air temperatures by up to 1??C. The smaller trees did little to reduce external wall surface temperatures, and moving the tall trees further away from the building wall eliminated their cooling benefits. Wall surface temperatures were best predicted by shade cover and solar irradiance, and was most poorly predicted by shading coefficients, that varied greatly through the day and the season, as tree height and leaf area index increased. Trees can reduce external solar irradiance loads when they are close enough and tall enough to shade the majority of the wall. To simulate the thermal performance benefits that trees provide, it is necessary to account for seasonal, growth and phenological changes in tree shade amount and quality.

Berry, R., et al. (2013). "Tree canopy shade impacts on solar irradiance received by building walls and their surface temperature." Building and Environment 69: 91-100. Shading coefficients are used to predict the seasonal and diurnal benefit of architectural shading devices. It is more difficult to model the impact of tree shade on building thermal performance, and data is rare and varies greatly with species and season. We established a range of tree shade amounts and shade qualities from which to develop simple, robust models that predict external wall surface temperatures. We measured percentage shade cover, solar irradiance and external surface temperature on north and west sun-bearing walls of three identical buildings in spring and summer 2010/11. One building was shaded by tall Angophora trees, another by smaller Fraxinus trees and one was unshaded. Tree shade reduced wall surface temperatures by up to 9 C and external air temperatures by up to 1 C. The smaller trees did little to reduce external wall surface temperatures, and moving the tall trees further away from the building wall eliminated their cooling benefits. Wall surface temperatures were best predicted by shade cover and solar irradiance, and was most poorly predicted by shading co- efficients, that varied greatly through the day and the season, as tree height and leaf area index increased. Trees can reduce external solar irradiance loads when they are close enough and tall enough to shade the majority of the wall. To simulate the thermal performance benefits that trees provide, it is necessary to account for seasonal, growth and phenological changes in tree shade amount and quality.

Amorim, J. H., et al. (2013). "CFD modelling of the aerodynamic effect of trees on urban air pollution dispersion." Science of The Total Environment 461–462: 541-551. The current work evaluates the impact of urban trees over the dispersion of carbon monoxide (CO) emitted by road traffic, due to the induced modification of the wind flow characteristics. With this purpose, the standard flow equations with a kε closure for turbulence were extended with the capability to account for the aerodynamic effect of trees over the wind field. Two CFD models were used for testing this numerical approach. Air quality simulations were conducted for two periods of 31 h in selected areas of Lisbon and Aveiro, in Portugal, for distinct relative wind directions: approximately 45° and nearly parallel to the main avenue, respectively. The statistical evaluation of modelling performance and uncertainty revealed a significant improvement of results with trees, as shown by the reduction of the NMSE from 0.14 to 0.10 in Lisbon, and from 0.14 to 0.04 in Aveiro, which is independent from the CFD model applied. The consideration of the plant canopy allowed to fulfil the data quality objectives for ambient air quality modelling established by the Directive 2008/50/EC, with an important decrease of the maximum deviation between site measurements and CFD results. In the non- aligned wind situation an average 12% increase of the CO concentrations in the domain was observed as a response to the aerodynamic action of trees over the vertical exchange rates of polluted air with the above roof-level atmosphere; while for the aligned configuration an average 16% decrease was registered due to the enhanced ventilation of the street canyon. These results show that urban air quality can be optimised based on knowledge-based planning of green spaces.

Ziemann, P. J. and R. Atkinson (2012). "Kinetics, products, and mechanisms of secondary organic aerosol formation." Chem Soc Rev 41. Secondary organic aerosol (SOA) is formed in the atmosphere when volatile organic compounds (VOCs) emitted from anthropogenic and biogenic sources are oxidized by reactions with OH radicals, O3, NO3 radicals, or Cl atoms to form less volatile products that subsequently partition into aerosol particles. Once in particles, these organic compounds can undergo heterogenous/multiphase reactions to form more highly oxidized or oligomeric products. SOA comprises a large fraction of atmospheric aerosol mass and can have significant effects on atmospheric chemistry, visibility, human health, and climate. Previous articles have reviewed the kinetics, products, and mechanisms of atmospheric VOC reactions and the general chemistry and physics involved in SOA formation. In this article we present a detailed review of VOC and heterogeneous/multiphase chemistry as they apply to SOA formation, with a focus on the effects of VOC molecular structure on the kinetics of initial reactions with the major atmospheric oxidants, the subsequent reactions of alkyl, alkyl peroxy, and alkoxy radical intermediates, and the composition of the resulting products. Structural features of reactants and products discussed include compound carbon number; linear, branched, and cyclic configurations; the presence of C[double bond, length as m-dash]C bonds and aromatic rings; and functional groups such as carbonyl, hydroxyl, ester, hydroxperoxy, carboxyl, peroxycarboxyl, nitrate, and peroxynitrate. The intention of this review is to provide atmospheric chemists with sufficient information to understand the dominant pathways by which the major classes of atmospheric VOCs react to form SOA products, and the further reactions of these products in particles. This will allow reasonable predictions to be made, based on molecular structure, about the kinetics, products, and mechanisms of VOC and heterogeneous/multiphase reactions, including the effects of important variables such as VOC, oxidant, and NOx concentrations as well as temperature, humidity, and particle acidity. Such knowledge should be useful for interpreting the results of laboratory and field studies and for developing atmospheric chemistry models. A number of recommendations for future research are also presented.

Wania, A., et al. (2012). "Analysing the influence of different street vegetation on traffic- induced particle dispersion using microscale simulations." J Environ Manage 94. Urban vegetation can be viewed as compensation to the environmental drawbacks of urbanisation. However, its ecosystem function is not well-known and, for urban planning, vegetation is mainly considered as an element of urban design. This article argues that planning practice needs to re-examine the impact of vegetation cover in the urban fabric given our evaluation of vegetation’s effects on air quality, including the dispersion of traffic-induced particles at street level. Using the three-dimensional microclimate model ENVI-met®, we evaluate these effects regarding the height-to-width ratio of streets flanked by buildings and the vertical and horizontal density of street vegetation. Our results reveal vegetation’s effect on particle dispersion through its influence on street ventilation. In general, vegetation was found to reduce wind speed, causing inhibition of canyon ventilation and, consequently, an increase in particle concentrations. Vegetation was also found to reduce wind speed at crown-height and to disrupt the flow field in close vicinity to the canopy. With increasing height-to-width ratio of street canyons, wind speed reduction increases and the disturbance of the flow impacts across a canyon’s entire width. We also found that the effect is more pronounced in configurations with poor ventilation, such as the low wind speed, perpendicular inflow direction, and in deep canyons cases.

Strohbach, M. W., et al. (2012). "Erratum to “The carbon footprint of urban green space— A life cycle approach” [Landsc. Urban Plann. 104 (2012) 220–229]." Landscape and Urban Planning 105(4): 445. Cities play an important role in the global carbon cycle. They produce a large proportion of CO2 emissions, but they also sequester and store carbon in urban forests and green space. However, sequestration by urban green space is difficult to quantify and also involves emissions. The carbon footprint analysis is an established method for systematically quantifying carbon sinks and sources throughout the lifetime of goods and services. We applied this method to an urban green space project in Leipzig, Germany. To the best of our knowledge it is the first application in this field. We simulated carbon sequestration by growing trees and contrasted it with all related carbon sources, from construction and maintenance over the lifetime of 50 years. In addition, we explored alternative design and maintenance scenarios. Total net sequestration was predicted to be between 137 and 162 MgCO2 ha−1 . Park-like design and maintenance is less effective than forest-like design and maintenance. Much uncertainty is linked to tree growth and tree mortality. Increasing annual tree mortality from 0.5 to 4% reduces sequestration by over 70%. In conclusion, urban green space can act as a carbon sink and the design and maintenance have a strong influence on the carbon footprint. The carbon footprint analysis is a valuable tool for estimating the long- term environmental performance of urban green space projects. Compared to emissions from people, the overall potential for carbon mitigation is limited, even in cities such as Leipzig with widely available space for new urban green space.

Strohbach, M. W., et al. (2012). "The carbon footprint of urban green space—A life cycle approach." Landscape and Urban Planning 104(2): 220-229. Cities play an important role in the global carbon cycle. They produce a large proportion of CO2 emissions, but they also sequester and store carbon in urban forests and green space. However, sequestration by urban green space is difficult to quantify and also involves emissions. The carbon footprint analysis is an established method for systematically quantifying carbon sinks and sources throughout the lifetime of goods and services. We applied this method to an urban green space project in Leipzig, Germany. To the best of our knowledge it is the first application in this field. We simulated carbon sequestration by growing trees and contrasted it with all related carbon sources, from construction and maintenance over the lifetime of 50 years. In addition, we explored alternative design and maintenance scenarios. Total net sequestration was predicted to be between 137 and 162 MgCO2 ha−1. Park-like design and maintenance is less effective than forest-like design and maintenance. Much uncertainty is linked to tree growth and tree mortality. Increasing annual tree mortality from 0.5 to 4% reduces sequestration by over 70%. In conclusion, urban green space can act as a carbon sink and the design and maintenance have a strong influence on the carbon footprint. The carbon footprint analysis is a valuable tool for estimating the long-term environmental performance of urban green space projects. Compared to emissions from people, the overall potential for carbon mitigation is limited, even in cities such as Leipzig with widely available space for new urban green space.

Pugh, T. A. M., et al. (2012). "Effectiveness of green infrastructure for improvement of air quality in urban street canyons." Environ Sci Technol 46. Street-level concentrations of nitrogen dioxide (NO2) and particulate matter (PM) exceed public health standards in many cities, causing increased mortality and morbidity. Concentrations can be reduced by controlling emissions, increasing dispersion, or increasing deposition rates, but little attention has been paid to the latter as a pollution control method. Both NO2 and PM are deposited onto surfaces at rates that vary according to the nature of the surface; deposition rates to vegetation are much higher than those to hard, built surfaces. Previously, city- scale studies have suggested that deposition to vegetation can make a very modest improvement (<5%) to urban air quality. However, few studies take full account of the interplay between urban form and vegetation, specifically the enhanced residence time of air in street canyons. This study shows that increasing deposition by the planting of vegetation in street canyons can reduce street-level concentrations in those canyons by as much as 40% for NO2 and 60% for PM. Substantial street-level air quality improvements can be gained through action at the scale of a single street canyon or across city-sized areas of canyons. Moreover, vegetation will continue to offer benefits in the reduction of pollution even if the traffic source is removed from city centers. Thus, judicious use of vegetation can create an efficient urban pollutant filter, yielding rapid and sustained improvements in street-level air quality in dense urban areas.

Pham, T. T. H., et al. (2012). "Spatial distribution of vegetation in Montreal: an uneven distribution or environmental inequity?" Landscape Urban Plann 107. Growing evidence is showing that across North American cities, underprivileged populations and racial and/or visible groups have disproportionally less access to vegetation than affluent groups, raising concerns of environmental inequity. This study aims to verify whether in Montreal (Canada) there is environmental inequity resulting from variations in urban vegetation for low-income people and visible minorities. More specifically, various vegetation indicators were extracted from very-high-resolution satellite images, including the proportion of city blocks, streets, alleys and backyards covered by total vegetation and trees/shrubs. Socio- demographic variables were obtained from 2006 Canada Census and rescaled to the city block level, by using a population-based weighing method. Statistical analysis indicates that there are disparities in the distribution of vegetation in Montreal which disfavour low-income people and, to a lesser extent, visible minorities. Disparities are also more pronounced on public land (streets, alleys) than on private land (backyards). Income is a major factor but cannot fully explain inequities among visible minorities. Notwithstanding the weak extent of such disparities, those vulnerable communities might need a better access to ecological services provided by vegetation, notably such as heat island mitigation. Compensatory equity needs to be addressed and our findings call for authorities to reconsider greening budgetary allocation and practices, especially in the most deprived neighbourhoods of the city.

Islam, M. N., et al. (2012). "Pollution attenuation by roadside greenbelt in and around urban areas." Urban Forestry & Urban Greening 11(4): 460-464. Greenbelts are effective tools for mitigation of traffic induced air and noise pollution. In this study, the potential role of greenbelts along the roadside for the reduction of air pollution and noise levels has been assessed by using seasonally monitored data in a megacity of Bangladesh. Correlation analysis was performed between the vegetation status, measured by canopy density and shelterbelt porosity, and the total suspended particles (TSP) removal percentage. Further, the reduction of noise level was also analyzed. The results showed that the greenbelts greatly contributed to reduce TSP pollution and it was as much as 65%. Noise level reduction was also achieved up to 17 dB when compared to the open area. Moreover, TSP removal percentage was correlated to the crown density. Area having higher crown density demonstrated less air pollution and lower level of noise compared to the area having lower crown density. Greenbelt showed better performance in summer time than winter.

Hagler, G. S. W., et al. (2012). "Field investigation of roadside vegetative and structural barrier impact on near-road ultrafine particle concentrations under a variety of wind conditions." Sci Total Environ 419. Roadside barriers, such as tree stands or noise barriers, are prevalent in many populated areas and have been shown to affect the dispersion of traffic emissions. If roadside noise barriers or tree stands are found to consis- tently lower ground-level air pollution concentrations in the near-road environment, this may be a practical strategy for reducing exposures to air contaminants along populated traffic corridors. This study measured ultra- fine particle (UFP) concentrations using an instrumented mobile measurement approach, collecting data on major roadways and in near-road locations for more than forty sampling sessions at three locations in central North Carolina, USA. Two of the sampling sites had relatively thin tree stands, one evergreen and one deciduous, along a portion of the roadway. The third sampling site had a brick noise wall along a portion of the road. At 10 m from the road, UFPs measured using a mobile sampling platform were lower by approximately 50% behind the brick noise wall relative to a nearby location without a barrier for multiple meteorological conditions. The UFP trends at the vegetative barrier sites were variable and the barrier effect is uncertain. In some cases, higher con- centrations were observed behind the vegetative barrier, with respect to the clearing, which may be due to gaps in the thin tree stands allowing the transport of traffic-related air pollution to near-road areas behind the vege- tation. On-road sampling revealed no consistent difference in UFP levels in on-road portions of the road with or without a roadside barrier present. These findings support the notion that solid roadside barriers may mitigate near-road impact. Given the co-benefits of vegetative barriers in the urban landscape, research regarding the mitigation potential of vegetative barriers of other configurations (e.g., greater density, wider buffer) is encouraged.

Dirks, K. N., et al. (2012). "Personal exposure to air pollution for various modes of transport in Auckland, New Zealand." Open Atmos Sci J 6. This paper investigates the carbon monoxide (CO) doses received while commuting by different modes (car, bus, train, motorcycle, bicycle and running), taking into account the commute time as well as the level of physical activity required. While the participants were constrained to travel at specific peak traffic times and between designated start and end points, they were free to choose a route appropriate for their mode of transport. The results of this study suggest that the lowest exposures (concentrations of pollutants) are experienced by train commuters, largely a reflection of the routes being removed from any significant road traffic. Motorcyclists experienced significantly higher average concentrations as a result of high-concentration and very-short-duration peaks not seen in the traces of car and bus commuters travelling on the same road. Travel by bus along a dedicated busway was also found to be effective in reducing commuter air pollution exposure compared to travel by car on a congested stretch of motorway. The average concentrations to which cyclists and runners were exposed were found to be not significantly different for those travelling by car or bus (except when on dedicated pedestrian/cycleways). However, when the increased physical activity that is required is taken into account (leading to higher volumes of air breathed) along with the increased commuting time (especially in the case of runners), the air pollution doses (as estimated by the product of the concentration, commute time and breathing factor) were found to be significantly higher than for the motorised modes. The results suggest that separate pedestrian/cycleways go some way towards providing healthier options for cyclists and pedestrians.

Center, N. E. E. F. (2012). "Green Infrastructure Resource Directory." Green infrastructure is an approach for managing stormwater that uses vegetation and soils to capture and treat rainwater where it falls. Unlike single-purpose gray infrastructure, green infrastructure realizes multiple benefits at once, including flood mitigation, improved water and air quality, community beautification, provision of recreational opportunities, and energy and cost savings. This resource directory is intended to help communities design, implement, fund, and monitor green infrastructure practices and programs. It was compiled by the Environmental Finance Center Network through the Capacity Building for Sustainable Communities program funded by U.S. Department of Housing and Urban Development and U.S. Environmental Protection Agency. Through this program, EFCN is providing capacity building and technical assistance to recipients of grants from the federal Partnership for Sustainable Communities.

Cameron, R. W. F., et al. (2012). "The domestic garden – Its contribution to urban green infrastructure." Urban Forestry & Urban Greening 11(2): 129-137. Domestic gardens provide a significant component of urban green infrastructure but their relative contribution to eco-system service provision remains largely un-quantified. ‘Green infrastructure’ itself is often ill-defined, posing problems for planners to ascertain what types of green infrastructure provide greatest benefit and under what circumstances. Within this context the relative merits of gardens are unclear; however, at a time of greater urbanization where private gardens are increasingly seen as a ‘luxury’, it is important to define their role precisely. Hence, the nature of this review is to interpret existing information pertaining to gardens/gardening per se, identify where they may have a unique role to play and to highlight where further research is warranted. The review suggests that there are significant differences in both form and management of domestic gardens which radically influence the benefits. Nevertheless, gardens can play a strong role in improving the environmental impact of the domestic curtilage, e.g. by insulating houses against temperature extremes they can reduce domestic energy use. Gardens also improve localized air cooling, help mitigate flooding and provide a haven for wildlife. Less favourable aspects include contributions of gardens and gardening to greenhouse gas emissions, misuse of fertilizers and pesticides, and introduction of alien plant species. Due to the close proximity to the home and hence accessibility for many, possibly the greatest benefit of the domestic garden is on human health and well-being, but further work is required to define this clearly within the wider context of green infrastructure.

Wang, Z. and J. S. Zhang (2011). "Characterization and performance evaluation of a full- scale activated carbon-based dynamic botanical air filtration system for improving indoor air quality." Building and Environment 46(3): 758-768. A dynamic botanical air filtration system (DBAF) was developed for evaluating the short and long-term performance of botanical air cleaning technology under realistic indoor conditions. It was a fan-assisted with controlled airflow, activated-carbon/hydroculture based potted plant unit. The DBAF was first tested using a full-scale stainless chamber to evaluate its short-term performance. It was then integrated in the HVAC system of a new office space (96.8 m2) to study the effects of moisture content in the root bed on the removal efficiency, and the long-term performance. The results indicated that 5% outdoor air plus botanical filtration lead to the similar indoor formaldehyde/toluene concentration level as 25% outdoor air without filtration, which means that the filtration system was equivalent to 20% outdoor air (476 m3/h). The DBAF was effective for removing both formaldehyde and toluene under 5–32% volumetric water content of the root bed. It also performed consistently well over the relatively long testing period of 300 days while running continuously. The reduction in outdoor ventilation rate while using the botanical filtration system to maintain acceptable air quality would lead to 10–15% energy saving for the cold climate (Syracuse, NY), based on simulation analysis using EnergyPlus. For winter condition, the filter was also found to increase the supply air RH by 20%, which would decrease the dryness of air. For summer condition, the increase of RH in summer would be within 15% of the RH condition when no botanical air filtration is present.

Tallis, M., et al. (2011). "Freer-Smith: Estimating the removal of atmospheric particulate pollution by the urban tree canopy of London, under current and future environments." Landscape Urban Plann 103. Urban green space and particularly the tree canopy have been highlighted as offering a mitigation potential against atmospheric particulate pollution. In this paper current and future particulate (PM10) deposition to the urban tree canopy of the Greater London Authority (GLA) was estimated. A modelling approach was used based on the Urban Forest Effects Model (UFORE) and a modified version. Here we give evidence showing that these deposition models can be adapted to run from annual mean meteorological and PM10 concentration data, thus providing a methodology to examine future scenarios. Depending on the modelling approach, the urban canopy of the GLA is currently estimated to remove between 852 and 2121 tonnes of PM10 annually; representing between 0.7% and 1.4% of PM10 from the urban boundary layer. Estimates of PM10 removal which take into account a planned increased in tree cover, from the current 20% to 30% of the GLA land area, suggest deposition of 1109–2379 tonnes (1.1–2.6% removal) by the year 2050. The evidence provided here suggests that the targeting of tree planting in the most polluted areas of the GLA and particularly the use of street trees which have the greatest exposure to PM10, would have the greatest benefit to future air quality. The increased deposition would be greatest if a larger proportion of coniferous to broadleaved trees were used at such sites.

Smith, C. L., et al. (2011). "Fine-scale spatial temperature patterns across a UK conurbation." Clim Change 109. The public health implications of a warming urban environment mean that appropriate action by planners, designers and health workers will be necessary to minimise risk under future climate scenarios. Data at an appropriate spatial scale are required by user groups in order to identify key areas of vulnerability. Thermal mapping of a UK urban conurbation was carried out during the summers of 2007 and 2008 with the aim of providing high spatial resolution temperature data. The air temperature results showed an average daytime (night time) urban– rural thermal contrast of 3◦C (5◦C) on summer days (nights) with ideal urban heat island (UHI) conditions. The intensity of the daytime surface temperature heat island was found to exceed 10◦C. The measured data were used to derive an empirical model of spatial temperature patterns based upon characteristics of land use, distance from urban centre and building geometry. This model can be used to provide sub-kilometre resolution temperature data which are required by decision makers and can provide a mechanism for downscaling climate model output.

Mitchell, R., et al. (2011). "A comparison of green space measures for epidemiological research." J Epidemiol Community Health 65. Background The potential for natural environments to be salutogenic has received growing interest from epidemiologists, but there has been no critical examination of the extent to which associations between green space and health might vary according to the indicator of green space coverage used. Methods Three different indicators of green space coverage were derived for a set of 268 small areas in four cities within Britain. The indicators had different origins and provided a spectrum of sensitivity from larger spaces only, through to ambient greenery. Two indicators reproducible for anywhere in Europe were included. Agreement between the indicators on the quantity of green space in a small area, and their independent association with measures of mortality and self-reported morbidity, were compared. Results Overall, the indicators showed relatively close overall agreement (all r2>0.89, p<0.001). However, agreement varied by level of area socioeconomic deprivation (p<0.001). The indicator that detected larger spaces only found less green space in areas of socioeconomic deprivation than the other two. Despite this difference, all indicators showed similar protective associations with the risk of mortality and self-reported morbidity suggesting that larger green spaces may be more important for health effects than smaller spaces. Conclusions Associations between green space indicator and health were not sensitive to indicator origin and type. This raises the possibility of trans-European epidemiological studies. Larger green spaces may be the most important for health effects, but may also be less prevalent in more deprived areas.

Leung, D. Y. C., et al. (2011). "Effects of urban vegetation on urban air quality." Landscape Res 36. Vegetation has been well recognized for its ability in improving air quality and alleviating global warming. Tree planting has been used to mitigate urban heat island phenomena, sequester carbon dioxide, and help to trap air pollutants on leaves. Because some plant species emit biogenic volatile organic compounds (BVOCs), planting of some cultivars increase ozone and particulate matter ambient concentration and hence deteriorate air quality. Moreover, pollen grains and fungal spores from plants are health hazards for allergic or other sensitive members of the population. This paper reviews benefits and limited hazards of urban vegetation on air quality, highlighting useful computer simulations for predicting some of the interaction between urban forestry and the ambient atmosphere. To maximize the beneficial environmental effects of urban forestry, careful design, planning, and cost–benefit analysis would be required.

Kays, S. J. (2011). "Phytoremediation of indoor air–Current state of the art." The Value Creation of Plants for Future Urban Agriculture: 3-21. Phytoremediation of indoor air utilizes plants to remove or neutralize environmental contaminants such as volatile organic compounds (VOCs) in the air of homes, offices and other enclosed buildings. Certain plant species, working in tandem with yet unidentified microorganisms in the root zone, have the ability to remove VOCs and purify the air. Hundreds of VOCs have been identified as indoor contaminants (ACGIH, 1995; EPA, 1989; Won et al., 2005). For example, the U.S. Environmental Protection Agency (EPA) reported detection of more than 900 VOCs in the air of public buildings (EPA, 1989). In a Finnish study, over 200 VOCs were identified in each of 26 homes (Kostiainen, 1995). An example of the types of volatiles that might be encountered is presented in Table 1 which lists the VOCs found in two houses surveyed in Athens, Georgia that had serious air quality problems. The volatiles in the first house were emanating from toxic drywall and in the second from insulation that had been blown into the air space within the outside walls. Indoor air in cities has been reported to be as much as 5 to 1000 times more polluted than exterior air (Brown et al., 1994; Godish, 1995; Kostianen, 1995; Brown, 1997; Ingrosso, 2002; Yang et al., 2004; Zabiegała, 2006). The chemicals are absorbed into human and animal bodies through inhalation and in some instances, through direct penetration of the skin (McDougal et al., 1990). While the initial work on phytoremediation of indoor air was done in the 1970s, it has not been until recently that interest in the subject has spread. Currently, the leading research programs are in South Korea. To date, a significant portion of the research has been directed toward identifying superior phytoremediation species of indoor plants. While the results have been very positive, the lack of adequate funding has impeded exploring the basic mechanisms operative and making the transition from the laboratory to real world homes and offices. As a consequence, what we currently know is vastly exceeded by what we do not, a situation that is evident from, for example, the very limited number of VOCs that have been tested. The public has displayed tremendous interest in the potential of phytoremediation and there is a growing awareness of the serious health issues arising from breathing polluted indoor air. Four popular books on the subject are currently available (Son, 2004; Son, 2009; Wolverton, 1996; Wolverton and Takenaka, 2010).

Joye, Y. and A. van den Berg (2011). "Is love for green in our genes? A critical analysis of evolutionary assumptions in restorative environments research." Urban Forestry & Urban Greening 10(4): 261-268. Within the field of restorative environments research, it is commonly assumed that restorative responses, triggered by exposure to natural elements and settings, are ultimately adaptive traits originating from our species’ long evolutionary history in natural environments. The aim of this article is to critically investigate the viability of this evolutionary view on restoration. In doing so, we specifically focus on Stress Recovery Theory (SRT), as this theoretical framework has most extensively elaborated on the supposed evolutionary origins of restoration. A detailed analysis of SRT’s psycho- evolutionary framework shows that neither current empirical evidence nor conceptual arguments provide any strong support for the hypothesis of restorative responses to nature as an ancient evolved adaptive trait. Based on this conclusion we put forward an alternative model for restorative responses to nature based on processing fluency, which prima facie circumvents some of the pitfalls associated with evolutionary accounts for restoration. The Discussion section reflects on the implications of our critical discussion for the theory and practice of urban forestry and urban greening.

Buccolieri, R., et al. (2011). "Analysis of local scale tree-atmosphere interaction on pollutant concentration in idealized street canyons and application to a real urban junction." Atmos Environ 45. This paper first discusses the aerodynamic effects of trees on local scale flow and pollutant concentration in idealized street canyon configurations by means of laboratory experiments and Computational Fluid Dynamics (CFD). These analyses are then used as a reference modelling study for the extension a the neighbourhood scale by investigating a real urban junction of a medium size city in southern Italy. A comparison with previous investigations shows that street-level concentrations crucially depend on the wind direction and street canyon aspect ratio W/H (with W and H the width and the height of buildings, respectively) rather than on tree crown porosity and stand density. It is usually assumed in the literature that larger concentrations are associated with perpendicular approaching wind. In this study, we demonstrate that while for tree-free street canyons under inclined wind directions the larger the aspect ratio the lower the street-level concentration, in presence of trees the expected reduction of street-level concentration with aspect ratio is less pronounced. Observations made for the idealized street canyons are re-interpreted in real case scenario focusing on the neighbourhood scale in proximity of a complex urban junction formed by street canyons of similar aspect ratios as those investigated in the laboratory. The aim is to show the combined influence of building morphology and vegetation on flow and dispersion and to assess the effect of vegetation on local concentration levels. To this aim, CFD simulations for two typical winter/spring days show that trees contribute to alter the local flow and act to trap pollutants. This preliminary study indicates that failing to account for the presence of vegetation, as typically practiced in most operational dispersion models, would result in non-negligible errors in the predictions. Research Highlights: ► Trees influence pollutant concentration distribution in urban street canyons. ► Failing to account for the presence of trees may result in critical errors in model predictions. ► Building morphology and vegetation have to be analysed together. ► Analyses of data from various sources (CFD modelling, wind tunnel and monitoring stations) are necessary to produce a comprehensive picture of complex flow and dispersion phenomena within urban areas.

Beruto, M. (2011). Introduction of new ornamental plants and production technologies: case studies. VII International Symposium on New Floricultural Crops 1000. The floriculture is a dynamic sector where a wide range of products are considered. To stand the global competitiveness it is mandatory to introduce novelties into the market. Moreover a strong cooperation among the different links of the productive chain is a prerequisite for shortening the time to valorise the new products. R&D is an important step to introduce product and process innovation. The intended outcomes of this work are to present some case studies carried out at Regional Institute for Floriculture (IRF), Sanremo, addressed to support the productive world in enhancing niche crops for the export. New articles for the market have been obtained through the development of new propagation schemes (Ranunculus asiaticus), the achievement of innovative genotypes (Argyranthemum frutescens) and the exploitation of wild sources (Euphorbia spinosa).

Aydogan, A. and L. D. Montoya (2011). "Formaldehyde removal by common indoor plant species and various growing media." Atmospheric Environment 45(16): 2675-2682. Three porous materials (growstone, expanded clay and activated carbon) were evaluated as hydroponic growing media and for their individual ability to remove the indoor volatile organic compound form- aldehyde under three conditions: growing medium alone, dry medium in a pot, and wet medium in a pot. The total percent-reduction of formaldehyde by each growing media was evaluated over a 10-h period. In all cases, activated carbon achieved the highest removal under the three conditions studied with average percent reductions measured at about 98%. Four common interior plants: Hedera helix (English ivy), Chrysanthemum morifolium (pot mum), Dieffenbachia compacta (dump cane) and Epi- premnum aureum (golden pathos) growing in growstone were then tested for their ability to remove formaldehyde. The removal capacity of the aerial plant parts (AP), the root zone (RZ) and the entire plant (EP) growing in growstone were determined by exposing the relevant parts to gaseous formaldehyde (w2000 mg m 3) in a closed chamber over a 24-h period. The removal efficiency between species and plant parts were compared by determining the time interval required to decrease about 2/3 of the total formaldehyde concentration reduction, T2/3. The T2/3 measured were 23, 30, 34 and 56 min for EP of C. morifolium, E. aureum, D. compacta and H. helix, respectively. The formaldehyde removal by the root zone was found to be more rapid than the removal by the aerial plant parts.

Shashua-Bar L, P. D., Erell E. (2010b). The influence of trees and grass on outdoor thermal comfort in a hot-arid environment. The effects of vegetation on human thermal stress in a hot-arid region were tested in two semi-enclosed urban spaces with various combinations of mature trees, grass, overhead shading mesh and paving. The index of thermal stress was calculated hourly from measured meteorological data in the studied sites to evaluate thermal comfort in the different spaces based on radiative and convective pedestrian–environment energy exchanges and sweat efficiency, and expressed on a thermal sensation scale ranging from ‘comfortable’ to ‘very hot’. The efficiency of water use in providing improved comfort was gauged for each of the vegetative landscaping treatments by comparing the total evapotranspiration with the reduction in thermal stress, both expressed in terms of their values in equivalent energy. While conditions in a paved, unshaded courtyard were found to be uncomfortable throughout the daytime hours (with half of these hours defined by severe discomfort), each of the landscape treatments made a clear contribution to improved thermal comfort. With shading, either by trees or mesh, discomfort was reduced in duration by over half and limited in maximum severity when the shading was placed above paving. When combined with grass, both shading mechanisms yielded comfortable conditions at all hours. In both cases, the effect of trees was more pronounced than that of the mesh, but by a small margin. With unshaded grass, ‘hot’ conditions in the courtyard were restricted to a short period in mid-afternoon, a considerable improvement over unshaded paving, attributable mainly to the lower radiant surface temperatures.

Shashua-Bar L, P. O., Bitan A, Boltansky D, Yaakov Y. (2010a). Microclimate modelling of street tree species effects within the varied urban morphology in the Mediterranean city of Tel Aviv, Israel. Microclimate formation and its significance in urban planning was examined through two components that predominate in affecting the city’s climate: built-up morphology and urban shade trees. The methodological approach focus is on a generalization procedure for quantifying the thermal effect of any studied situation through parameterization of the vegetated variables and the built-up forms. The analysis is integrative, using empirical climatic data followed by an analytical study for generalization and sensitivity analysis using an integrative model, the Green CTTC model. Three urban tree species predominant in the Tel Aviv gardens and streets, with different canopy characteristics, and three levels of building densities were analysed to determine their thermal effect on an urban street microclimate. The variables were parameterized according to six basic cooling attributes for the studied tree species in urban gardens in Tel Aviv, and according to three geometric built-up parameters for the studied urban street. The integrative modelling approach of considering all changes simultaneously was illustrated on an urban boulevard in Tel Aviv. The analysis demonstrates the shortcomings of piecemeal modelling and the merits of the integrative approach. The study indicates the importance of urban trees in alleviating the heat island effect in a hot and humid summer. The tree cooling effect was found to be strongly related to the built form geometry. In all the studied cases, the thermal effect of the tree was found to depend mainly on its canopy coverage level and planting density in the urban street and little on other species characteristics. The methodology of analysis presented in this paper can be applied to develop an operational tool in assessing for an urban open space the integrative thermal effects of different tree species, and of the varied urban morphology and the interaction between them.

Thornes, J., et al. (2010). "Communicating the value of atmospheric services." Meteorol Appl 17. The atmosphere is one of the most valuable resources on the planet and yet because it is largely invisible it tends to be taken for granted and is increasingly being exploited and commodified. This paper presents 12 Atmospheric Services that are vital to human well-being and the existence of the biosphere. The Total Economic Value of the atmosphere is estimated to be at least between 100 and 1000 times the Gross World Product (GWP was approximately £43 Trillion in 2008). It is only by appreciating the value of the atmosphere to society that we can understand how we need to communicate sustainable management of the atmosphere and treat it as a global commons. It is also important to realize which Atmospheric Services are currently under threat. Only by appreciating the full range of services provided by the atmosphere can the real cost of geo-engineering the climate be calculated. Before geo-engineering of the climate can ever be considered seriously a Law of the Atmosphere will be required.

Sellmer, J. C. (2010). "Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens." HortTechnology 20(1): 257-. Bringing Nature Home is the first book that this reviewer has found on the market to provide a discussion on how by using native plants in the home landscape, we can support the native fauna in the garden, landscape, and surrounding community. The book consists of 14 chapters with the first seven chapters providing arguments against non-native plants. Chapters 8 through 10 begin the discussion of biodiversity and approaches for using natives in the landscape. Chapters 11 through 13 provide insight into what native plants to use to attract native insects that feed upon those plants. The final chapter provides answers to common tough questions surrounding the debate about the use of native and non-native plants in the home landscape. The appendices consist of three sections with the first listing native plants classified by type (e.g., shade and specimen trees, shrub and understory trees, conifers, vines, grasses, herbaceous perennials) with wildlife value for general regions across the country (e.g., Mid- Atlantic, Southeast, Southwest, and Pacific Northwest). Appendix two is a table of butterflies and moths and their hosts, and appendix three provides some unpublished data from the author's research on insect herbivory on woody native and alien species in his backyard and published work by his graduate student on early successional perennials.

Seaman, P. J., et al. (2010). "It’s not just about the park, it’s about integration too: why people choose to use or not use urban greenspaces." Int J Behav Nutr Phys Act 7. Background: Greenspace has the potential to be a vital resource for promoting healthy living for people in urban areas, offering both opportunities for physical activity and wellbeing. Much research has explored the objectively measurable factors within areas to the end of explaining the role of greenspace access in continuing health inequalities. This paper explores the subjective reasons why people in urban areas choose to use, or not use, local public greenspace. Methods: In-depth interviews with 24 people living in two areas of Glasgow, United Kingdom were conducted, supplemented with participant photography and participatory methods. Data was thematically categorised to explore subjectively experienced facilitators and barriers to greenspace use in urban areas. Results: From the perspective of current and potential urban greenspace users, access is revealed to be about more than the physical characteristics of neighbourhoods, greenspace resources or objectively measurable features of walkability and connectivity. Subjectively, the idea of walkability includes perceptions of social cohesion at a community level and the level of felt integration and inclusion by individuals in their communities. Individual's feelings of integration and inclusion potentially mitigate the effects of experiential barriers to urban greenspace access, such as evidence of anti-social behaviour. Conclusions: We conclude that improving access to greenspace for all in urban communities will require more than providing high quality resources such as parks, footpaths, activities and lighting. Physical availability interacts with community contexts already established and a holistic understanding of access is required. A key cultural component of areas and neighbourhoods is the level of social cohesion, a factor that has the potential to reinforce existing health inequalities through shaping differentiated greenspace access between subgroups of the local population.

Rae RA, S. G., Braden J. (2010). Public reactions to new street tree planting. MillionTrees NYC, which has the goal of planting one million trees in New York City by 2017, is intended to make New York City a greener, more sustainable city and is part of the Mayor’s comprehensive long term strategic plan, PlaNYC. Through planting a tree at every suitable sidewalk location in the city, the City of New York is transforming blocks and communities, and providing a variety of environmental, social and aesthetic benefits. This article examines the large scale municipal planting of new street trees and the reaction by some of the pubic to this planting. Trees offer benefits to the city overall, but the public may not understand these benefits or the street tree planting process. Between 2007 and 2009, the Department of Parks & Recreation planted 53,235 new street trees, and received 4,108 items of correspondence from the public. The majority of this correspondence consisted of public comments about the City’s new street tree planting policies and processes including placement objections, maintenance concerns, reports of resultant damage from tree planting operations, requests for new street trees and reports of tree conditions. This study describes the operational policies that guide New York City's municipal street tree planting, and results of content and spatial analysis of the correspondence. Qualitative analysis of the correspondence revealed public perceptions and concerns related to the MillionTreesNYC program. Spatial analysis explored the relationship between the planting locations of new street trees and the locations of the citizen correspondence. Public reactions to this large scale municipal planting are related to the dual public and private nature of the sidewalk, issues of territoriality, responsibility, aesthetics and place attachment. Correspondence volume was associated with the scale of the new street tree block planting program, and the effectiveness of NYC’s 311 Customer Service Center. The discussion suggests that increased public education on tree benefits and notification of planting processes could change perceptions of new street tree planting. This study also identifies the potential for targeted research studies to further investigate public reactions to new street tree planting.

Norgaard, R. B. (2010). "Ecosystem services: From eye-opening metaphor to complexity blinder." Ecol Econ 69. What started as a humble metaphor to help us think about our relation to nature has become integral to how we are addressing the future of humanity and the course of biological evolution. The metaphor of nature as a stock that provides a flow of services is insufficient for the difficulties we are in or the task ahead. Indeed, combined with the mistaken presumption that we can analyze a global problem within a partial equilibrium economic framework and reach a new economy project-by-project without major institutional change, the simplicity of the stock- flow framework blinds us to the complexity of the human predicament. The ecosystem services approach can be a part of a larger solution, but its dominance in our characterization of our situation and the solution is blinding us to the ecological, economic, and political complexities of the challenges we actually face.

Lundholm, J., et al. (2010). "Plant Species and Functional Group Combinations Affect Green Roof Ecosystem Functions." PLoS ONE 5(3). Background: Green roofs perform ecosystem services such as summer roof temperature reduction and stormwater capture that directly contribute to lower building energy use and potential economic savings. These services are in turn related to ecosystem functions performed by the vegetation layer such as radiation reflection and transpiration, but little work has examined the role of plant species composition and diversity in improving these functions. Methodology/Principal Findings: We used a replicated modular extensive (shallow growing-medium) green roof system planted with monocultures or mixtures containing one, three or five life-forms, to quantify two ecosystem services: summer roof cooling and water capture. We also measured the related ecosystem properties/processes of albedo, evapotranspiration, and the mean and temporal variability of aboveground biomass over four months. Mixtures containing three or five life-form groups, simultaneously optimized several green roof ecosystem functions, outperforming monocultures and single life-form groups, but there was much variation in performance depending on which life-forms were present in the three life-form mixtures. Some mixtures outperformed the best monocultures for water capture, evapotranspiration, and an index combining both water capture and temperature reductions. Combinations of tall forbs, grasses and succulents simultaneously optimized a range of ecosystem performance measures, thus the main benefit of including all three groups was not to maximize any single process but to perform a variety of functions well. Conclusions/Significance: Ecosystem services from green roofs can be improved by planting certain life-form groups in combination, directly contributing to climate change mitigation and adaptation strategies. The strong performance by certain mixtures of life-forms, especially tall forbs, grasses and succulents, warrants further investigation into niche complementarity or facilitation as mechanisms governing biodiversity-ecosystem functioning relationships in green roof ecosystems.

