The Effect of Policy and Procedures on Tree-lined Streets Increasing Urban Canopy in Sydney’s Western Parkland City
Christina Silk
A thesis in fulfilment of the requirements for the degree of Master of Philosophy
Faculty of Built Environment
January 2020 Thesis/Dissertation Sheet
Surname/Family Name : Silk Given Name/s : Christina Abbreviation for degree as give in the University calendar : M.Phil Faculty : Built Environment School : Built Environment : Thesis Title The Effect of Policy and Procedures on Tree-lined Streets: Increasing Urban Canopy in Sydney’s Western Parkland City
Abstract 350 words maximum: (PLEASE TYPE)
Local residential streets that can support the growth of significant shade trees are critical for mitigating urban heat - an increasing public health risk in Western Sydney; and for increasing total urban canopy. In the state of New South Wales, regional and district plans for the rapidly developing suburbs of Western Sydney include a planning priority to increase urban canopy. However, planning controls that encourage increased density, combined with development models that continue to favour single-family, detached dwellings, result in decreased lot sizes with insufficient space to support canopy trees around homes or in the streetscape.
Using a qualitative methodology, the research undertook a comparative analysis of local residential streets in two areas of the Camden Local Government Area in the metropolitan region of Western Sydney - one that was developed in the mid-1990s and the other constructed within the past three years. The investigation sought to reveal the spatial factors that contribute to the realisation of tree-lined streets. A tree-focussed reading of the urban planning and development controls, codes, guidelines and specifications that specifically apply to local streets was carried out to assess how these documents impact on the implementation of tree-lined streets. Council officers involved in the planning, design, certification and maintenance of streets were first interviewed individually and later participated together in a focus group discussion.
Findings indicate that although there is political will to implement tree-lined local streets, codes and specifications for other infrastructure impact on the space available for trees. The research concludes that unless trees are accepted as a critical component of the streetscape, urban canopy will not increase and the potential for street trees to mitigate urban heat will not be realised. The discussion suggests actions for policy and for codes and practices that impact on trees. If implemented these actions would result in more tree-lined streets in Western Sydney. The actions could also be replicated in other jurisdictions.
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Date: 17.01.2020
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Christina Silk 17.01.2020
Acknowledgements
Sincere thanks to my supervisors Professor Linda Corkery and Associate Professor Paul Osmond for their patience and support.
Camden Council provided unlimited access to Council staff, data and resources. Council officers who are under pressure to deliver on the NSW Government’s planning priorities for the LGA were very generous with their time and their ideas. I found their commitment to the community and environment of the Camden Local Government Area inspiring. In particular, thanks to Tim Vyse who facilitated contact with staff and the Camden executive.
Landcom provided funding in the form of the M. Phil Top Up Scholarship and also provided data for Oran Park. Thanks in particular to Michael Parsons and Nick Lennon.
Thanks to Ali Gaunt for assisting with graphics.
Final thanks go to my family and in particular my son Dasch.
Christina Silk
Table of Contents
1 Introduction ...... 1 1.1 Background ...... 3
1.2 Methodology ...... 4
1.3 Outcomes ...... 4
1.4 Structure of the thesis ...... 5
2 Literature review ...... 7
2.1 Introduction ...... 7
2.2 Background of the discipline of landscape architecture and theoretical foundation of the research ...... 7
2.3 The planning context ...... 8 2.3.1 The Environmental Planning and Assessment Act ...... 8 2.3.2 State Environmental Planning Policies ...... 9 2.3.3 Regional and district plans ...... 10 2.3.4 Local Environmental Plans ...... 10 2.3.5 Development Control Plans ...... 11 2.3.6 The Environmental Planning and Assessment Amendment Act ...... 11 2.3.7 The Greater Sydney Commission ...... 12 2.3.8 Greater Sydney Region Plan: A Metropolis of Three Cities ...... 12 2.3.9 Western City District Plan ...... 15 2.3.10 Greener Places and the urban tree canopy guidelines ...... 16 2.3.11 City Deals ...... 17
2.4 Projected impacts of climate change ...... 17
2.5 Streets ...... 19
2.6 Benefits of the urban forest ...... 20
2.7 Street tree master plans ...... 22
2.8 The definition of a tree-lined street ...... 22
2.9 Infrastructure ...... 25 2.9.1 Introduction ...... 25 2.9.2 Utilities, underground space and the NSW Streets Opening Coordination Council ……………………………………………………………………………………………………………………………………….25 2.9.3 Spatial requirements of trees ...... 29 2.9.4 Conflicts between trees and other infrastructure ...... 30
Christina Silk 3 Methodology ...... 35 3.1 Introduction ...... 35
3.2 Theoretical background ...... 35
3.3 Research strategies ...... 37
3.4 Research design ...... 38
3.5 Case study methodology ...... 43
3.6 Mapping methodology ...... 45
3.7 Camden LGA – a brief history ...... 46 3.7.1 Introduction ...... 46 3.7.2 History ...... 47 3.7.3 Geology and soils ...... 48 3.7.4 Vegetation communities ...... 50 3.7.5 Climate ...... 50 3.7.6 Heat Island ...... 50 3.7.7 Population statistics ...... 51 3.7.8 Camden organisational structure ...... 52
4 Findings ...... 53 4.1 Introduction ...... 53
4.2 Planning controls ...... 53 4.2.1 Application of SEPP, the Camden LEP and Development Control Plans ...... 53 4.2.2 Camden Development Control Plan 2019 ...... 55 4.2.3 Oran Park Precinct Development Control Plan 2007 and Turner Road Precinct Development Control Plan 2018 ...... 57 4.2.4 Growth Centre Precincts Development Control Plan 2016 ...... 58
4.3 Interviews ...... 58
4.4 Case study mapping ...... 60 4.4.1 Background to the cases ...... 61 4.4.2 Case Study Measurements...... 62
4.5 Focus group process ...... 65 4.5.1 Definition of a tree-lined street ...... 72 4.5.2 Barriers ...... 72 4.5.3 Alternatives ...... 73 4.5.4 Research themes ...... 73
4.6 Factors affecting the potential for tree-lined streets ...... 74 4.6.1 Government support for trees ...... 74
Christina Silk 4.6.2 Planning controls and processes ...... 74 4.6.3 Austroads Guide ...... 74 4.6.4 Engineering specifications ...... 76 4.6.5 Staged construction ...... 77 4.6.6 Waste collection requirements ...... 80 4.6.7 Camden Council specifications for access driveways ...... 80 4.6.8 Lot Sizes ...... 84 4.6.9 Community perceptions ...... 88 4.6.10 Pace of development ...... 89
5 Discussion ...... 91 5.1 A Discussion of the Findings...... 92
5.2 Action One: create a new SEPP for urban trees ...... 94
5.3 Action Two: amend the Development Control Plans ...... 96
5.4 Action Three: mandate driveway locations and widths ...... 100
5.5 Action Four: create a Camden-wide street tree master plan ...... 102
6 Conclusion ...... 105 6.1 Research outcomes ...... 105
6.2 Further research ...... 108
6.3 Final thoughts ...... 108
7 References ...... 111
8 Appendices ...... 121
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Figures
Figure 2.1: New South Wales planning policy structure ...... 9 Figure 2.2: The strategy-led planning and feedback loop ...... 12 Figure 2.3: The districts of Greater Sydney showing Camden Local Government Area ...... 13 Figure 2.4: Climate of the three cities in the Sydney Region ...... 14 Figure 2.5: Aerial view of Oran Park ...... 18 Figure 2.6: General and specific contributions of trees to urbanised sites ...... 21 Figure 2.7: Wellington Street, Woollahra (Platanus species planted in a narrow verge) ...... 24 Figure 2.8: Hazelbank Road, Wollstonecraft, (Platanus and Lophostemon species planted in the parking lane) ...... 24 Figure 2.9: The electricity network in New South Wales ...... 25 Figure 2.10: NSW Streets Opening Coordination Council space allocation for verges, 1969 (left) and 2018 (right) ...... 28 Figure 2.11: Typical root system of a tree in unrestricted soil ...... 30 Figure 2.12: Pipe failure due to wind throw ...... 31 Figure 2.13: Forces exerted on pipes beneath trees ...... 32 Figure 3.1: Map of soil types in Camden Local Government Area ...... 49 Figure 3.2: Heat Vulnerability Index for Camden Local Government Area ...... 51 Figure 4.1: Camden Council land where Camden Development Control Plan applies ...... 54 Figure 4.2: Land to which Schedules in the Camden Development Control Plan apply ...... 54 Figure 4.3: Minimum lot sizes in Oran Park Precinct and Turner Road Precinct ...... 58 Figure 4.4: Coding word cloud for the interview transcripts ...... 59 Figure 4.5: Aerial map of Camden local government area showing location Oran Park and Harrington Park ...... 61 Figure 4.6: Aerial views of the case study areas: (a) Oran Park and (b) Harrington Park ...... 62 Figure 4.7: Houses representing the median lot size in (a) Oran Park and (b) Harrington Park 64 Figure 4.8: Oran Park area showing existing trees with projected maximum canopy ...... 67 Figure 4.9: Oran Park area showing 8m trees in regular rows ...... 68 Figure 4.10: Oran Park area showing 12m trees in regular rows ...... 68 Figure 4.11: Tree templates issued to small groups within the focus group ...... 70 Figure 4.12: Focus group ideal street for Group 1 ...... 70 Figure 4.13: Focus group ideal street for Group 2 ...... 71 Figure 4.14: Focus group ideal street for Group 3 ...... 71 Figure 4.15: Focus group ideal street for Group 4 ...... 72 Figure 4.16: Cilento Street, Spring Farm ...... 82 Figure 4.17: Car Parking on the Verge ...... 83 Figure 4.18: 8m tree on the prolongation of the boundary - random driveways ...... 85 Figure 4.19: 8m tree on the prolongation of the boundary - 4m driveways in consistent position ...... 85 Figure 4.20: Tree size comparison on a 9m lot frontage a) 16m trees, b) 8m trees, c) 5m trees ...... 87 Figure 4.21: Minimum lot frontage to accommodate trees, driveways and waste ...... 88 Figure 5.1: McLucas Circuit, Elderslie ...... 97 Figure 5.2: Typical street section comparison ...... 99 Figure 6.1: Royal George Drive, Harrington Park ...... 109
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Tables
Table 2.1 Landcom street tree spacing recommendations ...... 23 Table 3.1: Classification of theories ...... 36 Table 3.2: Classification of research strategies ...... 37 Table 3.3: Case study characteristics ...... 39 Table 3.4: Research methodology matrix ...... 41 Table 3.5: Western Parkland City LGA area size and SEPP growth centres, 2016 ...... 43 Table 3.6: Population projections for Western Parkland City LGAs ...... 43 Table 3.7: Criteria for selection of the local government area for the case study ...... 44 Table 3.8: Application of the selection criteria to Western Parkland City local government areas ...... 44 Table 3.9: Map layers ...... 46 Table 3.10: Properties of Soils found in in Camden LGA ...... 49 Table 4.1: Statistical dimensions of the case study areas ...... 63 Table 4.2: Dimensions of frontages and driveways in the case study areas ...... 64 Table 4.3: Projected maximum street tree canopy in the case study areas ...... 65 Table 4.4: Local street controls comparison ...... 79 Table 4.5: Driveway widths across public land ...... 80
List of Abbreviations Used in This Thesis AWHC Available Water Holding Capacity DCP Development Control Plan EP+A Act Environmental Planning and Assessment Act GSC Greater Sydney Commission LEP Local Environmental Plan LGA Local Government Area LSPS Local Strategic Planning Statement SEPP State Environmental Planning Policy
List of NSW Legislation and Planning Instruments Camden Local Environmental Plan 2010 Environmental Planning and Assessment Act 1979 Environmental Planning and Assessment Amendment Act 2017 Greater Sydney Commission Act 2015 Roads Act 1993 State Environmental Planning Policy No.19 – Bushland in Urban Areas State Environmental Planning Policy No 44 – Koala Habitat Protection State Environmental Planning Policy No 47 – Moore Park Showground
Christina Silk State Environmental Planning Policy (Coastal Management) 2018 State Environmental Planning Policy (Exempt and Complying Development Codes) 2008 State Environmental Planning Policy (Gosford City Centre) 2018 State Environmental Planning Policy (Housing for Seniors or People with a Disability) 2004 State Environmental Planning Policy (Sydney Region Growth Centres) 2006 State Environmental Planning Policy (Vegetation in Non-Rural Areas) 2017 Threatened Species Conservation Act 1995
Terminology for Government Departments.
During the course of writing, the NSW Government restructured a number of departments. The Department of Planning became the Department of Planning and Environment and later the Department of Planning, Industry and Environment. All three terms are used in the thesis to refer to the peak body for planning in NSW.
Christina Silk
1 Introduction In 1943, the year after three Japanese mini-submarines attacked Sydney Harbour, a series of aerial photographs were taken of Sydney to assist air raid planning. In high resolution, these photos are a fascinating record of Sydney at a time when New South Wales had a population of approximately 1.4 million people (1947 Census Data “exclusive of full-blood Aboriginals”), much of Greater Sydney was not connected to the sewerage system, and sealed roads and kerbs and gutters were uncommon.
These photos are freely available as a map layer from NSW Government’s Land and Property Information (www.six.nsw.gov.au) and it is easy to click between the 1943 and 2006 aerial photos to see the development of Sydney. The resolution of both sets of photos means that it is possible to zoom to a scale of 1:1000 and view the detail of the streets. By selecting a couple of familiar locations, it appears that Sydney’s urban forest is now more verdant, more extensive and more mature than it was in 1943. It is easy to infer that the urban forest is in good shape.
If this were true, it is great news – recent literature around urban trees highlights their importance to the wellbeing of people, the economy and the ecosystem (Moore (2009). Although governments are unable to agree on strategies for reducing the impacts of climate change, trees are quietly delaying the effects of climate change by sequestering carbon (Davies et al. (2011); they can assist in slowing flood waters (Moore 2011); their root systems stabilise embankments and steep topography (Rees & Ali 2011); their leaves have been found to remove airborne particulates (Tallis et al. 2011; Vailshery, Jaganmohan & Nagendra 2013); and they assist in the treatment of urban stormwater (Coutts et al. 2013). A number of studies (Grahn & Stigsdotter 2003; Williams, O'Brien & Stewart 2013) have identified a link between urban forests and mental and physical health, and one study found that in post-operative patients, those who had a view of a tree “had shorter postoperative hospital stays, had fewer negative evaluative comments from nurses, took fewer moderate and strong analgesic doses, and had slightly lower scores for minor postsurgical complications” (Ulrich 1984, p 225). In addition, heat stress is a significant contributor to premature mortality in urban areas and trees assist in reducing temperatures by shading buildings and hard surfaces (Gago et al. 2013; Mackey, Lee & Smith 2012; Millward et al. 2014).