Lin, B. S. and Y. J. Lin (2010). "Cooling effect of shade trees with different characteristics in a subtropical urban park." HortScience 45. The effect of shade trees on the air and surface-soil temperature reduction under the canopy was studied in a park in subtropical Taipei City, Taiwan. Ten species of trees and two species of bamboo, which had tightly clustered tall stems and spreading branches resembling trees in shape, were chosen for the study. In the summer of 2007, we measured leaf and canopy characteristics of each species. The microclimate conditions under the tree canopies and an unshaded open space were measured repeatedly at middays without precipitation. In comparison with the nearby unshaded open space, air temperatures under the canopies were 0.64 to 2.52 °C lower, whereas the surface-soil temperatures were 3.28 to 8.07 °C lower. Regression analysis revealed the relative contributions to air cooling effect by the plant's leaf color lightness, foliage density, leaf thickness, and leaf texture (surface roughness) in decreasing order. Foliage density had the greatest contribution to surface-soil cooling followed by leaf thickness, leaf texture, and leaf color lightness in that order. Regression analysis also revealed that solar radiation, wind velocity, and vapor pressure at the site had significant effects on temperature reduction attributable to shade trees or bamboo.

Jeon, J. Y., et al. (2010). "Perceptual assessment of quality of urban soundscapes with combined noise sources and water sounds." J Acoust Soc Am 127. In this study, urban soundscapes containing combined noise sources were evaluated through field surveys and laboratory experiments. The effect of water sounds on masking urban noises was then examined in order to enhance the soundscape perception. Field surveys in 16 urban spaces were conducted through sound-walking to evaluate the annoyance of combined noise sources. Synthesis curves were derived for the relationships between noise levels and the percentage of highly annoyed %HA and the percentage of annoyed %A for the combined noise sources. Qualitative analysis was also made using semantic scales for evaluating the quality of the soundscape, and it was shown that the perception of acoustic comfort and loudness was strongly related to the annoyance. A laboratory auditory experiment was then conducted in order to quantify the total annoyance caused by road traffic noise and four types of construction noise. It was shown that the annoyance ratings were related to the types of construction noise in combination with road traffic noise and the level of the road traffic noise. Finally, water sounds were determined to be the best sounds to use for enhancing the urban soundscape. The level of the water sounds should be similar to or not less than 3 dB below the level of the urban noises.

Goddard, M. A., et al. (2010). "Scaling up from gardens: biodiversity conservation in urban environments." Trends Ecol Evol 25(2): 90-98. As urbanisation increases globally and the natural environment becomes increasingly fragmented, the importance of urban green spaces for biodiversity conservation grows. In many countries, private gardens are a major component of urban green space and can provide considerable biodiversity benefits. Gardens and adjacent habitats form interconnected networks and a landscape ecology framework is necessary to understand the relationship between the spatial configuration of garden patches and their constituent biodiversity. A scale-dependent tension is apparent in garden management, whereby the individual garden is much smaller than the unit of management needed to retain viable populations. To overcome this, here we suggest mechanisms for encouraging 'wildlife-friendly' management of collections of gardens across scales from the neighbourhood to the city.

Georgi, J. N. and D. Dimitriou (2010). "The contribution of urban green spaces to the improvement of environment in cities: Case study of Chania, Greece." Building and Environment 45(6): 1401-1414. This paper investigates how vegetation, mainly through evapotranspiration, affects the improvement of microclimatic conditions in urban areas and, more specifically, it examines the case for the city of Chania in Crete. The objectives of this study are to examine the bioclimatic role of green areas in urban sites as they affect the thermal comfort of residents, and to study the cross-correlation of factors that participate in this process. To achieve these objectives, we have examined the parameters that contribute to the microclimate of a space and consider how it is influenced by vegetation. In addition, we have analyzed the effect of vegetation with respect to evapotranspiration, and have recorded the existing vegetation of Chania city and the relationship with the geomorphologic and urban characteristics of the city. This has involved calculating the evapotranspiration of various plant species, and collecting measurements at various places in Chania. These studies are designed to determine the cause of the changes of thermal comfort in different parts of the city, and to examine the differentiation of thermal comfort that is observed between different plant species with respect to the evapotranspiration measure that has been calculated for each of them. The intention of this work is to aid efforts to improve the environment of Chania through better planning and the appropriate choice of the species used for planting open spaces. Finally, it is hoped that the results of this work will be of use in planning the environments of spaces in other cities that have similar characteristics.

Dvorak, B. and A. Volder (2010). "Green roof vegetation for North American ecoregions: A literature review." Landscape and Urban Planning 96(4): 197-213. A green roof is a vegetated roof or deck designed to provide urban greening for buildings, people, or the environment. Made popular across Europe over the past few decades, green roofs are now becoming more familiar to North Americans as some cities have built green roof pilot projects and adopted incentives for using green roofs or even require their use. Green roof standards and guidelines are also emerging to be used for governance and project specification. Although much is known about the application of green roofs across Europe, much less is known about their application across North America's diverse ecological regions. When considering the many decisions required in applying green roof technology to a specific place, there are few choices more critical to their success than the selection of appropriate vegetation. We conducted a review of green roof research to investigate what is known about the application of plants on green roofs across North America and their ecological implications. Results indicate that investigation sites across ecoregions begin to reveal differences in plant survival. Although ecological investigations are limited, their results show improved plant performance and ecological services with diverse green roofs. We conclude that as green roofs continue to become regulated and adopted in policy, further development of standards and guidelines is needed. To date, there is no common ground for reporting of green roof research, and we make recommendations for facilitating such efforts for improved research, policy development and their management across North America's diverse ecological regions.

Dennis, J. H., et al. (2010). "Sustainable Production Practices Adopted by Greenhouse and Nursery Plant Growers." HortScience 45(8): 1232-1237. Given recent consumer and market interest in more sustainable products and business practices, researchers conducted a nationwide survey of greenhouse and nursery crop growers to determine the current state of the industry in terms of sustainability. Growers were asked about the importance of sustainability, their views of state environmental regulations, sustainable practices in place and ones they would like to implement in the next 1 to 3 years, and interest in sustainable certification. None of the grower respondents in this survey were certified sustainable, but at least one fourth (25.8%) were interested in certification. More than half of the respondents currently recycle plastic pots, use controlled-release fertilizers, and composted plant waste. However, only 12% of growers want to use biodegradable plant containers or implement water conservation measures into their production system within the next 1 to 3 years. Grower respondents felt the biggest obstacle toward implementation was the sustainable production practice would not be compatible with their existing system of production.

Dearborn, D. C. and S. Kark (2010). "Motivations for conserving urban biodiversity." Conserv Biol 24(2): 432-440. In a time of increasing urbanization, the fundamental value of conserving urban biodiversity remains controversial. How much of a fixed budget should be spent on conservation in urban versus nonurban landscapes? The answer should depend on the goals that drive our conservation actions, yet proponents of urban conservation often fail to specify the motivation for protecting urban biodiversity. This is an important shortcoming on several fronts, including a missed opportunity to make a stronger appeal to those who believe conservation biology should focus exclusively on more natural, wilder landscapes. We argue that urban areas do offer an important venue for conservation biology, but that we must become better at choosing and articulating our goals. We explored seven possible motivations for urban biodiversity conservation: preserving local biodiversity, creating stepping stones to nonurban habitat, understanding and facilitating responses to environmental change, conducting environmental education, providing ecosystem services, fulfilling ethical responsibilities, and improving human well-being. To attain all these goals, challenges must be faced that are common to the urban environment, such as localized pollution, disruption of ecosystem structure, and limited availability of land. There are, however, also challenges specific only to particular goals, meaning that different goals will require different approaches and actions. This highlights the importance of specifying the motivations behind urban biodiversity conservation. If the goals are unknown, progress cannot be assessed.

Day, S. D., et al. (2010). "Tree root ecology in the Urban environment and implications for a sustainable rhizosphere." Arboriculture Urban Forestry 36. This review examines current understandings of how the belowground characteristics of urban settings affect tree roots as well as how tree roots contribute to biogeochemical processes in this belowground environment. Soil characteristics common to the urban environment include soil compaction and other physical impediments to root exploration, elevated pH, altered temperature and moisture patterns, and the presence of contaminants. These conditions may alter the growth dynamics, morphology, and physiology of roots. At the same time, roots have a profound effect on the soil environment, with trees directing 40%–73% of assimilated carbon below ground. Urban rhizosphere ecology is a topic of renewed interest for research not only because of its critical role in the urban ecosystem, but also because of its role in global environmental issues. In addition to its obvious contribution to aboveground growth, root exploration of the soil environment can influence environmental sustainability through root contributions to soil structure and drainage. Root influence is further mediated by the intimate role of roots in soil biological activity and thus carbon storage and nutrient cycling. Current advances and implications for emerging research are discussed.

Bassuk, N. and P. Trowbridge (2010). "Creating the Urban Eden: Sustainable Landscape Establishment in Theory and Practice." HortTechnology 20(3): 485-486. Creating the Urban Eden, a course taught jointly by faculty in Landscape Architecture and Horticulture at Cornell University, is a unique two-semester class spanning the academic year from August to May. Students face the task of creating viable, sustainable landscapes both in theory and practice. The success and sustainability of any planting design is ultimately dependent upon knowledgeable site assessment and analysis, appropriate plant selection, and clear communication of design intentions. This class teaches all aspects of landscape establishment, including detailed site assessment, woody plant identification, choice of appropriate plants, planting design, soil remediation, transplanting, and early maintenance in human-impacted landscapes. In addition to designing for a specific site, students learn about written specifications for technical planting and graphic details to communicate and implement design proposals. Every year on the Cornell University campus, the students in this class implement, in a hands-on manner, all aspects of landscape establishment that they have learned by creating new landscapes that serve to integrate theory, principles, practice, and provide a demonstration of fundamentals taught in the class.

Behe, B. K., Campbell, B., Dennis, J., Hall, C., Lopez, R., & Yue, C. (2010). "Gardening consumer segments vary in ecopractices." Savvy marketers rely on the principles of customer segmentation and product targeting to more efficiently allocate scarce resources and effectively reach groups of consumers with similar likes, preferences, or demands. Our objective was to identify and profile consumer segments with regard to their gardening purchases to determine whether there were differences in their ecofriendly attitudes and behaviors such as recycling. Our underlying hypothesis was that different types of gardeners may exhibit more environmentally friendly behavior, predisposing them to be more receptive to product innovations specifically designed to be ecofriendly. Researchers collected plant purchases, recycling attitudes and behaviors, and preferences for ecofriendly containers from 763 consumers in Indiana, Michigan, Minnesota, and Texas. A cluster analysis based on plant purchases yielded three consumer segments: low use, woody plant buyers, and herbaceous plant buyers. There were some differences with regard to recycling behaviors among consumers in the three groups, including recycling aluminum drinking cans, newspapers, magazines, use of energy-saving bulbs, and composting yard waste. Generally, herbaceous plant buyers were most ecofriendly followed by woody plant buyers and low use. Given these differences, there appears to be some merit in the future to segment consumers by plant purchases versus others to target specific types of ecofriendly products to them.

Yang, D. S., et al. (2009). "Screening Indoor Plants for Volatile Organic Pollutant Removal Efficiency." HortScience 44(5): 1377-1381. Twenty-eight ornamental species commonly used for interior plantscapes were screened for their ability to remove five volatile indoor pollutants: aromatic hydrocarbons (benzene and toluene), aliphatic hydrocarbon (octane), halogenated hydrocarbon [trichloroethylene (TCE)], and terpene ({alpha}-pinene). Individual plants were placed in 10.5-L gas-tight glass jars and exposed to {approx}10 ppm (31.9, 53.7, 37.7, 46.7, and 55.7 mg{middle dot}m-3) of benzene, TCE, toluene, octane, and{alpha} -pinene, respectively. Air samples (1.0 mL) within the glass containers were analyzed by gas chromatography-mass spectroscopy 3 and 6 h after exposure to the test pollutants to determine removal efficiency by monitoring the decline in concentration over 6 h within sealed glass containers. To determine removal by the plant, removal by other means (glass, plant pot, media) was subtracted. The removal efficiency, expressed on a leaf area basis for each volatile organic compound (VOC), varied with plant species. Of the 28 species tested, Hemigraphis alternata, Hedera helix, Hoya carnosa, and Asparagus densiflorus had the highest removal efficiencies for all pollutants; Tradescantia pallida displayed superior removal efficiency for four of the five VOCs (i.e., benzene, toluene, TCE, and{alpha} -pinene). The five species ranged in their removal efficiency from 26.08 to 44.04 {micro}g{middle dot}m- 3{middle dot}m-2{middle dot}h-1 of the total VOCs. Fittonia argyroneura effectively removed benzene, toluene, and TCE. Ficus benjamina effectively removed octane and{alpha} -pinene, whereas Polyscias fruticosa effectively removed octane. The variation in removal efficiency among species indicates that for maximum improvement of indoor air quality, multiple species are needed. The number and type of plants should be tailored to the type of VOCs present and their rates of emanation at each specific indoor location.

Tait, R. J., et al. (2009). "An electronic tree inventory for arboriculture management." Knowledge-Based Systems 22(7): 552-556. The integration of Global Positioning System (GPS) technology into mobile devices provides them with an awareness of their physical location. This geospatial context can be employed in a wide range of applications including locating nearby places of interest as well as guiding emergency services to incidents. In this research, a GPS-enabled Personal Digital Assistant (PDA) is used to create a computerised tree inventory for the management of arboriculture. Using the General Packet Radio Service (GPRS), GPS information and arboreal image data are sent to a web-server. An office-based PC running customised Geographical Information Software (GIS) then automatically retrieves the GPS tagged image data for display and analysis purposes. The resulting application allows an expert user to view the condition of individual trees in greater detail than is possible using remotely sensed imagery.

Stewart, G. H., et al. (2009). "URban Biotopes of Aotearoa New Zealand (URBANZ) II: Floristics, biodiversity and conservation values of urban residential and public woodlands, Christchurch." Urban Forestry & Urban Greening 8(3): 149-162. Urban forests are increasingly valued for multiple benefits such as amenity, cultural values, native biodiversity, ecosystem services, and carbon sequestration. Urban biodiversity in particular, is the new focus although global homogenisation is undermining regional differentiation. In the northern hemisphere (e.g., Canada and USA) and in the southern hemisphere, particularly in countries like South Africa, Australia, South America and New Zealand, local biodiversity is further impacted by historical colonisation from Europe. After several centuries, urban forests are now composed of synthetic and spontaneous mixtures of native species, and exotic species from around the temperate world (e.g., Europe, North and South America, South Africa, Asia). As far as we are aware no-one has carried out in-depth study of these synthetic forests in any Southern Hemisphere city. Here we describe the composition, structure, and biodiversity conservation imperatives of urban temperate forests at 90 random locations in Christchurch city, New Zealand. We document considerable plant diversity; the total number of species encountered in the 253 sampled urban forest patches was 486. Despite this incredibly variable data set, our ability to explain variation in species richness was surprisingly good and clearly indicates that total species richness was higher in larger patches with greater litter and vegetation cover, and taller canopy height. Species richness was also higher in patches surrounded by higher population densities and closer to very large native forest patches. Native species richness was higher in patches with higher soil pH, lower canopy height, and greater litter cover and in patches closer to very large native forest patches indicating dispersal out of native areas and into gardens. Eight distinct forest communities were identified by Two-Way INdicator SPecies ANalysis (TWINSPAN) using the occurrence of 241 species that occurred in more than two out of all 253 forest patches. Christchurch urban forest canopies were dominated by exotic tree species in parklands and in street tree plantings (linear parkland). Native tree and shrub species were not as common in public spaces but their overall density high in residential gardens. There was some explanatory power in our data, since less deprivation resulted in greater diversity and density, and more native species, which in turn is associated with private ownership. We hypothesise that a number of other factors, which were not well reflected in our measured environmental variables, are responsible for much of the remaining variation in the plant community structure, e.g., advertising, peoples choice. For a more sustainable asset base of native trees in New Zealand cities we need more, longer-lived native species, in large public spaces, including a greater proportion of species that bear fruit and nectar suitable for native wildlife. We may then achieve cities with ecological integrity that present multiple historical dimensions, and sequester carbon in legible landscapes.

Sanford, M. P., et al. (2009). "Effects of Urban Development on Ant Communities: Implications for Ecosystem Services and Management." Conservation Biology 23(1): 131- 141. Research that connects the effects of urbanization on biodiversity and ecosystem services is lacking. Ants perform multifarious ecological functions that stabilize ecosystems and contribute to a number of ecosystem services. We studied responses of ant communities to urbanization in the Lake Tahoe basin by sampling sites along a gradient of urban land development. We sampled ant communities, measured vegetation characteristics, quantified human activities, and evaluated ant-community responses by grouping ants into service- providing units (SPUs), defined as a group of organisms and their populations that perform specific ecosystem services, to provide an understanding of urbanization impacts on biodiversity and their delivery of ecosystem services. Species richness and abundance peaked at intermediate levels of urban development, as did the richness of 3 types of ant SPUs (aerators, decomposers, and compilers). With increasing land development aerator and decomposer ants significantly declined in abundance, whereas compiler ants significantly increased in abundance. Competing models demonstrated that precipitation was frequently among the strongest influences on ant community structure; however, urban development and human activities also had a strong, negative influence on ants, appearing in most models with Delta AIC(c) < 2 for species richness and abundance patterns of SPUs and generalists. Response diversity was observed within SPUs, which suggests that the corresponding ecosystem services were maintained until development reached 30-40%. Our data provide evidence that ecosystem functions, such as water infiltration and soil productivity, may be diminished at sites subject to greater levels of urbanization and that conserving ant communities and the ecosystem services they provide could be an important target in land-use planning and conservation efforts.

Rosenzweig, C., et al. (2009). "Mitigating New York City’s Heat Island: integrating stakeholder perspectives and scientific evaluation." Bull Am Meteorol Soc 90. The urban heat island effect1 can be detected throughout the year, but it is of particular pub- lic policy concern during the summer, because higher surface air temperature is associated with increases in electricity demand for air conditioning, air pollution, and heat stress-related mortality and illness (Rosenfeld et al. 1995; Nowak et al. 2000; Sailor et al. 2002; Hogrefe et al. 2004). In New York City, New York (NYC), the heat island impacts interact with aging energy and water infrastructure and the anticipated regional effects of global climate change. This has led local decision makers to ask whether heat island mitigation can help to address some of these related urban challenges, for example, by reducing electricity demand for cooling, absorbing stormwater runoff, and reducing the health impacts of heat waves. Our main goal was to compare the possible effectiveness of heat island mitigation strategies to increase urban vegetation, such as planting trees or incorporating vegetation into rooftops, with strategies to increase the albedo of impervious surfaces. The specific stakeholder question guiding our research was the following: can heat island mitigation strate- gies reduce peak electricity demand in neighbor- hoods with potential electric distribution constraints

Randhir, T. and P. Ekness (2009). "Urbanization effects on watershed habitat potential: a multivariate assessment of thresholds and interactions." Ecohydrology 2(1): 88-101. A watershed-based assessment is used to assess the effect of urbanization on vertebrate habitat potential in Westfield River Watershed in Massachusetts, USA. A spatial analysis is used to develop urban indicators and habitat potential for each subbasin in the watershed. It is observed that threshold effect of urbanization on habitat potential of vertebrates is at 10 to 12 percent impervious cover. Amphibian habitat is influenced by available open space and land use disturbance in the watershed. The reptile habitat is sensitive to impervious coverage and land use disturbance, and decreased with fragmentation. The habitat for birds is influenced by land use disturbance, human population densities, size of forest patch, and open space in the watershed. Mammal habitat is influenced by human population density, land use disturbance, and fragmentation. A watershed-based assessment is useful to identify critical areas of high urban influence. Threshold values and nature of interactions between urbanization and habitat are assessed and used in policy recommendations. Policies and practices that minimize effects of urbanization in the watershed include impervious taxes, zoning policies, and open space protection. The need for provision of education and information on the relationship between urbanization and habitat potential is emphasized for sustainable use of watershed resources.

Patterson, T. M. and D. L. Coelho (2009). "Ecosystem services: Foundations, opportunities, and challenges for the forest products sector." Forest Ecology and Management 257(8): 1637-1646. The ecosystem service concept has been proposed as a meaningful framework for natural resource management. In theory it holds concomitant benefit and consequence for the forest product sector. However, numerous barriers impede practitioners from developing concrete and enduring responses to emerging ecosystem service markets, policies, and initiatives. Principle among these barriers is that the ecosystem service concept has a complex history, numerous definitions in use, and an astounding diversity in rationale and application. This article provides a conceptual review of ecosystem services and its economic foundations, distinguishes among several current definitions of the term and their relatedness to strategies in practical application, discusses diverse approaches to valuation, and explores potential for future relevance in forest product and other sectors.

Paoletti, E. (2009). "Ozone and urban forests in Italy." Environmental Pollution 157(5): 1506-1512. Ozone levels along urban-to-rural gradients in three Italian cities (Milan, Florence, Bari) showed that average AOT40 values at rural and suburban sites were 2.6 times higher than those determined at urban sites. However, O-3 also exceeded the European criteria to protect forest health at urban sites, even when the standards for human health protection were met. For protecting street trees in Mediterranean cities, the objectives of measurement at urban sites should extend from the protection of human health to the protection of vegetation as well. A review of forest effects on O-3 pollution and of O-3 pollution on forest conditions in Italian cities showed that it was not possible to distinguish the effect of O-3 in the complex mixture of urban pollutants and stressors. A preliminary list of tree species for urban planning in the Mediterranean area shows the average tree capacity of O-3 removal and VOC emission.

Musacchio, L. (2009). "The scientific basis for the design of landscape sustainability: A conceptual framework for translational landscape research and practice of designed landscapes and the six Es of landscape sustainability." Landscape Ecology 24(8): 993-1013. Landscape researchers and practitioners, using the lens of sustainability science, are breaking new ground about how people’s behaviors and actions influence the structure, function, and change of designed landscapes in an urbanizing world. The phrase—the scientific basis of the design for landscape sustainability—is used to describe how sustainability science can contribute to translational landscape research and practice about the systemic relationships among landscape sustainability, people’s contact with nature, and complex place-based problems. In the first section of this article, important definitions about the scientific basis of the design for landscape sustainability are reviewed including the six Es of landscape sustainability— environment, economic, equity, aesthetics, experience, and ethics. A conceptual framework about the six Es of landscape sustainability for designed landscapes is introduced. The interrelatedness, opportunities, contradictions, and limitations of the conceptual framework are discussed in relation to human health/security, ecosystem services, biodiversity, and resource management. The conceptual framework about the six Es of landscape sustainability for designed landscapes follows the tradition in which landscape researchers and practitioners synthesize emerging trends into conceptual frameworks for advancing basic and applied activities.

Marks, B. K. and R. S. Duncan (2009). "Use of Forest Edges by Free-ranging Cats and Dogs in an Urban Forest Fragment." Southeastern Naturalist 8(3): 427-436. Free-ranging Felis catus (Domestic Cat) and Canis familiaris (Domestic Dog) can greatly impact native prey populations, but little is known about their occurrence in urban forest fragments. In this study, we used camera traps to photograph (capture) cats, dogs, and native wildlife in a 409-ha urban forest in Birmingham, AL from Jan-Apr 2007. Habitat treatments included forest interior and forest edges by industrial lands, neighborhoods with higher house values, and neighborhoods with lower house values. We employed both conservative (n = 31) and liberal (n = 64) methods of tallying the number of individual dogs, cats, and native mammals captured. Dogs and cats combined comprised 19% (conservative) and 26% (liberal) of all photographic captures. Procyon lotor (Raccoon) were the most abundant of the 7 native species at 32% (conservative) and 53% (liberal) of all captures. Dogs were more abundant in neighborhood edges, and cats were more abundant in the forest interior. Cats and dogs combined were 75% (conservative) and 86% (liberal) of captures from the forest interior. Captures of native species were far more frequent in neighborhood edges (conservative = 86.9%, and liberal = 92.3%) than in other treatments. These findings demonstrate that exotic predators can be an important ecological presence in certain portions of urban forest fragments, and more extensive studies of their impact are needed.

Maas, J., et al. (2009). "Morbidity is related to a green living environment." Journal of Epidemiology and Community Health 63(12): 967-973. Background: As a result of increasing urbanisation, people face the prospect of living in environments with few green spaces. There is increasing evidence for a positive relation between green space in people's living environment and self-reported indicators of physical and mental health. This study investigates whether physician assessed morbidity is also related to green space in people's living environment. Methods: Morbidity data were derived from electronic medical records of 195 general practitioners in 96 Dutch practices, serving a population of 345 143 people. Morbidity was classified by the general practitioners according to the International Classification of Primary Care. The percentage of green space within a 1 km and 3 km radius around the postal code coordinates was derived from an existing database and was calculated for each household. Multilevel logistic regression analyses were performed, controlling for demographic and socio economic characteristics. Results: The annual prevalence rate of 15 of the 24 disease clusters was lower in living environments with more green space in a 1 km radius. The relation was strongest for anxiety disorder and depression. The relation was stronger for children and people with a lower socioeconomic status. Furthermore, the relation was strongest in slightly urban areas and not apparent in very strongly urban areas. Conclusion: This study indicates that the previously established relation between green space and a number of self-reported general indicators of physical and mental health can also be found for clusters of specific physician assessed morbidity. The study stresses the importance of green space close to home for children and lower socioeconomic groups.

Lorenz, K. and R. Lal (2009). "Biogeochemical C and N cycles in urban soils." Environment International 35(1): 1-8. The percentage of urban population is projected to increase drastically. In 2030, 50.7 to 86.7% of the total population in Africa and Northern America may live in urban areas, respectively. The effects of the attendant increases in urban land uses on biogeochemical C and N cycles are, however, largely unknown. Biogeochemical cycles in urban ecosystems are altered directly and indirectly by human activities. Direct effects include changes in the biological, chemical and physical soil properties and processes in urban soils. Indirect effects of urban environments on biogeochemical cycles may be attributed to the introductions of exotic plant and animal species and atmospheric deposition of pollutants. Urbanization may also affect the regional and global atmospheric climate by the urban heat island and pollution island effect. On the other hand, urban soils have the potential to store large amounts of soil organic carbon (SOC) and, thus, contribute to mitigating increases in atmospheric CO2 concentrations. However, the amount of SOC stored in urban soils is highly variable in space and time. and depends among others on soil parent material and land use. The SOC pool in 0.3-m depth may range between 16 and 232 Mg ha(-1), and between 15 and 285 Mg ha(-1) in 1-m depth. Thus, depending on the soil replaced or disturbed, urban soils may have higher or lower SOC pools, but very little is known. This review provides an overview of the biogeochemical cycling of C and N in urban soils, with a focus on the effects of urban land use and management on soil organic matter (SOM). In view of the increase in atmospheric CO2 and reactive N concentrations as a result of urbanization, urban land use planning must also include strategies to sequester C in soil, and also enhance the N sink in urban soils and vegetation. This will strengthen soil ecological functions such as retention of nutrients, hazardous compounds and water, and also improve urban ecosystem services by promoting soil fertility.

Lo, R. H. (2009). "Walkability: what is it?" J Urbanism 2. The literature shows single-use, low-density land development and disconnected street networks to be positively associated with auto dependence and negatively associated with walking and transit use. These factors in turn appear to affect health by influencing physical activity, obesity, and emissions of air pollutants. We evaluated the association between a single index of walkability that incorporated land use mix, street connectivity, net residential density, and retail floor area ratios, with health-related outcomes in King County, Washington. We found a 5% increase in walkability to be associated with a per capita 32.1% increase in time spent in physically active travel, a 0.23-point reduction in body mass index, 6.5% fewer vehicle miles traveled, 5.6% fewer grams of oxides of nitrogen (NOx) emitted, and 5.5% fewer grams of volatile organic compounds (VOC) emitted. These results connect development patterns with factors that affect several prevalent chronic diseases.

Kenwick, R. A., et al. (2009). "Preferences for riparian buffers." Landscape and Urban Planning 91(2): 88-96. Intensive management of riparian zones in the Mid-Western United States has long involved clearing vegetation, straightening meandering streams, and lining earthen banks with stone or concrete. Recently. however, scholars have begun to document the ecological costs of such practices. Replacing barren stream edges with more natural alternatives such as vegetated buffers can improve the visual appeal, environmental services, and ecological health of these ecosystems. Despite their potential benefits. these alternatives are rarely employed. Is it because individual landowners dislike these management strategies or is it that professional planners disapprove of such options? This paper examines the approval of various riparian buffer types by landowners and planners in Illinois using a photo-questionnaire. Participants rated their preferences for tree buffers, grass buffers, and a 'no buffer' condition along waterways in rural and suburban landscapes. They also rated their preferences for meandering streams in rural areas and earthen banks in the suburbs. The results show substantial support for tree buffers by both residents and planners. Participants also demonstrated considerable approval for meandering streams in rural areas. These findings add to the growing body of literature on preferences for buffers in different landscape settings and provide ample evidence for planners and policy- makers to take necessary steps to preserve or restore vegetated riparian buffers and meandering channels along Mid-western waterways. These natural alternatives to existing strategies are not only visually attractive and ecologically beneficial. they are also positive steps towards more sustainable riparian management practices.

Kalansuriya CM, P. A., Sonnadara DU. (2009). Effect of roadside vegetation on the reduction of traffic noise levels. In Proceedings of the Technical Sessions – Institute of Physics. A study was carried out to determine the effect of roadside vegetation on the reduction of road traffic noise levels under varying traffic conditions. Roadside vegetation which have the potential to act as noise barriers were selected for this study. The road traffic noise was measured together with the parameters that control the vegetation. Several noise level descriptors were recorded together with the A-weighted continuous noise level. The results show that higher frequency noise (above 4 kHz) is heavily attenuated by the vegetation barriers with virtually no attenuation for low frequency noise (below 100 Hz). The width of the vegetation barrier is linearly proportional to the amount of sound absorption. Without the vegetation barrier, the observed maximum and minimum noise levels were 72 dB(A) and 64 dB(A) respectively. On average, vegetation barriers were able to reduce the noise by 4 dB(A) which corresponds to an approximately 40% acoustic energy reduction. Thus, with careful planning and growing of roadside vegetation, the effect of road noise can be reduced.

James, P., et al. (2009). "Towards an integrated understanding of green space in the European built environment." Urban Forestry & Urban Greening 8(2): 65-75. In recent years social, economic and environmental considerations have led to a reevaluation of the factors that contribute to sustainable urban environments. Increasingly, urban green space is seen as an integral part of cities providing a range of services to both the people and the wildlife living in urban areas. With this recognition and resulting from the simultaneous provision of different services, there is a real need to identify a research framework in which to develop multidisciplinary and interdisciplinary research on urban green space. In order to address these needs, an iterative process based on the delphi technique was developed, which comprised email-mediated discussions and a two-day symposium involving experts from various disciplines. The two outputs of this iterative process were (i) an integrated framework for multidisciplinary and interdisciplinary research and (ii) a catalogue of key research questions in urban green space research. The integrated framework presented here includes relevant research areas (i.e. ecosystem services, drivers of change, pressures on urban green space, human processes and goals of provision of urban green space) and emergent research themes in urban green space studies (i.e. physicality, experience, valuation, management and governance). Collectively these two outputs have the potential to establish an international research agenda for urban green space, which can contribute to the better understanding of people's relationship with cities.

Gherardi, M., et al. (2009). "Heavy metals in the soil-plant system: monitoring urban and extra-urban parks in the Emilia Romagna Region (Italy)." Agrochimica 53(3): 196-208. For each of three Emilia Romagna Region (Italy) cities (Bologna. Ferrara and Cesena) an urban park situated in the historical heart of the city and an extra-urban park were selected. The aim of the study was to assess the concentration of heavy metals and microelements in different environmental matrixes, namely: soil, leaf tissues of coniferous and deciduous trees, mosses (spp. Hypnum cupressiforme) and grass, and washed-leaves water. The concentration of heavy metals (Cd, Co, Cu. Cr, Ni, Pb, Zn) was detected using an ICP-OE Spectrometer. For sampling point of Massari park in Ferrara city (FE-M1) and of Giardini Margherita park in Bologna city (BO-M3) heavy metals concentrations exceeded the threshold values established by the current Italian laws for soils of "public, residential and private areas" (D. Lgs 152/2006). The correlation between the concentration values of top- and subsoil highlights that some elements, such as Cd, Cu, Pb and Zn, have an anthropic origin and are mainly linked to the deposition of airborne pollutants, while other elements (Co, Cr and Ni) have a lithologic origin. The study of mosses, grass and the washed-leaves water made it possible to identify seasonal variations of pollutants deposition and, furthermore, to calculate the enrichment coefficient and the accumulation of heavy metals over time.

Getter, K. L., et al. (2009). "Carbon Sequestration Potential of Extensive Green Roofs." Environmental Science & Technology 43(19): 7564-7570. Two studies were conducted with the objective of quantifying the carbon storage potential of extensive green roofs. The first was performed on eight roofs in Michigan and four roofs in Maryland, ranging from 1 to 6 years in age. All 12 green roofs were composed primarily of Sedum species, and substrate depths ranged from 2.5 to 12.7 cm. Aboveground plant material was harvested in the fall of 2006. On average, these roofs stored 162 g C·m−2 in aboveground biomass. The second study was conducted on a roof in East Lansing, MI. Twenty plots were established on 21 April 2007 with a substrate depth of 6.0 cm. In addition to a substrate only control, the other plots were sown with a single species of Sedum (S. acre, S. album, S. kamtshaticum, or S. spurium). Species and substrate depth represent typical extensive green roofs in the United States. Plant material and substrate were harvested seven times across two growing seasons. Results at the end of the second year showed that aboveground plant material storage varied by species, ranging from 64 g C·m−2 (S. acre) to 239 g C·m−2 (S. album), with an average of 168 g C·m−2. Belowground biomass ranged from 37 g C·m−2 (S. acre) to 185 g C·m−2 (S. kamtschaticum) and averaged 107 g C·m−2. Substrate carbon content averaged 913 g C·m−2, with no species effect, which represents a sequestration rate of 100 g C·m−2 over the 2 years of this study. The entire extensive green roof system sequestered 375 g C·m−2 in above- and belowground biomass and substrate organic matter.

Escobedo, F. J. and D. J. Nowak (2009). "Spatial heterogeneity and air pollution removal by an urban forest." Landscape and Urban Planning 90(3-4): 102-110. Estimates of air pollution removal by the urban forest have mostly been based on mean values of forest structure variables for an entire city. However, the urban forest is not uniformly distributed across a city because of biophysical and social factors. Consequently, air pollution removal function by urban vegetation should vary because of this spatial heterogeneity. This paper presents a different approach to evaluate how the spatial heterogeneity of the urban forest influences air pollution removal at the socioeconomic subregion scale. Air pollution removal for July 1997 to June 1998 and July 2000 to June 2001 were estimated using measured urban forest structure data from three socioeconomic subregions in Santiago, Chile. Dry deposition was estimated using hourly climate, mixing height, and pollutant concentration data. Pollution removal rates among the three socioeconomic subregions were different because of heterogeneous urban forest structure and pollution concentrations. Air pollution removal per square meter of tree cover was greatest in the low socioeconomic subregion. Pollution removal during 1997-1998 was different from 2000 to 2001 due to pollution concentration differences. Seasonal air quality improvement also differed among the subregions. Results can be used to design management alternatives at finer administrative scales such as districts and neighborhoods that maximize the pollution removal rates by the urban forest in a subregion. Policies that affect the functionality of urban forest structure must consider spatial heterogeneity and scale when making region-wide recommendations. Similarly, when modeling the functionality of the urban forest, models must capture this spatial heterogeneity for inter-city comparisons.

Dwivedi, P., et al. (2009). "Ecological benefits of urban forestry: The case of Kerwa Forest Area (KFA), Bhopal, India." Applied Geography 29(2): 194-200. In developing countries like India, migration of people from rural to urban areas is responsible for ever expanding urban boundaries. This trend is exerting significant pressure on unprotected natural forests located near urban centers. This paper highlights the case of Kerwa Forest Area (KFA), located at about 10 km from the city of Bhopal, capital of Madhya Pradesh state. The objectives of this study are to quantify the extent of disturbance faced and ecosystem services provided by the KFA. Suitable spatial technologies and forest sampling techniques have been used to achieve the objectives of the study. It was found that the KFA is currently facing severe anthropogenic pressure. Parts of the KFA, located close to the settlements, were found more disturbed than the parts which were located far from the settlements. In spite of disturbances, KFA is a habitat for many threatened and endangered plant, animal, and bird species. KFA also plays a critical role of a carbon sink with a total storage of about 19.5 thousand tons of aboveground carbon. Immediate precautionary measures are required to prevent further degradation of the KFA for ensuring better environmental quality for the residents of Bhopal city in the future.

Davies, Z. G., et al. (2009). "A national scale inventory of resource provision for biodiversity within domestic gardens." Biological Conservation 142(4): 761-771. The human population is increasingly disconnected from nature due to urbanisation. To counteract this phenomenon, the UK government has been actively promoting wildlife gardening. However, the extent to which such activities are conducted and the level of resource provision for biodiversity (e.g., food and nesting sites) within domestic gardens remains poorly documented. Here we generate estimates for a selection of key resources provided within gardens at a national scale, using 12 survey datasets gathered across the UK. We estimate that 22.7 million households (87% of homes) have access to a garden. Average garden SiZe is 190 m(2), extrapolating to a total area of 432,924 ha. Although substantial, this coverage is still an order of magnitude less than that of statutory protected areas. Approximately 12.6 million (48%) households provide supplementary food for birds, 7.4 million of which specifically use bird feeders. Similarly, there are a minimum of 4.7 million nest boxes within gardens. These figures equate to one bird feeder for every nine potentially feeder-using birds in the UK, and at least one nest box for every six breeding pairs of cavity nesting birds. Gardens also contain 2.5-3.5 million ponds and 28.7 million trees, which is just under a quarter of all trees occurring outside woodlands. Ongoing urbanisation, characterised by increased housing densities, is inevitable throughout the UK and elsewhere. The important contribution domestic gardens make to the green space infrastructure in residential areas must be acknowledged, as their reduction will impact biodiversity conservation, ecosystem services, and the well-being of the human population.

Burghardt, K. T., et al. (2009). "Impact of Native Plants on Bird and Butterfly Biodiversity in Suburban Landscapes." Conservation Biology 23(1): 219-224. Managed landscapes in which non-native ornamental plants are favored over native vegetation now dominate the United States, particularly east of the Mississippi River. We measured how landscaping with native plants affects the avian and lepidopteran communities on 6 pairs of suburban properties in southeastern Pennsylvania. One property in each pair was landscaped entirely with native plants and the other exhibited a more conventional suburban mixture of plants2014a native canopy with non-native groundcover and shrubs. Vegetation sampling confirmed that total plant cover and plant diversity did not differ between treatments, but non-native plant cover was greater on the conventional sites and native plant cover was greater on the native sites. Several avian (abundance, species richness, biomass, and breeding- bird abundance) and larval lepidopteran (abundance and species richness) community parameters were measured from June 2006 to August 2006. Native properties supported significantly more caterpillars and caterpillar species and significantly greater bird abundance, diversity, species richness, biomass, and breeding pairs of native species. Of particular importance is that bird species of regional conservation concern were 8 times more abundant and significantly more diverse on native properties. In our study area, native landscaping positively influenced the avian and lepidopteran carrying capacity of suburbia and provided a mechanism for reducing biodiversity losses in human-dominated landscapes.