At a strategic level, government policies in New South Wales recognise the importance of the urban forest, as evidenced in the plans of the Greater Sydney Commission (GSC) for the Sydney Region (Greater Sydney Commission 2018a) and the Western Sydney District (Greater Sydney
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Commission 2018b) as well as in the Draft Urban Tree Canopy Guide prepared by the Government Architect New South Wales (2018). However, accommodating Sydney’s projected population puts the urban forest under pressure. In western Sydney the dominant housing typology is detached single-family homes and the construction of thousands of such homes results in dense residential subdivisions where house footprints and paved landscape occupy up to 70% of the land (Camden Council 2019a, p 159). The remainder that is shared between driveways, paved areas and soft landscape does not accommodate large trees.
The GSC prioritises increasing urban canopy with a target of 40% canopy cover in suburban development. In new residential subdivisions, achieving the urban canopy targets will require maximising the use of public land, including the streets, and the process of implementing tree- lined streets in new subdivisions will require changes to procedures and controls. The solution requires a collaborative approach – strategic planners and policy makers need to ensure that controls are in place that mandate the installation of trees so that they can provide the desired ecosystem services; and engineers and services decision-makers need to work with arborists and landscape professionals to resolve the spatial and functional conflicts between trees and other infrastructure.
This research examines this cross-disciplinary complexity through the lens of the GSC and the application of its priorities and strategies in the development of the Camden Local Government Area (LGA). The research aims to:
- identify the barriers to street tree planting; and - outline policy and procedural amendments that address those barriers.
The research also aims to demonstrate that cross-disciplinary collaborations that solve complex problems are possible. Landscape architects are well placed to facilitate these cross- disciplinary collaborations. Their training equips them to liaise with different disciplines and professions to gather specific requirements for a project and to generate design responses to address them. In regard to streets, landscape architects are conversant in the hydraulic, civil and structural requirements; transport and movement hierarchies; social and cultural perceptions; ecology; arboriculture; and soils. Landscape architects also work at all spatial scales. They contribute to strategies and policies for whole regions, create masterplans for suburbs and town centres, design at a site-specific scale and have a working knowledge of materials and details for individual elements. One council landscape architect mentioned that one of the most gratifying aspects of his job is that on one day he may be involved in the implementation of state-wide policies at the local level, and the next he could be supervising
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the installation of a single seat in a public space (Tim Vyse, personal communication, 25 September 2019). Landscape architects frequently find themselves at the intersection of other professions, being the advocates for the environment and having carriage of a scope that spans spatial, temporal and professional boundaries.
1.1 Background In March 2018, the GSC published the Greater Sydney Region Plan: A Metropolis of Three Cities, outlining the NSW Government’s vision for the Sydney Region (Greater Sydney Commission 2018b). This strategic document proposes a spatial framework of three cities: the Eastern Harbour City, the Central River City and the Western Parkland City, with planning priorities and aspirations pertinent to each. This research concerns the Western Parkland City and in particular the planning priority to provide “increased tree canopy cover [that] will provide shade and shelter for walkable neighbourhoods” (Greater Sydney Commission 2018a, p 16).
This research focuses on the conflicts between conventional human-made (grey) infrastructure and street trees, and the implementation of the vision for tree-lined streets where there is limited space in the street verge. The research takes as a starting point the strategic goals and policy aspirations for increasing the urban canopy and reviews the process proposed for implementing these aspirations – from policy and controls to procedures – to tease out the likelihood of achieving canopy targets in Western Sydney.
The value of trees is recognised at the strategic level in policy and there is support for the implementation of policy. However, to realise the urban canopy metrics defined in the GSC’s Greater Sydney Region Plan and the Government Architect’s Draft Urban Tree Canopy Guide (Government Architect New South Wales 2018), changes need to be made to planning instruments, controls and procedures.
This research is underpinned by the premise that current design practices for streets always prioritise non-living infrastructure over living infrastructure. Non-living infrastructure includes underground utilities (water, gas, sewerage, communications and electricity) and above- ground elements such as kerbs, footpaths, driveways and electricity infrastructure. These components of the street are consistently considered essential, whereas a review of new subdivisions suggests that trees are considered desirable but not essential. In the road reserve, trees get the space left over once the “essential” infrastructure has been placed. To achieve the urban canopy targets, the approach to subdivision and street design needs to change, to ensure that all infrastructure can be accommodated – including street trees.
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The growth patterns of trees can be unpredictable, and their underground spatial requirements are difficult to quantify. Guidelines such as Landcom’s Street Tree Design Guidelines (Landcom 2008) are helpful but, not being statutory instruments, cannot be legally enforced. This research suggests that the vision of tree-lined streets in the Western Parkland City will not be realised unless there is a rethinking about the allocation of space in road reserves so that infrastructure conflicts can be resolved and more space for trees can be provided.
Increased heat as a result of climate change and land-use transformation is a compelling reason to grow trees but heat also acts as a barrier to growing mature street trees. The shade created by trees mitigates heat but the heat itself, coupled with unpredictable rainfall, means that establishing street trees is difficult. Optimising conditions for trees in the street is essential to maximising the benefits that trees offer.
In this respect, the research seeks to answer two questions. First, what are the barriers to achieving the GSC’s vision for tree-lined streets in the Western Parkland City? Second, what changes need to be made to address these barriers?
1.2 Methodology The qualitative research methodology commences with a literature review spanning the policy documents of the different authorities (the GSC, local councils, the NSW Government) to understand the policy framework, aspirations and requirements for new streets. An analysis of existing legislation, codes and best practice approaches identifies barriers to street tree- planting.
A focused study of Camden LGA involved mapping two areas that demonstrated the results of different approaches to designing and implementing the streetscape in local roads of the same overall width. A series of in-depth interviews with council staff were undertaken to identify the barriers to street tree planting. This stage of the research culminated in a cross- disciplinary workshop that enabled participants to understand the barriers specific to each discipline and revealed opportunities to address these barriers.
1.3 Outcomes This research found that the policies that apply to development in Western Sydney do support the implementation of tree-lined streets. It found that council officers responsible for the planning, certification and maintenance of streets also support the vision for the Western Parkland City but that they indicated frustration with the urban design outcomes being
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realised across the LGA. The findings suggest that the controls and procedures that apply in the Camden LGA do not compel the implementation of tree-lined streets and often discourage them by providing reasons not to plant. The concern that tree roots may impact on infrastructure has been addressed in the procedures by requiring removal of trees from the street rather than understanding the needs of trees and designing to accommodate these needs.
The future role of trees in the urban landscape is being redefined not by horticulturists, but by others who have little interest or expertise in urban planning and vegetation management, but are driven by other imperatives. (Moore 2000, p 9)
The GSC outlines the imperatives for development to accommodate population growth and employment opportunities. The importance of trees in suburban developments is accepted, but the research found that there are numerous procedures that impact on the street verge. Perhaps the most unexpected finding in the research is that conflicts between underground utilities and trees are not the main reason that trees are not planted. One of the most significant reasons is the perceived right to locate a driveway anywhere in the reserve that a resident chooses. Driveways and the space required for waste collection mean that consistency in the verge is difficult if not impossible to achieve.
This research is an exploration of the barriers to implementing tree-lined streets. It uses Western Sydney and in particular Camden LGA as a case study to reveal the challenges and barriers to installing and growing street trees. With the cooperation of Camden Council, it makes recommendations to assist in achieving-tree lined streets and increasing urban canopy. These recommendations are underpinned by the NSW Government’s planning priorities for Western Sydney but could be adopted by state and local governments in other jurisdictions. The outcomes of the research contribute to the development of knowledge about the culture and practice of the planning process and the impacts, both deliberate and unintended, on street trees. The recommended policy and procedural changes could enable better street outcomes and reduce ambiguity for developers, planners, designers and certifiers.