Wolf, D. and J. T. Lundholm (2008). "Water uptake in green roof microcosms: Effects of plant species and water availability." Ecological Engineering 33(2): 179-186. Green roofs are engineered ecosystems that rely on vegetation to provide services such as reduction of roof temperatures. Drought resistance is critical for plant survival on shallow- substrate green roofs, but potential trade-offs exist between water-use efficiency and ecosystem functions like transpirative cooling. Water loss from simulated green roof systems (microcosms) each containing 1 of 14 plant species belonging to 4 growth forms (succulents, herbaceous dicots, grasses and woody creeping shrubs) was quantified for 3 watering treatments (watering to field capacity every 4, 11 and 24 days). After 2 months only succulents survived the dry treatment. The dry treatment was the only treatment in which planted microcosms showed consistently greater water loss (∼30% greater) than the controls (soil-only microcosms). Microcosms planted with Poa compressa lost the most water in all moisture treatments but in the wet and intermediate treatments, respectively, native species Rhodiola rosea and Campanula rotundifolia had equivalent performance to P. compressa. The mat-forming Sedum acre retained more water than controls and other species in the wet and intermediate treatments suggesting that its growth form impeded evaporation from the soil surface. Performance differences among growth forms and species across soil moisture gradients suggest that optimal water loss and roof surface cooling could be enhanced by planting multiple species.

Whelan, C. J., et al. (2008). Ecosystem Services Provided by Birds. Ecosystem services are natural processes that benefit humans. Birds contribute the four types of services recognized by the UN Millennium Ecosystem Assessment2014provisioning, regulating, cultural, and supporting services. In this review, we concentrate primarily on supporting services, and to a lesser extent, provisioning and regulating services. As members of ecosystems, birds play many roles, including as predators, pollinators, scavengers, seed dispersers, seed predators, and ecosystem engineers. These ecosystem services fall into two subcategories: those that arise via behavior (like consumption of agricultural pests) and those that arise via bird products (like nests and guano). Characteristics of most birds make them quite special from the perspective of ecosystem services. Because most birds fly, they can respond to irruptive or pulsed resources in ways generally not possible for other vertebrates. Migratory species link ecosystem processes and fluxes that are separated by great distances and times. Although the economic value to humans contributed by most, if not all, of the supporting services has yet to be quantified, we believe they are important to humans. Our goals for this review are 1) to lay the groundwork on these services to facilitate future efforts to estimate their economic value, 2) to highlight gaps in our knowledge, and 3) to point to future directions for additional research.

Van Rossum, F. (2008). "Conservation of long-lived perennial forest herbs in an urban context: Primula elatior as study case." Conservation Genetics 9(1): 119-128. Urban forests are generally fragmented in small isolated remnants, embedded in an inhospitable human-used matrix, and incur strong anthropogenic pressures (recreational activities, artificialization, pollution and eutrophication). These lead to particularly high constraints even for common forest herbs, whose genetic response may depend on life-history traits and population demographic status. This study investigated genetic variation and structure for 20 allozyme loci in 14 populations of Primula elatior, a self-incompatible long-lived perennial herb, occurring in forest fragments of Brussels urban zone (Belgium), in relation to population size and young plants recruitment rate. Urban populations of P. elatior were not genetically depauperate, but the small populations showed reduced allelic richness. Small populations showing high recruitment rates-and therefore potential rejuvenation-revealed lower genetic diversity (H (o) and H (e)) than those with low or no recruitment. No such pattern was observed for the large populations. There was a significant genetic differentiation among populations within forest fragments (F (SC) = 0.052, P < 0.001), but not between fragments (F (CT) = 0.002, P > 0.10). These findings suggest restricted gene flow among populations within fragments and local processes (genetic drift, inbreeding) affecting small populations, strengthened when there is recruitment. Urban forest populations of long-lived perennial herbs can be of conservation value. However, restoration of small populations by increasing population size through regeneration by seedling recruitment may lead to negative genetic consequences. Additional management, aiming to restore gene flow among populations, may need to be applied to compensate the loss of genetic diversity and to reduce inbreeding.

Vallet, J., et al. (2008). "Plant species response to urbanization: comparison of isolated woodland patches in two cities of North-Western France." Landscape Ecology 23(10): 1205-1217. The effect of urbanization on species distribution has been extensively documented, but a main challenge in urban ecology is to better understand the factors causing different distributions among species in response to urbanization. Hence, this paper aims to compare the effects of urbanization on woodland plant assemblages in two cities and to describe species responses by using several indicators. The study was carried out in the cities of Angers and Rennes (North- Western France) where 11 isolated woodlands were surveyed along an urban-rural gradient in each city. Abundance data of spontaneous species were collected from 220 quadrats. The effect of land cover (within a 500 m buffer around each woodland) on species assemblages was investigated by Canonical Correspondence Analysis. Buildings and pavement areas were the most significant predictors of species composition, and the effect of location in Angers or Rennes appeared on the second axis. More than 60% of the most frequent plant species were indicator of urban or rural location and their preferences were similar in the two cities. These lists of urban and rural indicator species were compared with Ellenberg's indicator values and two other indicators specific to forest environment. The species which grow preferentially in urban woodlands are species which are already known to be associated with recent forests rather than ancient forests; with hedgerows rather than woodlands. The opposite pattern was observed concerning rural species. Moreover, urban indicator species have higher optima for soil pH and soil nitrogen content than rural indicator species. Different characteristics and history of forest habitat-continuity of the forest land cover, linearity of the habitat, change in adjacent land cover and land use-could select the same species, and the responses of the latter might involve different preferences concerning soil alkalinity and nutrient status.

Terho, M. and A. M. Hallaksela (2008). "Decay characteristics of hazardous Tilia, Betula, and Acer trees felled by municipal urban tree managers in the Helsinki City Area." Forestry 81(2): 151-159. In order to improve the management and protection of old urban trees, the decay characteristics of trees that had been removed as hazardous according to the local management protocol were investigated. The stage and the cross-sectional extent of decay were examined on a total of 181 park and street trees in the Helsinki city area: 64 trees of Tilia spp., 58 Betula spp. and 59 Acer spp. For Tilia, hollowed heartwood with low fungal expression and advanced decay caused by Ganoderma lipsiense were the two most common characteristics of cross-section samples from the points where stem breakage was most likely. For Betula, the primary reason for tree removal was usually lowered amenity value in terms of a declined appearance of the crown. Advanced decay, mainly caused by Inonotus obliquus, Piptoporus betulinus and Cerrena unicolor, were the most potential causes for stem breakage on Betula . For Acer, internal cracks, most often due to weak fork formation, were common causes of potential hazard. Decay caused by Rigidoporus populinus often increased the risk of stem breakage of these trees. In addition, advanced decay caused by Phellinus igniarius and Kretzschmaria deusta were the most important reasons for decreased safety of Acer trees.

Stovin, V. R., et al. (2008). "Street trees and stormwater management." Arboricultural J 30. Urban trees play an important role in the urban hydrological cycle. Yet little consideration has been given in the UK either to the increasing pressures that act to reduce urban tree cover or the opportunities that might be provided by land-use planning policies to increase it. Research in North America, particularly by American Forests (2007), suggests that urban tree cover may be directly equated to stormwater volumes and, therefore, to the costs of providing engineered structures for stormwater management. Tree planting policies have been justified on the financial benefits associated with their stormwater management function alone, notwithstanding the broader spectrum of benefits they provide within the urban environment. This paper presents preliminary research aimed at transferring these findings into a UK context. Two residential morphology units (RMUs) have been defined within the city of Sheffield, for which current levels of tree cover have been accurately quantified. Current tree cover levels are relatively low, but approaches to integrating more trees into these two landscape types are outlined.

Sarr, D. A. and K. J. Puettmann (2008). "Forest management, restoration, and designer ecosystems: Integrating strategies for a crowded planet." Ecoscience 15(1): 17-26. As the global human population increases, the demand to conserve, restore, create, and sustainably manage ecosystems will increase as well. Forested ecosystems are of particular interest because of the biodiversity they support and their diverse values to people. Developments in conservation, restoration forestry, and in the study of designer ecosystems provide a diverse set of tools with which to pursue sustainable forestry goals. Nonetheless, we suggest that sustainable forestry can only be achieved by fully considering ecological, economic, and social needs in landscapes. This will require a clear realization of the trade-offs in site- specific management approaches and a multifaceted, landscape-scale perspective for evaluation of sustainability criteria. We propose collaborative creation of Sustainable Forestry Portfolios as a means to encourage the breadth of thinking required to guide sustainable forest management. We discuss 3 examples of Sustainable Forestry Portfolios with relevance to different settings in the future: 1) the Triad Approach, 2) Forest Landscape Restoration, and 3) Urban Forestry. In all settings, sustainable forestry is not solely a technical problem, but a challenge that must be met through a multidimensional perspective, interdisciplinary collaboration, and with active engagement of the people that live and work in the landscape.

Roach, W. J., et al. (2008). "Unintended consequences of urbanization for aquatic ecosystems: A case study from the Arizona desert." BioScience 58(8): 715-727. Many changes wrought during the construction of "designer ecosystems" arc intended to ensure-and often succeed in ensuring-that a city call provide ecosystem goods and services; but other changes have unintended impacts oil the ecology of the city, impairing its ability to provide these critical functions. Indian Bend Wash, all urbanizing watershed in the Central Arizona- Phoenix (CAP) ecosystem, provides all excellent case study of how human alteration of land cover, streamchannel structure, and hydrology affect ecosystem processes, both intentionally and unintentionally The construction of canals created new flowpaths that cut across historic stream channels, and the creation of artificial lakes produced sinks for fine sediments and hotspots for nitrogen processing. Further hydrologic manipulations, such as groundwater pumping, linked surface flows to the aquifer and replaced ephemeral washes with perennial waters. These alterations of hydrologic structure are typical by-products of urban growth in and and semiarid regions and create distinct spatial and temporal patterns of nitrogen availability.

Petroff, A., et al. (2008). "Aerosol dry deposition on vegetative canopies. Part I: Review of present knowledge." Atmos Environ 42. This paper reviews the present knowledge of aerosol dry deposition, with respect to modelling and experimental aspects. In the first part, special attention is given to the existing mechanistic models, either with an analytical or a differential structure. Their predictions are compared against available measurements for grass and forest environments, obtained under controlled aerosol size and aerodynamic conditions. The observed differences are largely related to the parameterisation of the aerosol collection within the canopy. In the second part, existing experimental results are reviewed and a synthesis is provided through different inter- comparisons concerning: (1) the influence of atmospheric stability on fine particle deposition, (2) the evolution of coarse aerosol deposition with aerodynamic conditions and (3) the aerosol size dependence of deposition on grass and forest canopies. A wider compilation of measurements obtained on different canopies is finally proposed.

Peros, M. C., et al. (2008). "Continental-scale tree population response to rapid climate change, competition and disturbance." Global Ecology and Biogeography 17(5): 658-669. Aim Using a new approach to analyse fossil pollen data, we investigate temporal and spatial patterns in Populus (poplar, cottonwood, aspen) from the Late Glacial to the present at regional to continental scales. Location North America. Methods: We extracted data on the timing and magnitude of the maximum value of Populus pollen from each pollen diagram in the North American Pollen Database (NAPD). The information was plotted in histograms of 150-year bins to identify times when Populus was abundant on the landscape. We also mapped the maximum values to identify spatial patterns and their causes.Results Our analyses show that there have been several periods since the Late Glacial when Populus was abundant on the landscape: (1) from 12.35 to 12.65 kyr bp, in eastern North America, largely in response to the opening of the forest following the onset of the Younger Dryas; (2) from 10.85 to 11.75 kyr bp, following the termination of the Younger Dryas; and (3) during the last 150 years, as land was cleared for agricultural use, especially in the midwestern United States.Main conclusion Since the Late Glacial, changes in the abundance of Populus were caused more by the effects of abrupt climate change on its major competitors, rather than the direct effects of climate on Populus itself.

Nicholls, N., et al. (2008). "A simple heat alert system for Melbourne, Australia." Int J Biometeorol 52. A simple heat alert system, based solely on predicted maximum and minimum daily temperatures, has been developed for the city of Melbourne in southeast Australia. The system is based upon a demonstration that, when mean daily temperature exceeds a threshold of 30°C (mean of today’s maximum temperature and tonight’s minimum temperature), the average daily mortality of people aged 65 years or more is about 15–17% greater than usual. Similar numbers of excess deaths also occur when daily minimum temperatures exceed 24°C (increases of 19– 21% over expected death rate), so a heat alert system based solely on this widely available weather forecast variable is also feasible. No strong signal of excess heat-related deaths appears when the data are stratified using daily maximum temperatures. This may be because in Melbourne some days with very high maximum temperatures will be affected by the passage of cool changes and cold fronts in the afternoon, leading to a rapid drop in temperature (i.e., some days with high maximum temperatures will not continue to be hot throughout the day and into the evening). A single day with temperatures exceeding the thresholds noted above is sufficient to cause this increase in mortality, rather than requiring an extended heat wave. The increased daily mortality does not appear to represent a short-term advancement of mortality.

Naidoo, R., et al. (2008). "Global mapping of ecosystem services and conservation priorities." Proceedings of the National Academy of Sciences of the United States of America 105(28): 9495-9500. Global efforts to conserve biodiversity have the potential to deliver economic benefits to people (i.e., "ecosystem services"). However, regions for which conservation benefits both biodiversity and ecosystem services cannot be identified unless ecosystem services can be quantified and valued and their areas of production mapped. Here we review the theory, data, and analyses needed to produce such maps and find that data availability allows us to quantify imperfect global proxies for only four ecosystem services. Using this incomplete set as an illustration, we compare ecosystem service maps with the global distributions of conventional targets for biodiversity conservation. Our preliminary results show that regions selected to maximize biodiversity provide no more ecosystem services than regions chosen randomly. Furthermore, spatial concordance among different services, and between ecosystem services and established conservation priorities, varies widely. Despite this lack of general concordance, "win-win" areas-regions important for both ecosystem services and biodiversity-can be usefully identified, both among ecoregions and at finer scales within them. An ambitious interdisciplinary research effort is needed to move beyond these preliminary and illustrative analyses to fully assess synergies and trade-offs in conserving biodiversity and ecosystem services.

Muratet, A., et al. (2008). "Evaluation of floristic diversity in urban areas as a basis for habitat management." Applied Vegetation Science 11(4): 451-460. Questions: How can floristic diversity be evaluated in conservation plans to identify sites of highest interest for biodiversity? What are the mechanisms influencing the distribution of species in human-dominated environments? What are the best criteria to identify sites where active urban management is most likely to enhance floristic diversity Location: The Hauts-de- Seine district bordering Paris, France. Methods: We described the floristic diversity in one of the most urbanized French districts through the inventory of ca. 1000 sites located in 23 habitats. We built a new index of floristic interest (IFI), integrating information on richness, indigeneity typicality and rarity of species, to identify sites and habitats of highest interest for conservation. Finally, we explored the relationship between site IFI and land use patterns (LUP). Results: We observed a total of 626 vascular plant species, Habitats with highest IFI were typically situated in semi-natural environments or environments with moderate human impact. We also showed that neighbouring (urban) structures had a significant influence on the floristic interest of sites: for example. the presence of collective dwellings around a site had a strong negative impact on IFI. Conclusions: Our approach can be used to optimize management in urban zones: we illustrate such possibilities by defining a 'Site Potential Value'. which was then compared with the observed IFI, to identify areas (e.g. river banks) where better management could improve the district's biodiversity.

Mielke, H. W., et al. (2008). "Urban soil-lead (Pb) footprint: retrospective comparison of public and private properties in New Orleans." Environmental Geochemistry and Health 30(3): 231-242. Lead (Pb) is a toxin that after childhood exposure poses a lifetime of health risks. One route of exposure is soil-Pb as a result of ~12 million metric tons of Pb residue in paint and gasoline sold in the US during the 20th Century. Pb accumulated in soil of the community is a good predictor for blood Pb of children living there. This retrospective study compares the soil- Pb on Housing Authority of New Orleans (HANO) properties with adjacent private residential (RES) properties within a 0.8 km (0.5 mile) radius. The sample subset (n=951) is from two soil-Pb surveys (total n=9,493) conducted between 1989 and 2000. The properties were in both the inner city (CORE) and outlying (OUTER) communities. The data were analyzed using multi-response permutation procedures (MRPP). The soil-Pb results differ significantly (P-value <0.001) on same-aged HANO properties at different locations; thus, year of construction does not give adequate explanation for the soil-Pb differences. HANO and RES soils are significantly more Pb contaminated in the CORE than in OUTER communities (P-value <0.001). The CORE has many more years of traffic congestion than OUTER communities; therefore, the lead additives to gasoline, and not lead-based paint, best elucidate the differences of the soil-Pb footprint at HANO and RES properties in the CORE and OUTER communities. Currently HANO properties are being redeveloped with cleaner soil, but soil on RES properties in the CORE of New Orleans remains a large source of Pb (median=707 mg/kg in this study) for human exposure, especially children.

Luber, G. and M. McGeehin (2008). "Climate change and extreme heat events." Am J Prev Med 35. The association between climate change and the frequency and intensity of extreme heat events is now well established. General circulation models of climate change predict that heatwaves will become more frequent and intense, especially in the higher latitudes, affecting large metropolitan areas that are not well adapted to them. Exposure to extreme heat is already a significant public health problem and the primary cause of weather-related mortality in the U.S. This article reviews major epidemiologic risk factors associated with mortality from extreme heat exposure and discusses future drivers of heat-related mortality, including a warming climate, the urban heat island effect, and an aging population. In addition, it considers critical areas of an effective public health response including heat response plans, the use of remote sensing and GIS methodologies, and the importance of effective communications strategies.

Loring, P. A., et al. (2008). "The services-oriented architecture: Ecosystem services as a framework for diagnosing change in social ecological systems." Ecosystems 11(3): 478-489. Computational thinking (CT) is a way to solve problems and understand complex systems that draws on concepts fundamental to computer science and is well suited to the challenges that face researchers of complex, linked social-ecological systems. This paper explores CT's usefulness to sustainability science through the application of the services-oriented architecture (SOA). The SOA is a popular organizational framework in information technology that enables businesses to describe the services they offer, including how, where, to whom, and under what terms these services are available to consumers. It provides a straightforward, scalable, and portable way to describe and organize complex business systems, with an emphasis on system controls and component interactions rather than on the system components themselves. Here, we present the SOA as a path to a more mature ecosystem services concept, in support of integrated assessment frameworks such as the Millennium Ecosystem Assessment (MA). With the SOA we capture important interrelationships among ecosystems, ecosystem service consumers, and ecosystem service governance authorities, particularly the effects of their interactions on the viability of ecosystem services. By standardizing the description and relationships involving ecosystem services, the SOA supports a diagnostic approach for evaluating stability and change in ecosystem service use across both space and time, when influenced by drivers of social, political, and/or ecological change, whether directional or stochastic, planned or otherwise. We present here a prototype of the SOA and illustrate its utility with an example from rural Alaskan communities.

Litschke, T. and W. Kuttler (2008). "On the reduction of urban particle concentration by vegetation - a review." Meteorol Z 17. In order to assess the filtration performance of plants with respect to atmospheric dust, deposition on vegeta- tion has been investigated by a number of different methods (field studies, numerical and physical modelling) over the past few years. The intention of this review is to assess the extent to which a reduction in particle concentration (especially PM10) can be accomplished by existing vegetation or targeted planting on the basis of international publications. The range of this assessment however is limited to the quantitative filtration potential of urban vegetation. Deposition velocity was taken as a measure of filtration performance as a parti- cle deposited on a plant is in effect taken from the atmosphere. As regarding published deposition velocities, there are differences of an order of magnitude between measured values and the results of model calculations. The average published value (∼1 cm s−1) corresponds to a reduction in pollutant concentration (PM10) of about 1 % in urban areas. In addition, analyses carried out for a busy arterial road show that very large vege- tation areas (in excess of 10,000 m2) would be needed to compensate for local emissions of particles (PM10) by vehicles at a deposition velocity of 1 cm s−1. However, current in-situ measurements indicate deposition velocities considerably higher than 1 cm s−1 and, for PM1, velocities above 10 cm s−1. If these results were confirmed by further measurements, local planting campaigns covering small areas could also be beneficial for a reduction of particle concentrations.

Kaye, J. P., et al. (2008). "Hierarchical Bayesian scaling of soil properties across urban, agricultural, and desert ecosystems." Ecological Applications 18(1): 132-145. Ecologists increasingly use plot-scale data to inform research and policy related to regional and global environmental change. For soil chemistry research, scaling from the plot to the region is especially difficult due to high spatial variability at all scales. We used a hierarchical Bayesian model of plot-scale soil nutrient pools to predict storage of soil organic carbon (oC), inorganic carbon (iC), total nitrogen (N), and available phosphorus (avP) in a 7962- km(2) area including the Phoenix, Arizona, USA, metropolitan area and its desert and agricultural surroundings. The Bayesian approach was compared to a traditional approach that multiplied mean values for urban mesic residential, urban xeric residential, nonresidential urban, agricultural, and desert areas by the aerial coverage of each land-use type. Both approaches suggest that oC, N, and avP are correlated with each other and are higher (in g/m(2)) in mesic residential and agricultural areas than in deserts or xeric residential areas. In addition to traditional biophysical variables, cultural variables related to impervious surface cover, tree cover, and turfgrass cover were significant in regression models predicting the regional distribution of soil properties. We estimate that 1140 Gg of oC have accumulated in human- dominated soils of this region, but a significant portion of this new C has a very short mean residence time in mesic yards and agricultural soils. For N, we estimate that 130 Gg have accumulated in soils, which explains a significant portion of "missing N" observed in the regional N budget. Predictions for iC differed between the approaches because the Bayesian approach predicted iC as a function of elevation while the traditional approach employed only land use. We suggest that Bayesian scaling enables models that are flexible enough to accommodate the diverse factors controlling soil chemistry in desert, urban, and agricultural ecosystems and, thus, may represent an important tool for ecological scaling that spans land-use types. Urban planners and city managers attempting to reduce C emissions and N pollution should consider ways that landscape choices and impervious surface cover affect city-wide soil C, N, and P storage.

Jim, C. Y. and W. Y. Chen (2008). "Assessing the ecosystem service of air pollutant removal by urban trees in Guangzhou (China)." Journal of Environmental Management 88(4): 665-676. In Chinese cities, air pollution has become a serious and aggravating environmental problem undermining the sustainability of urban ecosystems and the quality of urban life. Besides technical solutions to abate air pollution, urban vegetation is increasingly recognized as an alternative ameliorative method by removing some pollutants mainly through dry deposition process. This paper assesses the capability and monetary value of this ecosystem service in Guangzhou city in South China. The results indicated an annual removal of SO2, NO2 and total suspended particulates at about 312.03Mg, and the benefits were valued at RMB90.19 thousand (US$1.00 = RMB8.26). More removal was realized by recreational land use due to a higher tree cover. Higher concentration of pollutants in the dry winter months induced more removal. The lower cost of pollution abatement in China generated a relatively subdued monetary value of this environmental benefit in comparison with developed countries. Younger districts with more extensive urban trees stripped more pollutants from the air, and this capacity was anticipated to increase further as their trees gradually reach final dimensions and establish a greater tree cover. Tree cover and pollutant concentration constitute the main factors in pollutant removal by urban trees. The efficiency of atmospheric cleansing by trees in congested Chinese cities could be improved by planting more trees other than shrubs or grass, diversifying species composition and biomass structure, and providing sound green space management. The implications for greenery design were discussed with a view to maximizing this ecosystem service in Chinese cities and other developing metropolises.

Jim, C. Y. and W. Y. Chen (2008). "Pattern and divergence of tree communities in Taipei's main urban green spaces." Landscape and Urban Planning 84(3-4): 312-323. Urban vegetation increasingly contributes to nature conservation and ecosystem services, but lacking understanding of site variations has restricted such uses. This study analyzed the spatial pattern and differentiation of tree communities in three major green landscape types (urban parks, riverside parks and street verges) in Taipei city. In each landscape type, 10 representative tree communities were studied. Statistical tests for ecological communities were employed: Jaccard and Q species similarity indices, two-way indicator species analysis (TWINSPAN), and new species fidelity, landscape fidelity and composite Q indices. Significant recent increase in Taipei's green spaces was traced. The study area contained 164 tree species, but few were shared by the three landscape types and none by 30 communities. Native evergreen broadleaf species with large final dimensions were dominant. Urban parks registered the highest species richness, landscape fidelity, rare species and urban endemics. Such exclusive species constitution deviated notably from riverside parks and street verges, with relatively simple and converging intra-site species ingredients. Pronounced species differentiation between urban parks reflected diversified site topography, natural woodland inheritance, woodland creation, and past landscape fashion. TWINSPAN classified the communities into nine groups each with signature characteristics. Inherent site variations offered main determinants of tree heterogeneity, superimposed by human modification to satisfy pre-determined site functions. A hybrid urban park with high species diversity and nature contents is advocated by amalgamating conventional but polarized designs of country and urban parks. The findings could inform management of urban forest, urban nature conservation, and ecological services of urban green spaces.

Jarup, L., et al. (2008). "Hypertension and exposure to noise near airports: the HYENA study." Environ Health Perspect 116. Background: An increasing number of people are exposed to aircraft and road traffic noise. Hypertension is an important risk factor for cardiovascular disease, and even a small contribution in risk from environmental factors may have a major impact on public health. Objectives: The HYENA (Hypertension and Exposure to Noise near Airports) study aimed to assess the relations between noise from aircraft or road traffic near airports and the risk of hypertension. Methods: We measured blood pressure and collected data on health, socioeconomic, and lifestyle factors, including diet and physical activity, via questionnaire at home visits for 4,861 persons 45–70 years of age, who had lived at least 5 years near any of six major European airports. We assessed noise exposure using detailed models with a resolution of 1 dB (5 dB for United Kingdom road traffic noise), and a spatial resolution of 250 × 250 m for aircraft and 10 × 10 m for road traffic noise. Results: We found significant exposure–response relationships between night-time aircraft as well as average daily road traffic noise exposure and risk of hypertension after adjustment for major confounders. For night-time aircraft noise, a 10-dB increase in exposure was associated with an odds ratio (OR) of 1.14 [95% confidence interval (CI), 1.01–1.29]. The exposure–response relationships were similar for road traffic noise and stronger for men with an OR of 1.54 (95% CI, 0.99–2.40) in the highest exposure category (> 65 dB; ptrend = 0.008). Conclusions: Our results indicate excess risks of hypertension related to long-term noise exposure, primarily for night-time aircraft noise and daily average road traffic noise.

Jackson, L. E., et al. (2008). "Roots nitrogen transformations, and ecosystem services." Annual Review of Plant Biology 59: 341-363. This review considers some of the mechanistic processes that involve roots in the soil nitrogen (N) cycle, and their implications for the ecological functions that retain N within ecosystems: 1) root signaling pathways for N transport systems, and feedback inhibition, especially for NO3- uptake; 2) dependence on the mycorrhizal and Rhizobium/legume symbioses and their tradeoffs for N acquisition; 3) soil factors that influence the supply of NH4+ and NO3- to roots and soil microbes; and 4) rhizosphere processes that increase N cycling and retention, such as priming effects and interactions with the soil food web. By integrating information on these plant-microbe-soil N processes across scales and disciplinary boundaries, we propose ideas for better manipulating ecological functions and processes by which the environment provides for human needs, i.e., ecosystem services. Emphasis is placed on agricultural systems, effects of N deposition in natural ecosystems, and ecosystem responses to elevated CO2 concentrations. This shows the need for multiscale approaches to increase human dependence on a biologically based N supply.

Grimm, N. B., et al. (2008). "The changing landscape: ecosystem responses to urbanization and pollution across climatic and societal gradients." Frontiers in Ecology and the Environment 6(5): 264-272. Urbanization, an important driver of climate change and pollution, alters both biotic and abiotic ecosystem properties within, surrounding, and even at great distances from urban areas. As a result, research challenges and environmental problems must be tackled at local, regional, and global scales. Ecosystem responses to land change are complex and interacting, occurring on all spatial and temporal scales as a consequence of connectivity of resources, energy, and information among social, physical, and biological systems. We propose six hypotheses about local to continental effects of urbanization and pollution, and an operational research approach to test them. This approach focuses on analysis of "megapolitan" areas that have emerged across North America, but also includes diverse wildland-to-urban gradients and spatially continuous coverage of land change. Concerted and coordinated monitoring of land change and accompanying ecosystem responses, coupled with simulation models, will permit robust forecasts of how land change and human settlement patterns will alter ecosystem services and resource utilization across the North American continent. This, in turn, can be applied globally.

Fornara, D. A. and D. Tilman (2008). "Plant functional composition influences rates of soil carbon and nitrogen accumulation." Journal of Ecology 96(2): 314-322. Summary 1. The mechanisms controlling soil carbon (C) and nitrogen (N) accumulation are crucial for explaining why soils are major terrestrial C sinks. Such mechanisms have been mainly addressed by imposing short-term, step-changes in CO2, temperature and N fertilization rates on either monocultures or low-diversity plant assemblages. No studies have addressed the long-term effects of plant functional diversity (i.e. plant functional composition) on rates of soil C accumulation in N-limited grasslands where fixation is the main source of N for plants. 2. Here we measure net soil C and N accumulation to 1 m soil-depth during a 12-year-long grassland biodiversity experiment established on agriculturally degraded soils at Cedar Creek, Minnesota, USA. 3. We show that high-diversity mixtures of perennial grassland plant species stored 500% and 600% more soil C and N than, on average, did monoculture plots of the same species. Moreover, the presence of C4 grasses and legumes increased soil C accumulation by 193% and 522%, respectively. Higher soil C and N accrual resulted both from increased C and N inputs via (i) higher root biomass, and (ii) from greater root biomass accumulation to 60 cm soil depth resulting from the presence of highly complementary functional groups (i.e. C4 grasses and legumes). 4. Our results suggest that the joint presence of C4 grass and legume species is a key cause of greater soil C and N accumulation in both higher and lower diversity plant assemblages. This is because legumes have unique access to N, and C4 grasses take up and use N efficiently, increasing below-ground biomass and thus soil C and N inputs. 5. Synthesis. We demonstrate that plant functional complementarity is a key reason why higher plant diversity leads to greater soil C and N accumulation on agriculturally degraded soils. We suggest the combination of key C4 grass-legume species may greatly increase ecosystem services such as soil C accumulation and biomass (biofuel) production in both high- and low-diversity N-limited grassland systems.

Elmendorf, W. (2008). "The importance of trees and nature in community: A review of the relative literature." Arboriculture and Urban Forestry 34(3): 152. A growing body of literature and experience revolves around the beneficial and connected relationships among nature, social settings, and social processes like interaction. This literature argues that the natural environment is a critical component of personal and community pride and well-being and a stimulus for collaborative action. Furthermore, it argues that empowering people to become involved in the process of landscape and park creation and maintenance increases social interaction, builds community capacity, and supports both development of community and community. Tree plantings and other civic environmental projects can be used to promote both healthy environments and healthy social structure even in the most deteriorated neighbor- hoods. As such, participatory environmental projects are strong tools of community development, and the work of arborists and urban foresters can play an important part in the process of community.

Deng, H. B., et al. (2008). "Current situation and development of Chinese urban forestry." International Journal of Sustainable Development and World Ecology 15(4): 371-377. This paper introduces Chinese urban forestry research in terms of the concept, forest types, ecosystem services, spatial structure, planning and construction, assessment and management. Modern Chinese urban forest had a close relationship with traditional landscape architecture. Urban forest services had been quantified in some case cities, and determined by urban forest spatial patterns and internal structures. Based on landscape ecology and urban planning, urban forest spatial patterns have been analysed and planned rationally in some cities. However, studies on urban forestry generally lack long-term, continuous and systemic observations, as well as in-depth research on ecological processes and mechanisms. The development trends in urban forestry in China might include extensive application of '3S' technology, research on the relationship between urban forest landscape spatial patterns and their ecological effects, economic assessment, ecological and economic benefits and studies on the negative effects of pollutants.

Carter, T. and L. Fowler (2008). "Establishing Green Roof Infrastructure Through Environmental Policy Instruments." Environmental Management 42(1): 151-164. Traditional construction practices provide little opportunity for environmental remediation to occur in urban areas. As concerns for environmental improvement in urban areas become more prevalent, innovative practices which create ecosystem services and ecologically functional land cover in cities will be in higher demand. Green roofs are a prime example of one of these practices. The past decade has seen the North American green roof industry rapidly expand through international green roof conferences, demonstration sites, case studies, and scientific research. This study evaluates existing international and North American green roof policies at the federal, municipal, and community levels. Green roof policies fall into a number of general categories, including direct and indirect regulation, direct and indirect financial incentives, and funding of demonstration or research projects. Advantages and disadvantages of each category are discussed. Salient features and a list of prompting standards common to successfully implemented green roof strategies are then distilled from these existing policies. By combining these features with data collected from an experimental green roof site in Athens, Georgia, the planning and regulatory framework for widespread green roof infrastructure can be developed. The authors propose policy instruments be multi-faceted and spatially focused, and also propose the following recommendations: (1) Identification of green roof overlay zones with specifications for green roofs built in these zones. This spatial analysis is important for prioritizing areas of the jurisdiction where green roofs will most efficiently function; (2) Offer financial incentives in the form of density credits and stormwater utility fee credits to help overcome the barriers to entry of the new technology; (3) Construct demonstration projects and institutionalize a commitment greening roofs on publicly-owned buildings as an effective way of establishing an educated roofing industry and experienced installers for future green roof construction.

Campanella, B., et al. (2008). "Urban tree management in walloon municipalities: overview of available means." Biotechnologie Agronomie Societe Et Environnement 12(3): 239-244. A survey has been sent in 2006 to the 262 municipalities from Wallonia concerning their green areas management and particularly focused on local arboricultural heritage. The questionnaire was structured by 3 themes: (1) the managed heritage. (2) economical and technical means available for municipalities, (3) available management tools. Fifty-three answers have been gathered which represent 20.2%. This enquiry gives a first overview of the situation. It shows that 70% of answering municipalities have no specific green service. Tree management is a priority for only 11% of the municipal services that are involved in urban greening. Half of the municipalities are delegating at least a part of green area management to private societies. That concerns tree pruning, safety diagnosis, tree care and revitalisation. Only 15% of municipalities have a complete inventory of their trees. Ninety percent declare they have no planning toot and 95% have no legal text describing good management practices. All important information and formation work is then necessary to reinforce local tree managers to avoid that well known mistakes Continue to be done (death of veteran trees after herbicide misuse, tree topping, root destruction during public works. etc.).

Byrne, L. B., et al. (2008). "Ecosystem Properties of Urban Land Covers at the Aboveground-Belowground Interface." Ecosystems 11(7): 1065-1077. Understanding of ecological differences among urban land covers can guide the sustainable management of urbanized landscapes for conservation of ecosystem services. The objective of our study was to compare ecosystem properties at the aboveground-belowground interface of three land-cover types commonly found in residential landscapes: lawns, bark mulch, and gravel mulch. Using unmowed vegetation as a reference land cover, we measured surface soil variables (to 5 cm depth), CO2 fluxes, and ground temperatures in experimental field plots within 3 years after their creation. Each land cover had a distinctive set of ecosystem properties. Mulched plots had significantly warmer soil and surface temperatures, wetter soils and faster surface litter decomposition than vegetated plots. Variables associated with soil C and earthworm numbers were consistently lowest in gravel-covered soils, whereas bark mulch plots had highest earthworm abundances, lowest soil bulk density, and temporally variable soil organic matter dynamics. Compared to unmowed plots, lawns had higher soil carbon, CO2 fluxes, and temperatures but lower earthworm abundances especially during 2005 drought conditions. We conclude that ecosystem properties of the land covers were influenced by the composition, density, and arrangement of materials comprising their aboveground habitat structures. We discuss our results within an ecosystem services framework and suggest that interpretations of our findings depend on in situ urban environmental contexts and landscape management objectives. Future studies of urban land covers, their ecosystem properties and associated ecosystem services are needed to help provide a scientific basis for sustainable urban landscape management.

Burley, S., et al. (2008). "Post-hurricane vegetation recovery in an urban forest." Landscape and Urban Planning 85(2): 111-122. Urban forests are increasingly vulnerable to catastrophic disturbance, and their isolation and human use may challenge the ability of vegetation to recover spontaneously. We examined vegetation responses to recent hurricane disturbance in a temperate mixedwood urban forest: Point Pleasant Park in Halifax, Nova Scotia, which suffered over 70% canopy loss during Hurricane Juan in fall 2003. In 2005 we surveyed 30 paired plots with disturbed and intact tree canopies to assess early regeneration patterns and seed banks. Native early successional tree species dominated seed bank and seedling layers. Soil properties were similar between intact and disturbed urban plots and local reference forests, thus long-term woody debris removal, hurricane disturbance and subsequent clean-up activities have not caused substantial soil degradation. Non-native species were not abundant throughout the park but were concentrated at the park boundary adjacent to residential neighbourhoods. The results of this study suggest that urban forests can show natural successional trajectories after catastrophic disturbance, and management is probably not necessary for forest recovery in Point Pleasant Park. Conversely, intervention to speed up regeneration of shade-tolerant canopy species may be desired by local citizens, so managers will have to balance conflicting values in developing a restoration plan for the park.

Bonan, G. B. (2008). "Forests and climate change: Forcings, feedbacks, and the climate benefits of forests." Science 320(5882): 1444-1449. The world's forests influence climate through physical, chemical, and biological processes that affect planetary energetics, the hydrologic cycle, and atmospheric composition. These complex and nonlinear forest-atmosphere interactions can dampen or amplify anthropogenic climate change. Tropical, temperate, and boreal reforestation and afforestation attenuate global warming through carbon sequestration. Biogeophysical feedbacks can enhance or diminish this negative climate forcing. Tropical forests mitigate warming through evaporative cooling, but the low albedo of boreal forests is a positive climate forcing. The evaporative effect of temperate forests is unclear. The net climate forcing from these and other processes is not known. Forests are under tremendous pressure from global change. Interdisciplinary science that integrates knowledge of the many interacting climate services of forests with the impacts of global change is necessary to identify and understand as yet unexplored feedbacks in the Earth system and the potential of forests to mitigate climate change.

Beier, C. M., et al. (2008). "Ecosystem services and emergent vulnerability in managed ecosystems: A geospatial decision-support tool." Ecosystems 11(6): 923-938. Managed ecosystems experience vulnerabilities when ecological resilience declines and key flows of ecosystem services become depleted or lost. Drivers of vulnerability often include local management actions in conjunction with other external, larger-scale factors. To translate these concepts to management applications, we developed a conceptual model of feedbacks linking the provision of ecosystem services, their use by society, and anthropogenic change. From this model we derived a method to integrate existing geodata at relevant scales and in locally meaningful ways to provide decision-support for adaptive management efforts. To demonstrate our approach, we conducted a case study assessment of southeast Alaska, where managers are concerned with sustaining fish and wildlife resources in areas where intensive logging disturbance has occurred. Individual datasets were measured as indicators of one of three criteria: ecological capacity to support fish/wildlife populations (provision); human acquisition of fish/wildlife resources (use); and intensity of logging and related land-use change (disturbance). Relationships among these processes were analyzed using two methods-a watershed approach and a high-resolution raster-to identify where provision, use and disturbance were spatially coupled across the landscape. Our results identified very small focal areas of social-ecological coupling that, based on post-logging dynamics and other converging drivers of change, may indicate vulnerability resulting from depletion of ecosystem services. We envision our approach can be used to narrow down where adaptive management might be most beneficial, allowing practitioners with limited funds to prioritize efforts needed to address uncertainty and mitigate vulnerability in managed ecosystems.

Zhang, G., et al. (2007). "Urban soil environment issues and research progresses." Acta Pedologica Sinica 44(5): 925-933. Urban soils act functionally as an ecological screen in protecting urban environment. Their degradation, however, is in essence a process of providing ecological services, such as sink of all kinds of pollutants, at the cost of their own quality. Therefore, as a result, they often come across a variety of environmental problems. Besides physical degradation, such as compaction, enrichment of various elements associated with human activities, heavy metals, and organic pollution are the major problems with urban soil environment. The main features of urban soil contamination are characterized firstly by strong accumulation of so-called 'urban elements' such as Cu, Zn, Pb and Hg, but less of other heavy metals; and secondly by spatial isolation, which means the contamination is not spatially continuous. During the process of urban development, heavy metal contamination of urban soils happens not only nowadays, but also did in the past, especially when primitive mining and metal processing prevailed. Furthermore, urban soils are often polluted by organic pollutants, especially polycyclic aromatic hydrocarbons (PAHs), with roadsides and industrial sites being the major vulnerable areas. PAHs therein have normally 2-6 rings and predominantly 2-4 rings, strongly suggesting their pyrogenic background, including motor vehicles, industrial activities and coal burning.

Xiao, Q., et al. (2007). "Hydrologic processes at the urban residential scale." Hydrological Processes 21(16): 2174-2188. In the face of increasing urbanization, there is growing interest in application of microscale hydrologic solutions to minimize storm runoff and conserve water at the source. In this study, a physically based numerical model was developed to understand hydrologic processes better at the urban residential scale and the interaction of these processes among different best management practices (BMPs). This model simulates hydrologic processes using an hourly interval for over a full year or for specific storm events. The model was applied to treatment and control single-family residential parcels in Los Angeles, California. Data collected from the control and treatment sites over 2 years were used to calibrate and validate the model. Annual storm runoff to the street was eliminated by 97% with installation of rain gutters, a driveway interceptor, and lawn retention basin. Evaluated individually, the driveway interceptor was the most effective BMP for storm runoff reduction (65%), followed by the rain gutter installation (28%), and lawn converted to retention basin (12%). An 11 m(3) cistern did not substantially reduce runoff, but provided 9% of annual landscape irrigation demand. Simulated landscape irrigation water use was reduced 53% by increasing irrigation system efficiency, and adjusting application rates monthly based on plant water demand. The model showed that infiltration and surface runoff processes were particularly sensitive to the soil's physical properties and its effective depth. Replacing the existing loam soil with clay soil increased annual runoff discharge to the street by 63% when climate and landscape features remained unchanged. van Roon, M. (2007). "Water localisation and reclamation: Steps towards low impact urban design and development." Journal of Environmental Management 83(4): 437-447. Numerous drivers are providing stimulus for increased water cycle localisation within urban neighbourhoods. This paper uses predominantly Australasian case studies to highlight trends, successes and challenges in the transition to neighbourhood centred water-based services using 'Low Impact' and 'Water Sensitive' design and development techniques. Major steps towards urban sustainability are demonstrated, for example, up to 70% reduction in the demand for potable water (Aurora, Melbourne), removal of contaminated stormwater and sewage effluent discharge to natural waterways vulnerable to nutrient or toxin accumulation, and up to 55% of the area of the greenfield site planted in indigenous species (Regis Park, New Zealand). Reduced demand for potable water would enable continued undiluted use of 'pure' water sources from limited bush catchments (Waitakere Ranges, New Zealand), and less dependence on rivers stressed by low flows. Reductions and dispersion of sewage effluent discharges protects receiving waters, such as Port Phillip Bay, Melbourne, from eutrophication. Reduced stormwater discharge favours retention of the natural hydrological regime of rivers and minimises bioaccumulation of toxins in aquatic ecosystems.

Troy, A. R., et al. (2007). "Predicting opportunities for greening and patterns of vegetation on private urban lands." Environmental Management 40(3): 394-412. This paper examines predictors of vegetative cover on private lands in Baltimore, Maryland. Using high-resolution spatial data, we generated two measures: "possible stewardship," which is the proportion of private land that does not have built structures on it and hence has the possibility of supporting vegetation, and "realized stewardship," which is the proportion of possible stewardship land upon which vegetation is growing. These measures were calculated at the parcel level and averaged by US Census block group. Realized stewardship was further defined by proportion of tree canopy and grass. Expenditures on yard supplies and services, available by block group, were used to help understand where vegetation condition appears to be the result of current activity, past legacies, or abandonment. PRIZM (TM) market segmentation data were tested as categorical predictors of possible and realized stewardship and yard expenditures. PRIZM (TM) segmentations are hierarchically clustered into 5, 15, and 62 categories, which correspond to population density, social stratification (income and education), and lifestyle clusters, respectively. We found that PRIZM 15 best predicted variation in possible stewardship and PRIZM 62 best predicted variation in realized stewardship. These results were further analyzed by regressing each dependent variable against a set of continuous variables reflective of each of the three PRIZM groupings. Housing age, vacancy, and population density were found to be critical determinants of both stewardship metrics. A number of lifestyle factors, such as average family size, marriage rates, and percentage of single-family detached homes, were strongly related to realized stewardship. The percentage of African Americans by block group was positively related to realized stewardship but negatively related to yard expenditures.

Tratalos, J., et al. (2007). "Urban form, biodiversity potential and ecosystem services." Landscape and Urban Planning 83(4): 308-317. Using data from selected areas in five UK cities, we studied the relationships between urban form and the following measures of ecosystem performance: availability and patch characteristics of tree cover, gardens and green space; storm-water run-off; maximum temperature; carbon sequestration. Although most measures of ecosystem performance declined with increasing urban density, there was considerable variability in the relationships. This suggests that at any given density, there is substantial scope for maximising ecological performance. The social status of residents was related to measures of tree cover. Housing type was significantly associated with some types of ecosystem service provision, indicating that the type of development may be important independent of its density. These findings have implications for understanding the distribution of ecosystem services and biodiversity across urban landscapes, and the management of development aimed at meeting UK government housing density targets.

Takebayashi, H. and M. Moriyama (2007). "Surface heat budget on green roof and high reflection roof for mitigation of urban heat island." Building and Environment 42(8): 2971- 2979. In this study, the surface temperature, net radiation, water content ratio, etc., of green roofs and high reflection roofs are observed. The heat and water budget are compared to each other. In the daytime, the temperature of the cement concrete surface, the surface with highly reflective gray paint, bare soil surface, green surface and the surface with highly reflective white paint are observed to be in descending order. On a surface with highly reflective white paint, the sensible heat flux is small because of the low net radiation due to high solar reflectance. On the green surface, the sensible heat flux is small because of the large latent heat flux by evaporation, although the net radiation is large. On the cement concrete surface and the surface with a highly reflective gray paint, the sensible heat fluxes have almost the same values because their solar reflectance is approximately equal. These tendencies of the sensible heat flux accord with the pitch relation of the surface temperature. Methods to estimate the quantity of evaporation, evaporative efficiency, heat conductivity, and thermal capacity are explained, and the observation data is applied to these methods.

Pataki, D. E., et al. (2007). "Inferring biogenic and anthropogenic carbon dioxide sources across an urban to rural gradient." Oecologia 152(2): 307-322. We continuously monitored CO2 concentrations at three locations along an urban-to-rural gradient in the Salt Lake Valley, Utah from 2004 to 2006. The results showed a range of CO2 concentrations from daily averages exceeding 500 p.p.m. at the city center to much lower concentrations in a non-urbanized, rural region of the valley. The highest values were measured in the wintertime and under stable atmospheric conditions. At all three sites, we utilized weekly measurements of the C and O isotope composition of CO2 for a 1-year period to evaluate the CO2 sources underlying spatial and temporal variability in CO2 concentrations. The results of an inverse analysis of CO2 sources and the O isotope composition of ecosystem respiration (delta O-18(R)) showed large contributions (> 50%) of natural gas combustion to atmospheric CO2 in the wintertime, particularly at the city center, and large contributions (> 60%) of biogenic respiration to atmospheric CO2 during the growing season, particularly at the rural site. delta O- 18(R) was most enriched at the rural site and more isotopically depleted at the urban sites due to the effects of irrigation on ecosystem water pools at the urban sites. The results also suggested differences in the role of leaf versus soil respiration between the two urban sites, with seasonal variation in the contribution of leaf respiration at a residential site and relatively constant contributions of leaf respiration at the city center. These results illustrate that spatial and temporal patterns of urban CO2 concentrations and isotopic composition can be used to infer patterns of energy use by urban residents as well as plant and soil processes in urban areas.

Oleksyn, J., et al. (2007). "Ecophysiology of horse chestnut (Aesculus hippocastanum L.) in degraded and restored urban sites." Polish Journal of Ecology 55(2): 245-260. We explored changes in growth, phenology, net CO2 assimilation rate, water use efficiency, secondary defense compounds, substrate and foliage nutrient concentration of a degraded urban horse chestnut (Aesculus hippocastanum L.) site restored for three years using mulching (tree branches including foliage) and fertilization (primarily nitrogen addition). Prior to restoration, this site was characterized by high pH (ca. 8), low foliage and substrate N, and high Na and Cl concentration. Our data indicated that in untreated plots NaCl used for road deicing is the decisive factors that may be responsible for the decrease of foliar N concentration (via a reduction in NO3- uptake), for the decrease in photosynthesis (through high concentrations of Na and Cl in the leaves) and for increased senescence of the leaves. After three years of treatment, total nitrogen concentration in substrate increased by 3- to 4-fold and calcium concentration decreased by more than 50% in relation to pretreatment levels. Treatment significantly increased seed production (from less than 12 to more than 100 seeds per tree), individual leaf mass (from 1.8 to 3.3 g/leaf), CO2 assimilation rate (by 21 to 30%), improved leaf C:N ratio, and increased foliage life span by as much as six weeks. The beginning of leaf fall in untreated control trees started in mid-July and those of mulched and fertilized trees in late October. Applied treatment also eliminated visible symptoms of leaf damage due to high sodium and chlorine levels, indicating the possible role of other factors in the development of necroses. After three years of treatment, pH of most degraded plots declined from 8.2 to 7.8. That decline was accompanied by an increase in foliar Zn, Cu, and Pb concentration in the mulched and fertilized plants. In addition, treatment lowered foliage phenolics making these plants potentially more vulnerable to insect herbivory. Our study indicates that stable carbon isotope discrimination is of little value as an indicator of cumulative salinity and urban environment stress in A. hippocastanum due to pronounced differences in leaf phenology and ontogeny. The results of our study show that street tree recovery can take as little as two to three years after application of fertilization and mulching.

Liu, Y.-J., et al. (2007). "Which ornamental plant species effectively remove benzene from indoor air?" Atmospheric Environment 41(3): 650-654. Phytoremediation—using plants to remove toxins—is an attractive and cost effective way to improve indoor air quality. This study screened ornamental plants for their ability to remove volatile organic compounds from air by fumigating 73 plant species with 150 ppb benzene, an important indoor air pollutant that poses a risk to human health. The 10 species found to be most effective at removing benzene from air were fumigated for two more days (8 h per day) to quantify their benzene removal capacity. Crassula portulacea, Hydrangea macrophylla, Cymbidium Golden Elf., Ficus microcarpa var. fuyuensis, Dendranthema morifolium, Citrus medica var. sarcodactylis, Dieffenbachia amoena cv. Tropic Snow; Spathiphyllum Supreme; Nephrolepis exaltata cv. Bostoniensis; Dracaena deremensis cv. Variegata emerged as the species with the greatest capacity to remove benzene from indoor air.

Lehvävirta, S. (2007). "Non-anthropogenic dynamic factors and regeneration of (hemi)boreal urban woodlands - synthesising urban and rural ecological knowledge." Urban Forestry & Urban Greening 6(3): 119-134. The natural dynamics of urban woodlands are seldom discussed despite the general acknowledgement that understanding of natural processes is a prerequisite for successful management of ecosystems. This paper reviews the non-anthropogenic dynamic factors, and anthropogenic changes in them, in urban woodlands. Several gaps in the knowledge are identified: (1) amount of tree regeneration and factors affecting it, (2) seedbed availability for poor competitors, (3) wind as a dynamic factor, (4) insect outbreak severity, (5) effect of urban climate on tree regeneration, (6) pollination and dispersal and (7) effect of herbivory on tree regeneration. It is concluded that natural dynamics drive regeneration in urban woodlands, but the disturbance regime and successional pathways may be altered. Natural colonisation of derelict land and natural dynamics in existing woodlands are beneficial because of decreased management costs, and the biodiversity, educational, recreational and psychological values they provide.

Lal, R. (2007). "Soil science and the carbon civilization." Soil Science Society of America Journal 71(5): 1425-1437. Soil science must play a crucial role in meeting present and emerging societal needs of the 21st century and beyond for a population expected to stabilize around 10 billion and having increased aspirations for a healthy diet and a rise in the standards of living. In addition to advancing food security by eliminating hunger and malnutrition, soil resources must be managed regarding numerous other global needs through interdisciplinary collaborations. Some of which are to mitigate global warming; to improve quantity and quality of freshwater resources; to enhance biodiversity; to minimize desertification; serve as a repository of Waste; air archive of human and planetary history; meet growing energy demands; develop strategies of sustainable management of urban ecosystems; alleviate poverty of agricultural communities as an engine of economic development; and fulfill aspirations of rapidly urbanizing and industrializing societies. In addition to food and ecosystem services, bio-industries (e.g., plastics, solvents, paints, adhesives, pharmaceuticals and chemicals) through plant-based compounds (carbohydrates, proteins, and oils) and energy plantations (bioethanol and biodiesel) can revolutionize agriculture. These diverse and complex demands on soil resources necessitate a shift in strategic thinking and conceptualizing sustainable management of soil resources in agroecosystems to provide A ecosystem services while also meeting the needs for food, feed, fiber, and fuel by developing multifunctional production systems. There is a strong need to broaden the scope of soil science to effectively address ever changing societal needs. To do this, soil scientists must rally with allied sciences including hydrology, climatology, geology, ecology, biology, physical sciences (chemistry, physics), and engineering. Use of nanotechnology, biotechnology, and information technology can play an important role in addressing emerging global issues. Pursuit of sustainability, being a moral/ethical and political challenge, must be addressed in cooperation with economists and political scientists. Soil scientists must work in cooperation with industrial ecologists and urban planners toward sustainable development and management of soils in urban and industrial ecosystems. More than half of the world's population (3.3 billion) live in towns and cities, and the number of urban dwellers is expected to increase to 5 billion by 2030. Thus, the study of urban soils for industrial use, human habitation, recreation, infrastructure forestry, and urban agriculture is a high priority. Soil scientists Must nurture symbiotic/synergistic relations with numerous stake holders including land managers, energy companies and carbon traders, urban planners, waste disposal organizations, and conservators of natural resources. Trading of C credits in a trillion-dollar market by 2020 must be made accessible to land managers, especially the resource-poor farmers in developing countries. Soil science curricula, at undergraduate and graduate levels, Must be revisited to provide the needed background in all basic and applied sciences with focus on globalization. We must raise the profile of soil science profession and position Students in the competitive world of ever flattening Earth.

Konijnendijk, C. C., et al. (2007). "Decision-support for land-use planning through valuation of urban forest benefits." Allgemeine Forst Und Jagdzeitung 178(4): 74-84. Many environmental and social services provided by urban and peri-urban forests are difficult to assess and quantify, for example, in monetary terms. This weakens the position of urban forestry in urban development and land use planning discussions. Therefore, there is a need to develop assessment approaches that can strengthen the policy-science interface by acting as decision-support tools within wider urban and regional policy-making contexts. Examples are presented where different methods for assessing social and environmental values of existing and new urban woodland were applied. These include an economic valuation study applying hedonic pricing assessing the effect of peri-urban afforestation on house prices in Denmark. Social valuation through social value mapping was studied in Helsinki, Finland. Finally, in Malaysia, various tools were combined to assess the multiple costs and benefits association with preserving one of the last remaining original forest areas near Kuala Lumpur. The different assessment tools have their respective strengths and weaknesses from a decision-support perspective, and for use under different circumstances. Combining different urban forest valuation tools is the preferred option in land-use planning.

Irwin, E. G. and N. E. Bockstael (2007). "The evolution of urban sprawl: Evidence of spatial heterogeneity and increasing land fragmentation." Proceedings of the National Academy of Sciences of the United States of America 104(52): 20672-20677. We investigate the dynamics and spatial distribution of land use fragmentation in a rapidly urbanizing region of the United States to test key propositions regarding the evolution of sprawl. Using selected pattern metrics and data from 1973 and 2000 for the state of Maryland, we find significant increases in developed and undeveloped land fragmentation but substantial spatial heterogeneity as well. Estimated fragmentation gradients that describe mean fragmentation as a function of distance from urban centers confirm the hypotheses that fragmentation rises and falls with distance and that the point of maximum fragmentation shifted outward over time. However, rather than outward increases in sprawl balanced by development infill, we find substantial and significant increases in mean fragmentation values along the entire urban-rural gradient. These findings are in contrast to the results of Burchfield et al. [Burchfield M, Overman HG, Puga D, Turner MA (2006) Q J Econ 121:587-633], who conclude that the extent of sprawl remained roughly unchanged in the Unites States between 1976 and 1992. As demonstrated here, both the data and pattern measure used in their study are systematically biased against recording low-density residential development, the very land use that we find is most strongly associated with fragmentation. Other results demonstrate the association between exurban growth and increasing fragmentation and the systematic variation of fragmentation with nonurban factors. In particular, proximity to the Chesapeake Bay is negatively associated with fragmentation, suggesting that an attraction effect associated with this natural amenity has concentrated development.

Hodges, A. W. and J. J. Haydu (2007). "Growth and challenges in Florida's environmental horticulture industry." HortTechnology 17(3): 371-378. Total Florida environmental horticulture industry sales in 2005 were $15.24 billion (B), whereas total industry output amounted to $10.39 B with $3.01 B for wholesale nurseries, $5.25 B for landscape services, and $2.13 B for horticultural retailers, which reflects the average gross margin on retail sales. Direct employment in the industry was 190,000 full-time jobs plus nearly 104,000 temporary, part-time, or seasonal jobs. Total employment impacts were 319,000 full- time and part-time/seasonal jobs, including 24,000 jobs created in other sectors of the economy. Total value-added or income impacts of $8.65 B included $5.19 B in labor income for employee wages, salaries, and business owner (proprietor) income. Fiscal impacts included $549 million (M) in indirect business taxes paid to local and state governments. Results for 2005 compared with previous studies performed for 1997 and 2000 indicate that growth in the industry has been dramatic over this time period. Industry sales increased from $8.35 B in 1997 to $15.24 B in 2005, representing a 7.8% average annual compound growth rate, whereas employment impacts grew at a 9.2% annual rate, and value-added impacts grew by 4.7%. The study also evaluated the impacts to the industry from eight hurricanes that struck Florida during 2004 and 2005. Nearly 80% of surveyed firms were adversely impacted by at least one hurricane. Total damages and losses resulting from hurricanes were estimated at $2.12 B, including product (crop) losses of $1.05 B, structural damages of $465 M, and cleanup costs of $605 M. Product losses of at least $100,000 were sustained by 22% of firms, whereas structural damages and cleanup costs of this level were suffered by 12% and 8% of firms, respectively. Nearly half (48%) of the firms had their business interrupted for 3 weeks or more. Despite these large losses, the industry continues to thrive.

Godefroid, S., et al. (2007). "The role of soil and microclimatic variables in the distribution patterns of urban wasteland flora in Brussels, Belgium." Landscape and Urban Planning 80(1-2): 45-55. Despite increased recognition of the importance of urban vegetation research, few attempts have been made to assess the relative influence of ecological variables on the species composition of urban wastelands. The main aim of this paper is to assess the relative importance of soil and microclimatic variables in structuring plant species richness and diversity in this habitat. Field investigations were carried out in 22 wasteland sites situated within the city of Brussels. The vegetation has been recorded in 38 4 m(2)-plots according to the Braun-Blanquet- method. A total of 19 environmental variables were taken into consideration, among others the presence of different kinds of anthropogenic substrates and microclimatic variables. Results indicate that plant species composition in urban wastelands is mainly driven by soil nutrient content, soil moisture, soil pH and light intensity (as inferred by the mean Ellenberg's indicator values). Various types of anthropogenic substrates such as concrete, pebbles, sand and rubble had different effects on the species composition, the proportion of neophytes, hemeroby and urbanity level. Air temperature and humidity did show a significant influence on the presence of some species. The contribution of these environmental variables to the species composition and diversity of urban wastelands is discussed. (c) 2006 Elsevier B.V. All rights reserved.

Godefroid, S. and N. Koedam (2007). "Urban plant species patterns are highly driven by density and function of built-up areas." Landscape Ecology 22(8): 1227-1239. This paper aims to assess the relative importance of the type of built-up area in structuring plant species composition and richness in urbanised environments. The study was carried out in the city of Brussels where all vascular plant species were recorded in 189 grid cells of 1 km(2) each. The effect of urban land use type on species composition was investigated using first Canonical Correspondence Analysis. Densely built-up area was the most powerful predictor for species composition, followed by industrial built-up areas, half open or open built-up areas with plantations, and open built-up areas with much natural vegetation in the surroundings. Indicator species were found for each type of built-up area and a response curve to the amount of built land was produced using Generalised Additive Modelling. Various types of built-up areas had different effects on environmental conditions as inferred by Ellenberg's indicator values, as well as on the species richness, species rarity, number of exotic species and proportion of extinction-prone species. It is concluded that future ecological studies should not treat urban areas as homogeneous areas by combining all anthropogenic factors into one aggregated variable. Instead, the urban matrix should be categorised in subsystems as it is multidimensional and highly variable across space.

Gill, S. E., et al. (2007). "Adapting cities for climate change: the role of the green infrastructure." Built Environ 33. The urban environment has distinctive biophysical features in relation to surrounding rural areas. These include an altered energy exchange creating an urban heat island, and changes to hydrology such as increased surface runoff of rainwater. Such changes are, in part, a result of the altered surface cover of the urban area. For example less vegetated surfaces lead to a decrease in evaporative cooling, whilst an increase in surface sealing results in increased surface runoff. Climate change will amplify these distinctive features. This paper explores the important role that the green infrastructure, i.e. the greenspace network, of a city can play in adapting for climate change. It uses the conurbation of Greater Manchester as a case study site. The paper presents output from energy exchange and hydrological models showing surface temperature and surface runoff in relation to the green infrastructure under current and future climate scenarios. The implications for an adaptation strategy to climate change in the urban environment are discussed.

Endlicher, W., et al. (2007). "Urban ecology—Definitions and concepts." Shrinking Cities: Effects on Urban Ecology and Challenges on Urban Development: 1-13. Earth’s population more than doubled during the second half of the twentieth century: from approximately 2.5 billion in 1950 to over 6 billion in 2000, and at the time of writing in 2007 has reached a gure of over 6.6 billion. Alongside this exponential growth of population is another important demographic trend: Ac- cording to the United Nations, the anticipated population growth between 2000 and 2030, approximately 2 billion people, will be concentrated in urban areas (UN 2004). The 21st century will be the century of urbanisation. By the year 2030 more than 60 per cent (4.9 billion) of the estimated world population (8.1 billion) will live in urban settlements, compared to 29 per cent in 1950. The 50 per cent mark is expected to be reached in the year 2007. In 2025, more than a dozen urban agglomerations will have over 20 million inhabitants, and some will have over 30 million. 23 of the 25 biggest urban agglomerations on the planet will be in Africa, Asia, and Latin America, rather than in Europe or North America (kRaaS 2003). These megacities are considered ‘hotspots’ of global change (kRaaS 2007). Urbanised areas cover between approximately one and six per cent of Earth’s surface, yet they have extraordinarily large ecological ‘footprints’ and complex, powerful, and often indirect effects on ecosystems (ReeS & WackeRnagel 1994).

Egoh, B., et al. (2007). "Integrating ecosystem services into conservation assessments: A review." Ecological Economics 63(4): 714-721. A call has been made for conservation planners to include ecosystem services into their assessments of conservation priority areas. The need to develop an integrated approach to meeting different conservation objectives and a shift in focus towards human wellbeing are some of the motivations behind this call. There is currently no widely accepted approach to planning for ecosystem services. This study contributes towards the development of this approach through a review of conservation assessments and the extent to which they include ecosystem services. Of the 476 conservation assessments identified by a set of search terms on the Web of Science, 100 were randomly selected for this review. Of these only seven had included ecosystem services, while another 13 had referred to ecosystem services as a rationale for conservation without including them in the assessment. The majority of assessments were based on biodiversity pattern data while 19 used data on ecological processes. A total of 11 of these 19 assessments used processes, which could be linked to services. Ecosystem services have witnessed an increase in attention received in conservation assessments since the year 2000, however trends were not apparent beyond this date. In order to assess which types of ecosystem services and how they have been accounted for in conservation assessments, we extended our review to include an additional nine conservation assessments which included ecosystem services. The majority included cultural ecosystem services, followed by regulatory, provisioning and supporting services respectively. We conclude with an analysis of the constraints and opportunities for the integration of ecosystem services into conservation assessments and highlight the urgent need for an appropriate framework for planning for ecosystem services.

Crossman, N. D., et al. (2007). "Systematic landscape restoration in the rural-urban fringe: meeting conservation planning and policy goals." Biodiversity and Conservation 16: 3781- 3802. Many landscapes that straddle the rural/urban divide suffer from low levels of species diversity following extensive clearing and fragmentation of native vegetation communities and conversion of land to agriculture. Further pressures are placed on remnant vegetation by encroaching urban expansion. These landscapes now exhibit a mosaic of small, patchy vegetation remnants that are under considerable pressure from housing and light-industrial development. Furthermore, agriculture in these landscapes tends to be of high economic value from uses such as intensive horticulture. Concerted and well-planned efforts are needed to balance the many conflicts of interest and competing demands for land with the need to restore landscapes for the protection of biodiversity. There has been a recent move in Australia toward regional biodiversity planning and goal setting, however specific detail on how to plan for achieving targets in complex landscapes is lacking. This paper applies a systematic landscape restoration model to a mixed-use, peri-urban landscape on the northern fringes of Adelaide, South Australia. The region contains fragments of remnant vegetation amongst a mosaic of high- value horticulture, light industry and urban development. Models produce maximally efficient solutions that meet comprehensive, adequate and representative conservation targets. Further constraints are added to the model to take into account the value of agricultural output, the biodiversity value of remnants, and property size and tenure. The effects on solution efficiencies as the number of constraints increase are investigated. This paper demonstrates the flexibility found in applying a systematic landscape restoration methodology. The process we present can be transferred to any rural-urban fringe region.

Ali-Toudert, F. and H. Mayer (2007). "Effects of asymmetry, galleries, overhanging facades and vegetation on thermal comfort in urban street canyons." Solar Energy 81. The present paper deals with the dependence of outdoor thermal comfort on the design of an urban street. The effects of the street vertical profile, including asymmetrical canyon shapes, the use of galleries and further shading devices on the façades, arranged in various orientations are assessed. The study is conducted by means of numerical modelling by using the three- dimensional microclimate model ENVI-met 3.0 which prognosticates the microclimatic changes within urban environments. Thermal comfort is evaluated for the daytime hours across the canyon in high spatial resolution and by means of the physiologically equivalent temperature PET. The results revealed that all design aspects investigated have a moderate impact on the air temperature and a strong effect on the heat gained by a human body and hence on the resulting thermal sensation. The larger the openness to the sky of the canyon, the higher the heat stress. For canyons with a smaller sky view, the orientation is also decisive: E–W canyons are the most stressful and deviating from this orientation ameliorates the thermal conditions. Basically, galleries and further shading through overhanging façades or vegetation enable a sensitive decrease of the period of time and of the area of thermal discomfort. Yet, this efficiency varies with the orientation and the vertical proportions of the canyon. Therefore, if appropriately combined, all investigated design elements can effectively mitigate heat stress in the summer and promote thermal comfort.

Yasuda, M. and F. Koike (2006). "Do golf courses provide a refuge for flora and fauna in Japanese urban landscapes?" Landscape and Urban Planning 75(1-2): 58-68. Golf courses have historically been seen as places of heavy pesticide and fertilizer use, however, there are few scientific studies on the ecology of golf courses. The aim of this study was to assess the value of golf courses for conserving forest biota in urban landscapes. The biota occurring in 12 Japanese golf courses and their surrounding areas was investigated. Investigations were done at golf course sites located on the green, fairway, rough, green belts between holes, and the out of bounds forest. Roadside, paddy fields, park and forest sites were investigated outside the golf courses. Presence/absence data for plants, arthropods and vertebrates in each sample habitat were analysed by TWINSPAN. As a result, communities in golf courses were classified by the part of course (e.g. green, fairway), and not by the location of the course nor chemical use. However, differences between golf courses in urban and rural landscapes were detected in the biota of the whole course. The out of bounds forest of golf courses was similar to forests that exist outside the courses, and this area held more flora and fauna than turf vegetation and artificial biotopes outside the course such as roadside and paddy. This suggests that golf courses in urbanised areas can be a refuge for flora and fauna, since forest cover occurs in only limited proportions in urban landscapes. Furthermore, the application of regulations for golf course construction seemed to be useful in maintaining forest species on golf courses. This may contribute to the conservation of native forest biota within Japanese urban landscapes.

Xian, G. and M. Crane (2006). "An analysis of urban thermal characteristics and associated land cover in Tampa Bay and Las Vegas using Landsat satellite data." Remote Sensing of Environment 104(2): 147-156. Remote sensing data from both Landsat 5 and Landsat 7 systems were utilized to assess urban area thermal characteristics in Tampa Bay watershed of west-central Florida, and the Las Vegas valley of southern Nevada. To quantitatively determine urban land use extents and development densities, sub-pixel impervious surface areas were mapped for both areas. The urban-rural boundaries and urban development densities were defined by selecting certain imperviousness threshold values and Landsat thermal bands were used to investigate urban surface thermal patterns. Analysis results suggest that urban surface thermal characteristics and patterns can be identified through qualitatively based urban land use and development density data. Results show the urban area of the Tampa Bay watershed has a daytime heating effect (heat-source), whereas the urban surface in Las Vegas has a daytime cooling effect (heat-sink). These thermal effects strongly correlated with urban development densities where higher percent imperviousness is usually associated with higher surface temperature. Using vegetation canopy coverage information, the spatial and temporal distributions of urban impervious surface and associated thermal characteristics are demonstrated to be very useful sources in quantifying urban land use, development intensity, and urban thermal patterns.

Tyrvainen, L., et al. (2006). "Visualization and landscape laboratories in planning, design and management of urban woodlands." Forest Policy and Economics 8(8): 811-823. Although participatory approaches are increasingly used in planning and management of urban woodlands, efficient tools are also needed to make the processes work. In urban forest planning impacts of proposed management regimes on aesthetic and recreational values are among the factors that interest the local residents the most. This article explores two potential methods for improving collaborative urban forest planning and design in Europe, based primarily on experience gained in the Nordic countries. The methods relate to the use of (i) computer- based visualization methods and (ii) demonstration forests and landscape laboratories. We suggest that use of both methods may lead to a major enhancement in forest planning and design.

Pataki, D. E., et al. (2006). "Urban ecosystems and the North American carbon cycle." Global Change Biology 12(11): 2092-2102. Approximately 75-80% of the population of North America currently lives in urban areas as defined by national census bureaus, and urbanization is continuing to increase. Future trajectories of fossil fuel emissions are associated with a high degree of uncertainty; however, if the activities of urban residents and the rate of urban land conversion can be captured in urban systems models, plausible emissions scenarios from major cities may be generated. Integrated land use and transportation models that simulate energy use and traffic-related emissions are already in place in many North American cities. To these can be added a growing dataset of carbon gains and losses in vegetation and soils following urbanization, and a number of methods of validating urban carbon balance modeling, including top down atmospheric monitoring and urban 'metabolic' studies of whole ecosystem mass and energy flow. Here, we review the state of our understanding of urban areas as whole ecosystems with regard to carbon balance, including both drivers of fossil fuel emissions and carbon cycling in urban plants and soils. Interdisciplinary, whole-ecosystem studies of the socioeconomic and biophysical factors that influence urban carbon cycles in a range of cities may greatly contribute to improving scenarios of future carbon balance at both continental and global scales.

Nowak, D. J., et al. (2006). "Air pollution removal by urban trees and shrubs in the United States." Urban Forestry Urban Greening 4. A modeling study using hourly meteorological and pollution concentration data from across the coterminous United States demonstrates that urban trees remove large amounts of air pollution that consequently improve urban air quality. Pollution removal (O3, PM10, NO2, SO2, CO) varied among cities with total annual air pollution removal by US urban trees estimated at 711,000 metric tons ($3.8 billion value). Pollution removal is only one of various ways that urban trees affect air quality. Integrated studies of tree effects on air pollution reveal that management of urban tree canopy cover could be a viable strategy to improve air quality and help meet clean air standards.

Li, W. F., et al. (2006). "Plant species composition in relation to green cover configuration and function of urban parks in Beijing, China." Ecological Research 21(2): 221-237. Parks, as one specific type of urban open space, play important roles in the conservation of urban biodiversity and provision of recreational services for local residents. As there is a lack of specific insight into park plant species composition in relation to park features, 24 sample parks within the inner city of Beijing, the capital of China, were studied by stratified random plot sampling of their tree, shrub, and herbaceous communities, respectively, in order to investigate how human activities have influenced park green cover configuration and floristic characteristics. The quantitative correlation of species richness and the park green cover indices (patch size, shape, etc.) were studied. The importance value index for plant species (trees, shrubs, and herbaceous species) of each park was calculated. The two-way indicator species analysis approach (TWINSPAN) was applied to classify the 24 parks into different groups based on their species assemblages. Two-hundred and eighty-eight species were recorded within the 24 study parks, belonging to 184 genera and 72 families dominated by Gramineae, Compositae, and Leguminosae. Among all the recorded species, 41% are exotic. The species occurrence, abundance and diversity vary significantly among different parks. Besides the positive correlation (R=0.505, P < 0.05) between herbaceous species abundance and the park green cover size, no other significant relations were found between the species abundance and other indices of park green cover configuration. Remarkably, the TWINSPAN classification resulted in a good discrimination between park functional types and the variation in their species assemblage. For the parks of similar age (development history) or landscape design, their species assemblages show more similarity. The methodology adopted and results can be employed to improve baseline information on urban plant ecology and support the setting of priorities for future park management and vegetation protection.

Lavelle, P., et al. (2006). "Soil invertebrates and ecosystem services." European Journal of Soil Biology 42(Supplement 1): S3-S15. Invertebrates play significant, but largely ignored, roles in the delivery of ecosystem services by soils at plot and landscape scales. They participate actively in the interactions that develop in soil among physical, chemical and biological processes. We show that soils have all the attributes of self-organized systems as proposed by Perry (Trends Ecol. Evol. 10 (1995) 241) and detail the scales at which invertebrates operate and the different kinds of ecosystem engineering that they develop. This comprehensive analysis of invertebrate activities shows that they may be the best possible indicators of soil quality. They should also be con- sidered as a resource that needs to be properly managed to enhance ecosystem services provided by agro- ecosystems.

Klumpp, A., et al. (2006). "Ozone pollution and ozone biomonitoring in European cities. Part I: Ozone concentrations and cumulative exposure indices at urban and suburban sites." Atmospheric Environment 40(40): 7963-7974. In the frame of a European research project on air quality in urban agglomerations, data on ozone concentrations from 23 automated urban and suburban monitoring stations in 11 cities from seven countries were analysed and evaluated. Daily and summer mean and maximum concentrations were computed based on hourly mean values, and cumulative ozone exposure indices (Accumulated exposure Over a Threshold of 40 ppb (AOT40), AOT20) were calculated. The diurnal profiles showed a characteristic pattern in most city centres, with minimum values in the early morning hours, a strong rise during the morning, peak concentrations in the afternoon, and a decline during the night. The widest amplitudes between minimum and maximum values were found in central and southern European cities such as Dusseldorf, Verona, Klagenfurt, Lyon or Barcelona. In the northern European cities of Edinburgh and Copenhagen, by contrast. maximum values were lower and diurnal variation was much smaller. Based on ozone concentrations as well as on cumulative exposure indices, a clear north-south gradient in ozone pollution, with increasing levels from northern and northwestern sites to central and southern European sites, was observed. Only the Spanish cities did not fit this pattern; there, ozone levels were again lower than in central European cities, probably due to the direct influence of strong car traffic emissions. In general, ozone concentrations and cumulative exposure were significantly higher at suburban sites than at urban and traffic-exposed sites. When applying the newly established European Union (EU) Directive on ozone pollution in ambient air, it was demonstrated that the target value for the protection of human health was regularly surpassed at urban as well as suburban sites, particularly in cities in Austria, France, northern Italy and southern Germany. European target values and long-term objectives for the protection of vegetation expressed as AOT40 were also exceeded at many monitoring sites.

Jenerette, G. D., et al. (2006). "Linking ecological footprints with ecosystem valuation in the provisioning of urban freshwater." Ecological Economics 59(1): 38-47. Two prominent and alternate approaches, ecosystem service valuation and ecological footprints, link the production of ecosystem services with their consumption by societies. An overlapping goal of both approaches is to promote the sustainable use of ecosystem services such that their production rates are not compromised. Yet, little integration of these perspectives and their emphasis on distinct units, dollars and area, has been attempted. We combined these two approaches to better understand variation in the societal demand and production of freshwater, a critical ecosystem service, for 121 cities in the United States. The analysis linked previously compiled data on urban water use and the spatial distribution of run-off water throughout the conterminous United States. Incorporating the spatial distribution of water consumption and production, we computed heterogeneous urban water use footprints for all 121 cities. From the relationship between annual municipal utility expense and footprint area, the median monetary value for water footprint area was $88,808 km(-2) yr(-1) from all the cities we considered. The ratio between the footprint-estimated cost and the utility-observed cost was negatively related to the local availability of water, and was independent of population size. By linking ecosystem service valuation and ecological footprint analyses into a coherent framework, we developed an integrated metric for understanding the provisioning of ecosystem services, which could help inform sustainable pricing guidelines for renewable freshwater.

Jenerette, G. D. and L. Larsen (2006). "A global perspective on changing sustainable urban water supplies." Global and Planetary Change 50(3-4): 202-211. Ensuring the sustainable supply of water for the world's largest cities has been and is a current challenge. Future trends in urban water consumption patterns will be determined by changes in population concentration, per-capita water use, climate, and the proportion of water retained for the production of instream ecosystem services. The objective of our research was to identify patterns of renewable water availability and urban consumption throughout the globe between the years 2000 and 2015. To better understand the interactions between urban consumption and regional availability of renewable water we used a modified ecological footprint (EF) approach. Urban water footprint areas were differentially sensitive to changes in consumption and changes in water availability; our results suggest climate induced reductions in water availability may be more of a concern than population growth or increased per-capita for securing continued supplies of water to large cities. Our results provide a comprehensive description of global urban water demand and highlight the variation between consumption and availability relationships for the 524 largest cities.

Hodgson, P., et al. (2006). "Comparison of foraging behaviour of small, urban-sensitive insectivores in continuous woodland and woodland remnants in a suburban landscape." Wildlife Research 33(7): 591-603. Small patches of remnant vegetation are often considered to have low conservation value. In urban landscapes their value may potentially be higher than in other landscapes because they can be the only representatives of original native vegetation. Despite this potential, many small insectivorous birds that rely on native vegetation demonstrate sensitivities within urban landscapes through reduced numbers or total absence. One reason for this sensitivity may be that remnants are of suboptimal quality, which may be reflected in behavioural changes. Using five insectivorous species that were present ( in low numbers) in remnants surrounded by highdensity housing, foraging behaviour was examined in relation to vegetation. The proportion of time birds spent on different foraging substrates and plant species was compared with that of conspecifics in continuous vegetation. Canopy and shrub foragers showed minimal behavioural changes. Ground foragers in remnants tended to forage at lower heights than those in continuous vegetation; however, these changes did not appear to reflect a negative effect. These changes were partially explained by structural differences between vegetation in remnants and continuous sites. The number of times a bird attacked prey items was significantly higher in continuous habitat for only two species. Overall, the foraging behaviour of small insectivorous birds in remnants surrounded by high- density housing was not adversely affected by urbanisation and it appears that remnants have potential value as habitat and foraging sources in an urban landscape. Despite this, small insectivores are still sensitive to urbanisation, suggesting that other factors, probably in the matrix, are important.