1.4 Structure of the thesis Chapter 2 is a literature review that explores the planning process in New South Wales and the instruments and controls that affect street trees. It then discusses the value of urban trees and examines the spatial conflicts in streets due to contrasting requirements of trees and other forms of infrastructure.
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Chapter 3, Methodology, provides a theoretical foundation for the research and describes the strategies, methods and techniques used.
The research studies two areas in the Camden LGA to illustrate the different temporal and spatial approaches to street design, and this chapter introduces Camden by briefly looking at its history, natural landscape, urban heat and population trends. The significance of urban heat in Camden also provides context for the importance of trees.
The findings presented in Chapter 4 include the results of the review of planning instruments and controls; the maps of the two case studies (Harrington Park and Oran Park); and the themes identified through the interviews and focus group.
The discussion in Chapter 5 synthesises the findings of the literature review and the results of the consultation process and mapping exercises. Four recommendations that may improve the urban canopy of streets in Camden are made, including the creation of a new policy and amending existing controls and procedures.
Chapter 6 concludes the thesis by summarising the outcomes of the research and identifying opportunities for future research.
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2 Literature review
2.1 Introduction The literature review sets out the context for the research by reviewing factors that influence the implementation of street trees, including planning instruments; the benefits of urban vegetation and trees; and the conflict between trees and utilities. It includes a tree-focused reading of the planning instruments, controls, guidelines and specifications that affect street trees. To establish the importance of street trees it also looks at the climate of Western Sydney and urban heat. It then provides a brief background to the physical and cultural history of the Camden Local Government Area (LGA) being studied in this research.
2.2 Background of the discipline of landscape architecture and theoretical foundation of the research Landscape architecture is a relatively young discipline in Australia – the first postgraduate diploma of Landscape Design was offered in 1966 (The University of New South Wales 1966, p 43), the Australian Institute of Landscape Architects (AILA) was inaugurated in 1967 (Australian Institute of Landscape Architects 2018) and a bachelor degree offered in 1974 (The University of New South Wales 1974, p 61). All professions develop a body of knowledge “to provide a foundation for current practice, and a theoretical platform from which to reach for new knowledge needed for the future” (Swaffield & Deming 2011, p 35). This is true of landscape architecture, but Brown and Corry suggest that “much of contemporary practice in landscape architecture is still based on beliefs rather than facts” and that both “the profession and the discipline of landscape architecture have a culture of non-reporting” (2011, p 327). Landscape journals publish descriptions, illustrations, reviews and design critiques of recently completed projects, but the publication of long-term reflections on a project or in-depth analysis that would assist in the development of the body of knowledge is unusual.
Van den Brink & Bruns 2014, p 8 cite a number of sources that suggest that landscape architecture is not recognised as a research discipline but that this is changing as more academics and practitioners recognise the value of landscape research in the creation of the knowledge base. An effective body of knowledge must be in continual development and must also be accessible to practitioners. In the five years since van den Brink and Bruns published, the body of knowledge in Australia has developed and become more accessible through AILA’s publication of an online resource centre – the “Tree of Knowledge” (available in the member’s page at www.aila.org.au) that provides members with access to e-books, films, reports and publications on a range of topics.
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2.3 The planning context
2.3.1 The Environmental Planning and Assessment Act
The primary legislation governing planning in New South Wales is the Environmental Planning and Assessment Act 1979 (EP+A Act), which sets out the objects for planning and development and a framework for delivery. Objects of the Act are set out in s 1.3; and those that are particularly relevant to tree-lined streets and the urban environment are:
(a) to promote the social and economic welfare of the community and a better environment by the proper management, development and conservation of the State’s natural and other resources, (b) to facilitate ecologically sustainable development by integrating relevant economic, environmental and social considerations in decision-making about environmental planning and assessment, … (g) to promote good design and amenity of the built environment, ... (i) to promote the sharing of the responsibility for environmental planning and assessment between the different levels of government in the State,
… .
(NSW Government 2018, Cl 1.3)
The EP+A Act describes instruments to deliver these objects at all scale units from instruments that apply to the entire state (State Environmental Planning Policies) to those that affect only a small portion of a Local Government Area (LGA) (such as Development Control Plans for a specific land release area). Figure 2.1 shows the relationship between these planning instruments. The locations, sizes and likelihood of success of street trees are affected by these planning instruments; although the instruments seem to agree in principle that street trees are an important part of the urban fabric, they are sometimes in conflict when it comes to implementation. This is particularly evident when they refer to informative guidelines of other agencies (such as Roads and Maritime Services and the NSW Streets Opening Coordination Council). The findings described in Chapter 4 demonstrate the impact on the individual street of planning instruments, but to provide context for the case study, the instruments that apply are summarised below.
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Figure 2.1: New South Wales planning policy structure Source: author
2.3.2 State Environmental Planning Policies
State Environmental Planning Policies (SEPPs) are statutory instruments at the state-wide level. The purpose of a SEPP is to consider matters of “State or regional environmental planning significance or of environmental planning significance to a district” (EP+A Act 1979 (NSW) Div. 3.3, cl 3.29(2). Generally, they either outline a policy direction for the entire state or allow the Minister for Planning closer oversight of planning in a particular area. Examples of SEPPs that consider an issue that affects the entire state include Housing for Seniors or People with a Disability; Coastal Management; and Koala Habitat Protection. Examples that consider a single geographical area with state significance include Gosford City Centre; No 47: Moore Park Showground; and Sydney Region Growth Centres.
Of particular relevance to Camden is State Environmental Planning Policy (Sydney Region Growth Centres) 2006 (SEPP SRGC), which coordinates the release of land for urban development (cl 2(a)) to accommodate a a significant portion of Sydney’s predicted population increase through the provision of housing, employment and allied commercial and human services. SEPP SRGC describes three different areas – the North West Growth Centre, the South West Growth Centre and the Wilton Growth Area (cl 2(a)) and within the South West Growth Area includes tracts of land in the north of the Camden LGA (including the town centre of Oran Park) (SEPP SRGC cl 2 and App 9). This is important as SEPP SRGC removes planning
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control from the local government and delegates it to the NSW Government’s Department of Planning, Industry and Environment. Although Camden Council is a stakeholder, it does not control the development of this part of the Camden LGA. It means that controls that apply here may be different to those that apply in the remainder of the LGA.
The other significant SEPP for street trees is State Environmental Planning Policy (Exempt and Complying Development Codes) 2008 (SEPP ECDC). SEPP ECDC applies to private land and defines certain types of development as either so minor that it is exempt from planning approval (exempt development) or for which development consent is implied by compliance with relevant codes and the National Construction Code (complying development). Classification as complying development is a fast-tracked assessment process for dwellings where assessment and certification is completed by a private certifier or the local council. The impact on the urban canopy and trees arises through the combination of housing and lot size and will be discussed in Chapter 41.
2.3.3 Regional and district plans
The next scale of planning instruments applies at the regional level. The state is broken into regions that are declared by the Minister for Planning (with the exception of the Greater Sydney Region (GSR). Regional plans are visionary – they describe strategies to achieve planning goals that align with the economic, social and environmental needs of a region and they must give effect to any state policies that apply to the region. Camden is part of the GSR and the vision for the region is outlined in the Greater Sydney Region Plan: A Metropolis of Three Cities (Greater Sydney Commission 2018a).
A district is a part of a region and is declared by either the Minister for Planning or the regional planning committee. District plans are more specific and place-based than regional plans. Camden is within the Western Sydney District and the planning vision for the district is described by the Western City District Plan (Greater Sydney Commission 2018b).
2.3.4 Local Environmental Plans
A Local Environmental Plan (LEP) is an environmental planning instrument that is specific to an LGA. LEPs have numerous purposes, including to control development, to reserve land for public use and to preserve vegetation and trees (EPA+A Act s 3.14). LEPs also determine minimum lot sizes for new subdivisions. One of the objectives of the minimum lot size is “to ensure that the density of development is consistent with the existing and proposed future road and utility infrastructure in the locality” (Camden Local Environment Plan 2010
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cl 4.1(1)(e)). The Camden Local Environment Plan 2010 is currently in force (although in review at the time of writing). Like SEPPs, LEPs are statutory and therefore prescriptive; however, they are also visionary and do not specify the practicalities of how the vision is to be delivered.
2.3.5 Development Control Plans
Controls that provide for the implementation of the policy vision are found in Development Control Plans (DCPs). These are informative documents that guide the implementation of the planning instruments in development. Only one DCP can apply to a piece of land; in Camden, the South West Growth Centre is guided by the Growth Centre Precincts: Development Control Plan (NSW Department of Planning and Environment 2017), the Turner Road Precinct: Development Control Plan (NSW Department of Planning and Environment 2018) and the Oran Park Precinct: Development Control Plan (NSW Department of Planning and Environment 2016b). The rest of Camden is controlled by the Camden Development Control Plan 2019 (Camden Council 2019a). It is worth noting that only the Camden DCP is managed and regulated by Camden Council. The other DCPS are regulated by the NSW Government and although Council is consulted, the approval process to adopt theses DCPs lies with the NSW Department of Planning, Industry and Environment and the Minister for Planning.
2.3.6 The Environmental Planning and Assessment Amendment Act
The EP+A Act has been amended and revised a number of times during its history, but in 2017 was overhauled by the Environmental Planning and Assessment Amendment Act 2017 (NSW). This overhaul restructured the planning process in New South Wales and increased the potential for public participation through the requirement for LGAs to make Community Participation Plans (CPPs) and Local Strategic Planning Statements (LSPSs). These instruments provide for a local focus to planning and the EP+A Amendment Act describes a process that enables local feedback to the strategic level, allowing for iterative improvement to planning controls that apply to each LGA (Figure 2.2). Following the adoption of the LSPS by Camden Council, the Camden LEP will be amended to reflect the LSPS. The deadline to exhibit the draft LSPS for comment by the community was 1 July 2019. On the 10th December 2019 Council endorsed the draft LSPS for Phase 3 assurance from the GSC – the final GSC approval that initiates the LEP amendment process.
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Figure 2.2: The strategy-led planning and feedback loop Source: (NSW Government, p 5)
2.3.7 The Greater Sydney Commission
The GSC is a government agency established by the NSW Government through the Greater Sydney Commission Act 2015 (NSW) (GSC Act) to encourage development and to promote orderly development in Sydney (GSC Act s 9(b)). The EP+A Act provides the GSC with a mandate to prepare the Regional Plan for Sydney and the District Plans that make up the Sydney Region.
2.3.8 Greater Sydney Region Plan: A Metropolis of Three Cities
In the Greater Sydney Region Plan: A Metropolis of Three Cities (Greater Sydney Commission 2018a) (Greater Sydney Region Plan), the GSC set out a vision for the Sydney Region that is based on the character of the city and the experience of living within it. The Region Plan is human-centred, describing values and the character of the city on account of those values: Sydney is a region which is “inclusive” and where “freedom of expression and creativity will be supported” (Greater Sydney Commission 2018a, p 6). In the vision outlined in the plan, the GSC states that:
Green infrastructure such as urban tree canopy, green ground cover, bushland, waterways, parks and open spaces will be valued for its economic, social and environmental benefits and will help to establish the Greater Sydney Green Grid, a network of walking and cycling links that will become increasingly important in daily travel arrangements improving sustainability and the wellbeing of residents. (Greater Sydney Commission 2018a, p 6)
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This aspirational statement places landscape at the heart of the GSC’s vision for Sydney – a sustainable city with a healthy population (both physically and psychologically) who benefit socially, environmentally and economically from the quality of their local area. It is noteworthy that the GSC has elevated urban tree canopy to the top of the list, suggesting that it recognises the importance of the trees in the city, and it can be inferred that the GSC recognises that trees are the single biggest provider of ecosystem services (defined as "the benefits humankind derives from the workings of the natural world. " (Harrison & Hester 2010, p 1).
The Greater Sydney Region Plan outlines an argument for dividing the region into three cities (across five districts) based on history, geography and demographics, and names them Central River City, Eastern Harbour City and Western Parkland City (see Figure 2.3). District plans for each of these cities, as well as the northern and southern districts, have been adopted by the Department of Planning Industry and Environment.
Figure 2.3: The districts of Greater Sydney showing Camden Local Government Area Source: Adapted from (Greater Sydney Commission 2018b).
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Although the vision of urban canopy as a valued part of the region pertains to all three cities, the drier, hotter climate (see Section 2.10.5 below) combined with the relatively small percentage of urban tree canopy of the Western City suggest that resolving the urban canopy challenge is of critical importance to liveability in Western Sydney.
Figure 2.4: Climate of the three cities in the Sydney Region Yellow represents the Western Parkland City, red the Central River City and blue the Eastern Harbour City. Source: (Greater Sydney Commission 2018a, p 9).
The Greater Sydney Region Plan has 10 “directions” in four interlinked areas (Greater Sydney Commission 2018b, pp. 22–23):
A city supported by infrastructure
1. A collaborative city 2. A city for people 3. Housing the city 4. A city of great places 5. A well-connected city 6. Jobs and skills in the city 7. A city in its landscape 8. An efficient city 9. A resilient city.
The potential indicators under each of these directions are quantifiable and supported by objectives to enable the indicator to be achieved. Under the direction A city in its landscape, the potential indicators are “Increased urban tree canopy; Expanded Greater Sydney Green Grid” and the objectives, which pertain to the entire region, include “Objective 30: Urban tree canopy cover is increased” (Greater Sydney Commission 2018a, p 23).
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Urban tree canopy is defined as being made up of “trees along streets, in parks and other public spaces, and on privately owned land including front and backyards” (Greater Sydney Commission 2018a, p 164). Although this research is concerned with the urban tree canopy of the streets, it is worth noting that the front and back yards of Sydney are intended to support trees. The importance of this is apparent when new subdivisions are mapped in Chapter 4: Findings.
Local government is required to ‘give effect’ to the regional and district plans for Sydney. This means that the planning and feedback loop shown in Figure 2.2 requires that the provisions of the plans are considered in the Local Strategic Planning Statement that then informs all other local controls. This is significant as it requires councils to increase the urban tree canopy. However, the Greater Sydney Region Plan does not include a metric for the canopy increase, and for implementation refers to the district plans.
2.3.9 Western City District Plan
The 20-year vision for the Western City District, also called the Western Parkland City, is outlined in the GSC’s Western City District Plan (Greater Sydney Commission 2018b). The planning priorities in this plan are the same as in the Greater Sydney Region Plan, but the broad objectives for the region are developed into Planning Priorities. Planning Priority W15: “Increasing urban canopy and green grid connections” is supported by Objective 30: “Urban tree cover is increased” and Objective 31: “The Green Grid links parks, open spaces, bushland and walking and cycling trails” (Greater Sydney Commission 2018b, p 119).