Georgi, N. and K. Zafiriadis (2006). "The impact of park trees on microclimate in urban areas." Urban Ecosystems 9(3): 195-209. Trees in cities have an important positive effect on people’s lives. One such positive effect is the amelioration of microclimate. The aim of this research is to assess the correlation between parameters that affect the microclimate of parks during the summer. We measured air temperature, relative humidity and solar radiation in the sun and shade of the trees in urban parks in Thessaloniki, Greece. The results indicate that: the air (A) temperature reduction percentage (dTair%), air relative humidity increase (dTRh%), discontent index reduction percentage (DI%) (cooling effect) and solar radiation (L) percentage that passes through the trees’ foliage to their shade creates an exponential function of dA% = a.e-bL. These functions are also applicable to the limiting variation values of the parameters. If we use L = 0 (meaning Lightsh = 0, which is the case for an extremely dense tree), then the values that we expect from this particular parameter are the maximum possible. These maximum values are a characteristic feature of the parameter variation for this particular research area. These maximum values for the trees in the parks of Thessaloniki are: maxdTair% ≈ 24%, maxdRh% ≈ 41% and maxdDI% ≈16%.

Fanelli, G., et al. (2006). "Ecological indicators applied to urban and suburban floras." Ecological Indicators 6(2): 444-457. Among the many approaches to ecological indicators, ecological indicators derived from the floristic composition of a site (i.e. Raunkiaer's forms spectrum or the percentage of different geographical distribution types-chorotypes) are well established in botanical and ecological literature. Nonetheless their relationship with other indicators, such as Ellenberg's ecological indicators, or the Grime model [Grime, J.P., 2002. Plant Strategies, Vegetation Processes and Ecosystem Properties. Wiley, Chichester] and the Hemeroby index [Kowarik, L, 1990. Some responses of flora and vegetation to urbanization in Central Europe. In: Sukopp, H., Hejny, S., Kowarik, I. (Eds.), Urban Ecology. Plants and plant communities in urban environments. SPB Academic Publishing, The Hague] is still poorly explored. We concentrated on an urban ecosystem because such areas, due to their high degree of artificialization, are particularly well suited for studying the interaction of anthropical disturbance with other processes of the ecosystems. This paper attempts to select a small indicator frameset of many already proposed indicators which best express the variability of the sites studied. A floristic-ecological investigation has been carried out in 10 urban sites, of which 6 were archeological, located in the centre of Rome and 4 suburban, semi-natural, in the NE of the town. Ecological indicators have been calculated on this data set. The Pearson correlation test was then applied to verify whether the indicators were independent, while stepwise regression analysis was done to evaluate the statistical weight of each ecoindicator. Disturbance and temperature are the main factors shaping the composition of the sites studied. They are largely interacting and are well expressed with the help of a small subset of the initial set of 19 indicators, namely, by indicators related to life forms and to the geographical distribution of species: Therophytes/Hemicryptophytes, Mediterranean/large distribution, Eurasiatic/ large distribution, Mediterranean/Eurasiatic species. The information provided by Ellenberg's indicators values and Grime's life strategies are largely summarized by these chorological indicators.

Crow, T., et al. (2006). "The Riverside and Berwyn experience: Contrasts in landscape structure, perceptions of the urban landscape, and their effects on people." Landscape and Urban Planning 75(3-4): 282-299. Humans not only structure the landscape through their activities, but their perceptions of nature are affected by the spatial and temporal arrangements (structure) in the landscape. Our understanding of these interactions, however, is limited. We explored the relationship between landscape structure and peoples' perceptions of nature in the Chicago, IL, USA, suburbs of Riverside and Berwyn because they offer contrasting paradigms of an urban landscape. Designed in the 1800s by Frederick Law Olmsted, Riverside has several unique design elements (curvilinear streets, ample setbacks, parkways of variable width with mowed grass and naturalistic groupings of trees) that define the structure and composition of this landscape. The urban forest was the keystone of Olmsted's desire to create a harmonious community characterized by "refined sylvan beauty". In contrast, the adjacent community of Berwyn has right-angled streets with small lots and narrow setbacks for houses. Differences in landscape structure between the two communities produced differences in the diversity, size, and composition of woody vegetation. As measured by patch-size distribution, Riverside had greater diversity in landscape structure than Berwyn, and in turn, Riverside had greater diversity in the composition and size of the woody vegetation compared to Berwyn. Riverside tended toward a "natural" appearance with vegetation, while yards in Berwyn tended to be trimmed and edged. Significant differences between the mean ratings of Riverside and Berwyn respondents were found for six of seven community attribute categories. Riverside participants reported receiving greater benefit from the visual and nature-related features of the urban forest than did Berwyn respondents. Berwyn residents ranked social atmosphere for the community and locomotion (wayfinding) highest among the seven community attribute categories. Despite differences between the two communities, residents valued the green residential environment provided by vegetation. However, the more diverse urban landscape as measured by built structures, woody vegetation, and lot size and shape proved to be more satisfying to the residents of these two communities. The design concepts developed and implemented by Olmsted more than century ago in Riverside are still relevant to city planners striving to develop living environments that are satisfying to urban and suburban residents.

Borgstrom, S. T., et al. (2006). "Scale mismatches in management of urban landscapes." Ecology and Society 11(2). Urban landscapes constitute the future environment for most of the world's human population. An increased understanding of the urbanization process and of the effects of urbanization at multiple scales is, therefore, key to ensuring human well-being. In many conventional natural resource management regimes, incomplete knowledge of ecosystem dynamics and institutional constraints often leads to institutional management frameworks that do not match the scale of ecological patterns and processes. In this paper, we argue that scale mismatches are particularly pronounced in urban landscapes. Urban green spaces provide numerous important ecosystem services to urban citizens, and the management of these urban green spaces, including recognition of scales, is crucial to the well-being of the citizens. From a qualitative study of the current management practices in five urban green spaces within the Greater Stockholm Metropolitan Area, Sweden, we found that 1) several spatial, temporal, and functional scales are recognized, but the cross-scale interactions are often neglected, and 2) spatial and temporal meso-scales are seldom given priority. One potential effect of the neglect of ecological cross-scale interactions in these highly fragmented landscapes is a gradual reduction in the capacity of the ecosystems to provide ecosystem services. Two important strategies for overcoming urban scale mismatches are suggested: 1) development of an integrative view of the whole urban social -ecological landscape, and 2) creation of adaptive governance systems to support practical management.

Boeckx, P., et al. (2006). "Spatial patterns of delta C-13 and delta N-15 in the urban topsoil of Gent, Belgium." Organic Geochemistry 37(10): 1383-1393. Urban ecosystems are characterized by a diverse land use pattern, strongly influenced by anthropogenic activities. The aim of this study was to assess whether the spatial distribution of delta N-15 and delta C-13 signatures in soil and plants could be reflected in patterns of functional urban land use. The study area (81.5 km(2)) was the city of Gent in Belgium. In the study area 200 sample locations were identified and the delta N-15 and delta C-13 signature of soil (0-5 cm) and grass samples was measured. The spatial structure of the isotopic distribution has been investigated using simple kriging with land use as complete categorical secondary information. The delta N-15(soil) and delta N-15(grass) data varied between -1.5 parts per thousand to 11.7 parts per thousand and -4.0 parts per thousand to 16.2 parts per thousand, respectively. The delta C-13(soil) and delta C-13(grass) data varied between -30.7 parts per thousand to -12.0 parts per thousand and -33.8 parts per thousand to -19.9 parts per thousand, respectively. Despite the overlapping standard deviations, the average delta N-15(soil), delta N-15(grass), delta C-13(soil), delta C-13(grass) data showed a clear land use dependent pattern. The delta N-15(soil), values showed the highest continuity with land use. The agricultural areas showed the highest delta N- 15(soil) data, which could be attributed to a more open N cycle and the loss of N-15 depleted N species or the use of N-15 enriched organic fertilizers. The wet grasslands of the nature reserves also showed higher delta N-15(soil) data, probably caused by enhanced denitrification losses. Urban greens showed the lowest delta N-15(soil) data, which could be explained by the absence of fertilizer input and the presence of N-2-fixing species (clover). The historic city centre and the residential areas showed average delta N-15(soil) data. The delta N-15(grass) correspond very well to the delta N-15(soil) data, but the delta N-15(grass) data were on average 1.1 parts per thousand depleted and showed a more random distribution. The delta C-13(soil) data indicated the introduction of maize (C4 plant) in agriculture, causing an increase of the delta C-13(soil) values of the agricultural zone of the study area. The wet grasslands of the nature reserves showed the lowest C3-signals in delta C-13(soil). The harbor area and the historic city centre and some isolated industrial sites showed the highest delta C-13(soil) data. These high values can be explained through the introduction of carbonate-rich materials from, e.g. constructions material, metallurgic activities, use of carbonate rich soils for the construction works and bulk C deposition (e.g. coal dust). It could be concluded that the stable isotopic composition of the topsoil and grass showed a moderate to strong relationship with land use of the studied urban ecosystem.

Andersson, E. (2006). "Urban landscapes and sustainable cities." Ecology and Society 11(1): 34. Ecological research targeting sustainable urban landscapes needs to include findings and methods from many lines of ecological research, such as the link between biodiversity and ecosystem function, the role of humans in ecosystems, landscape connectivity, and resilience. This paper reviews and highlights the importance of these issues for sustainable use of ecosystem services, which is argued to be one aspect of sustainable cities. The paper stresses the need to include social and economic factors when analyzing urban landscapes. Spatially explicit data can be used to assess the roles different green areas have in providing people with ecosystem services, and whether people actually have access to the services. Such data can also be used to assess connectivity and heterogeneity, both argued to be central for continuous, long-term provision of these services, and to determine the role urban form has for sustainability.

Schroter, D., et al. (2005). "Ecosystem service supply and vulnerability to global change in Europe." Science 310(5752): 1333-1337. Global change will alter the supply of ecosystem services that are vital for human well- being. To investigate ecosystem service supply during the 21st century, we used a range of ecosystem models and scenarios of climate and land-use change to conduct a Europe-wide assessment. Large changes in climate and land use typically resulted in large changes in ecosystem service supply. Some of these trends may be positive (for example, increases in forest area and productivity) or offer opportunities (for example, "surplus land" for agricultural extensification and bioenergy production). However, many changes increase vulnerability as a result of a decreasing supply of ecosystem services (for example, declining soil fertility, declining water availability, increasing risk of forest fires), especially in the Mediterranean and mountain regions.

Scharenbroch, B. C., et al. (2005). "Distinguishing urban soils with physical, chemical, and biological properties." Pedobiologia 49(4): 283-296. Modifications associated with urban infrastructure directly impact soil. properties. In particular, soil bulk density, microbial biomass and activity, and organic matter are impacted by anthropogenic activities. We proposed that urban soil properties are not only distinguishable from other systems, but also variable within types of landscapes in urban environments. We found soils from older urban landscapes (mean landscape age of 64 years) to be distinct from newer urban landscapes (mean landscape age of 9 years). Soil bulk densities were significantly greater in newer (1.73 g cm(-3)) compared to older urban soils (1.41 g cm(-3)) Older urban soils had significantly greater extractable phosphorous, weak Bray P (24%), strong Bray P (51%), and K (45%) than newer urban soils. Soil. biological measures of nitrogen availability were significantly greater in old compared to new urban soils, microbial biomass N (71%), potential C mineralization (20%), and potential N mineralization (83%). We found exponentially decreasing metabolic quotient values, qCO(2), suggesting the impact of site disturbance decreases rapidly with time, and older urban landscapes are closer to steady-state conditions relative to younger urban Landscapes. Total soil organic matter was significantly greater (35%) in old urban soils. Fine POM was a larger contributor to total SOM in old compared to new urban soils. Particulate organic matter C/N ratios from older urban soils were less (coarse POM 14% less and fine POM 13% less) than newer urban soils. Of the soil forming factors, time played the most significant rote in soil physical, chemical, and biological differences. We believe that as time since initial disturbance increases, the impacts of urbanization are reduced by processes improving physical, biological, and chemical soil properties.

McPherson, E. G. and J. Muchnick (2005). "Effects of Street Tree Shade on Asphalt Concrete Pavement Performance." Journal of Arboriculture 31(6): 303-310. Forty-eight street segments were paired into 24 highand low-shade pairs in Modesto, California, U.S. Field data were collected to calculate a Pavement Condition Index (PCI) and Tree Shade Index (TSI) for each segment. Statistical analyses found that greater PCI was associated with greater TSI, indicating that tree shade was partially responsible for reduced pavement fatigue cracking, rutting, shoving, and other distress. Using observed relations between PCI and TSI, an unshaded street segment required 6 slurry seals over 30 years, while an identical one planted with 12 crape myrtles (Lagerstroemia indica, 4.4 m [14 ft] crown diameter) required 5 slurry seals, and one with 6 Chinese hackberry (Celtis sinensis, 13.7 m [45 ft] crown diameter) required 2.5 slurry seals. Shade from the large hackberries was projected to save $7.13/m2 ($0.66/ft2) over the 30-year period compared to the unshaded street.

Li, F., et al. (2005). "Comprehensive concept planning of urban greening based on ecological principles: a case study in Beijing, China." Landscape and Urban Planning 72(4): 325-336. Greenspace is an important part of complex urban ecosystems and provides significant ecosystem services. It benefits urban communities environmentally, esthetically, recreationally and economically. Beijing Province is in north of China, and has a total area of 16,807.8 km(2) and a population of about 13.8 million. This paper aims to develop a comprehensive conceptual framework for urban greening of Beijing Province based on landscape ecological principles. It attempts to answer how to establish an urban greening plan at the regional, city and neighborhood levels to achieve long-term sustainability. At the regional level, a big natural and semi-natural forest area in the northwest and an ecological buffer belt in the southeast are planned to protect the environmental quality of Beijing and provide habitats for wildlife. At the city level, a green network system of green wedges, parks and green corridors has been proposed. This green network helps to limit future urban expansion, improve urban environmental quality and serve as habitats and migration routes for wildlife. At the neighborhood level, green extensions and connections of riverside greenway, road greenway, parks and vertical greening permeate into the built-up areas. They provide open space close to residential areas and offer places for recreation. This three-level green system constitutes an integrated ecological network for urban sustainable development of Beijing. For future development of Beijing, urban parks, forestry, agriculture, water and infrastructure should be planned and designed in an integrated way. After this greenspace plan is legislated and completely realized, Beijing will develop an interconnected and integrated network of urban greenspaces. It has the prospect of achieving the aim of "Green Olympic City 2008" and the long-term goal of developing Beijing towards an "Eco-City".

Lepedus, H., et al. (2005). "Photosystem II efficiency, chloroplast pigments and fine structure in previous-season needles of Norway spruce (Picea abies L. Karst.) affected by urban pollution." Periodicum Biologorum 107(3): 329-333. Industry and road traffic are considered to be main sources of air pollutants in urban areas. Changes in chloroplast structure, biochemistry and function appeared as very fast and reliable indicators of stress conditions. The arm of our study was to compare the needles of Norway spruce trees growing on differently polluted sites in the city of Osijek (Croatia) regarding photosynthetic pigment content, chloroplast ultra-structure and the efficiency of photosystem II. Materials for the study were previous-season needles collected from the middle crown of ten, about 25 year-old cultivated Norway spruce (Picae abies L. Karst.) trees grown in the City of Os jell, Croatia. According to the data on pollution levels obtained from the Croatian National Institute of Public Health, two sampling plots were defined: less (reference) and more polluted. Photosynthetic pigments were extracted with absolute acetone and quantified spectrophotometrically. For electron microscopy, the plant material was fixed in glutaraldehyde, dehydrated and embedded in Spurr's resin. Ultrathin sections were contrasted with lead citrate and uranyl acetate. The measurements of chlorophyll fluorescence were performed with the pulse-amplitude-modulated photosynthesis yield analyser (Mini-PAM, Waltz), using pulse- saturating method. The plant material was dark-adapted for 30 minutes. Minimal (Fo) and maximal (Fin) fluorescence yields were measured in the dark-adapted samples. The same parameters (F and Pin, respectively) were measured at two different irradiance levels: low light (125 mu mol(PHOTONS) m(-2)z s(-1)) and high light (1400 mu mol(PHOTONS) m(-2) s(-1)). The concentration of photosynthetic pigments was lower in more affected needles than in the reference ones. However; only changes in chlorophyll b revealed statistical signficance, increasing the chlorophyll a to chlorophyll b ratio. Chloroplast ultrastructure and shape were changed in more affected needles: these chloroplasts were roundish with much bigger starch grains and snore pronounced thylakoid swelling than the chloroplast from the reference needles. Maximal photochemical efficiency of photosystem II (Fv/Fm) measured in the dark-adapted samples teas almost the same for both samples, while lower values of the effective quantum yield of photosystem II (Delta F/F'm) were determined in more affected needles. It can be concluded that after a prolonged period of exposure to a higher pollution level (two years), spruce needles revealed biochemical, ultrastructural and functional changes when compared with the needles exposed to a lower pollution level.

Latalowa, M., et al. (2005). "Diurnal patterns of airborne pollen concentration of the selected tree and herb taxa in Gdansk (northern Poland)." Grana 44. The diurnal variation of airborne pollen concentrations of Alnus, Betula, Pinus, Poaceae, Urtica and Artemisia was examined at the sampling station in Gdańsk, northern Poland. Diurnal patterns of Alnus and Pinus pollen show distinctly lower values and low frequency of diurnal maxima between midnight and late morning and a clear rise of pollen counts at around noon. The rather high values remain during the afternoon and evening. The Betula pollen counts are almost evenly distributed along day and night and diurnal maxima appear in similar frequency at any time of day. Pollen concentrations of Poaceae increase at about 9.00 hours and remain high till late evening. Diurnal patterns of Urtica and Artemisia show very clear variation with high peaks at around 9.00 hours (Artemisia) and 13.00 hours (Urtica). The comparison of the data from Gdańsk with the data from other aerobiological stations shows very similar general features in the diurnal patterns irrespective the region or the local situation.

Kanakidou, M., et al. (2005). "Organic aerosol and global climate modelling: a review." Atmos Chem Phys 5. The present paper reviews existing knowledge with regard to Organic Aerosol (OA) of importance for global climate modelling and defines critical gaps needed to reduce the involved uncertainties. All pieces required for the representation of OA in a global climate model are sketched out with special attention to Secondary Organic Aerosol (SOA): The emission estimates of primary carbona- ceous particles and SOA precursor gases are summarized. The up-to-date understanding of the chemical formation and transformation of condensable organic material is outlined. Knowledge on the hygroscopicity of OA and measurements of optical properties of the organic aerosol constituents are summarized. The mechanisms of interactions of OA with clouds and dry and wet removal processes parameterisations in global models are outlined. This information is synthe- sized to provide a continuous analysis of the flow from the emitted material to the atmosphere up to the point of the cli- mate impact of the produced organic aerosol. The sources of uncertainties at each step of this process are highlighted as areas that require further studies.

Hill, S. J., et al. (2005). "Relationships between anthropogenic disturbance, soil properties and plant invasion in endangered Cumberland Plain Woodland, Australia." Austral Ecology 30(7): 775-788. Invasive exotic plants are a significant threat to areas of conservation value, with endangered ecological communities being especially vulnerable. We assessed the role of different anthropogenic disturbances in determining the success of exotic plants in the endangered Cumberland Plain Woodland community of western Sydney and examined the impact of these disturbances on soil characteristics that are likely to impact on vegetation, including total P, pH, water retention capacity, organic matter content and electrical conductivity. The disturbance types were: (i) land use incorporating clearing, agriculture and grazing by stock; (ii) creeks draining a developed catchment; and (iii) roads. Remnants that had been cleared and grazed had higher exotic and lower native species richness and cover than all other disturbance types. Areas that had been grazed but not cleared did not have more exotic species richness or cover than uncleared/ungrazed areas, thus retaining high conservation value. Areas within 2 m of a creek edge had higher exotic species richness and cover than areas further from the creek edge. Areas downslope of sealed roads had significantly higher exotic species richness and cover than areas below unsealed roads. No single soil attribute or combination of soil attributes was consistently able to account for variation in exotic species cover under the different disturbance types. Thus it appears that other factors such as site history and propagule pressure may be more important in determining exotic species success than soil characteristics alone, in this vegetation community.

Grimm, N. B., et al. (2005). "N retention and transformation in urban streams." Journal of the North American Benthological Society 24(3): 626-642. Nutrient spiraling in theory and application provides a framework for comparing nutrient retention efficiency of urban streams to relatively unaltered streams. Previous research indicated that streams of the southwestern USA deserts are highly retentive of N because of N limitation, high productivity, and high channel complexity (in particular, extensive transient storage associated with the hyporheic zone). Most southwestern urban streams have extensively modified channels and experience N loading from urban runoff and inputs of NO3-- contaminated groundwater. Therefore, we predicted southwestern urban streams are neither N- limited nor retentive. For some urban streams, however, restoration efforts reestablish flow in long-dry channels, create nonstructural flood-management solutions, and design riparian areas as a public recreation amenity. These human modifications may, in part, restore N retention functions if channel complexity and heterogeneity are as important to N retention efficiency as believed. We conducted experimental tracer studies using NO3-, as part of the Lotic Intersite Nitrogen eXperiment (LINX) project, and several separate nutrient-addition experiments (using slight increases in NO3- concentration), to evaluate N retention in southwestern urban streams. We present preliminary results of those experiments, comparing results to similar experiments in unaltered streams to test our predictions. Our results allow an evaluation of the use of nutrient spiraling metrics as a tool for assessing the status of stream ecosystem services in urban restoration projects.

Gaston, K. J., et al. (2005). "Urban domestic gardens (II): experimental tests of methods for increasing biodiversity." Biodiversity and Conservation 14(2): 395-413. The extent and continued expansion of urbanisation has focused attention on the significance for native biodiversity of those green spaces remaining within such areas and the most appropriate methods of managing them. In the UK, a high proportion of urban space is comprised of the private or domestic gardens associated with residential dwellings, and many recommendations have been made for simple changes to improve their value for biodiversity ('wildlife gardening'). Here, we report the results of replicated experimental tests of five such common recommendations, involving the introduction to gardens of (i) artificial nest sites for solitary bees and wasps; (ii) artificial nest sites for bumblebees; (iii) small ponds; (iv) dead wood for fungi and other saproxylic organisms; and ( v) patches of nettles Urtica dioica L. for butterfly larvae. The broad conclusion is that whilst some methods for increasing the biodiversity of garden environments may be very effective, others have a low probability of success on the timescales and spatial scales likely to be acceptable to many garden owners. If one of the functions of small scale biodiversity enhancement is to develop and encourage awareness of biodiversity and its conservation, then encouragement to conduct particular activities must be balanced with a realistic appraisal of their likely success.

Ehrenfeld, J. G. (2005). "Vegetation of forested wetlands in urban and suburban landscapes in New Jersey." Journal of the Torrey Botanical Society 132(2): 262-279. Forested wetlands in the northeastern US are increasingly surrounded by urban and suburban land-use, as development spreads outwards from city centers. I have studied a sample of 21 mature deciduous forested wetlands in a densely populated and long-settled region, northeastern New Jersey, in order to 1) describe characteristics of the plant communities of wetlands in such human-dominated landscapes, and 2) test the utility of hydrogeomorphic classification (HGM) in explaining the variation in composition and structure observed among the sites. The wetlands support a rich flora of over 300 species, with a mean richness of 66-92 species per site for the different HGM classes; common species were similar to those reported in previous studies of undisturbed red maple swamps. Structural characteristics (tree diameter and stem densities) were, like species richness and species composition, similar to those reported in previous reviews of red maple swamps, suggesting that despite the urban setting, community composition and structure of these wetlands are similar to those of undisturbed wetlands. Exotic species represented on average 5-11 % of the flora of the sites, a value similar to other forested wetlands, suggesting that the urban setting does not result in a higher degree of exotic invasion than expected for forested wetlands in non-urban landscapes. HGM classification was poorly related to all aspects of vegetation structure, suggesting that at least in urban landscapes, it is not useful for predicting characteristics of the vegetation. The ability of these communities to resist major changes due to the urban setting may reflect the facultative-wetland status of most of the species; their ability to tolerate a wide range of wetland conditions allows them to persist despite alterations of hydrological regimes. Forested wetlands in developed landscapes can evidently maintain community composition and structure similar to those in undeveloped landscapes.

Donovan, R. G., et al. (2005). "Development and application of an urban tree air quality score for photochemical pollution episodes using the Birmingham, United Kingdom, area as a case study." Environ Sci Technol 39. An atmospheric chemistry model (CiTTyCAT) is used to quantify the effects of trees on urban air quality in scenarios of high photochemical pollution. The combined effects of both pollutant deposition to and emission of biogenic volatile organic compounds (BVOC) from the urban forest are considered, and the West Midlands, metropolitan area in the UK is used as a case study. While all trees can be beneficial to air quality in terms of the deposition of O3, NO2, CO, and HNO3, some trees have the potential to contribute to the formation of O3 due to the reaction of BVOC and NOx. A number of model scenarios are used to develop an urban tree air quality score (UTAQS) that ranks trees in order of their potential to improve air quality. Of the 30 species considered, pine, larch, and silver birch have the greatest potential to improve urban air quality, while oaks, willows, and poplars can worsen downwind air quality if planted in very large numbers. The UTAQS classification is designed with practitioners in mind, to help them achieve sustainable urban air quality. The UTAQS classification is applicable to all urban areas of the UK and other mid-latitude, temperate climate zones that have tree species common to those found in UK urban areas. The modeling approach used here is directly applicable to all areas of the world given the appropriate input data. It provides a tool that can help to achieve future sustainable urban air quality.

Dlugosch, K. M. (2005). "Understory community changes associated with English ivy invasions in Seattle's urban parks." Northwest Science 79(1): 53-60. English ivy has become a common invader in Seattle's urban parks and in forests throughout the Pacific Northwest. Despite a great deal of concern over the potential impacts of this species, no studies have investigated ivy's effects on native vegetation in this region. In this study, paired comparisons between ivy-invaded and adjacent non-invaded plots in three Seattle parks were used to quantify changes associated with ivy invasion in the forest understory. Species diversity, percent cover, and tree regeneration were surveyed. Differences in species diversity, calculated as both richness and evenness, were not significantly different between invaded and non-invaded plots. Ivy-invaded plots did have significantly higher total cover, and significantly lower non-ivy cover, than non-invaded plots. The reduction of percent cover in invaded plots was primarily due to the loss of native shrubs. A plot where ivy had been removed over five years was also surveyed, and percent cover in this plot showed intermediate values relative to invaded and non-invaded plots, for both total cover and cover of native shrubs. The number of trees regenerating in the understory was higher in invaded plots, though this difference was not significant. These results suggest that English ivy invasions have substantial impacts on understory cover, and may influence the species composition and diversity of forest communities over the long-term by increasing vegetative cover and suppressing dominant native shrubs.

Carreiro, M. M. and C. E. Tripler (2005). "Forest remnants along urban-rural gradients: Examining their potential for global change research." Ecosystems 8(5): 568-582. Over the next century, ecosystems throughout the world will be responding to rapid changes in climate and rising levels of carbon dioxide, inorganic N and ozone. Because people depend on biological systems for water, food and other ecosystem services, predicting the range of responses to global change for various ecosystem types in different geographic locations is a high priority. Modeling exercises and manipulative experimentation have been the principle approaches used to place upper and lower bounds on community and ecosystem responses. However, each of these approaches has recognized limitations. Manipulative experiments cannot vary all the relevant factors and are often performed at small spatio-temporal scales. Modeling is limited by data availability and by our knowledge of how current observations translate into future conditions. These weaknesses would improve if we could observe ecosystems that have already responded to global change factors and thus presage shifts in ecosystem structure and function. Here we consider whether urban forest remnants might offer this ability. As urban forests have been exposed to elevated temperature, carbon dioxide, nitrogen deposition and ozone for many decades, they may be ahead of the global change "response curve" for forests in their region. Therefore, not only might forests along urbanization gradients provide us with natural experiments for studying current responses to global change factors, but their legacy of response to past urbanization may also constitute space-for-time substitution experiments for predicting likely regional forest responses to continued environmental change. For this approach to be successful, appropriate criteria must be developed for selecting forest remnants and plots that would optimize our ability to detect incipient forest responses to spatial variation in global change factors along urbanization gradients, while minimizing artifacts associated with remnant size and factors other than those that simulate global change. Studying forests that meet such criteria along urban-to-rural gradients could become an informative part of a mixed strategy of approaches for improving forecasts of forest ecosystem change at the regional scale.

Alberti, M. (2005). "The effects of urban patterns on ecosystem function." International Regional Science Review 28(2): 168-192. Urban ecological systems are characterized by complex interactions among social, economic, institutional, and environmental variables. These interactions generate complex human-dominated landscapes, which significantly influence the functioning of local and global earth ecosystems and the services they provide to humans and other life on earth. Urban development fragments, isolates, and degrades natural habitats; simplifies and homogenizes species composition; disrupts hydrological systems; and modifies energy flow, and nutrient cycling. Urban areas also appropriate a large share of earth's carrying capacity front other regions in terms of resource input and waste sinks. Change in ecological conditions that result from human actions in urban areas ultimately affect human health and well-being. In this article, the author reviews the empirical evidence on the effects that patterns of urban development have on ecosystem function. Urban development affects the spatial heterogeneity of the landscape (i.e., pattern of variation in land cover) and spread of disturbance (i.e., invasive species). The author proposes that alternative urban patterns generate differential ecological effects. The review; reveals that the interactions between urban development patterns and ecosystem dynamics are still poorly understood. The author draws on an empirical study of the Puget Sound metropolitan region currently developed at the University of Washington to propose directions for future empirical research that can inform strategies to minimize urban impacts on ecosystems.

Wessel, W. W., et al. (2004). "A qualitative ecosystem assessment for different shrublands in western Europe under impact of climate change." Ecosystems 7(6): 662-671. Climate change may affect the dynamics of ecosystems and the goods and services they provide. To investigate the consequences of warming and drought for the goods and services provided by different shrublands in various western European countries, an assessment was carried out using results of field manipulation experiments of the CLIMOOR and VULCAN projects. Goods and services of these shrublands mainly encompass biodiversity, various forms of recreation, conservation of culturally and historically important landscapes, groundwater as a drinking water source, and carbon sequestration. Warming of dry lowland heathlands in The Netherlands and Denmark increases nutrient availability, which may lead to grass encroachment reducing biodiversity and decreasing recreational values. Drought may reduce the chances of grass encroachment but increase the chances of disturbances to heather vegetation. Similarly, warming increases and drought decreases the chances of nitrate pollution to the groundwater, which is often used as a drinking water source. Warming of the upland heathland in the UK increases its productivity, which might enable higher grazing densities leading to improved agricultural production. However, complex interactions between heather and invading species may be affected. Furthermore, nitrate production is increased, which may lead to groundwater pollution. Under drought conditions, productivity decreases and agricultural production capacity drops. in the Mediterranean shrubland in Spain, both warming and drought led to a shift in the species composition of seedlings and recruitment, which might lead to a change in the plant community and a reduction in biodiversity. In the drought treatment, a decreasing soil carbon content may lead to a loss of biodiversity, recreational possibilities, and an increased threat of wildfires and erosion.

Sullivan, W. C., et al. (2004). "The fruit of urban nature - Vital neighborhood spaces." Environment and Behavior 36(5): 678-700. What makes a neighborhood space vital? This article explores the possibility that the presence of trees and grass may be one of the key components of vital neighborhood spaces. We report on 758 observations of individuals in 59 outdoor common spaces in a residential development. Twenty-seven of the neighborhood common spaces were relatively green, whereas 32 were relatively barren. Results indicate that the presence of trees and grass is related to the use of outdoor spaces, the amount of social activity that takes place within them, and the proportion of social to nonsocial activities they support. The findings improve and broaden our understanding of the physical characteristics that influence social contact among neighbors and provide evidence that nature plays an important role in creating vital neighborhood spaces.

Pysek, P., et al. (2004). "Trends in species diversity and composition of urban vegetation over three decades." Journal of Vegetation Science 15(6): 781-788. Question: What was the change in diversity of urban synantropic vegetation in a medium- sized Central European city during the period of increasing urbanization (1960s-1990s)? Location: The city of Plzen, an industrial centre of the western part of the Czech Republic. Methods: Sampling of various types of synanthropic vegetation, conducted in the 1960s, was repeated by using the same methods in the 1990s. This yielded 959 releves, of which 623 were made in the 1960s and 336 in the 1990s. The releves were assigned to the following phytosociological classes: Chenopo-dietea, Artemisietea vulgaris, Galio-Urticetea, Agropyretea repentis and Plantaginetea majoris. Total number of vascular plant species, evenness index J, number of alien species (classified into archaeophytes and neophytes), and mean Ellenberg indicator values for light, temperature, continentality, moisture, soil reaction, and nutrients were obtained for each releve. Results: From 1960s to 1990s, there was a significant decrease of species richness and diversity in synanthropic vegetation. The proportion of archaeophytes decreased in most vegetation types, indicating the contribution of this group of species, often confined to specific rural-like habitats, to the observed impoverishment of ruderal vegetation. The proportion of neophytes did not change between the two periods. Comparison between 1960s and 1990s indicated a decrease in light, temperature, moisture, soil reaction and nutrient indicator values in some vegetation types. In both periods, Artemisieta, Galio-Urticetea and Chenopodietea formed a distinct group harbouring more species than Agropyretea and Plantaginetea. Neophytes, i.e. recently introduced species, were most represented in the early successional annual vegetation of Chenopodietea, rather than in perennial vegetation of the other classes. Conclusions: Synanthropic vegetation of Plzen exhibited a general trend of decrease in species diversity.

Powe, N. A. and K. G. Willis (2004). "Mortality and morbidity benefits of air pollution (SO2 and PM10) absorption attributable to woodland in Britain." J Environ Manage 70. Forests in Britain produce social and environmental benefits, in addition to marketable timber outputs. One such non-market benefit is the reduction in air pollution, linked to health impacts (mortality and morbidity). This study assesses the benefits of SO2 and PM10 absorption by trees in terms of extending life expectancy of the population and reducing hospital admissions. Working at a resolution of 1km with woodland over 2 hectares, it is estimated that, for Britain as a whole, woodland saves between 5 and 7 deaths, that would otherwise have been brought forward, and between 4 and 6 hospital admissions each year. The economic value of the health effect of woodland is estimated to be at least £900,000 per year. Smaller areas of woodland, often located closer to population, sometimes strategically planted close to pollution sources, will generate additional air pollution absorption benefits to those estimated here. Researching such benefits would require more detailed data than is available at present for a national study. However, the health benefits of woodland are relatively small in comparison to other non-market forestry benefits.

Platt, R. H. (2004). Regreening the metropolis: Pathways to more ecological cities. Urban Biosphere and Society: Partnership of Cities. 1023: 49-61. Eighty percent of the American population now lives in metropolitan regions whose geographic extent continues to expand even as many core cities and inner-tier suburbs lose middle-class populations, jobs, and tax base. Urban sprawl and the socioeconomic polarizing of metropolitan America have been fostered by public policies including (1) federal subsidies for new infrastructure on the urban fringe; (2) tax policies that favor home ownership over rental properties; (3) local zoning codes; and (4) federal and state neglect of older urban neighborhoods. In the face of diminished access to "nature" outside of metropolitan areas, locally based efforts to protect and restore greenspaces within urban areas seek to make older communities more habitable and more "ecological." Some pathways to more ecological cities include the following: (1) the notion of rus in urbe ("the country in the city"); (2) the "usable outdoors"; (3) garden cities and eco-villages; (4) green buildings and green roofs; (5) urban biodiversity; (6) ecological services; and (7) space, nature, and place.

Nali, C., et al. (2004). "Plants as indicators of urban air pollution (ozone and trace elements) in Pisa, Italy." Journal of Environmental Monitoring 6(7): 636-645. A biennial integrated survey, based on the use of vascular plants for the bioindication of the effects of tropospheric ozone, was performed in the area of Pisa (Tuscany, Central Italy). It also investigated the distribution of selected trace elements in plants and the data were compared with those obtained from the use of passive samplers, automatic analysers of ozone and lichen biodiversity. Photochemically produced ozone proved to be present during the warm season, with maximum hourly means surpassing 100 ppb: the use of supersensitive tobacco Bel-W3 confirmed the value of detailed, cost-effective, monitoring surveys. Trials with clover clones demonstrate that sensitive plants undergo severe biomass reduction in the current ozone regime. The mean NC-S ( clover clone sensitive to ozone): NC-R ( resistant) biomass ratio ranged from 0.7 ( in 1999) to 0.5 ( in 2000). The economic impact of these reductions deserves attention. The data obtained using passive ozone samplers exceeded those obtained using an automatic analyser. The mapping of epiphytic lichen biodiversity was not related to the geographical ozone distribution as can be seen from the tobacco's response. Lettuce plants grown under standardized conditions were used positively as bioaccumulators of trace elements: Pb was abundantly recovered, but a large portion of this element was removed by washing.

Martin, C. A. and L. B. Stabler (2004). "Urban horticultural ecology: Interactions between plants, people and the physical environment." Expanding Roles for Horticulture in Improving Human Well-Being and Life Quality (639): 97-101. Growing interest in the ecology of cities is providing a unique opportunity for horticultural scientists to study plant processes in an environmental setting that is foreign to most ecologists. Past studies in urban plant ecology have been limited to inventories and distribution of the plants present or have focused on areas of remnant native vegetation and impacts of urbanization on those remnant patches. Classic ecological pedagogy depicts exotic species as invaders, and human manipulations of the geo-surface as disturbance events. The real essence of urban vegetation as a system that has been carefully designed and is intensively managed to serve human interests has been overlooked. While the concepts of human/plant interactions are common and inherent to horticultural research, they may present a difficult obstacle to be overcome for those trained in conventional ecological circles. In conjunction with the Central Arizona Phoenix Long Term Ecological Research initiative, we have approached plant ecological studies in an and urban system as an interacting triad of plants, people, and the physical environment. People arrange and manage plants in cities for aesthetic as well as practical purposes. Plant viability is predicated on horticultural practices, and the anthropogenic environment in which landscape plants grow can be physiologically stressful. At the same time, the arrangement of plants affects the biophysical environment of the city and the quality of life of the people living there. We propose that a better understanding of urban plant ecology is attained using a landscape horticultural perspective, one that is familiar with the interactions between plants, people, and the physical environment. Understanding the ecology of urban plants might lead to design and management strategies that maximize benefits associated with plants in cities and improve human well being and quality of life.

Koh, L. P. and N. S. Sodhi (2004). "Importance of reserves, fragments, and parks for butterfly conservation in a tropical urban landscape." Ecological Applications 14(6): 1695- 1708. We assessed the effectiveness of forest reserves (i.e., protected old secondary and primary forests), fragments (i.e., scattered ruderal vegetation), and urban parks (i.e., artificially revegetated habitats) in conserving butterfly diversity in a highly urbanized tropical landscape (i.e., Singapore), by testing the hypothesis that forest reserves have the highest butterfly species richness among these habitats. We investigated which environmental factors (e.g., canopy cover) affect the distribution of butterflies across the habitats; and also tested the hypothesis that butterfly communities of different habitats have distinct ecological traits. Further, we examined the important determinants (e.g., area) of butterfly richness in urban parks, by testing the hypothesis that the number of potential larval host plant species occurring in the park is the best predictor of butterfly species richness. Rarefaction analyses showed that forest reserves had the highest number of species, number of unique species, density of species, and community evenness among the habitats, implying that, in urban landscapes, the least human-disturbed habitats should be given the highest conservation priority. Forest reserves and urban parks adjoining forests collectively accounted for 91% of all butterfly species recorded in this study, suggesting that their preservation will likely achieve maximum complementarity for effective butterfly conservation. Ordination analyses revealed that different butterfly species responded differently to environmental factors (e.g., canopy cover), highlighting the importance of maintaining environmental heterogeneity for the conservation of different butterfly species. Classification tree analysis indicated that butterfly communities of different habitats (e.g., forests, urban parks) have distinct ecological traits (e.g., host plant specificity), whereby urban avoiders were 89% likely to be forest dependent and 63% likely to be monophagous, while urban adapters were 87% likely to be cosmopolitan and 67% likely to be oligo- or polyphagous. Regression analyses showed that the number of potential larval host plant species and isolation from forests were important determinants of butterfly species richness in urban parks, indicating that urban parks should be revegetated with a diversity of potential larval host plants and should be situated as near as possible to a forest, in order to maximize their conservation value.

Haberl, H., et al. (2004). "Land use and sustainability indicators. An introduction." Land Use Policy 21(3): 193-198. Bioproductive land is one of the most significant natural resources. People use the land for receiving ecological services. This leads to humans using and favouring certain species, while competing with all other species. Land use can create diverse cultural landscapes of outstanding aesthetic, economic and ecological value, but it may equally result in land degradation, soil loss and impoverished ecosystems. Hence land use is shaped by processes of society-nature interaction. These processes can detract from sustainability--in other words, society-nature interaction may deplete the natural capital upon which the provision of ecosystem services for humans depends. Sustainability indicators aim at monitoring key aspects of society- nature interaction in order to generate information needed to document the current state and the history leading up to it. Moreover, they are useful to communicate complex sustainability problems within the scientific community, to policy-makers and the broad public. This paper introduces a special issue that seeks to contribute to the development of sustainability indicators that track society-nature interaction. We focus on a variety of concepts that measure socio- economic metabolism. All the discussed approaches relate socio-economic energy and material flows to the bioproductive area needed to support them, above all, the ecological footprint and the human appropriation of net primary production. In addition, this special issue also analyses the consequences of land use intensity on the diversity, naturalness and patterns of landscapes.

Gardner, J. G., et al. (2004). "Pricing Powdery-mildew-resistant Dogwoods: Simulated Impacts on the Nursery-industry Supply Chain." HortTechnology 14(1): 114-119. The University of Tennessee developed a flowering dogwood tree (Cornus florida) that is resistant to powdery mildew (Microspaera pulchra). A simulated cooperative game was created to estimate a university fee and predict the behavior of nursery growers and nursery product retailers. The simulation suggests a university fee of $3.51, leading to an average retail price premium for the resistant tree of $10.41. At this price level the simulation predicts that 62 percent of all retail dogwood trees sold would be powdery mildew resistant. Based on 1998 sales of 1.475 million dogwood trees nationwide, 914,500 were predicted to be the powdery mildew resistant varieties, resulting in $3.2 million in revenue for the university. Given this level of sales and markup pricing, the cost of the trees will rise in subsequent stages of the distribution channel, and revenues will increase as well. The simulation suggests nursery revenue will increase by nearly $4 million and costs by $3.2 million, resulting in a net nursery gain of $0.8 million. Similar computations for the retail level are $9.5 million in revenue and a net increase of $5.5 million.

Folke, C., et al. (2004). "Regime shifts, resilience, and biodiversity in ecosystem management." Annual Review of Ecology Evolution and Systematics 35: 557-581. We review the evidence of regime shifts in terrestrial and aquatic environments in relation to resilience of complex adaptive ecosystems and the functional roles of biological diversity in this context. The evidence reveals that the likelihood of regime shifts may increase when humans reduce resilience by such actions as removing response diversity, removing whole functional groups of species, or removing whole trophic levels; impacting on ecosystems via emissions of waste and pollutants and climate change; and altering the magnitude, frequency, and duration of disturbance regimes. The combined and often synergistic effects of those pressures can make ecosystems more vulnerable to changes that previously could be absorbed. As a consequence, ecosystems may suddenly shift from desired to less desired states in their capacity to generate ecosystem services. Active adaptive management and governance of resilience will be required to sustain desired ecosystem states and transform degraded ecosystems into fundamentally new and more desirable configurations.

Chiesura, A. (2004). "The role of urban parks for the sustainable city." Landscape and Urban Planning 68(1): 129-138. International efforts to preserve the natural environment are mainly concerned with large, bio-diverse and relatively untouched ecosystems or with individual animal or vegetal species, either endangered or threatened with extinction. Much less attention is being paid to that type of nature close to where people live and work, to small-scale green areas in cities and to their benefits to people. Increasing empirical evidence, however, indicates that the presence of natural areas contributes to the quality of life in many ways. Besides many environmental and ecological services, urban nature provides important social and psychological benefits to human societies, which enrich human life with meanings and emotions. The main concern of this paper is to address the importance of urban nature for citizens' well being and for the sustainability of the city they inhabit. Some results of a survey conducted among visitors of an urban park in Amsterdam (The Netherlands) are presented and discussed. The issues investigated concern people's motives for urban nature, the emotional dimension involved in the experience of nature and its importance for people's general well being. Results confirm that the experience of nature in urban environment is source of positive feelings and beneficial services, which fulfill important immaterial and non-consumptive human needs. Implications for the sustainability of the city will be analyzed and discussed. (C) 2003 Elsevier B.V. All rights reserved.

Chee, Y. E. (2004). "An ecological perspective on the valuation of ecosystem services." Biological Conservation 120(4): 549-565. Ecosystem services are the conditions and processes through which natural ecosystems and the species that make them up, sustain and fulfil human life. Ecosystem service valuation is being developed as a vehicle to integrate ecological understanding and economic considerations to redress the traditional neglect of ecosystem services in policy decisions. This paper presents a critical review on the neoclassical economic framework, tools used for economic valuation of ecosystem services and the economic welfare approach to collective decision-making, from an ecological perspective. The applicability of the framework and techniques for valuing ecosystem services are evaluated in light of the challenges posed by the complex, non-linear nature of many ecosystem services. Decisions concerning ecosystem management are often complex, socially contentious and fraught with uncertainty. Although judicious application of economic valuation techniques to ecosystem services can provide valuable information for conceptualizing decision choices and evaluating management options, there are serious limitations in the economic welfare approach to decision-making. These shortcomings and their implications for ecosystem management are elucidated and alternative approaches that emphasize participation, explicit treatment of uncertainty and transparent decision-making processes are discussed.

Breuste, J. H. (2004). "Decision making, planning and design for the conservation of indigenous vegetation within urban development." Landscape and Urban Planning 68(4): 439-452. Utilization of indigenous vegetation as parts of the urban landscape is still a problematic matter in decision making and planning. On one hand, there are many activities in cities and towns aimed at providing more green areas. On the other hand, there is an increasing destruction of indigenous vegetation, not only for building purposes, but also partly by extreme maintenance of urban open spaces and an increasing number of recreation activities. Despite there is a considerable amount of scientific knowledge on indigenous plants in urban and sub-urban areas, the use of this knowledge is still low. The socio-economic knowledge about such vegetation (acceptance, utilization, economic value, etc.) is mostly non-existent in many regions. The indigenous vegetation has to become an important aspect of urban biodiversity as well as part of the living space of the urban dwellers. This links two important subjects: the specific nature of the original biomes in which the urban region is situated, and the cultural aspect of acceptance of various kinds of nature. The nature preservation strategies, especially of Central European cities, show a lack of willingness to preserve indigenous vegetation sites. But there are instruments of planning and methods which allow better preservation of these areas. Furthermore, it must be determined whether it is possible to reduce the human impact on open spaces by reintroducing indigenous vegetation, and under what circumstances this works. The cost reduction of maintenance of urban green areas is seen as one major factor linking to this target. Human acceptance is still an uncertain factor which has to be investigated and will, in the long term, be improved by education and evaluated under different cultural and social aspects. The management of the classical conflict between pure species or habitat preservation in open urban spaces of untouched nature and the high pressure of recreation on the same sites, is explained by example. An important question follows: will it be possible to establish "new" indigenous nature in the urban and sub-urban spaces?

Anna, C. (2004). "The role of urban parks for the sustainable city." Landscape and Urban Planning 68(1): 129-138. International efforts to preserve the natural environment are mainly concerned with large, bio-diverse and relatively untouched ecosystems or with individual animal or vegetal species, either endangered or threatened with extinction. Much less attention is being paid to that type of nature close to where people live and work, to small-scale green areas in cities and to their benefits to people. Increasing empirical evidence, however, indicates that the presence of natural areas contributes to the quality of life in many ways. Besides many environmental and ecological services, urban nature provides important social and psychological benefits to human societies, which enrich human life with meanings and emotions. The main concern of this paper is to address the importance of urban nature for citizens’ well being and for the sustainability of the city they inhabit. Some results of a survey conducted among visitors of an urban park in Amsterdam (The Netherlands) are presented and discussed. The issues investigated concern people’s motives for urban nature, the emotional dimension involved in the experience of nature and its importance for people’s general well being. Results confirm that the experience of nature in urban environment is source of positive feelings and beneficial services, which fulfill important immaterial and non-consumptive human needs. Implications for the sustainability of the city will be analyzed and discussed.

Turner, R. K., et al. (2003). "Valuing nature: lessons learned and future research directions." Ecological Economics 46(3): 493-510. This paper critically reviews the literature on environmental valuation of ecosystem services across the range of global biomes. The main objective of this review is to assess the policy relevance of the information encompassed by the wide range of valuation studies that have been undertaken so far. Published and other studies now cover most ecosystems, with aquatic and marine contexts attracting the least attention. There is also a predominance of single function valuation studies. Studies valuing multiple functions and uses, and studies which seek to capture the 'before and after' states as environmental changes take place, are rare. By and large it is the latter types of analyses that are most important as aids to more rational decision taking in ecosystem conservation versus development situations involving different stakeholders (local, national and global). Aggregate (global scale) estimates of ecosystems value are problematic, given the fact that only 'marginal' values are consistent with conventional decision-aiding tools such as economic cost-benefit analysis. In general, valuation data provide prima facie support for the hypothesis that net ecosystem service value diminishes with biodiversity and ecosystem loss [Balmford et al. (2002), Science 297, p. 950]. Future research effort should include complementary research on multiple ecosystem services that seeks to capture the temporal disturbance profile and its causal factors. The explicit recognition of multiple, interdependent ecosystem services and values, poses both conceptual and empirical research challenges. It would serve to transform the practice of research in this sub-field via the a priori assumption of multiple (and inter-dependent) use, instead of independent single use. This line of reasoning can then be extended to the institutional arrangements that determine which values are captured. New institutional processes and arrangements are probably required in order to best realise benefit streams from multiple ecosystem use and non-use provision, across a range of different stakeholders.

Streiling, S. and A. Matzarakis (2003). "Influence of single and small clusters of trees on the bioclimate of a city: A case study." J Arboriculture 29. This study examines the effects of single trees and small clusters of trees on the bioclimate of a city. Investigations of the thermal environment and air quality of the urban climate were carried out on September 19 and September 29, 2000, at Fahnenbergplatz, in the northern city center of Freiburg in southwest Germany. The study area, approximately 1,700 m2, contains 12 horsechestnut trees (Aesculus, hippocastanum) of different ages and sizes. The positive effect of trees on the thermal environment and air quality component was confirmed by the study. In particular, the mean radiation temperature and the human biometeorlogical thermal index known as the physiolgoical equivalent temperature showed distinct differences between areas with trees and areas without trees, despite the small size of the investigation area. A high reduction potential for nitrogen oxides and ozone was found inside the tree corwns, but outside the crowns there was no measurable reduction. The most important result regarding volatile organic compounds (VOC) was the absence of terpene emission sform the horsechestnuts. SImilary, no isoprene emissions from the horsechestnuts. Therefore, horsechestnut trees have a very small ozone-forming potential.

Pauleit, S. (2003). "Urban street tree plantings: indentifying the key requirements." Proceedings of the Institution of Civil Engineers-Municipal Engineer 156(1): 43-50. Trees fulfil important aesthetic, social and environmental functions in urban areas. However, tree life is increasingly under stress, leading to poor vitality and tree decline, particularly in urban streets. The requirements for healthy tree life are broadly known. Criteria for the design of planting sites in streets, choice of tree species and maintenance requirements are outlined in the paper. However, a European survey reveals the wide variance of tree planting and management practice. UK cities and towns performed poorly against criteria such as level of expenditure for trees, street tree quality and site preparation. Evidently, trees are very much undervalued and only an afterthought in the process of planning, design and management of streets. There is an urgent need to develop and apply comprehensive concepts for sustainable urban forests and specifically for street tree plantings. Standards for site planning, as well as increased knowledge of suitable tree species and tree quality standards are key to achieving this goal. Information on best practice needs to be more widely disseminated. The European pilot survey was a first step towards establishing an information network across Europe to collect the information needed for this purpose. There is a need for close collaboration between civil engineers and landscape architects from a very early stage to integrate tree plantings into the design of streets, in order to maximise their benefits and avoid potential conflicts with traffic and utilities.

Pataki, D. E., et al. (2003). "Seasonal cycle of carbon dioxide and its isotopic composition in an urban atmosphere: Anthropogenic and biogenic effects." Journal of Geophysical Research-Atmospheres 108(D23). Atmospheric CO2 mixing ratios and carbon and oxygen isotope composition were measured at 18 m above the ground in Salt Lake City, Utah, United States, for a one-year period. Mixing ratios were highest in the wintertime with maximum values approaching 600 mmol mol(- 1) during atmospheric inversions. Nighttime carbon and oxygen isotope ratios of source CO2 showed a seasonal pattern with isotopically depleted values in the wintertime and isotopically enriched values in the spring and summer. The effects of gasoline combustion, natural gas combustion, and biogenic respiration of plants and soils on CO2 mixing ratio were quantified with a mass balance calculation using dual carbon and oxygen isotopic tracers. The calculations showed large contributions of natural gas combustion in the winter and significant nighttime biogenic respiration in the spring and late summer/early fall. The isotope-tracer technique used shows promise for quantifying the impacts of urban processes on the isotopic composition of the atmosphere and partitioning urban CO2 sources into their component parts.

Parr, T. W., et al. (2003). "Detecting environmental change: science and society - perspectives on long-term research and monitoring in the 21st century." Science of The Total Environment 310(1-3): 1-8. Widespread concern over the state of the environment and the impacts of anthropogenic activities on ecosystem services and functions has highlighted the need for high-quality, long- term datasets for detecting and understanding environmental change. In July 2001, an international conference reviewed progress in the field of long-term ecosystem research and monitoring (LTERM). Examples are given which demonstrate the need for long-term environmental monitoring and research, for palaeoecological reconstructions of past environments and for applied use of historical records that inform us of past environmental conditions. LTERM approaches are needed to provide measures of baseline conditions and for informing decisions on ecosystem management and environmental policy formulation. They are also valuable in aiding the understanding of the processes of environmental change, including the integrated effects of natural and anthropogenic drivers and pressures, recovery from stress and resilience of species, populations, communities and ecosystems. The authors argue that, in order to realise the full potential of LTERM approaches, progress must be made in four key areas: (i) increase the number, variety and scope of LTERM activities to help define the operational range of ecosystems; (ii) greater integration of research, monitoring, modelling, palaeoecological reconstruction and remote sensing to create a broad-scale early warning system of environmental change; (iii) development of inter-disciplinary approaches which draw upon social and environmental science expertise to understand the factors determining the vulnerability and resilience of the nature-society system to change; and (iv) more and better use of LTERM data and information to inform the public and policymakers and to provide guidance on sustainable development.

Ormerod, S. J. (2003). "Restoration in applied ecology: editor's introduction." Journal of Applied Ecology 40(1): 44-50. 1. The need to rehabilitate and restore ecological resources degraded by overuse was already established when the Journal of Applied Ecology was launched in 1964. In the intervening 40 years, submissions on restoration have increased and now contribute at least 8- 12% of the papers published annually. Examples from subjects such as conservation biology, pollution ecology and ecological modelling show that notions of restoration or recovery are now implicit in the philosophy of applied ecology. 2. The terminology of restoration ecology is increasingly clear, but there is still debate about the definition of restoration end-points. Although restoration constitutes the process of assisting recovery, success ultimately depends on whether populations, communities and ecological functions attain limits typical of un-degraded reference systems. With evidence increasing that the removal of stressors is not always sufficient to guarantee restoration success, the true arbiters will be the organisms and processes at which restoration is aimed. Stringent appraisal on these ecological criteria will be required if restored systems are to conserve biodiversity and deliver ecosystem services to the extent that many restoration ecologists believe is possible. 3. Botanical systems have figured most prominently among the Journal's restoration papers, but there is increasing emphasis on the restoration of individual populations or species, often invertebrates or vertebrates such as birds. 4. Recent contributions on restoration to the Journal of Applied Ecology include projects seeking the ideal technical solutions to specific restoration problems. Other papers are distinguished for their seminal value and often show that intervention is preferable to natural succession in delivering a successful outcome. Examples range from species and ecosystem-level restoration to real evidence that large-scale restoration can be achieved by policy instruments such as agri- environment. Papers published in the Journal also show how restoration can bring ecological value to urban locations, where many people now gain their first-ever wildlife experiences. 5. Synthesis and applications. This special profile of five papers follows these themes in developing the assessment of restoration end-points, in understanding the restoration process, and in identifying factors that promote success or bring failure. Restoration ecology offers yet another example where the application of ecology simultaneously provides academic leadership and solutions to real environmental problems. In an era in which the adverse economic and ecological consequences of environmental degradation are increasingly unacceptable, restoration ecology is emerging as one of the most important disciplines in the whole of environmental science.

Okuda, M. (2003). "Epidemiology of Japanese cedar pollinosis throughout Japan." Ann Allergy Asthma Immunol 91. Background: Japanese cedar pollinosis (JCP) is a common disease posing a major public health problem in Japan. For health care policy planning and development of new treatment modalities, investigation of the accurate prevalence and current status of JCP nationwide is imperative. Objective: To ascertain the prevalence and the current status of JCP in Japan with use of a cross-sectional random sampling method. Methods: In a nationwide survey conducted shortly after the peak pollen season, self-evaluation questionnaire were mailed to 10,920 subjects from 390 of 3,370 places in 12 regions in Japan. Results: The response rate was 53.7%, and the usable response rate was 51.5%. The age- adjusted prevalence was 19.4%; the estimated prevalence was 13.1% after adjustment for misdiagnosis, incorrect answers, response rate, and case mix. JCP was most prevalent in the Kanto, Tokai, and Kinki areas and in working adults rather than in children or subjects ages 60 to 79 years. Total pollen count during the pollen season correlated well with the prevalence of JCP in individual regions. In subjects with JCP, nasal symptom were more severe than eye symptoms, 62.5% had severe or moderate interference with daily activities and consulted physicians, 54.1% took prescribed drugs, and 82% used some method to avoid pollen. Conclusions: The age-adjusted prevalence of JCP was 19.4% of the Japanese population, and estimated prevalence after correction of possible biases was 13.1%. Prescribed drugs treated approximately 60% of subjects with JCP, and 80% of subjects tried self-care by avoiding pollen.

McPherson, E. G. (2003). "Urban forestry - The final frontier?" Journal of Forestry 101(3): 20-25. Forestry and urban forestry have more in common than practitioners in either field may think. The two disciplines could each take better advantage of the other's expertise, such as foresters' impressive range of scientific theory and technological sophistication, and urban foresters' experience in working with diverse stakeholders in the public arena. The wildland- urban interface is geographic center of convergence, and the nexus of forest ecology and human ecology will become forestry's next frontier-where forestry and urban forestry join together to construct healthier habitats for humans.

Maco, S. E. and E. G. McPherson (2003). "A practical approach to assessing structure, function and value of street tree population in small communities." Journal of Aboriculture 29(2): 84-97. This study demonstrates an approach to quantify the structure, benefits, and costs of street tree populations in resource-limited communities without tree inventories. Using the city of Davis, California, U.S., as a model, existing data on the benefits and costs of municipal trees were applied to the results of a sample inventory of the city’s public and private street trees. Results indicate that Davis maintained nearly 24,000 public street trees that provided $1.2 million in net annual environmental and property value benefits, with a benefit–cost ratio of 3.8:1. The city can improve long-term stability of this resource by managing maintenance, new plantings, and stand rejuvenation on a city zone basis.

Maco, S. E. and E. G. McPherson (2003). "A practical approach to assessing structure, function, and value of street tree populations in small communities." J Arboriculture 29. This study demonstrates an approach to quantify the structure, benefits, and costs of street tree populations in resource-limited communities without tree inventories. Using the city of Davis, California, U.S., as a model, existing data on the benefits and costs of municipal trees were applied to the results of a sample inventory of the city’s public and private street trees. Results indicate that Davis maintained nearly 24,000 public street trees that provided $1.2 million in net annual environmental and property value benefits, with a benefit–cost ratio of 3.8:1. The city can improve long-term stability of this resource by managing maintenance, new plantings, and stand rejuvenation on city zone basis.

Lichtfouse, E., et al. (2003). "delta C-13 values of grasses as a novel indicator of pollution by fossil-fuel-derived greenhouse gas CO2 in urban areas." Environmental Science & Technology 37(1): 87-89. A novel fossil fuel pollution indicator based on the C-13/C-12 isotopic composition of plants has been designed. This bioindicator is a promising tool for future mapping of the sequestration of fossil fuel CO2 into urban vegetation. Theoretically, plants growing in fossil- fuel-CO2-contaminated areas, such as major cities, industrial centers, and highway borders, should assimilate a mixture of global atmospheric CO2 of delta(13)C value of -8.02parts per thousand and of fossil fuel CO2 of average delta(13)C value of -27.28parts per thousand. This isotopic difference should, thus, be recorded in plant carbon. Indeed, this study reveals that grasses growing near a major highway in Paris, France, have strikingly depleted delta(13)C values, averaging at -35.08parts per thousand, versus rural grasses that show an average delta(13)C value of -30.59parts per thousand. A simple mixing model was used to calculate the contributions of fossil-fuel-derived CO2 to the plant tissue. Calculation based on contaminated and noncontaminated isotopic end members shows that urban grasses assimilate up to 29.1% of fossil-fuel-CO2-derived carbon in their tissues. The C-13 isotopic composition of grasses thus represents a promising new tool for the study of the impact of fossil fuel CO2 in major cities.

Konijnendijk, C. C. (2003). "A decade of urban forestry in Europe." Forest Policy and Economics 5(2): 173-186. Major changes in society have led to a call for structural changes in forestry, also in Europe. Urbanisation as one of the major driving forces has had a clear impact on European forestry. One of the new approaches emerging in response is the concept of urban forestry. It was developed in North America during the 1960s as innovative approach to managing natural resources in urban environments. Aimed at the integrated planning and management of all tree- based resources in cities and towns, the concept found broad support in North America after initial resistance from both foresters and urban green professionals. Similar resistance was met in Europe, and here it took until the early 1990s before the concept of urban forestry found broader acceptance and support. Since then, a European urban forestry research community has emerged, as have policies, programmes and higher education incorporating elements of urban forestry. Urban forest resources in Europe might be small in relative terms compared to other natural resources. They do, however, cover millions of hectares of land and provide multiple, highly demanded goods and services. Forestry can benefit from urban forestry experiences and innovations, for example in terms of better meeting the expectations and demands of urban society. Urban forestry, on the other hand, is firmly rooted in some of the basic concepts of traditional forestry, such as sustained yield. Review of a decade of urban forestry in Europe shows that strong links should be maintained for the benefit of both.

Hare, M., et al. (2003). "Participatory modelling in natural resource management: a comparison of four case studies." Integrated Assessment 4(2): 62-72. The need to understand what might constitute best practice in participatory methods for resource management is becoming ever more important as the requirement for a high level of participation becomes prescribed in the environmental directives of the EU and elsewhere. Since there are numerous potential stakeholders who may participate, various different goals of participation and many potential participatory methods designed to achieve them, there is a need for better understanding of how the methods can be practicably applied to particular stakeholders and for what purpose. As input into this process, this paper presents an overview of four natural resource management projects carried out using participatory modelling methods involving stakeholders in the co-design and social learning of management solutions. From these case studies, a description is elicited of the different types of participatory process structures adopted, as well as an analysis of the influences behind the selection of stakeholders and their level of involvement. Six influences in the design of such structures are identified and illustrated with examples: project goals, democratic participatory goals, existing power structures, stakeholder numbers, researchers' normative beliefs and the scale at which decisions need to be supported. These influences place limits on the freedom of practitioners to develop the type of processes they might otherwise intend. Classification of the process structures according to the level of involvement of stakeholders and their scale of action leads to a discussion about a particular problem of co-design processes: a scale of action mismatch. That is, some process structures, due to the influences mentioned above, end up not involving all the necessary decision makers in the co-design of management solutions. As a result, there has to be additional methods employed to ensure that the results of co-design, i.e. a set of management options, can be passed on to and adopted by excluded decision makers. The paper concludes by briefly looking at examples of possible methods, such as process extensions, e.g., consultation meetings and information campaigns, and the adoption of institutional safeguards.

Hare, M., et al. (2003). "Participatory modelling in natural resource management: a comparison of four case studies." Integr Assess 4. The need to understand what might constitute best practice in participatory methods for resource management is becoming ever more important as the requirement for a high level of participation becomes prescribed in the environmental directives of the EU and elsewhere. Since there are numerous potential stakeholders who may participate, various different goals of participation and many potential participatory methods designed to achieve them, there is a need for better understanding of how the methods can be practicably applied to particular stakeholders and for what purpose. As input into this process, this paper presents an overview of four natural resource management projects carried out using participatory modelling methods involving stakeholders in the co-design and social learning of management solutions. From these case studies, a description is elicited of the different types of participatory process structures adopted, as well as an analysis of the influences behind the selection of stakeholders and their level of involvement. Six influences in the design of such structures are identified and illustrated with examples: project goals, democratic participatory goals, existing power structures, stakeholder numbers, researchers’ normative beliefs and the scale at which decisions need to be supported. These influences place limits on the freedom of practitioners to develop the type of processes they might otherwise intend. Classification of the process structures according to the level of involvement of stakeholders and their scale of action leads to a discussion about a particular problem of co- design processes: a scale of action mismatch. That is, some process structures, due to the influences mentioned above, end up not involving all the necessary decision makers in the co- design of management solutions. As a result, there has to be additional methods employed to ensure that the results of co-design, i.e. a set of management options, can be passed on to and adopted by excluded decision makers. The paper concludes by briefly looking at examples of possible methods, such as process extensions, e.g., consultation meetings and information campaigns, and the adoption of institutional safeguards.

Godefroid, S. and N. Koedam (2003). "Distribution pattern of the flora in a peri-urban forest: an effect of the city-forest ecotone." Landscape and Urban Planning 65(4): 169-185. We studied the spatial variation of plant assemblages in a 4383 ha deciduous forest in the periphery of Brussels. All vascular plant species were recorded following a grid-map of I km(2)- cells totally or partly covered by the forest. A total of 414 plant species was observed. Species composition and plant functional groups in forest edges and the neighbouring forest interior are studied. The study quantifies plant functional groups (e.g. ancient forest plants, true forest species, rare species, geophytes, C, S or R-strategists) in the plots and tests for relationships with the geographical position in the forest according to a city-to-forest gradient. Our results led us to identify distinct characteristics of forest flora based on the distance to the actual city border. The study revealed significant outer edge effects on the flora. Plant composition of the forest interior and forest edge can be separated by ordination on species composition, suggesting that these two biotopes have a distinct species assemblage. chi(2)-test and Two-Way-Indicator-Species- Analysis detected significant edge-associated species that were recorded exclusively in the edge or were the most frequent in the forest edge. We found that forest stands close to urban areas support populations of indicators of disturbance (pioneer species, C and R-strategists and aliens) to plots which are distant from the city. However, our observations also suggest that species groups with high conservation value (e.g. ancient forest species, or rare species) may also be more represented at the edge than in the core of the forest. Moreover, no forest specialists which would occur only in the interior zone were found. These observations are in disagreement with the hypothesis that true forest plants and species groups of high conservation value would be more frequent in the forest than on the borders. These findings are applicable to the management of forests in an urban context. (C) 2003 Elsevier Science B.V. All rights reserved.

Godefroid, S. and N. Koedam (2003). "How important are large vs. small forest remnants for the conservation of the woodland flora in an urban context?" Global Ecology and Biogeography 12(4): 287-298. To test whether, in an urban area, small forest fragments are more important than large ones, the present study aimed at firstly exploring the relationship between plant functional groups or individual species and urban woodlot characteristics such as patch area and isolation, and secondly investigating whether equal-sized combinations of islands tend to differ in species richness. Location The city of Brussels. Methods We considered the relationship between size, species richness and plant functional groups among one very large (1666 ha) and 11 rather small (2-123 ha) woodlots. Results The largest woodlot harboured species missing in the smaller ones. The species-area relationship plotted for these wooded patches fitted the semilog model very well. Twenty-three species had a significantly higher frequency in the main forest. Only six species had a significantly higher frequency in smaller woodlots. The occurrence of species groups with high conservation value (e.g. ancient forest species, rare species) was higher in large patches. However, a SLOSS analysis showed that habitat subdivision appeared to be associated with increased species counts. A marginally nonsignificant effect of distance to the main forest became significant when matrix species were removed from the patch samples. Conclusions Although overall the data showed a higher conservation value for large woods, some plant functional groups (e.g. woodland species vs. ancient forest species) responded differently to fragmentation. This illustrates that, for conservation strategies, studies considering the biotic characteristics of remnants should focus on the species number of particular plant functional groups, especially those with high conservation value. Furthermore, matrix species should be removed from the analysis in order not to mask underlying patch size and distance effects.

Godefroid, S. and N. Koedam (2003). "Identifying indicator plant species of habitat quality and invasibility as a guide for peri-urban forest management." Biodiversity and Conservation 12(8): 1699-1713. A floristic survey has been carried out in a periurban forest, the Sonian Forest in Brussels, to identify indicator plant species in the herbaceous layer, which could be used as an aid within the framework of a more sustainable management of the forest. Three hundred and seventy two (372) taxa have been identified, 33 of which are non-native (i.e. non-indigenous species regarding the study area, whether invasive or not). Criteria of habitat quality that have been chosen are the species richness, the commonness of the habitat, based on constitutive species, and its invasibility (vulnerability for invasion). On the basis of a comparison of the value of these criteria when each considered (potential indicator) species is present or not, 17 species have been recognised as reliable indicators of at least one of these three criteria. In particular, vegetation types containing either Anthriscus sylvestris, Galeopsis tetrahit or Senecio ovatus were found to be more susceptible to invasion than other habitats. The way to how the predictability of invasions might be effectively used as a management tool is discussed. Furthermore, we found a positive significant correlation (Bonferroni corrected probabilities) between the species richness and luminosity factor (derived from Ellenberg's indices), and the proportion of grassland and wetland species. The species richness was significantly negatively correlated with the proportion of woodland species. An increase in commonness was significantly correlated with a decrease in the proportion of geophytes. The usefulness of these results as an ecological basis for forest management is discussed.

Chocholouskova, Z. and P. Pysek (2003). "Changes in composition and structure of urban flora over 120 years: a case study of the city of Plzen." Flora 198(5): 366-376. Floristic lists of the industrial city of Plzen, W Bohemia, Czech Republic, were compiled for the periods 1880-1910, 1960s and 1990s. Data were obtained for the city and its surroundings and abundance of each species was estimated from primary literature and recent field research. Changes in species richness on the time scale of 120 years were described, and dynamics of representation of alien species was analysed. Total number of species recorded decreased from 1173 in 1880-1910 to 988 in 1960s to 1043 in 1990s. These dynamics differed between city and surroundings. In the city, species number was gradually increasing while the trend was opposite in the surroundings. When expressed per to,, area, initial pattern of higher species richness in the surroundings was reversed in the course of the study period. The floristic similarity between 1880-1910 and 1990s was 0.57 for the surroundings and 0.41 for the city. In the 120 years covered, 805 species remained permanently present, 368 disappeared and 238 immigrated as new. Proportional representation of common species decreased and that of rare species increased. The representation of neophytes in the total flora of the study area increased from 6.2% in 1880- 1910 to 13.2% in 1960s to 17.0% in 1990s. The proportion of native species decreased accordingly, and that of archaeophytes was stable over the study period. The representation of woody plants increased in the city, namely among neophytes. Over the study period, there was an increase in the representation of C and CR-strategists, mainly on behalf of CSR and SR strategists. CSR and CS strategies are most typical of native flora elements, C and CR of neophytes, while R and CR are most represented among archaeophytes. No consistent temporal trends in indicator values were recorded but the flora of the city differed from that of the surroundings in higher demands for light, temperature, nitrogen and soil reaction and lower demands for moisture. The present paper demonstrates that historical data on urban floras provide a powerful tool to evaluate the effect of humans on the development of urban landscapes and their plant life.

Bjorheden, R., et al. (2003). "Systems analyses for harvesting small trees for forest fuel in urban forestry." Biomass & Bioenergy 24(4-5): 389-400. Forests in urban areas are important for recreation. Social, aesthetic and recreational values are at least as important for forest management as economy and conventional forestry considerations. Systems with short, intensive harvesting phases and limited damage to ground and trees are also advantageous, in order to reduce disturbance through harvesting operations. Further, slash free stands constitute a more attractive environment for recreational activities. Forest fuel harvesting may provide these conditions. This study analyses the economic feasibility of harvesting forest fuel in dense, small diameter stands. The analyses are performed as simulated treatments in selected stand types. Both existing and non-existing forest fuel systems are tested. Conventional cleaning and conventional thinning for pulpwood are included as reference systems. The average dbh of removed trees varied between 3.0 and 10.5 cm. The potential yield of biomass in the studied stand types is high-under Swedish conditions over 35 tonnes dry substance per ha. Harvesting pulpwood exclusively means that only a small portion of the potential is utilised. Forest fuel systems based on motor-manual work are the most competitive in the smallest diameter stands. They break even from dbh similar to4.5 cm in birch stands and from similar to5.5 cm in pine. Simulated systems include a feller-chipper-forwarder and a two-machine system with a feller-bundler and a forwarder. Both are suitable for larger tree sizes than the manual methods. The conventional pulpwood method shows the poorest result, but start competing with the poorest forest-fuel systems from dbh similar to10 cm (removed trees).

Xiao, Q. and E. G. McPherson (2002). "Rainfall interception by Santa Monica's municipal urban forest." Urban Ecosystems 6(4): 291-302. Effects of urban forests on rainfall interception and runoff reduction have been conceptualized, but not well quantified. In this study rainfall interception by street and park trees in Santa Monica, California is simulated. A mass and energy balance rainfall interception model is used to simulate rainfall interception processes (e.g., gross precipitation, free throughfall, canopy drip, stemflow, and evaporation). Annual rainfall interception by the 29,299 street and park trees was 193,168 m3 (6.6 m3/tree), or 1.6% of total precipitation. The annual value of avoided stormwater treatment and flood control costs associated with reduced runoff was $110,890 ($3.60/tree). Interception rate varied with tree species and sizes. Rainfall interception ranged from 15.3% (0.8 m3/tree) for a small Jacaranda mimosifolia (3.5 cm diameter at breast height) to 66.5% (20.8 m3/tree) for a mature Tristania conferta (38.1 cm). In a 25-year storm, interception by all street and park trees was 12,139.5 m3 (0.4%), each tree yielding $0.60 (0.4 m3/tree) in avoided flood control costs. Rainfall interception varied seasonally, averaging 14.8% during a 21.7 mm winter storm and 79.5% during a 20.3 mm summer storm for a large, deciduous Platanus acerifolia tree. Effects of differences in temporal precipitation patterns, tree population traits, and pruning practices on interception in Santa Monica, Modesto, and Sacramento, California are described.

Shepherd, J. M., et al. (2002). "Rainfall modification by major urban areas: Observations from spaceborne rain radar on the TRMM satellite." Journal of Applied Meteorology 41(7): 689-701. Data from the Tropical Rainfall Measuring Mission (TRMM) satellite's precipitation radar (PR) were employed to identify warm-season rainfall (1998-2000) patterns around Atlanta, Georgia; Montgomery, Alabama; Nashville, Tennessee; and San Antonio, Waco, and Dallas, Texas. Results reveal an average increase of about 28% in monthly rainfall rates within 30-60 km downwind of the metropolis, with a modest increase of 5.6% over the metropolis. Portions of the downwind area exhibit increases as high as 51%. The percentage changes are relative to an upwind control area. It was also found that maximum rainfall rates in the downwind impact area exceeded the mean value in the upwind control area by 48%-116%. The maximum value was generally found at an average distance of 39 km from the edge of the urban center or 64 km from the center of the city. Results are consistent with the Metropolitan Meteorological Experiment (METROMEX) studies of St. Louis, Missouri, almost two decades ago and with more recent studies near Atlanta. The study establishes the possibility of utilizing satellite-based rainfall estimates for examining rainfall modification by urban areas on global scales and over longer time periods. Such research has implications for weather forecasting, urban planning, water resource management, and understanding human impact on the environment and climate.

Shashua-Bar, L. and M. E. Hoffman (2002). "The Green CTTC model for predicting the air temperature in small urban wooded sites." Building and Environment 37(12): 1279- 1288. An analytical model, the Green CTTC (cluster thermal time constant) model, for predicting diurnal air temperature inside an urban wooded site, is the object of this study. The proposed model is based on the same principles as the CTTC model, developed earlier by M.E. Hoffman and colleagues, with the addition of vegetation effects. It is shown that the tree thermal effect can be evaluated either as the shade effect partly offset by the convection component of the tree radiation balance or, equivalently, as the combined effect of evapotranspiration and the change in the plant heat storage. In this paper, the former approach is adopted. Simulations for testing the validity of the Green CTTC model were carried out on summer data of 11 small urban wooded sites in the Tel-Aviv metropolitan area near the Mediterranean sea coast. Results show a satisfactory fit, with average root-mean-square-error < 0.5 K for all studied sites and time intervals at 09:00, 15:00, and 18:00 h (summer time). The CTTC values and the convection parameters were estimated from the empirical data, using a novel procedure. The proposed model, which can be enlarged to encompass the cases of groves and lawns, is an appropriate tool for assessment of the climatic impact of trees and other greeneries on urban design alternatives.

Orlinski, R. (2002). "Multipoint moss passive samplers assessment of urban airborne polycyclic aromatic hydrocarbons: concentrations profile and distribution along Warsaw main streets." Chemosphere 48(2): 181-186. Polycyclic aromatic hydrocarbons (PAHs) distribution along 28 km of Warsaw main street have been surveyed in July 2000 using moss passive samplers as a simple and economic surrogate of direct air sampling. Altogether 74 samplers at 39 crossroads with traffic lights were placed on the lamp post approximate to3.5 m above ground. PAHs levels determined in samplers are in range from 828 to 3573 ng/g moss dry weight. The spatial spread of pollution within this range is statistically close to normal distribution with mean value of 2332 ng/g. Variability within and between study areas are rationalized in terms of urban environmental factors. PAHs concentrations profiles across the town have appeared uniform. The dominant compounds are phenantrene, fluoranthene and pyrene. Their contribution is 49-68% of total PAHs burden.

Nowak, D. J. and D. E. Crane (2002). "Carbon storage and sequestration by urban trees in the USA." Environmental Pollution 116(3): 381-389. Based on field data from 10 USA cities and national urban tree cover data, it is estimated that urban trees in the coterminous USA currently store 700 million tonnes of carbon ($14,300 million value) with a gross carbon sequestration rate of 22.8 million tC/yr ($460 million/year). Carbon storage within cities ranges from 1.2 million tC in New York, NY, to 19,300 tC in Jersey City, NJ. Regions with the greatest proportion of urban land are the Northeast (8.5%) and the southeast (7.1%). Urban forests in the north central, northeast, south central and southeast regions of the USA store and sequester the most carbon, with average carbon storage per hectare greatest in southeast, north central, northeast and Pacific northwest regions, respectively. The national average urban forest carbon storage density is 25.1 tC/ha, compared with 53.5 tC/ha in forest stands. These data can be used to help assess the actual and potential role of urban forests in reducing atmospheric carbon dioxide, a dominant greenhouse gas.

Nowak, D. J. (2002). "The effects of urban trees on air quality." USDA Forest Service: 96- 102. Urban vegetation can directly and indirectly affect local and regional air quality by altering the urban atmospheric environment. The four main ways that urban trees affect air quality area: Temperature reduction and other microclimatic effects Removal of air pollutants Emission of volatile organic compounds and tree maintenance emissions Energy effects on buildings

McPherson, E. G. and J. R. Simpson (2002). "A comparison of municipal forest benefits and costs in Modesto and Santa Monica, California, USA." Urban Forestry & Urban Greening 1(2): 61-74. This paper presents a comparison of the structure, function, and value of street and park tree populations in two California cities. Trees provided net annual benefits valued at $2.2 million in Modesto and $805,732 in Santa Monica. Benefit-cost ratios were 1.85:1 and 1.52:1 in Modesto and Santa Monica, respectively. Residents received $1.85 and $1.52 in annual benefits for every $1 invested in management. Aesthetic and other benefits accounted for 50% to 80% of total annual benefits, while expenditures for pruning accounted for about 50% of total annual costs. Although these results were similar, benefits and costs were distributed quite differently in each city. Variations in tree sizes and growth rates, foliation characteristics, prices, residential property values, and climate were chiefly responsible for different benefits and costs calculated on a per tree basis.