The plan recognises the challenges to increasing urban tree cover and states:
Challenges to extending the urban tree canopy in public and private areas include the lack of sufficient space within existing street corridors, and the competition with other forms of infrastructure, both above and below the ground. (Greater Sydney Commission 2018b, p 119)
However, where the Green Grid actions specify priority corridor projects such as the creation of an open space corridor on South Creek, and open space connections between Camden Park and Menangle to Georges River, the action (Action 70) for increasing urban tree cover is simply stated as "Expand urban tree canopy in the public realm" (Greater Sydney Commission 2018b, p 120) and delegates responsibility for this to local government.
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The Western City District Plan references the NSW Government’s target of 40% urban canopy cover and includes maps of the extent of woody vegetation cover that show the canopy cover in 2011, sourced from the NSW Office of Environment and Heritage.
2.3.10 Greener Places and the urban tree canopy guidelines
In 2017, the NSW Department of Planning and Environment released a suite of draft documents, Greener Places, prepared by the Government Architect New South Wales “to guide the planning, design and delivery of Green Infrastructure in urban areas across NSW” (Government Architect of NSW 2017, p 10). Greener Places is supported by three draft manuals:
- Open Space for Recreation; - Bushland and Waterways; and - Urban Tree Canopy.
The suite of draft documents were produced for consultation with the community and stakeholders so that the NSW Government could develop a green infrastructure policy. The documents were released for consultation in 2017. Although at the time of writing, the draft manuals have not been finalised, the Draft Urban Tree Canopy Guide (Draft UTCG) supports the Greater Sydney Commission’s target of 40% urban tree canopy target so is worth exploring in the context of tree-lined streets.
The Draft UTCG argues that urban canopy is important for social, economic and environmental reasons, including health and energy costs; community and social connectedness; and biodiversity and pollution mitigation (Government Architect New South Wales 2018, p 20). It articulates challenges to urban canopy including the integration of “green, blue and grey infrastructure” (Government Architect New South Wales 2018, p 25). A regional target of 40% canopy cover is suggested for the Greater Sydney Region composed of targets that pertain to residential and central business district (CBD) densities (Government Architect New South Wales 2018, p 9):
- CBD >15% - Medium – high density >25% - Suburban >40%
Although these targets sound ambitious, the draft UTCG shows areas of Sydney where these targets have been nearly or actually achieved (for suburban low density neighbourhoods this includes the relatively new suburb of Newington with 37% cover and the older suburb of
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Avalon with 56% cover) (Government Architect New South Wales 2018, p 34). A canopy target of 40% is also consistent with the City of Melbourne’s target (City of Melbourne 2014, p 7). In the mapping shown in Chapter 4, the 40% canopy target has been used as an indicator to measure the efficacy of the policies and procedures for street trees.
Despite the NSW Government’s aim to prepare an infrastructure policy by early 2018, at the time of writing in late 2019, there has been no update on the preparation of the policy and the draft UTCG is no longer available on the Government Architect’s website.
2.3.11 City Deals
The Commonwealth Department of Infrastructure, Transport, Cities and Regional Development has established a City Deals program to deliver the vision for productive and liveable cities (Department of Infrastructure, Transport, Cities and Regional Development 30.11.19). Under the Western Sydney City Deal, a planning partnership made up of the eight councils of the GSC’s Western District City and Blacktown City Council has been established to deliver a range of planning and liveability outcomes (Commonwealth of Australia, p 6) Relevant to street trees is a project to deliver Western Sydney street design guidelines and an associated engineering specification.
2.4 Projected impacts of climate change In the State of the Climate 2018 report, the Australian Bureau of Meteorology (BOM) and the CSIRO found that “Australia has warmed by just over 1°C since 1910”, resulting in an increase in the frequency and severity of extreme heat events and drought (Bureau of Meteorology and CSIRO, p 4). The BOM has also stated that for the 2018–2019 summer, “[t]he national average temperature [summer] is expected to be about 2.1 above average” and that “[i]n December
2018 Australia saw its highest mean, maximum and℃ minimum temperatures on record (monthly averages, compared to all other Decembers)” (Bureau of Meteorology 01.03.19). The BOM climate models suggest that southeast Australia is likely to be between 1.5–2°C hotter than pre-industrial revolution temperatures (Bureau of Meteorology and CSIRO, p 22).
According to the International Panel on Climate Change
It is virtually certain that there will be more frequent hot and fewer cold temperature extremes over most land areas on daily and seasonal timescales, as global mean surface temperature increases. It is very likely that heat waves will occur with a higher frequency and longer duration. (IPCC 2014, p 60)
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This is significant in itself, but western Sydney also experiences heat waves from increased surface temperatures due to the urban heat islands (UHIs) where temperatures in a built-up area are higher than those in surrounding areas (Gartland 2008, p 1). These UHIs are a contributor to heat-related health conditions. Dark-coloured hard surfaces that absorb heat are common in urban areas – streets, roads and freeways that occupy a significant proportion of the land area are typically constructed from asphaltic concrete with a black bitumen seal. In addition, aerial photographs of recent developments in the Camden LGA indicate that dark roofs are common (Figure 2.5). These heat-absorbing surfaces contribute to temperature variations that peak in the late afternoon (Soltani & Sharifi 2017, p 534) at a time after the ambient temperature could otherwise have peaked.
Figure 2.5: Aerial view of Oran Park Source: NearMap aerial (05.11.18) accessed 29.10.19
As a result of UHIs, “[t]he largest average temperature increases for new urban developments, will occur on summer afternoons and last late into the night" (Adams, M., Duc, H. and Trieu, T. 2015, p 23). Areas of southwest Sydney that are converted from grasslands to an urban land use “are projected to more than double the projected temperature increases projected from climate change” (NSW Government 2015).
Although dramatic natural events such as bushfires tend to grip the collective national imagination, heat stress and associated air pollution is likely to have a greater impact on Sydney’s population due to an increase in premature deaths. In 2007, there were an estimated 430 premature deaths in Sydney attributable to exposure to anthropogenic air
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pollution and 160 premature deaths attributable to exposure to anthropogenic ozone (Broome et al. 2015, p 5). In the Victorian heat wave in 2009, there was a 46% increase in emergency department presentations and a 34-fold increase in heat-related health conditions. Elders (aged 75 and over) were the demographic most affected, and across all age groups there were 374 excess deaths compared to 2008 (Hughes, Hanna & Fenwick 2016, p 13). In September 2019, the Australian Medical Association (AMA) issued a press release that stated:
The Federal Council recognises climate change as a health emergency, with clear scientific evidence indicating severe impacts for our patients and communities now and into the future (AMA formally Recognises Climate Change as a Health Emergency 03.09.19, p 1)
The AMA went on to comment that “[c]limate change will cause higher mortality and morbidity from heat stress” (AMA formally Recognises Climate Change as a Health Emergency 03.09.19, p 1) and in its position paper stated: “Projected increases in heatwaves will result in increased heat-related deaths and hospital admissions, particularly among the elderly and compounded by ageing and population growth.” (Australian Medical Association Limited 2015, p 6)
The AMA also suggested that heat will impact Australia’s economy and cite Zander et al. as finding that “[t]he impact of heat on work performance in 2013/2014 alone was estimated to cost the Australian economy US $6.2 billion, representing 0.33 to 0.46% of Australia’s GDP.” (Australian Medical Association Limited 2015, p 7).