De Groot, R. S., et al. (2002). "A typology for the classification, description and valuation of ecosystem functions, goods and services." Ecological Economics 41(3): 393-408. An increasing amount of information is being collected on the ecological and socio- economic value of goods and services provided by natural and semi-natural ecosystems. However, much of this information appears scattered throughout a disciplinary academic literature, unpublished government agency reports, and across the World Wide Web. In addition, data on ecosystem goods and services often appears at incompatible scales of analysis and is classified differently by different authors. In order to make comparative ecological economic analysis possible, a standardized framework for the comprehensive assessment of ecosystem functions, goods and services is needed. In response to this challenge, this paper presents a conceptual framework and typology for describing, classifying and valuing ecosystem functions, goods and services in a clear and consistent manner. In the following analysis, a classification is given for the fullest possible range of 23 ecosystem functions that provide a much larger number of goods and services. In the second part of the paper, a checklist and matrix is provided, linking these ecosystem functions to the main ecological, socio-cultural and economic valuation methods.

Stefanov, W. L., et al. (2001). "Monitoring urban land cover change: An expert system approach to land cover classification of semiarid to arid urban centers." Remote Sensing of Environment 77(2): 173-185. The spatial and temporal distribution of land cover is a fundamental dataset for urban ecological research. An expert (or hypothesis testing) system has been used with Landsat Thematic Mapper (TM) data to derive a land cover classification for the semiarid Phoenix metropolitan portion of the Central Arizona-Phoenix Long Term Ecological Research (CAP LTER) site. Expert systems allow for the integration of remotely sensed data with other sources of georeferenced information such as land use data, spatial texture, and digital elevation models (DEMs) to obtain greater classification accuracy. Logical decision rules are used with the various datasets to assign class values to each pixel. TM reflectance data acquired in 1998 [visible to shortwave infrared (VSWIR) bands plus a vegetation index] were initially classified for land cover using a maximum likelihood decision rule. In addition, spatial texture of the TM data was calculated. An expert system was constructed to perform post classification sorting of the initial land cover classification using additional spatial datasets such as texture, land use, water rights, city boundaries, and Native American reservation boundaries. Pixels were reclassified using logical decision rules into 12 classes. The overall accuracy of this technique was 85%. Individual class user's accuracy ranged from 73% to 99%, with the exception of the commercial/industrial materials class. This class performed poorly (user's accuracy of 49%) due to the similarity of subpixel components with other classes. The results presented here indicate that the expert system approach will be useful both for ongoing CAP LTER research, as well as the planned global Urban Environmental Monitoring (UEM) program of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument.

Sorace, A. (2001). "Value to wildlife of urban-agricultural parks: A case study from Rome urban area." Environmental Management 28(4): 547-560. Urban-agricultural parks could have some advantages to wildlife because of less intensive agricultural procedures, absence of hunting pressure, and reduced human disturbance. In this study, the breeding and wintering bird communities and the small mammal community in an urban-agricultural park of Rome were compared to those of a close urban park and a close agricultural, area just outside the city, The aim was to assess the best destination and management of wildlife in natural areas at the urban-rural interface, Richness and diversity of bird communities were higher in the urban-agricultural park. Due to habitat features and probably human disturbances, but not to urbanization, predation, and competition factors, the urban park drastically reduces the abundance of decreasing open-land bird species. Abundance of these species was not significantly different in the urban-agricultural park and in the agricultural area. In the urban-agricultural and urban park, bird and mammal pest species were more abundant than they were in the agricultural area. Regarding decreasing abundance of small mammal species, no significant difference among the study areas was observed. Urban- agricultural park is a better choice than urban park for wildlife. Thus, a higher number of preserved urban natural areas should be devoted to urban-agricultural parks. However, to increase the abundance of open-land species and in general wildlife, a less intensive management of cultivated and pasture patches is necessary.

Porter, E., et al. (2001). "Woody vegetation and canopy fragmentation along a forest-to- urban gradient." Urban Ecosystems 5(2): 131-151. To identify patterns that can be used to predict vegetation and landscape characteristics in urban environments, we surveyed the species composition and size of woody plants, as well as the landscape structure of forest canopies, along a forest-to-urban gradient near Oxford, Ohio, USA. The gradient included six sites of increasingly urban land-use: a preserve, a recreational area, a golf course, a residential subdivision, apartment complexes, and a business district. We recorded species identity and stem diameter for all woody plants greater than 3 cm diameter at breast height (DBH) to examine the distribution of individual species as well as overall community composition. We used digitized aerial photographs to compare the spatial characteristics of the forest canopy at each site. We found predictable patterns in species diversity (Shannon index), spatial heterogeneity in species composition (mean percent dissimilarity), and all measures of patch fragmentation (canopy cover and patch number and size). There were clear differences in tree density and total basal area between forested sites and developed sites, but there was little resolution among developed sites. Species richness and average DBH showed no clear pattern, suggesting that landscaping preference largely determined these values. We present a modified version of an intermediate heterogeneity model that can be used to predict diversity patterns in urban areas. We discuss probable mechanisms that led to these patterns and the potential implications for animal communities in urban environments.

Kreuter, U. P., et al. (2001). "Change in ecosystem service values in the San Antonio area, Texas." Ecological Economics 39(3): 333-346. San Antonio is one of the fastest growing metropolitan areas in the USA. Urban sprawl may significantly impact ecosystem services and functions but such effects are difficult to quantify and watershed-level estimates are seldom attempted. The objective of the study reported here was to determine whether LANDSAT MSS could be used to quantify changes in land-use and ecosystem services due to urban sprawl in Bexar County, TX, in which San Antonio is centered. The size of six land cover categories in the summer of 1976, 1985, and 1991 were estimated in the 141 671 ha of three watersheds in Bexar County. Coefficients published by Costanza and co-workers in 1997 [Nature 387 (1997) 253] were used to value changes in ecosystem services delivered by each land cover category, and a sensitivity analysis was conducted to determine the effect of manipulating these coefficients on the estimated values. Although we estimated that there was a 65% decrease in the area of rangeland and a 29% increase in the area of urbanized land use between 1976 and 1991, there appeared to be only a 4% net decline in the estimated annual value of ecosystem services in the study area (i.e. $5.58 ha(-1) per year, with a 15-year cumulative total value of $6.24 million for the whole study area). This relatively small decline could be attributed to the neutralizing effect of the estimated 403% increase in the area of the woodlands, which were assigned the highest ecosystem value coefficient. When we assumed that the shift of rangelands to woodlands produced no net change in the value of ecosystem services per hectare, the estimated annual ecosystem service value declined by 15.4% ($23.22 ha(-1) per year) between 1976 and 1991. When conducting time- series studies of ecosystem services, it is important to identify parallel changes in land cover types in order to quantify the potentially neutralizing influence of positive land cover changes on the negative effects of urban sprawl on ecosystem services.

Khan, F. I. and S. A. Abbasi (2001). "Effective design of greenbelts using mathematical models." J Hazard Mater 81. Trees, shrubs, and other vegetation can absorb and assimilate certain air pollutants if the pollutants are present within tolerable levels. This concept is being increasingly used in developing strips of vegetation, often called ‘greenbelts’ around sources of pollution. But several intricacies are associated with the exercise of effective and optimal designing of greenbelts. The pattern of dispersion of air pollutants, as effected by the density of the gaseous plume and the meteorology of the area, must be studied with great precision because these aspects would determine the location and the geometry of the greenbelt. The species composition in the greenbelt should confirm to the pollutants to be attenuated as to the geoclimatic conditions of the region. Decisions on the tree heights, and the sequence of plantation of trees and other vegetation also similarly require complex inputs. In this paper, the authors have addressed these issues and have presented a set of mathematical models, which may help in the rational and optimal design of greenbelts.

Jo, H. K. and E. G. McPherson (2001). "Indirect carbon reduction by residential vegetation and planting strategies in Chicago, USA." Journal of Environmental Management 61(2): 165-177. Concern about climate change has evoked interest in the potential for urban vegetation to help reduce the levels of atmospheric carbon. This study applied computer simulations to try to quantify the modifying effects of existing vegetation on the indirect reduction of atmospheric carbon for two residential neighborhoods in north-west Chicago. The effects of shading, evapotranspiration, and windspeed reduction were considered and were found to have decreased carbon emissions by 3.2 to 3.9% per year for building types in study block I where tree cover was 33%, and -0.2 to 3.8% in block 2 where free cover was 11%. This resulted in a total annual reduction of carbon emission averaging 158.7 (+/-12.8) kg per residence in block I and 18.1 (+/- 5.4) kg per residence in block 2. Windspeed reduction greatly contributed to the decrease of carbon emission. However, shading increased annual carbon emission from the combined change in heating and cooling energy use due to many frees in the wrong locations, which increase heating energy use during the winter The increase of carbon emission from shading is somewhat specific to Chicago, due in part to the large amount of clean, nuclear-generated cooling energy and the long heating season. In Chicago, heating energy is required for about eight months from October to May and cooling energy is used for the remaining 4 months from June to September If fossil fuels had been the primary source for cooling energy and the heating season had been shorter, the shading effects on the reduction of carbon emission would be greater. Planting of large frees close to the west wall of buildings, dense planting on the north, and avoidance of planting on the south are recommended to maximize indirect carbon reduction by residential vegetation, in Chicago and other mid and high-latitude cities with long heating seasons.

Jackson, R. B., et al. (2001). "Water in a changing world." Ecological Applications 11(4): 1027-1045. Renewable fresh water comprises a tiny fraction of the global water pool but is the foundation for life in terrestrial and freshwater ecosystems. The benefits to humans of renewable fresh water include water for drinking, irrigation, and industrial uses, for production of fish and waterfowl, and for such instream uses as recreation, transportation, and waste disposal. In the coming century, climate change and a growing imbalance among freshwater supply, consumption, and population will alter the water cycle dramatically. Many regions of the world are already limited by the amount and quality of available water. In the next 30 yr alone, accessible runoff is unlikely to increase more than 10%, but the earth's population is projected to rise by approximately one-third. Unless the efficiency of water use rises, this imbalance will reduce freshwater ecosystem services, increase the number of aquatic species facing extinction, and further fragment wetlands, rivers, deltas, and estuaries. Based on the scientific evidence currently available, we conclude that: (1) over half of accessible freshwater runoff globally is already appropriated for human use; (2) more than 1 x 10(9) people currently lack access to clean drinking water and almost 3 x 10(9) people lack basic sanitation services; (3) because the human population will grow faster than increases in the amount of accessible fresh water, per capita availability of fresh water will decrease in the coming century; (4) climate change will cause a general intensification of the earth's hydrological cycle in the next 100 yr, with generally increased precipitation, evapotranspiration, and occurrence of storms, and significant changes in biogeochemical processes influencing water quality; (5) at least 90% of total water discharge from U.S. rivers is strongly affected by channel fragmentation from dams, reservoirs, interbasin diversions, and irrigation; and (6) globally, 20% of freshwater fish species are threatened or extinct, and freshwater species make up 47% of all animals federally endangered in the United States. The growing demands on freshwater resources create an urgent need to link research with improved water management. Better monitoring, assessment, and forecasting of water resources will help to allocate water more efficiently among competing needs, Currently in the United States, at least six federal departments and 20 agencies share responsibilities for various aspects of the hydrologic cycle. Coordination by a single panel with members drawn from each department, or by a central agency, would acknowledge the diverse pressures on freshwater systems and could lead to the development of a well-coordinated national plan.

Hamerlynck, E. P. (2001). "Chlorophyll fluorescence and photosynthetic gas exchange responses to irradiance of Tree of Heaven (Ailanthus altissima) in contrasting urban environments." Photosynthetica 39(1): 79-86. Sun-and shade-adapted plants of Ailanthus altissima utilized thermal-dissipative photoprotection (NPQ) across a range of photosynthetic photon flux densities (PPFD), with higher NPQ and lower maximum quantum yield of photosystem 2 photochemistry (F-v/F-m) in sun-adapted individuals, suggesting increased engagement of antennae-based quenching. Photosynthetic quantum requirements (Q(req); number of photons per CO2) were similar in sun and shade plants, but were low and comparable to forest understory species. Diurnal measurements showed that PPFDs in both habitats were consistently above photosynthetic compensation irradiance, and frequently exceeded saturating values. In addition, sun-and shade- adapted individuals possessed stomata that tracked short-term fluctuations in PPFD. Thus A. altissima may be unique in that it couples high, shade-plant like photosynthetic efficiency with high photosynthetic capacity in high-irradiance, while stomatal attributes that optimize water use efficiency are maintained in the shade. These features may contribute to success of A. altissima in establishing in disturbance-prone urban systems, and facilitate its spread into more PPFD- limited and competitive natural ecosystems.

Alves, C., et al. (2001). "Composition of extractable organic matter of air particles from rural and urban Portuguese areas." Atmospheric Environment 35(32): 5485-5496. Atmospheric particulate matter (PM10) was collected simultaneously Lit three sites in the West Coast of Portugal, during an intensive campaign in August 1996. The sites were located in line with the breezes blowing from the sea. The collected aerosol was analysed in relation to black and organic carbon content. The particulate organic matter was extracted with solvents and characterised by gas chromatography and mass spectrometry (GC-MS). Most of the organic mass identified consists of alkanes. polycyclic aromatic hydrocarbons (PAH), ketones, aldehydes, alcohols and fatty acids with both biogenic and anthropogenic origin. Many photochemical products from volatile organic compounds emitted by vegetation were also detected. Biomarkers such as 6,10,14-trimethylpentadecanone, abieta-8,11,13-trien-7-one and Patchouli alcohol were observed at higher concentrations in the rural sites. Samples from the urban site present lower values of "carbon preference index" and higher concentrations of petrogenic/pyrogenic species, such as PAH. The PM10 concentrations and the total organic extract measured for the more interior site were generally lower, indicating that dispersion and dry deposition into the forest canopy were more important during the transport of the air masses than aerosol production by condensation and photochemical reactions. On the contrary, The ratio between organic and black carbon was, in general, lower at sites near the coast, especially for compounds that evaporate at lower temperatures. The organic aerosol composition also seems to be strongly dependent on the meteorology. (C) 2001 Elsevier Science Ltd. All rights reserved.

Spronken-Smith, R. A., et al. (2000). "Advection and the surface energy balance across an irrigated urban park." International Journal of Climatology 20(9): 1033-1047. The surface energy balance in an irrigated urban park in suburban Sacramento, CA is observed. Three sites extend from the edge of the park to its centre, along a transect which is aligned with the prevailing wind. Direct measurements of the fluxes of net radiation, soil heat flux and evaporation are made at each site and the convective sensible heat is found by residual. Strong advective effects on evaporation are observed, especially in the afternoon and evening. The driving forces for this are the differences in surface and air temperature, and humidity, between the cool, wet park and its warmer, drier built-up surroundings. The control of the surroundings on park evaporation is demonstrated by comparing values with those from synchronous observations in the surrounding suburbs and at an irrigated sod farm just outside the city. Greatest evaporative enhancement is observed at the upwind edge. Throughout the afternoon evaporation considerably exceeds the net radiation. This is interpreted to be due to the microscale leading-edge effect which appears to be restricted to a fetch of about 20 m. Further into the park evaporation also exceeds the net radiation in the afternoon due to the oasis effect. At all sites the sensible heat flux density in the afternoon is negative. Daily and daytime total evaporation from the park is more than 300% that from the integrated suburban area, and more than 130% that from the irrigated rural grass site. The unlimited water supply and the high temperatures of the park allow it to behave like a wet leaf in that its surface temperature seems to be 'thermostatically' controlled-it never rises more than a few degrees above that of the park air and for much of the day is cooler than the park air.

Shashua-Bar, L. and M. E. Hoffman (2000). "Vegetation as a climatic component in the design of an urban street - An empirical model for predicting the cooling effect of urban green areas with trees." Energy Build 31. The cooling effect of small urban green wooded sites of various geometric configurations in summer is the object of this study. It was studied experimentally at 11 different wooded sites in the Tel-Aviv urban complex during the period July–August 1996. An empirical model is developed in this study for predicting the cooling effect inside the wooded sites. The model is based on the statistical analysis carried out on 714 experimental observations gathered each hour from the 11 sites on calm days, when urban climate is expressed. Two factors were found to explain over 70% of the air temperature variance inside the studied green site, namely, the partial shaded area under the tree canopy and the air temperature of the non-wooded surroundings adjoining the site. The specific cooling effect of the site due to its geometry and tree characteristics, besides the shading, was found to be relatively small, about 0.5 K, out of an average cooling of about 3 K at noon. The cooling effect of the green wooded areas on their immediate surroundings at noon was also analyzed. The findings corroborate earlier studies that the range is noticeable. At small green sites, the cooling effect estimated in this study is perceivable up to about 100 m in the streets branching out from the site. The empirical findings in this study permit development of tools for incorporating the climatic effects of green areas in the urban design. Some policy measures are proposed accordingly, for alleviating the ‘‘heat island’’ effect in the urban environment.

Shafer, C. S., et al. (2000). "A tale of three greenway trails: user perceptions related to quality of life." Landscape and Urban Planning 49(3-4): 163-178. Urban sprawl and renewed concern for the environment have helped create new policies and initiatives designed to enhance community quality of life. Among these are transportation enhancements mandated in ISTEA and TEA21. Funding through transportation enhancements has helped to spur the designation and development of greenway trails with the intent of fostering alternative transportation and generally making cities more livable. This paper presents research conducted on three greenway trails in Texas. The research was based on the human ecosystem concept and was intended to determine if and how such greenway facilities were contributing to quality of life and how people might perceive such contributions based on the way they used the trail (e.g. for transportation or recreation). Results indicated that most people used greenway h-ails for recreation but that trails differed in user types and activities based on location and policy. Users felt that these urban greenway trails were contributing most to community quality of life through resident health/fitness, the natural areas they provide, better land use and resident pride. They felt that they contributed least to diversifying industry, business development and access to shopping areas or public transportation. Those who used trails for transportation scored trails as contributing more toward reducing pollution, reducing transportation costs and providing better access to work than did those who used trails only for recreation. Implications for understanding use and users in the designation; design and development of urban greenway trails are discussed.

Savard, J. P. L., et al. (2000). "Biodiversity concepts and urban ecosystems." Landscape and Urban Planning 48(3-4): 131-142. The association of biodiversity and urban ecosystems has usually concerned the impact of urbanization on biodiversity. However, biodiversity concepts can easily be applied to the urban ecosystem itself. As more and more people live in cities, restoration, preservation and enhancement of biodiversity in urban areas become important. Concepts related to biodiversity management such as scale, hierarchy, species identity, species values, fragmentation, global approaches can be used to manage urban biodiversity. Application of these concepts in such artificial ecosystems may yield important insights for the management of natural ecosystems. Birds are highly visible and quite sensitive to changes in habitat structure and composition. Bird species richness in urban ecosystems is influenced both by local and landscape characteristics and a multiscale approach is essential to its proper management. People-wildlife conflicts are an integral component of wildlife management in urban ecosystems and must be addressed. Enhancement of biodiversity in urban ecosystems can have a positive impact on the quality of life and education of urban dwellers and thus facilitate the preservation of biodiversity in natural ecosystems.

Pauleit, S. and F. Duhme (2000). "Assessing the environmental performance of land cover types for urban planning." Landscape and Urban Planning 52(1): 1-20. Urban planning and decision-making for sustainable development urgently need data of high spatial resolution to establish the relationship between the socio-economic performance of the urban system and its different sub-units (i.e. housing schemes, commercial and industrial developments, services) on the one hand and their environmental impacts of these subunits on the other. To achieve this task, a system was developed to delineate urban land cover units. The approach was tested for the city of Munich. The units delineate the fine-grained pattern of urban built-up and open spaces. The typology was based on established categories of zoning and development plans. In addition, the units were delineated on an aggregated scale to generate a synoptic understanding of the urban "metabolism" for different "strategic" levels of urban planning. A case study on urban hydrology is presented to characterize aspects of the metabolism of the urban system. Additional case studies covered urban climates, energy demand for space heating and carbon dioxide emissions. Results showed that the cover units and types had distinct environmental features. Furthermore the causal links with urban physical and land use features were investigated. Based on the hydrological case study, environmental targets and standards to promote sustainable development are proposed.

Newell, R. G. and R. N. Stavins (2000). "Climate change and forest sinks: Factors affecting the costs of carbon sequestration." Journal of Environmental Economics and Management 40(3): 211-235. The possibility of encouraging the growth of forests as a means of sequestering carbon dioxide has received considerable attention, partly because of evidence that this can be a relatively inexpensive means of combating climate change. But how sensitive are such estimates to specific conditions? We examine the sensitivity of carbon sequestration costs to changes in critical factors, including the nature of management and deforestation regimes, silvicultural species, relative prices, and discount rates.

Montague, T., et al. (2000). "Surface energy balance affects gas exchange and growth of two irrigated landscape tree species in an arid climate." J Am Society Horticultural Sci 125. Research was conducted to investigate how energy balance of bark mulch and turf surfaces influence gas exchange and growth of recently transplanted trees. On several occasions over a 3-year period, stomatal conductance and leaf temperature were measured throughout the day on ‘Emerald Queen’ Norway maple (Acer platanoides L.) and ‘Greenspire’ littleleaf linden (Tilia cordata Mill.) trees growing over each surface. Tree water loss was estimated using a general transport flux equation applied to the tree crown apportioned between sunlit and shade layers. Microclimate variables were measured over each surface with a permanent weather station. Tree growth data were collected at the end of each growing season. Soil heat flux data revealed that a greater portion of incoming radiation was prevented from entering the soil below mulch than below turf. Due to this insulating effect, and consequent lack of evaporative cooling, mulch surface temperature was greater, and emitted more longwave radiation, than turf. Leaves over mulch intercepted more longwave radiation, had greater leaf temperature, and greater leaf- to-air vapor pressure difference than leaves over turf. As a result, leaves over mulch had greater stomatal closure than leaves over turf. Estimated tree water loss varied between surface treatments and with climatic conditions. Trees over turf had greater shoot elongation and leaf area than trees over mulch. These data suggest that gas exchange and growth of recently transplanted trees in an arid climate may be reduced if planted over nonvegetative, urban surfaces.

Konijnendijk, C. C. (2000). "Adapting forestry to urban demands - role of communication in urban forestry in Europe." Landscape and Urban Planning 52(2-3): 89-100. Similar to other parts of the world, European society is becoming increasingly urban, both in a physical as in an economic and socio-cultural sense. As a result. the relationships between society and nature, including forests. are changing, and forestry as structural intervention in forest ecosystems has had to adapt itself to changing societal pressures and demands. The planning and managing of woodlands in and near urban areas has been the most directly affected by the urbanisation process. Many European countries have a long tradition of 'town forestry', serving as basis for current developments in urban forestry, i.e. the planning and management of all forest and tree resources in and near urban areas for the benefit of local society. Through the adaptation to the specific demands of local urban societies, a type of forestry has emerged which is structurally different from classic forestry. It focuses, for example, on the social and environmental values of urban woodlands rather than on wood production and emphasising the importance of communication - ranging from information to participation/power sharing between stakeholders. This paper investigates ways to communicate urban forests and forestry to urban inhabitants and other stakeholders, based on results of a comparative study of main European cities. It explores the role which urban forestry has been playing in the development of forestry at large, especially with regards to better incorporating changing social values and interests.

Kocher, S. D. and E. H. Williams (2000). "The diversity and abundance of North American butterflies vary with habitat disturbance and geography." Journal of Biogeography 27(4): 785-794. Aim We used data from the annual Fourth of July Butterfly Count for the years 1989-97 to examine patterns of species richness and total butterfly abundance across North America and within topographically diverse and disturbed landscapes. Location We analysed counts from 514 different locations in North America. The counts represent all areas of the USA and southern Canada, with a few Mexican sites as well, although most counts were in the eastern USA. Methods First, we standardized published count data according to the effort expended per count (total party-hours). Using regression analysis and analysis of variance, we then examined the impact of latitude, longitude, topographical relief, habitat disturbance and different climatic measures on the species richness and total abundance of butterflies per count. We also examined the abundance of exotic species in disturbed landscapes. Results Our analyses suggest that: (1) species richness is highest at low latitudes and near Rocky Mountain longitudes; (2) the total abundance of individuals is highest in northern US latitudes and Great Plains longitudes; (3) species richness but not total abundance increases with greater topographical relief; (4) species richness and diversity indices are lower in more disturbed habitats; and (5) the abundance of the introduced Pieris rapae (L.) is greater in more disturbed habitats. Main conclusions Different factors control the abundance and species richness of North American butterflies. Along with geographical location, habitat disturbance and topographical variability affect species richness. Our analysis also shows the value of broad-based monitoring regimes, such as the North American Fourth of July Butterfly Count.

Ehrenfeld, J. G. (2000). "Evaluating wetlands within an urban context." Ecological Engineering 15(3-4): 253-265. Coastal regions are among the most rapidly urbanizing places on earth. The numerous effects of urbanization on hydrology, geomorphology, and ecology make wetlands in urban regions function differently from wetlands in non-urban lands. Furthermore, wetlands ill urban regions may take on human-related values that they lack in non-urban areas, as they provide some contact with nature, and some opportunities for recreations that an otherwise rare in the urban landscape. Evaluations of the success of restorations in urban regions require criteria first to determine the kinds, and intensities of urban influence on the site, and secondly to assess functional performance. The development of success criteria, at both the levels of assessment, depends on the proper definition of a reference domain (the set of wetlands to which success criteria will apply), and the documentation of a set of reference sites within the domain; both must be based within the urban context appropriate for the region of interest. An example is presented from a study of urban wetlands in New Jersey of a procedure for establishing the reference domain, the reference set of wetlands, and criteria for the assessment of urban influence.

Carlson, T. N. and S. T. Arthur (2000). "The impact of land use - land cover changes due to urbanization on surface microclimate and hydrology: a satellite perspective." Global and Planetary Change 25(1-2): 49-65. Vegetation cover, surface moisture availability (wetness) and radiant surface temperature constitute microclimatic variables derivable from multi-spectral satellite imagery. In addition, fraction impervious surface cover and urban-induced surface runoff (RO) are obtainable from such imagery when it is combined with a conventional image classification. Using AVHRR and Landsat TM data, we illustrate how these parameters respond to urbanization with a case study of Chester County, PA - a region that has undergone rapid urban development over the past decade. Specific factors affecting the change in the surface microclimatic variables are discussed. Based on a statistical analysis of the Chester County data, future values of these microclimatic parameters can be predicted, given the characteristics of the initial land surface and an estimate of the change in vegetation and urban coverage.

Beckett, K. P., et al. (2000). "Particulate pollution capture by urban trees: effect of species and windspeed." Global Change Biology 6(8): 995-1003. Particulate pollution is a serious health problem throughout the world, exacerbating a wide range of respiratory and vascular illnesses in urban areas. The use of trees to reduce the effects of these pollutants has been addressed in the literature, but has rarely been quantified. The aim of the present study was to quantify the effectiveness of five tree species-pine (Pinus nigra var. maritima), cypress (x Cupressocyparis leylandii), maple (Acer campestre), whitebeam (Sorbus intermedia), poplar (Populus deltoides x trichocarpa 'Beaupre')-in capturing pollutant particles. This was achieved by exposing them to NaCl droplets of approximately 1 mum diameter at a range of windspeeds in two windtunnels. The deposition velocity (V-g) and particle trapping efficiency (C-p) were calculated from these exposures. In addition, a variable dependent on foliage structure [Stokes number (St)] was correlated with C-p to gauge the effect of tree morphology on particle capture. Maximum C-p values ranged from 2.8% for P. nigra, to 0.12% and 0.06% for P. trichocarpa x deltoides and A. campertre, respectively. The finer, more complex structure of the foliage of the two conifers (P. nigra and C. leylandii) explained their much greater effectiveness at capturing particles. The data presented here will be used to model the effectiveness of tree planting schemes in improving urban air quality by capturing pollutant particles.

Barradas, V. L. (2000). "Energy balance and transpiration in an urban tree hedgerow in Mexico City." Urban Ecosystems 4(1): 55-67. A series of sap flow (transpiration, TRP) and energy balance components measurements were carried out in a representative tree hedgerow of Fraxinus uhdei in Mexico City (19° 19' N, 99° 11' W, 2250 m ASL). Measurements of sap flow in the trunks of the trees was selected as an alternative tool instead of eddy covariance or Bowen ratio-energy balance methods in order to determine the energy balance components of the tree canopy. These measurements were made in October (end of the rainy season) and December (dry season) in 1997, from 8:00 to 17:00 LST. TRP showed a unimodal pattern during the day. Mean daily transpiration was higher at the end of the rainy season (1506 g m-2 d-1) than in the begining of the dry season (972 g m-2 d-1) with maxima rates of 0.075 and 0.046 g m-2 s-1, respectively. During the rainy season net radiation (QN) was mainly dissipated by latent (QE) and sensible (QH) heat, 60 and 34 %, respectively. Latent heat increased in the day up to 184 W m-2. QN was dissipated by QH and QE by 75 and 25%, respectively, and QH had a maximum hourly value of 298 W m-2 during the day (8:00- 17:00 LST) in the dry season. Seasonal differences in QE and QH were probably due to differences of water availability. Heat storage of the tree hedgerow canopy was found to be a negligible component of the energy balance in both seasons. Actual transpiration of the system was always lower than transpiration at equilibrium. This was probably due to a low water availability in the substratum, a high atmospheric evaporative demand and an effective stomatal control. Because the tree hedgerow was completely surrounded by paved areas and wind was coming from a drier side, it is possible that transpiration rates were affected by advection probably supressing TRP.

Spronken-Smith, R. A. and T. R. Oke (1999). "Scale modelling of nocturnal cooling in urban parks." Boundary-Layer Meteorology 93(2): 287-312. Scale modelling is used to determine the relative contribution of heat transfer processes to the nocturnal cooling of urban parks and the characteristic temporal and spatial variation of surface temperature. Validation is achieved using a hardware model-to-numerical model-to-field observation chain of comparisons. For the calm case, modelling shows that urban-park differences of sky view factor (psi(s)) and thermal admittance (mu) are the relevant properties governing the park cool island (PCI) effect. Reduction in sky view factor by buildings and trees decreases the drain of longwave radiation from the surface to the sky. Thus park areas near the perimeter where there may be a line of buildings or trees, or even sites within a park containing tree clumps or individual trees, generally cool less than open areas. The edge effect applies within distances of about 2.2 to 3.5 times the height of the border obstruction, i.e., to have any part of the park cooling at the maximum rate a square park must be at least twice these dimensions in width. Although the central areas of parks larger than this will experience greater cooling they will accumulate a larger volume of cold air that may make it possible for them to initiate a thermal circulation and extend the influence of the park into the surrounding city. Given real world values of psi(s) and mu it seems likely that radiation and conduction play almost equal roles in nocturnal PCI development. Evaporation is not a significant cooling mechanism in the nocturnal calm case but by day it is probably critical in establishing a PCI by sunset. It is likely that conditions that favour PCI by day (tree shade, soil wetness) retard PCI growth at night. The present work, which only deals with PCI growth, cannot predict which type of park will be coolest at night. Complete specification of nocturnal PCI magnitude requires knowledge of the PCI at sunset, and this depends on daytime energetics.

Panno, S. V., et al. (1999). "Impact of urban development on the chemical composition of ground water in a fen-wetland complex." Wetlands 19(1): 236-245. A 15-month-long hydrogeologic investigation of a fen-wetland complex in northeastern Illinois, USA indicated the encroachment of ground-water-borne anthropogenic contaminants into two of three high quality fens. Ground-water flow directions and chemical evidence indicated that plumes of ground water with anomalously large concentrations of Na+ and Cl- originated from a private septic system and from rock salt spread on an adjacent road. The contamination, in turn, had an adverse effect on fen vegetation; within the plumes, diverse vegetation was replaced by the more salt-tolerant narrow-leaf cattail (Typha angustifolia). Ground water of the third fen contained large concentrations of SO42- as high as 516 mg/L. The SO42- anomaly was observed on a transient and/or seasonal basis in the fen ground water and in an adjacent marsh and pond. Isotopically light delta(34)S values in these waters indicated that the addition of SO42- resulted from the oxidation of pyrite within underlying pear and/or pyritic gravel. However, the large SO42- concentrations had no discernible effect on fen vegetation. The results of this investigation indicate how easily construction of houses with private septic systems and deicing agents from roadway maintenance can contaminate fen ground water with relatively large concentrations of Na+ and Cl-, resulting in a significant loss of biodiversity in fens.

Niemela, J. (1999). "Ecology and urban planning." Biodiversity and Conservation 8(1): 119-131. Urban areas harbour diverse nature ranging from semi-natural habitats to wastelands, parks and other highly human-influenced biotopes with their associated species assemblages. Maintenance of this urban biodiversity for the residents and for its intrinsic value in the face of increasing population and expanding cities requires that ecological knowledge should be better integrated into urban planning. To achieve this goal understanding of ecological patterns and processes in urban ecosystems is needed. The first step in the necessary urban ecological research is to find out what kind of nature exists in cities. Second, knowledge about ecological processes important in urban nature is required. Although ecological processes in cities are the same as in rural areas, some of them, such as invasion by alien species, are more prevalent in urban than in rural conditions. Third, based on ecological knowledge, management schemes maintaining the diversity of urban nature should be designed. These procedures should also include protection of urban nature, e.g. in urban national parks. Finally, as ecology alone cannot provide the complex information about human influence on urban ecosystems, interdisciplinary research involving natural and social sciences is imperative for a holistic approach to integrating ecology into the process of urban planning.

Long, A. J. and P. K. R. Nair (1999). "Trees outside forests: agro-, community, and urban forestry." New Forests 17(1-3): 145-174. Planted forests are often considered to consist of tree plantings at a scale large enough to satisfy such objectives as commercial production of timber and fiber, protection of watersheds, and preservation of natural habitats. However, trees are planted also at greatly reduced scales in agroforestry systems or as community woodlots to provide a mixture of products and services to resident households, local communities, and regional cultures. Agroforestry systems represent a major form of small-scale tree planting, where trees are grown in purposeful combinations with agricultural crops and/or livestock in order to take advantage of tree-crop interactions, and thereby enhance crop production, diversify farm output, stabilize or improve soils, or ameliorate harsh environmental conditions. Some important examples of these systems in tropical countries include home gardens, alley cropping, improved fallows, intercropped trees for shade and fodder production, and trees planted in hedgerows and along fence lines. Throughout the tropics, there is a large variety of indigenous practices and species mixtures that represent adaptations of these systems to meet localized needs and opportunities. Research and development programs have supported the expansion and refinement of many of these systems during the last 20 years, but substantial constraints on tree planting still exist in the form of land-tenure practices, population pressures that relegate agroforestry practices to degraded lands, subsistence needs that prevent extended periods of tree growth, and insufficient technical information or technology dissemination. Agroforestry systems in temperate, industrialized countries include combinations of trees, pasture, and livestock; fruit or nut trees interplanted with vegetable or grain crops; windbreaks and shelterbelts; multispecies riparian buffer strips; and forest farming systems for specialty crops. Compared to the tropics, however, temperate-zone systems tend to focus on one or two high-value crops, often involve some level of mechanization, and frequently represent an opportunistic approach to improving the economic profitability of farms rather than meeting subsistence needs. In both tropical and temperate regions, agroforestry systems and community woodlots will be an important component of new sustainable agriculture and environmental protection programs. Although species diversity is an essential feature of all agroforestry systems, community forests generally involve planting only a few species in small woodlots near farms, around villages, along roads, and as riparian buffers. Provincial or state governments and the local populace are often involved in landownership and plantation establishment. Major objectives of these forests are production of fuelwood for local consumption and of other tree products for market; soil stabilization, reclamation, or improvement; and protection of water quality. As with many other planted forests, the number of species widely used in community forests has been relatively small, with the genera Eucalyptus, Pinus, and Acacia providing the bulk of the species. Major issues with these "planted forests'' focus on rights for use of the products, tending responsibilities once trees are established, protection until trees are large enough for their designated use, increasing interest in using "native'' species, and greater community involvement in planning and management. Trees planted along streets and waterways, or as woodlots in parks and other public places, represent a major group of planted forests in many urban and periurban landscapes. In addition to providing many of the same environmental services that agroforests and community forests do, these urban plantings have unique aesthetic and recreational value. For much of the world's ever-increasing urban population, these may be the only tangible reference points for understanding planted forests. These relatively little-recognized forms of planted forests - planted trees, to be more appropriate - are now receiving much greater atte tion. There are, however, some serious technical and sociopolitico-institutional constraints to their development as more widely adopted systems in both tropical and temperate regions.

Kuttler, W. and A. Strassburger (1999). "Air quality measurements in urban green areas - a case study." Atmospheric Environment 33(24-25): 4101-4108. The influence of traffic-induced pollutants (e.g. CO, NO, NO2 and O-3) on the air quality of urban areas was investigated in the city of Essen, North Rhine-Westphalia (NRW), Germany. Twelve air hygiene profile measuring trips were made to analyse the trace gas distribution in the urban area with high spatial resolution and to compare the air hygiene situation of urban green areas with the overall situation of urban pollution. Seventeen measurements were made to determine the diurnal concentration courses within urban parks (summer conditions: 13 measurements, 530 30 min mean values, winter conditions: 4 measurements, 128 30 min mean values). The measurements were carried out during mainly calm wind and cloudless conditions between February 1995 and March 1996. It was possible to establish highly differentiated spatial concentration patterns within the urban area, These patterns were correlated with five general types of land use (motorway, main road, secondary road, residential area, green area) which were influenced to varying degrees by traffic emissions. Urban parks downwind from the main emission sources show the following typical temporal concentration courses: In summer rush- hour-dependent CO, NO and NO2 maxima only occurred in the morning. A high NO2/NO ratio was established during weather conditions with high global radiation intensities (K > 800 W m(- 2)), which may result in a high O-3 formation potential. Some of the values measured found in one of the parks investigated (Gruga Park, Essen, area: 0.7 km(2)), which were as high as 275 mu g m(-3) O-3 (30-min mean value) were significantly higher than the German air quality standard of 120 mu g m(-3) (30-min mean value, VDI Guideline 2310, 1996) which currently applies in Germany and about 20% above the maximum values measured on the same day by the network of the North Rhine-Westphalian State Environment Agency. In winter high CO and NO concentrations occur in the morning and during the afternoon rush-hour. The highest concentrations (CO = 4.3 mg m(-3), NO = 368 mu g m(-3), 30-min mean values) coincide with the increase in the evening inversion. The maximum measured values for CO, NO and NO2 do not, however, exceed the German air quality standards in winter and summer.

Hardy, P. B. and R. L. H. Dennis (1999). "The impact of urban development on butterflies within a city region." Biodiversity and Conservation 8(9): 1261-1279. The effect of urban development on butterfly species' richness and species' incidence is tested for the Greater Manchester conurbation and two sample areas, mapped at finer scales, within the southern part of the conurbation. The tests include measures of bias for recording effort (number of visits). Species' richness is found to increase with percentage urban cover for Greater Manchester (tetrad scale) and decrease with urban cover for the two sample areas in South West Manchester (1 km scale) and the Mersey Valley (100 m scale). For Greater Manchester, the increase in species' richness with increased urban cover is largely explained by lower species' richness at higher altitude in the Pennines bounding the conurbation. For the two sample areas, decreasing species' richness associated with increasing urban cover corresponds with reductions in the areas of a number of semi-natural habitats, hostplants and nectar sources. Despite these statistically significant correlations, the impact of urban cover on species' richness is weak. The maximum loss rate identified anywhere within the region is 0.81 species per 10% change in urban cover for South West Manchester. This finding may reflect on the generally low species diversity of the region. However, these results could be influenced by recording and sampling artefacts, particularly the failure of mapping programmes to distinguish vagrant individuals from breeding populations and a bias of records to vagrants. This is supported by the higher correlations between species' incidence and nectar sources than between species' incidence and their hostplants. Adult butterflies are opportunistic nectar users and nectar sources are more widely spread and thus less influenced by urban development than are specific butterfly hostplants. The finding may also reflect on the capacity of most of the butterfly species to breed successfully on tiny areas of hostplant existing within extensively built-up areas. Moreover, the capacity of butterfly species to persist by using small fragments of hostplants would be enhanced by vagrancy. If this is indeed the case, it is a finding that would support the value of small patches in butterfly metapopulations, albeit ones comprising incomplete complements of resources required during the life cycle. The incidence of most species decreases with increase in urban cover. Multivariate analyses indicate that this is owing to corresponding declines in hostplant-habitats and nectar sources. Five species increase with urban cover, but none attain formal significance. Associations among hostplants and habitat variables in a principal components analysis suggest that, in three cases (Pieris brassicae, P. rapae, Celastrina argiolus), this is owing to increasing areas of their hostplants within urban environments.