2.5 Streets Streets have many functions but are principally conduits for transportation (public buses, taxis and trams; private cars, motorbikes and bicycles; and pedestrians); access to properties; and easements for infrastructure. In New South Wales, the Roads Act 1993 defines roads that are owned and managed assets of the NSW Government as “classified”; these roads are generally high volume, significant connectors such as highways, freeways and tollways (Roads Act 1993, Dictionary). Roads that are owned and managed assets of the local government are “unclassified” (Roads Act 1993, Dictionary); these tend to have low volumes of traffic and are the fine grain of the suburbs. While classified roads connect cities, regions and centres, unclassified roads are the network that make up the majority of the streets in the city. In a public domain hierarchy, it could be argued that parks are the high-profile destination points, but it is the streets where people spend most of their time moving between destinations and, if they are outside a vehicle, having spontaneous social interactions.
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This research considers the potential for tree planting in the road reserves of unclassified streets in new residential areas (local streets). Classified, state-owned roads that have high volumes of traffic, allow high speeds and carry heavy vehicles are subject to onerous design parameters, and these characteristics also make them less amenable for walking. As such, they are outside the scope of this research.
Before reviewing tree planting in streets, it is worth summarising the literature that describes the benefits of urban trees.
2.6 Benefits of the urban forest Urban forest benefits have been extensively researched, (Coutts et al. (2013), Hewett (2002) Moore (2009)) and are part of the literature of conference proceedings. They can be loosely divided into climatic benefits, ecosystem benefits and social benefits. Climatic benefits include moderation of surface temperature (Millward et al. (2014)), which results in reduced energy use (and consequent carbon emissions) (Nowak et al. (2017)); carbon sequestration (Chen (2015), Davies et al. (2011), Nowak et al. (2013)); and filtration of air pollutants (Nowak, Crane & Stevens (2006), Vailshery, Jaganmohan & Nagendra (2013), Selmi et al. (2016), Baines (1994, p 231). When used as part of water-sensitive urban design, urban trees assist with the reduction of stormwater volume and velocity and can reduce nutrient levels in stormwater (Denman, L, Breen, PF, May, PB et al. (2006)).
Liveability or social benefits are difficult to quantify but studies suggest that trees provide numerous such benefits. In a study of minor surgery postoperative patients, patients who had a room with a view out of a window to a tree “had shorter postoperative hospital stays, had fewer negative evaluative comments from nurses, took fewer moderate and strong analgesic doses, and had slightly lower scores for minor postsurgical complications” than those patients whose view was of a wall (Ulrich 1984, p 225).
A 2015 study on exposure of school children to urban vegetation found “exposure to outdoor surrounding greenness was associated with a beneficial impact on cognitive development in schoolchildren” (Dadvand et al. 2015, p 6). This included an increase in working memory and a decrease in inattentiveness (Dadvand et al. 2015, p 4). Another study found that “[p]ublicly owned street trees provide benefits to all those with exposure to them, especially elementary school children” and that inequity could be perceived across cities where more affluent areas enjoyed the benefits of street trees, whereas poorer neighbourhoods did not (Paddle & Gilliland 2018, p 162).
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The link between urban vegetation and reduced stress has been made (Grahn & Stigsdotter (2003)) as has a link between urban vegetation and a reduction in violent crime (Wolfe & Mennis (2012). There is also research to suggest that trees increase house prices (Anderson, L. M., and Cordell, H. K. (1988), Escobedo, Adams & Timilsina (2015).
Benefits summarised by Greg Moore in his address to the Inaugural Tree Symposium in 2000 are shown in Figure 2.6.
Figure 2.6: General and specific contributions of trees to urbanised sites Source: (Moore 2000, p 12).
With temperatures projected to rise in urban areas of western Sydney, urban heat mitigation is an extremely important ecosystem service that the urban forest can provide. Large canopied trees could shade the public domain of the footpaths and carriageway as well as hard surfaces in private property such as driveways, walls and roofs.
Street trees are an important part of the urban forest and in addition to the benefits outlined above, street trees can also assist with walkability. The GSC recognises walkability as an important part of the liveability of a city: “Great places are walkable – this means they are designed, built and managed to encourage people of all ages and abilities to walk or cycle for leisure, transport or exercise." (Greater Sydney Commission 2018b, p 27).
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2.7 Street tree master plans Many councils and cities in Australia have a street tree master plan (STMP) to guide the planning and maintenance of their street tree assets. The City of Sydney describes their STMP as “a blueprint for the provision of street trees across the City” (City of Sydney 2011, v). STMPs can be prescriptive, showing every street and every tree (City of Sydney 2011, Part C); (Mosman Council 2017, p 8); or they can be guidance documents that describe a process for the selection of tree species (Newcastle City Council, p 15). Some regional councils, such as Toowoomba Regional Council, prescribe tree species for the major roads that connect towns and centres, but do not include the smaller local streets (Toowoomba Regional Council 2011, p 19). Some councils, such as the City of Melbourne and Moreland City Council, have a tree or urban forest strategy and include the STMP as part of that document (City of Melbourne 2014; Moreland City Council 2017).
STMPs generally have a number of common attributes, including objectives, principles of street tree selection, lists of tree species, and typical details for planting and for tree guards. Some specify the canopy cover as a percentage of land area as a baseline measure to review the efficacy of planting strategies (City of Melbourne 2014; Sunshine Coast Council 2017). The STMPs often identify risks and challenges of planting trees in streets and some include the diagrams from the NSW Streets Opening Coordination Council that shows no spatial allocation for street trees in a typical 3.6m verge (NSW Streets Opening Coordination Council 2018; Coffs Harbour City Council 1999).
The STMPs very often read as an education or sales document describing the benefits of trees. Cost/benefit analyses are also sometimes included (Frankston City 2006, p 16). A number of the documents contain technical guidelines and street tree species data sheets with images of the tree species, requirements for its growth, and maximum size that the tree is expected to grow to in that particular LGA (City of Sydney 2011, Parts D & E).
Notably, most STMPs describe specific objectives such as reducing risk or planting appropriate species, but do not have an overall statement regarding the vision for the streets. The exceptions are Toowoomba (Toowoomba Regional Council 2011), Melbourne (City of Melbourne 2014) and the Sunshine Coast (Sunshine Coast Council 2017).
2.8 The definition of a tree-lined street Although the DCPs that control development in Camden indicate spacings for trees, the term ‘tree-lined street’ is not defined in the controls or in the policies. Mosman Council’s STMP aims to implement tree-lined streets (Mosman Council 2017, p 3), but does not define what
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that means. Many of the STMPs reviewed above describe the aim of planting trees on streets as being “consistent” or “regular” or include images of regularly spaced trees in leafy streets (City of Whittlesea 2016, p 28) (Marrickville Council 2014, iv)
Landcom’s Street Tree Design Guidelines do suggest a useful definition:
At minimum these trees would be spaced to give a consistent visual presentation, the optimum would be a size and spacing to achieve interlocking canopies both along and over the road reserve. (Landcom 2008, p 13)
The Landcom guidelines also define tree sizes and suggest spacings for different sizes to achieve interlocking canopies. Table 2.1 summarises these recommendations.
Table 2.1 Landcom street tree spacing recommendations Tree size Spacing between tree centres Small – 6–8m high with 5m crown spread 5–7m Medium – 10–12m high with 8m crown spread 7–10m Large – 16–20m high with 16m crown spread 10–15m Source: (Landcom 2008, p 13).