Hafner, J. and S. Q. Kidder (1999). "Urban heat island modeling in conjunction with satellite-derived surface/soil parameters." Journal of Applied Meteorology 38(4): 448-465. Although it has been studied for over 160 years, the urban heat island (UHI) effect is still not completely understood, yet it is increasingly important. The main purpose of this work is to improve UHI modeling by using AVHRR (Advanced Very High Resolution Radiometer) satellite data to retrieve the surface parameters (albedo, as well as soil thermal and moisture properties). In this study, a hydrostatic three-dimensional mesoscale model was used to perform the numerical modeling. The Carlson technique was applied to retrieve the thermal inertia and moisture availability using the thermal AVHRR channels 4 and 5. The net urban effect was determined as the difference between urban and nonurban simulations, in which urban parameters were replaced by rural parameters. Two winter days were each used for two numerical simulations: a control and an urban-to-rural replacement run. Moisture availability values on the less windy day showed generally a south to north gradient downwind of the city and urban values less than rural values (the urban dry island day). Moisture availability was higher on the windy day, with uniform values in the rural and urban areas (uniform soil moisture day). The only exceptions were variations in the rural hills north of the city and the low rural values under the polluted urban plume downwind of the city. While thermal inertia values showed no urban-rural differences on the uniform soil moisture day, they exhibited larger values over Atlanta than in surrounding rural area on the (less moist) dry island day. Two puzzling facts exist in the data: 1) lack of a north-south thermal inertia gradient on the dry soil day to correspond to its above-mentioned moisture availability gradient and 2) rural thermal inertia values do not change between both days in spite of their large difference in soil moisture. The observed lack of corresponding urban change is expected, as its thermal inertia values depend more on urban building materials than on moisture of soil. In both cases both the 2-m and surface skin UHIs showed positive values at night and negative values tan urban cool island, UCI) during the day. The larger nighttime 2-m UHI was on the dry day (0.8 degrees vs 0.6 degrees C), while the larger daytime 2-m UCI was on the moist soil day (-0.3 degrees vs -0.5 degrees C). Note that the surface differences were almost always greater than the 2-m differences. These day-night differences imply a rural thermal inertia lower than its urban values on both days, which is in conflict with the observations on the wet uniform soil moisture day. On the uniform thermal inertia day (wet day), both the UHI and UCI amplitudes should be less than on the other day, bur this is not the case. A possible explanation for both of these conflicts is the improper influence of the urban plume on this day on lowering the thermal inertia and moisture availability values used in the replacement urban simulation.

Bolund, P. and S. Hunhammar (1999). "Ecosystem services in urban areas." Ecological Economics 29(2): 293-301. Humanity is increasingly urban, but continues to depend on Nature for its survival. Cities are dependent on the ecosystems beyond the city limits, but also benefit from internal urban ecosystems. The aim of this paper is to analyze the ecosystem services generated by ecosystems within the urban area. 'Ecosystem services' refers to the benefits human populations derive from ecosystems. Seven different urban ecosystems have been identified: street trees; lawns/parks; urban forests; cultivated land wetlands; lakes/sea; and streams. These systems generate a range of ecosystem services. In this paper, six local and direct services relevant for Stockholm are addressed: air filtration, micro climate regulation, noise reduction, rainwater drainage, sewage treatment, and recreational and cultural values. It is concluded that the locally generated ecosystem services have a substantial impact on the quality-of-life in urban areas and should be addressed in land-use planning.

Taylor, A. F., et al. (1998). "Growing up in the inner city - Green spaces as places to grow." Environment and Behavior 30(1): 3-27. Children growing up in the inner city are at risk for a range of negative developmental outcomes. Do barren, inner-city neighborhood spaces compromise the everyday activities and experiences necessary for healthy development? Sixty-four urban public housing outdoor spaces (27 low vegetation, 37 high vegetation) were observed on four separate occasions. Overall, inner-city children's everyday activities and access to adults appeared remarkably healthy; of the 262 children observed, most (73%) were involved in some type of play, and most groups of children (87%) were supervised to some degree. In relatively barren spaces, however, the picture was considerably less optimistic: Levels of play and access to adults were approximately half as much as those found in spaces with more trees and grass, and the incidence of creative play was significantly lower in barren spaces than in relatively green spaces.

Kuo, F. E., et al. (1998). "Transforming inner-city landscapes - Trees, sense of safety, and preference." Environment and Behavior 30(1): 28-59. How would inner-city residents respond to the incorporation of trees and grass in their neighborhoods? Law enforcement officials have argued that, in these settings, trees and other forms of vegetation increase fear. Tree density, tree placement, and levels of grass maintenance were manipulated in photo simulations of neighborhood outdoor space. One hundred residents of Chicago's Robert Taylor Homes living adjacent to the space rated the images with respect to preference and sense of safety. Although tree placement (subspaces created by trees, formality of arrangement) had little effect on sense of safety and no effect on preference, both tree density and grass maintenance had strong effects on preference and sense of safety (eta(2)s from .49 to .89), Surprisingly, tree density and grass maintenance increased both preference and sense of safety. Results suggest that-contrary to some views-trees and grass maintenance can increase sense of safety in inner-city neighborhoods.

Kjelgren, R. and T. Montague (1998). "Urban tree transpiration over turf and asphalt surfaces." Atmos Environ 32. Abstract--We used a two-layer canopy model to study transpiration of tree species as affected by energy-balance properties of a vegetated and paved surface. During several dawn-to- dusk studies, tree transpiration, stomatal conductance, leaf temperature (%), and several microclimate variables, were measured over turf and an asphalt surface. Cumulative transpiration was estimated from a leaf energy- balance equation applied to a tree crown apportioned between sunlit and shaded layers. Afternoon asphalt surface temperatures (Ts) were 20-25°C higher than turf T~ in all studies. Air-temperature differences between sites were minimal due to the size and proximity of the two surfaces that resulted in mixing of air. Trees over asphalt had consistently higher T, than those over turf, apparently due to interception of the greater upwards long-wave radiation flux from higher Ts. In one study flowering pear over asphalt in a humid environment had higher T/resulting in one-third more total water loss compared to trees over turf. In other studies, however, water loss of green ash and Norway maple over asphalt in an arid environment was either equal to or less than that over turf. Less water loss was due to higher T, over asphalt causing prolonged stomatal closure. Model manipulation indicated that tree water loss over asphalt will depend on the degree of stomatal closure resulting from how interception of increased energy-fluxes and ambient humidity affect leaf-to-air vapor pressure differences.

Idso, C. D., et al. (1998). "The urban CO2 dome of Phoenix, Arizona." Physical Geography 19(2): 95-108. Air temperatures, relative humidities, and atmospheric carbon dioxide concentrations were measured at a height of 2 m at approximate 1.6-km intervals prior to sunrise and in the middle of the afternoon on five days in January along a number of different transects through the extended metropolitan area of Phoenix, Arizona. Spatially interpolated maps of the data indicate the presence of an "urban CO2 dome" that reaches concentrations as high as 555 ppmv in the city center and decreases to a value of approximately 370 ppmv on the outskirts of the city at this time of year. Pre-dawn CO2 values inside the dome are considerably higher than mid-afternoon values, suggesting that solar-induced convective mixing and the photosynthetic uptake of CO2 by urban vegetation may play significant roles in diurnally redistributing the anthropogenically produced CO2 that, together with that produced by plant respiration, accumulates near the ground during the night and early morning hours. Temperature and relative humidity appear to have little influence on either the concentration or location of the CO2 dome, but variations in wind speed and direction at times may disrupt the pattern that develops under normally fair conditions. The high CO2 concentrations within the dome may help to ameliorate the deleterious effects of urban air pollution on vegetation growing within the city. Together with the urban heat island phenomenon, they may also provide a natural laboratory for studying the effects of contemporaneous warming and atmospheric CO2 enrichment within the context of predicted future global change.

Benjamin, M. T. and A. M. Winer (1998). "Estimating the ozone-forming potential of urban trees and shrubs." Atmos Environ 32. A method is presented for estimating the ozone-forming potential of biogenic hydrocarbon emissions from trees and shrubs, using the California South Coast Air Basin (SoCAB) as a case study. Hourly isoprene and monoterpenes emission rates for 308 tree and shrub species found in the SoCAB were combined with diurnal temperature and light intensity data for a representative summer day in the SoCAB to develop daily emission rates. These daily emission rates for each species were then normalized to a per tree basis using vegetation class biomass factors derived from reported leaf mass constants and tree canopy volumes. The ozone- forming potential for each of the tree and shrub species was estimated by combining the daily per tree emission rates with published maximum incremental reactivities (MIRs) for isoprene and monoterpenes. The resulting ranking of trees by ozone-forming potential can be used in tree species selection for future large-scale tree planting programs, and provides a more appropriate basis for selection than using only mass emissions of biogenic hydrocarbons.

Beckett, K. P., et al. (1998). "Urban woodlands: their role in reducing the effects of particulate pollution." Environmental Pollution 99(3): 347-360. In recent years a substantial research effort has focused on the links between particulate air pollution and poor health. As a result the PM10 value has been set as a measure of such pollutants which can directly cause illness. Due to their large leaf areas relative to the ground on which they stand and the physical properties of their surfaces, trees can act as biological filters, removing large numbers of airborne particles and hence improving the quality of air in polluted environments. The role of vegetation and urban woodlands in reducing the effects of particulate pollution is reviewed here. The improvement of urban air quality achieved by establishing more trees in towns and cities is also illustrated. vanRensburg, L., et al. (1997). "A phytocentric perspective of Asterolecanium quercicola Bouche infestation on Quercus robur L trees along an urbanization gradient." South African Journal of Botany 63(1): 25-31. Diurnal courses in gas exchange, photochemical efficiency and water relations were monitored during two late summers in three groups of adult Quercus robur L. trees, planted along an urbanization gradient that correlated positively with the degree of die-back exhibited by the trees. Leaf carbon:nitrogen ratios, proline and polyphenol levels were monitored to explain why the intermediate group of trees were more severely infested (p less than or equal to 0.01) with Asterolecanium quercicola (Bouche). All three groups of trees showed a significant correlation of net photosynthesis (A) with photon flux density (PPFD), but A correlated more positively with the pre-dawn leaf water potential psi(pd) Of the moderately (trees of group b, i.e. at the edge of town) and severely (trees of group c, i.e. urban) water-stressed trees. A of the rural trees and stomatal conductance (g) of the three groups of trees showed little correlation psi(pd) values. Possibly due to the long-term effect of stress, g, as reflected by changes in the transpiration rate (a, showed a significantly (p less than or equal to 0.01) higher sensitivity to relative ambient humidity (RH) in the trees of groups b and c. Photochemically, a close coupling was found to exist between A, psi(pd), RH, the time needed to reach the maximum fluorescence level, i.e. FTm, and S, i.e. the complementary area normalized to the variable fluorescence, indicating that the trees were also affected at this level of organization. Proline accumulation occurred in the trees of group c but not in the trees of group b, as opposed to the polyphenolic concentrations which were significantly (p less than or equal to 0.05) higher in the trees of group b than in the trees of group c. A possible explanation for the higher infestation of A. quercicola on the trees in group b is given in terms of their host specificity and changes in these trees' nitrogen levels.

McPhearson, E. G. (1997). "Quantifying urban forest structure, function, and value: the Chicago Urban Forest Climate Project." Urban Ecosystems 1.

This paper is a review of research in Chicago that linked analyses of vegetation structure with forest functions and values. During 1991, the region’s trees removed an estimated 5575 metric tons of air pollutants, providing air cleansing worth $9.2 million. Each year they sequester an estimated 315 800 metric tons of carbon. Increasing tree cover 10% or planting about three trees per building lot saves annual heating and cooling costs by an estimated $50 to $90 per dwelling unit because of increased shade, lower summertime air temperatures, and reduced neighborhood wind speeds once the trees mature. The net present value of the services trees provide is estimated as $402 per planted tree. The present value of long-term benefits is more than twice the present value of costs.

vanWilgen, B. W., et al. (1996). "Valuation of ecosystem services." BioScience 46(3): 184- 189. Presents a case study from the South African fynbos ecosystems, stating that watershed ecosystems provide quantifiable benefits that can justify management expenditure. Information regarding the invasion of alien plants and their affect on water sources in the mountain catchment areas of the Western Cape Province, South Africa; Economics of water and catchment management.

Obst, S. P., et al. (1996). "Economic Analysis of Arizona Ash Sequentially Produced in Copper-treated or Nontreated 0.21-, 2.5-, and 11.8-Liter Containers." HortScience 31(4): 651-a-. Arizona ash (Fraxinus velutina Torr.) seedlings were grown in 0.21-L plastic liner containers, half treated with 100 g Cu(OH)2/L latex carrier (formulated as Spin Out), and half nontreated. Seedlings were sequentially transplanted to larger containers, from liners to 2.5-L black plastic containers then to 11.8-L containers resulting in a 2 x 2 x 2 factorial combination of container sizes and Cu-treatments (eight combinations with 30 replicates/treatment). Nursery conditions and production procedures were determined from regional nurseries using a modified Delphi technique. Growth responses (height, caliper, market grade) and costs of production were determined for each treatment combination through marketable size in 11.8-L containers. Significant interactions (P [≤] 0.05) among liner and 2.5-L container treatments occurred for end of season trunk diameter and market ratings. Those seedlings grown in both Cu-treated liners and 2.5-L containers tended to have larger calipers and market ratings than other treatment combinations. Growth increases were not realized when containers were treated at a single stage. Copper-treated containers resulted in a 17-second labor savings per container at transplant from 2.5- to 11.8-L containers. Labor requirements were not significantly (P [≤] 0.05) different among treatments at transplant from 0.21- to 2.5-L containers.

Nowak, D. J., et al. (1996). "Measuring and analyzing urban tree cover." Landscape and Urban Planning 36(1): 49-57. Measurement of city tree cover can aid in urban vegetation planning, management, and research by revealing characteristics of vegetation across a city. Urban tree cover in the United States ranges from 0.4% in Lancaster, California, to 55% in Baton Rouge, Louisiana. Two important factors that affect the amount of urban tree cover are the natural environment and land use. Urban tree cover is highest in cities that developed in naturally forested areas (31%), followed by grassland cities (19%) and desert cities (10%), but showed wide variation based on individual city characteristics. Tree cover ranged from 15 to 55% for cities in forested areas, 5 to 39% for those in grassland areas, and 0.4 to 26% for cities developed in desert regions, Park and residential lands along with vacant lands in forested areas generally have the highest tree cover among different land uses. Methods of measuring urban tree cover are presented as are planning and management implications of tree-cover data.

Freedman, B., et al. (1996). "Tree species composition, structure, and carbon storage in stands of urban forest of varying character in Halifax, Nova Scotia." Canadian Field- Naturalist 110(4): 675-682. Characteristics of stands of urban forest in Halifax, Nova Scotia, were analyzed with regards to tree-species composition and carbon sequestration. Older stands in residential and institutional neighbourhoods are dominated by non-native species of trees, thus limiting their usefulness in terms of protection of indigenous biodiversity values. These stands do, however, provide substantial ecosystem service in terms of carbon storage, because they are dominated by relatively large trees with an almost closed canopy (averaging 83% cover), and supporting a relatively large stand biomass (averaging 131 t/ha of above-ground tree biomass). In comparison, younger residential neighbourhoods have larger frequencies of native tree species, reflecting a recent trend to preserving some natural forest as buffer strips between properties. However, the proportion of native species of trees in the younger neighbourhoods is expected to decrease with time, because non-indigenous species are the strongly dominant choice among recent plantings by homeowners. Because of recent disturbance, urban forest in younger neighbourhoods has a relatively small biomass, but this should increase with succession. Natural-forest urban parks have a tree-species composition and stand structure that are similar to that of more remote, natural forests.

ChristovaBoal, D., et al. (1996). "An investigation into greywater reuse for urban residential properties." Desalination 106(1-3): 391-397. Continuing moves towards full cost recovery for potable water and the impending privatization of water supplies in the Melbourne area have enhanced public interest in the reuse of wastewater, and particularly the domestic use of greywater. Victoria University of Technology, together with support from Melbourne Water and the Department of Health and Community Services, has been investigating the practicalities, costs and social attitudes of using greywater in and around the home. Four ''typical'' Melbourne homes were selected and plumbed to utilize greywater for toilet flushing and garden irrigation. Social surveys were conducted by mail and phone to homeowners to determine perceived attitudes towards greywater reuse, Greywater from baths, showers, laundry troughs and washing machines is being examined for physical, chemical and microbiological parameters to determine the potential health and environmental risks associated with reuse. Soil tests were also undertaken on gardens to determine any long-term detrimental effects that might occur as a result of using greywater. This paper describes the greywater testing, results of filtration and filter designs, appropriate disinfectants, and physical findings to date. The two-year project is due for completion early in 1995.

Sgardelis, S., et al. (1994). "Comparison of Chlorophyll Fluorescence and some Heavy- Metal Concentrations in Sonchus spp along an Urban Pollution Gradient." Science of The Total Environment 158(1-3): 157-164. Chlorophyll-a fluorescence induction kinetics of dark-adapted leaves of Sonchus spp. were measured in plants from areas of differing levels of urban pollution. Significant increases (similar to 200%) in the minimal (Fo) and maximal (Fm) fluorescence and decreases (similar to 50%) in the half-rise time from Fo to Fm (t(1/2)) were observed for plants in areas of high pollution. A stress index factor (SIF) was derived based on the variation in these variables, using canonical variance analysis, which increased with increasing pollution levels. Significant linear relationships between the fluorescence parameters of Sonchus spp. and Taraxacum spp. indicate that both plants exhibit the same changes in their chlorophyll fluorescence patterns in response to the pollution gradient. The ratio of Fm/Fo had a mean value of 5.2 +/- 0.24 for Taraxacum spp. and 4.9 +/- 0.23 for Sonchus spp. No significant variation in the ratio of variable to maximal fluorescence (Fv/Fm) was observed (0.75-0.82) which indicated that the efficiency of the primary photochemistry of photosystem II was not directly affected by pollution level. The concentrations of Pb, Zn and Cu in the soil and the plant tissue were higher in areas of higher traffic density and air pollution. Individual or combinations of the metal concentrations significantly accounted for at least 53% of the variation in SIF for both Taraxacum spp, and Sonchus spp.

RA, S.-S. (1994). Energetics and cooling in urban parks. PhD thesis. University of British Columbia. Geography Department. While there has been a long tradition for the integration of architecture and landscape to improve the urban environment, little is known about the effect of urban parks on local climate. In this study the park effect is determined through an integrated research approach incorporating field measurements of the thermal regime and energetics of urban parks, together with scale modelling of nocturnal cooling in urban parks. The research is limited to consideration of the park effect in two cities with different summer climates: Sacramento, California (hot summer Mediterranean) and Vancouver, British Columbia (cool summer Mediterranean). In both these cities, surveys of summer time air temperature patterns associated with urban parks confirm and extend previous findings. In temperate Vancouver, the park effect is typically 1—2°C, rarely more than 3°C, although it can be higher under ideal conditions. However, in a hot, dry city, the effect is considerably enhanced with parks as much as 5—7°C cooler than their urban surrounds. A comparison of the surface energy balance of small open, grassed parks in these two cities demonstrates the importance of evapotranspiration in park energetics. In hot, dry Sacramento, evaporation in the park was advectively—assisted and exceeded that at an irrigated rural site. Strong advective edge effects on evaporation were observed in this wet park. These decayed approximately exponentially with distance into the park. The urban park in Vancouver was moist, but unirrigated. While evaporation dominated the surface energy balance, the sensible heat flux was positive through most of the day, and evaporation was not strongly influenced by advection. The evaporation trend in the park probably reflected the turbulence and soil moisture regimes. However, an irrigated lawn in Vancouver did exhibit edge—type advection. This suggests the soil moisture regime may be critical in determining whether evaporation exceeds the potential rate. The contribution of processes to nocturnal cooling in urban parks was determined through scale modelling. It showed that surface geometry and the urban—park difference in thermal admittance may be of equal importance in nocturnal cooling. Parks with high sky view factors have increased radiative cooling and if the park is very dry (and therefore has a low thermal admittance), the cooling is further enhanced. Evaporative cooling is critical in establishing the park as a “cool island” at sunset, but the presence of moisture slows cooling through the night. Integration of the field and model data leads to the development of guidelines for planners regarding the design of parks for maximum climatic benefit. The optimum size of the park depends to a large extent, on the geometry of the urban surrounds. To maximize radiative cooling, the width of open park areas should be at least 7.5 times the height of the trees or buildings around the park border. Large parks increase the size of the volume of air cooled and this increases the potential for advection of cool air into the neighbourhood. It is suggested that if cooling is the objective, the optimum design is a savannah—type park with loose clusters of trees interspersed by wide open, irrigated grass. The arrangement of trees must be chosen with great care to allow the advection of air both into, and out of, the park.

Pirages, D. (1994). "Sustainability as an evolving process." Futures 26(2): 197-205. The growing number of human beings and the industrial lifestyles that they have embraced have combined to overwhelm the natural systems that sustain all life on Earth. Just as the process of natural selection forges a relationship between the constraints of nature and the human genome, a similar process, sociocultural evolution, links nature and a `sociocultural genome'. The dominant sociocultural genome, the product of industrial evolution, now contains much defective information that must be winnowed out through a long-term social genome project. Sustainability, in this context, is seen as a process of analysing and remedying the deficiencies within the social genome so that equilibrium can be restored between human demands for environmental services and the capability of the environment to provide them. New ways of approaching efficiency are suggested as guidelines for an ongoing process of social transformation leading to development of more sustainable future societies.

Mcpherson, E. G. (1994). "Using Urban Forests for Energy Efficiency and Carbon Storage." Journal of Forestry 92(10): 36-&. Although the long-term effects of greenhouse gas emissions are uncertain, the issue is garnering official attention. Forest management of carbon has been promoted in the Energy Policy act of 1992. Urban forest ameliorate climate and conserve energy through shading, which reduces the amount of radiant energy absorbed, stored, and radiated by buildings; evapotranspiration, which converts radiant energy into latent energy; and airflow modification, which affects transport and diffusion of energy, water vapor, and pollutants. This paper discusses the potential for urban forest conservation; how carbon offsets can be achieved by managing urban forests; the costs of conserved energy and carbon; the ancillary benefits of urban forestry programs; and current programs.

Liu, J. J., et al. (1994). "Predicting personal exposure levels to carbon-monoxide (CO) in Taipei, based on actual CO measurements in microenvironments and a Monte-Carlo simulation method." Atmos Environ 28. order to evaluate the severity of carbon monoxide (CO) pollution in Taipei, this study conducted a survey of commuting patterns (in a district) for random samples of primary school students and adult workers, and carried out CO measurements in vehicles and near roadsides. A Monte Carlo simulation was then implemented to estimate l-and 8-h CO exposure levels for the population. The microenvironment of the roadside included both the sidewalk and the corridor (a sheltered walkway farther removed from the road than the sidewalk). By computer simulations, this study showed that commuters on motorcycles and public buses were exposed to the highest CO exposure levels among all commuters on the roads in Taipei. This study also demonstrated that the Monte Carlo simulation method could better estimate CO exposure levels for the general public. It was found that roadside-fixed monitoring stations operated by the Taipei BEP(Bureau of Environmental Protection) underestimated the general population’s l-h CO exposure levels. For adult workers, the roadside-fixed monitoring stations reasonably estimated the roadside business workers’ 8-h CO exposure levels, but overestimated the exposure levels of general adult workers commuting by public bus, except for bus drivers whose CO exposure levels were underestimated. It is suggested that the computer simulation method can be used to better guide air quality management plans instead of only using the fixed-site monitoring data. The simulated results indicate that the CO exposure levels of commuters on motorcycles and public buses are high enough that prompt control measures are warranted in Taipei.

Levitt, D. G., et al. (1994). "Neighborhood-Scale Temperature Variation Related to Canopy Cover Differences in Southern California." 21st Conference on Agricultural and Forest Meteorology/11th Conference on Biometeorology and Aerobiology: 349-352 528.

Lanaras, T., et al. (1994). "Chlorophyll Fluorescence in the Dandelion (Taraxacum spp) - A Probe for Screening Urban Pollution." Science of The Total Environment 149(1-2): 61-68. The spatial dependence of early morning chlorophyll fluorescence parameters (F(o), non- variable fluorescence; F(m), maximum fluorescence; F(v) = F(m) - F(o), variable fluorescence; t1/2, half-rise time from F(o) to F(m)) and leaf chlorophyll concentration profiles of dandelion (Taraxacum spp.) were used to investigate the stress imposed on the plants by urban pollution. Leaf chlorophyll concentrations vary irrespective of pollution levels. F(v)/F(m), which is considered to be a good indicator of PSII damage over a wide range of environmental stresses did not show significant variation in relation to pollution level. There was a good relationship between dandelion chlorophyll fluorescence values F(o), F(m) and t1/2 and the concentration of air pollutants. Canonical variate analysis (CVA) based on the variation in values of F(o), F(m) and t1/2 was used to derive a linear combination of F(o), F(m) and t1/2 which was used as a stress index factor (SIF). The results are presented as a contour isostress map and show that chlorophyll fluorescence of intact plants can be used for screening urban pollution in the field or after transfer of the plants to the laboratory.

DJ., N. (1994). Air pollution removal by Chicago’s urban forest. Results of the 3-year Chicago Urban Forest Climate Project indicate that there are an estimated 50.8 million trees in the Chicago area of Cook and DuPage Counties; 66 percent of these trees rated in good or excellent condition. During 1991, trees in the Chicago area removed an estimated 6,145 tons of air pollutants, providing air cleansing valued at $9.2 million dollars, These trees also sequester approximately 155,000 tons of carbon per year, and provide residential heating and cooling energy savings that, in turn, reduce carbon emissions from power plants by about 12,600 tons annually. Shade, lower summer air temperatures, and a reduction in windspeed associated with increasing tree cover by 10 percent can lower total heating and cooling energy use by 5 to 10 percent annually ($50 to $90 per dwelling unit). The projected net present value of investment in planting and care of 95,000 trees in Chicago is $38 million ($402 per planted tree), indicating that the long-term benefits of trees are more than twice their costs. Policy and program opportunities to strengthen the connection between city residents and city trees are presented.

Mcpherson, E. G. (1993). "Monitoring Urban Forest Health." Environmental Monitoring and Assessment 26(2-3): 165-174. Renewed interest in urban forestry has resulted in significant public investment in trees during the past few years, yet comprehensive urban forest monitoring programs are uncommon. Monitoring is an integral component of a program to sustain healthy community forests and long term flows of net benefits. Volunteer-based monitoring will promote continued public involvement and support in community forestry. To overcome constraints to monitoring in urban environments, programs must be personally relevant, socially desirable, scientifically credible, and economically feasible. A three-tiered monitoring approach is presented. Canopy cover analysis documents net gains and losses in regional urban forest cover. Simplified detection monitoring uses trained volunteers to better understand tree population dynamics, while intensive monitoring characterizes urban forest functions and stressors. Implementation of an urban forest health initiative to develop, place, and evaluate monitoring programs is advocated.

Gallo, K. P., et al. (1993). "The use of a vegetation index for assessment of the urban heat- island effect." International Journal of Remote Sensing 14(11): 2223-2230. A vegetation index and radiative surface temperature were derived from NOAA-11 Advanced Very High Resolution Radiometer (AVHRR) data for the Seattle, WA region from 28 June through 4 July 1991. The vegetation index and surface temperature values were computed for locations of weather observation stations within the region and compared to observed minimum air temperatures. These comparisons were used to evaluate the use of AVHRR data to assess the influence of the urban environment on observed minimum air temperatures (the urban heat island effect). AVHRR derived normalized difference vegetation index (NDVI) and radiant surface temperature data from a one week composite product were both related significantly to observed minimum temperatures, however, the vegetation index accounted for a greater amount of the spatial variation observed in mean minimum temperatures. The difference in the NDVI between urban and rural regions appears to be an indicator of the difference in surface properties (i.e., evaporation and heat storage capacity) between the two environments that are responsible for differences in urban and rural minimum temperatures.

Sun, W. Q. and N. L. Bassuk (1991). "Approach to Determine Effective Sampling Size for Urban Tree Survey." Landscape and Urban Planning 20(4): 277-283. The collection of data on the current condition of street trees is the first step in developing an urban street tree planning and maintenance program. The objective of this study was to establish a recommendation of sampling size to facilitate street tree surveys through computer simulation. The hypothetical tree populations used for sampling simulation were set up according to published literature. Simulation results concluded that sample quality was improved little after a certain sampling size, but it declined significantly at a smaller size. With the assumption that a relative deviation from the true value (X) within +/- 10% (i.e. X +/- 10%.X) was permitted for estimating the percentage of species in a street tree population, the sampling sizes for urban street tree surveys were recommended on the basis of simulation results. The accuracy of surveys with recommended sampling sizes was estimated by using the street tree population of the City of Ithaca, New York. It was confirmed that recommended sampling size provided the estimates with relative deviations of approximately 10% for major species.

Hartig, T., et al. (1991). "Restorative Effects of Natural Environment Experiences." Environment and Behavior 23(1): 3-26. The utility of different theoretical models of restorative experience was explored in a quasi-experimental field study and a true experiment. The former included wilderness backpacking and nonwilderness vacation conditions, as well as a control condition in which participants continued with their daily routines. The latter had urban environment, natural environment, and passive relaxation conditions. Multimethod assessments of restoration consisted of self-reports of affective states, cognitive performance, and, in the latter study, physiological measures. Convergent self-report and performance results obtained in both studies offer evidence of greater restorative effects arising from experiences in nature. Implications for theory, methodology, and design are discussed.

Wilmers, F. (1990). Effects of vegetation on urban climate and buildings. Vegetation can play an important role in the topoclimate of towns and the microclimate of buildings too. It is different according to the macroclimatic circumstances, but in any case vegetation can give a significant contribution to the climatic conditions. Local climate is determined by atmospheric elements, such as net radiation, advection and convection, and by geographical factors, espe- cially longitude and latitude, oceanity and aridity, the relief graduations and the factors of the urban surface and structure. Those factors 'stress' the atmospheric elements and form the urban topoclimate and microclimate. The urban structures, volumes and special surfaces alter the near-surface conditions of the atmosphere. They form special climatotopes. These urban types can beorganized aspoleotopes of different density and structure which build - - more or less -- their own topoclimate: therefore we call them 'poleoclimatotopes'. Each poleoclimatotope, industrial, commer- cial/city, residential~urban~suburban, and different kinds of open spaces in towns, has its own mean structure and percentage of vegetation surface. But also in the 'choroclimatotopes' -- the climatotopes of the open landscape- as wood, grove, heath, farmland greenery, arable land, and open water surfaces -- special styles of vegetation surface and structure can be found. With buildings, some vegetative climatic effects can be made by combining green cover on walls, roofs, and in open spaces in the vicinity of buildings. According to the environmental conditions the different climatotopes show the effect of vegetation on the urban topoclimate and microclimate, regarding different styles of greenery at and around buildings.

Oke, T. R. (1989). "The micrometeorology of the urban forest." Philos Trans R Soc Lond B Biol Sci 324. Urban trees occupy a wide variety of habitats, from a single specimen competing in the urban jungle to extensive remnant or planted forest stands. Each is shown to produce distinct micro- to local scale climates contributing to the larger urban climate mosaic. These effects are discussed in relation to the radiative, aerodynamic, thermal and moisture properties of trees that so clearly set them apart from other urban materials and surfaces in terms of their exchanges of heat, mass and momentum with the atmosphere. Their resulting ability to produce shade, coolness, shelter, moisture and air filtration makes them flexible tools for environmental design.

Mcpherson, E. G., et al. (1988). "Impacts of Vegetation on Residential Heating and Cooling." Energy and Buildings 12(1): 41-51. Computer simulation has been used to test the effects of irradiance and wind reductions on the energy performance of similar residences of 143 m2 in four U.S. cities — Madison, Salt Lake City, Tucson and Miami — representing four different climates. Irradiance reductions from vegetation were modeled using SPS, which simulates shade cast from plants on buildings, and MICROPAS, a microcomputer-based energy analysis program. Space cooling costs were found to be most sensitive to roof and west wall shading, whereas heating costs were most sensitive to south and east wall shading. Irradiance reductions were shown to substantially increase annual heating costs in cold climates ($128 or 28% in Madison), and reduce cooling costs in hot climates ($249 or 61% in Miami). Dense shade on all surfaces reduced peak cooling loads by 31% – 49% or 3108 – 4086 W. A 50% wind reduction was shown to lower annual heating costs by $63 (11%) in Madison, and increased annual cooling costs by $68 (15%) in Miami. Planting designs for cold climates should reduce winter winds and provide solar access to south and east walls. This guideline also applies for temperate climates, however it is also important to avoid blocking summer winds. In hot climates, high-branching shade trees and low ground covers should be used to promote both shade and wind.

Mcpherson, E. G. (1988). "Functions of Buffer Plantings in Urban Environments." Agriculture Ecosystems & Environment 22-3: 281-298. Buffer plantings are linear strips of vegetation that have been either retained or purposefully planted in urban environments. As biologically diverse ecosystems interspersed among much simpler systems, buffer plantings function as environmental regulators that help stabilize the urban ecosystem while simultaneously separating incompatible land uses and providing visual amenity values. Sensitive land planning integrates existing buffers and new plantings into the urban fabric to maximize potential benefits. Mandatory tree protection and planting programs provide planners with a means of promoting the use of buffer plantings to enhance the livability of our cities. A comprehensive program would restrict the removal of existing vegetation, provide protective measures for vegetation not removed during development, and require planting of additional buffers with new developments. Standards that offer developers a variety of options to achieve a specified level of performance are currently preferred by most planners and developers. Further research is needed to help designers to design buffers that provide the functional benefits required, and which are relatively inexpensive to plant and maintain.

Chameides, W. L., et al. (1988). "The role of biogenic hydrocarbons in urban photochemical smog: Atlanta as a case study." Science 241. The effects of natural hydrocarbons must be considered in order to develop a reliable plan for reducing ozone in the urban atmosphere. Trees can emit significant quantities of hydrocarbons to metropolitan areas such as Atlanta, and model calculations indicate that these natural emissions can significantly affect urban ozone levels. By neglecting these compounds, previous investigators may have overestimated the effectiveness of an ozone abatement strategy based on reducing anthropogenic hydrocarbons.

Oke, T. R. (1982). "The energetic basis of the urban Heat-Island." Q J Roy Meteorol Soc 108. Data are averages for a 3-day period in September 1973 (after Nunez and Oke 1977). Sources (eg trees). The spatially-averaged energy balances for the three canyon surfaces in Fig. 6 show their primary peaks to occur at quite different times of day, due to differing times of maximum solar irradiance. The walls also show secotidary peaks associated with reflection from the other wall, but overall the floor is the most active energy exchange surface, Note that, in absolute terms, the magnitudes of the energy flux densities are rather small (eg by comparison with the rural).

Stephenson, W. R. and H. G. Merriam (1975). "Some effects of urban impact on the structure of lichen communities on trees in three deciduous woodlot types." Urban Ecology 1(2-3): 311-323. Variations in the corticolous lichen communities growing on the dominant tre species in certain woodlots were related in degree of exposure to the airborne pollutant complex from an urban center of one half million people (Ottawa, Canada). Sugar Maple (Acer saccharum), Red Maple (Acer rubrum), and Balsam Poplar (Populus balsamifera) woodlots were studied. Percent cover of all lichens, percent occurrence of dominant lichens, species number, and McIntosh's diversity indices were used to compare lichen communities among comparable woodlots with different degrees of exposure and with controls considered to be relatively free of urban influence. Lichen communities showed negative responses to urban influence of low intensity by reduced lichen cover, and, at higher intensities, in species composition and diversity. Local woodlot specific pollutants gave additive effects. The value of lichen community variations as indicators of pollutant impact on deciduous forest systems is discussed.

Riley, C. B., et al. "Exotic trees contribute to urban forest diversity and ecosystem services in inner-city Cleveland, OH." Urban Forestry & Urban Greening. Vacant land, a product of population and economic decline resulting in abandonment of infrastructure, has increased substantially in shrinking cities around the world. In Cleveland, Ohio, vacant lots are minimally managed, concentrated within low-income neighborhoods, and support a large proportion of the city’s urban forest. We quantified abundance, richness, diversity, and size class of native and exotic tree species on inner-city vacant lots, inner-city residential lots, and suburban residential lots, and used i-Tree Eco to model the quantity and economic value of regulating ecosystem services provided by their respective forest assemblages. Inner-city vacant lots supported three times as many trees, more exotic than native trees, and greater tree diversity than inner-city and suburban residential lots, with the plurality of trees being naturally-regenerated saplings. The urban forest on inner-city vacant lots also had two times as much leaf area and leaf biomass, and more tree canopy cover. The quantity and monetary value of ecosystem services provided by the urban forest was greatest on inner-city vacant lots, with exotic species contributing most of that value, while native taxa provided more monetary value on residential lots. The predominately naturally-regenerated, minimally managed exotic species on vacant land provide valuable ecosystem services to inner-city neighborhoods of Cleveland, OH.

Gunawardena, K. R., et al. "Utilising green and bluespace to mitigate urban heat island intensity." Science of The Total Environment. It has long been recognised that cities exhibit their own microclimate and are typically warmer than the surrounding rural areas. This ‘mesoscale’ influence is known as the urban heat island (UHI) effect and results largely from modification of surface properties leading to greater absorption of solar radiation, reduced convective cooling and lower water evaporation rates. Cities typically contain less vegetation and bodies of water than rural areas, and existing green and bluespace is often under threat from increasing population densities. This paper presents a meta-analysis of the key ways in which green and bluespace affect both urban canopy- and boundary-layer temperatures, examined from the perspectives of city-planning, urban climatology and climate science. The analysis suggests that the evapotranspiration-based cooling influence of both green and bluespace is primarily relevant for urban canopy-layer conditions, and that tree-dominated greenspace offers the greatest heat stress relief when it is most needed. However, the magnitude and transport of cooling experienced depends on size, spread, and geometry of greenspaces, with some solitary large parks found to offer minimal boundary-layer cooling. Contribution to cooling at the scale of the urban boundary-layer climate is attributed mainly to greenspace increasing surface roughness and thereby improving convection efficiency rather than evaporation. Although bluespace cooling and transport during the day can be substantial, nocturnal warming is highlighted as likely when conditions are most oppressive. However, when both features are employed together they can offer many synergistic ecosystem benefits including cooling. The ways in which green and bluespace infrastructure is applied in future urban growth strategies, particularly in countries expected to experience rapid urbanisation, warrants greater consideration in urban planning policy to mitigate the adverse effects of the UHI and enhance climate resilience.

Gómez-Muñoz, V. M., et al. "Effect of tree shades in urban planning in hot-arid climatic regions." Landscape and Urban Planning In Press, Corrected Proof. The present study is carried out for dry hot climate places, where excessive solar heating is felt throughout the year. The effect of tree shadowing buildings is found to reduce heating loads; hence trees have a beneficial effect in energy economics. The emerging economic value of tree shadows in hot climate cities grants the development of an appropriate simulation numerical method to establish relative advantages on energy savings related to dwelling envelopes. The results demonstrate that large trees can provide up to 70% shade during spring and autumn, thus saving a very large amount of energy along the whole year. Hence, economic value of larger trees is greater than that of younger species.