If a footpath is present, trees are typically planted midway between the kerb and the footpath. This locates them in the area reserved for water but away from the gas and electricity (see Figure 2.10). This offset is often matched on verges where no footpath is present. However, the Camden waste collection specification (refer to 4.6.6 below) requires a 3m-long area with no overhanging canopy to be kept clear for kerbside waste collection, which limits the size and location of trees in Camden (Camden Council 2019d, cl 4.2.1). Camden’s DCP also requires street trees to be planted more than 1m away from concrete structures (Camden Council 2019a, p 594).
Many streets in inner Sydney suburbs support large trees in relatively small verges. Examples are numerous and include Wellington Street (see Figure 2.7) and Rosemont Avenue in Woollahra, and Paddington Street in Paddington (Platanus and Ficus species). Other streets have utilised the parking lane by planting large trees that shade the verge and carriageway. Examples include Hazelbank Road, Wollstonecraft (see Figure 2.8) and Deakin Avenue, Haberfield. These older streets usually have overhead powerlines around which the canopies are cut in order to protect the electricity assets. In new subdivisions, where electricity cables are underground, it is the root system that constrains the optimum size of the tree.
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Figure 2.7: Wellington Street, Woollahra (Platanus species planted in a narrow verge) Source: author
Figure 2.8: Hazelbank Road, Wollstonecraft, (Platanus and Lophostemon species planted in the parking lane) Source: author
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2.9 Infrastructure
2.9.1 Introduction
As publicly owned assets, streets are excellent places to accommodate utilities that service the community. Road reserves act as easements servicing properties and reduce the need for easements over private property. The street usually always accommodates utilities such as power (electricity and gas), potable water, stormwater, telecommunications and streetlights. Sewer lines can also be present, but do not run along the road reserve. Footpaths and street trees are also usually present in streets.
2.9.2 Utilities, underground space and the NSW Streets Opening Coordination Council
The verge is the area between the kerb and the property boundary that accommodates numerous functions, including utilities reticulation, footpaths, cycleways, driveways, waste collection and street trees. The utilities reticulated through the streets are essential and need to be managed so that the risk of failure is minimised. Electrical assets are the most complex, probably the most important and definitely the most dangerous in the event of failure. Despite this, the electricity network in New South Wales (Figure 2.9) has been privatised (with bipartisan support) and various domestic superannuation and international pension funds and infrastructure companies now own the assets. Electricity in New South Wales is regulated by the Electricity Supply Act 1995 (NSW).
Figure 2.9: The electricity network in New South Wales Source: author generated from Energy Networks Association Limited (2008)
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Transgrid owns and operates the transmission network and there are three wholesale distributors that own and operate the distribution network (i.e. the above-ground poles and wires and underground assets): Ausgrid within eastern Sydney, Essential Energy in most of New South Wales outside Sydney, and Endeavour Energy in western Sydney, including the Camden LGA. Accredited service providers retail power to the consumer. High-voltage transmission lines are placed within easements, precluding any form of development or any trees that could impact on the lines. Street trees in local streets share space with the distribution network. New streets in Camden have underground assets owned by Endeavour Energy.
A Dial Before You Dig service exists in New South Wales to provide the location of utilities in streets. Gas in the Camden area is distributed by Jemena through a network of underground pipes. Plans for the two case study areas of Camden (Harrington Park and Oran Park) show the 32kPa nylon mains (32–110mm diameter) located in the street verge. Like electricity, gas mains are subject to separate easements with onerous requirements and generally are not present in local streets in residential subdivisions.
Sydney Water is responsible for both potable water and sewer assets throughout the greater Sydney region, the Illawarra and the Blue Mountains. Dial Before You Dig documentation indicates that potable water mains are 450mm in diameter and generally ductile iron or cast iron. The mains branch into smaller pipes (generally made of PVC) that service the lots and are located in the street verge. Sewer pipes run in the opposite direction to other utilities in that they remove waste from the lot rather than supply a service to the lot. Sewerage infrastructure is not reticulated along the verge but instead is within the private property of the house lots.
The other significant group of utilities in the street are communications assets. Until 1991, Australia had one government-owned telecommunications provider, Telecom, changing its name to Telstra in 1995. In older streets Telstra’s infrastructure is the only communications asset in the street. The deregulation of the Australian telecommunications industry and the privatisation of Telstra in 1997 allowed for the entry of numerous telecommunications companies to the Australian market. Many of these now reticulate assets through street verges and some streets in inner Sydney now accommodate more than one communications asset. The National Broadband Network (NBN), which is being rolled out across Australia, often shares a trench with Telstra.
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It is worth noting that gas is reticulated on both sides of the street, whereas electricity, communications and potable water are generally on one side only, with branches crossing the carriageway to service lots on the opposite side. Pipes are therefore designed to withstand weights and pressures experienced in a carriageway without failure.
Underground urban space has been recognised as a finite resource by authorities and researchers (Bobylev 2009; Canto-Perello & Curiel-Esparza 2013; Curiel-Esparza, Canto-Perello & Calvo 2004). In many places it is a contested zone where the “placement of utility services underground has not been generally accomplished in any systematic manner resulting in a veritable maze in high-density districts” (Curiel-Esparza, Canto-Perello & Calvo 2004, p 524). New South Wales is unusual and fortunate in having a cooperative body that coordinates the reticulation of utilities in streets. The NSW Streets Opening Coordination Council (SOCC) was established in 1909 and meets biennially to agree spatial allocations for utilities in the street. These are freely available in the SOCC’s Guide to Codes and Practices for Streets Opening (SOCC Guide), the principle non-binding but “authoritative” reference for the allocation for utilities in the street verge (NSW Streets Opening Coordination Council 2018, p 5).
Although the SOCC acknowledges the requirements for other functions, the organisation is principally concerned with the allocation of underground space. The SOCC Guide specifies minimum depth to the obvert of the utility, so surface features such as footpaths, driveways and cycleways that generally do not impact on utilities are not considered. Trees, however, require space both above and below ground and potentially impact utilities. The importance of underground utilities and the need to protect them is not in dispute, but there are some key points about the SOCC Guide that are worth noting, including the historic development of the code and the references to street trees.
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The SOCC (or its unincorporated predecessor) has been meeting biennially since 1909 to agree on space allocation for underground utilities. The SOCC Guide has been published multiple times, and editions as early as 1969 are available on the SOCC website (http://www.streetsopening.com.au/history/). Of interest in these historic guides is the allocation of space – despite the increase in the type and number of utilities and the technological advances in utilities design, the space allocation has not changed.
(a) 1969 (b) 2018
Figure 2.10: NSW Streets Opening Coordination Council space allocation for verges, 1969 (left) and 2018 (right) Source: (NSW Streets Opening Conference 1969, p 6) and (NSW Streets Opening Coordination Council 2018, p 19).
Section 5.7 (Street Trees) of the SOCC Guide states: “Trees and vegetation are a normal component of a streetscape. Utility infrastructure should be designed accordingly.” (NSW Streets Opening Coordination Council 2018, p 24). However, the section goes on to say that “[i]n pathways less than 3600mm wide, where utility services are placed within separate utility allocations, it is not possible to identify any specific allocation for trees” (NSW Streets Opening Coordination Council 2018, p 24). In terms of subdivisions, the SOCC Guide suggests that the “[p]referred width for the road verge is 4.0 metres” (NSW Streets Opening Coordination Council 2018, p 9) and it is worth noting that this is not the minimum allocation suggested for residential subdivisions in the DCPs regulated by the NSW Government and Camden Council, but is the recommended minimum width in the Camden Council Engineering Design Specification (Camden Council 2017, p. 28). Of interest in the SOCC Guide’s statement on the 3.6m verge, quotation above, is the term “separate utility allocations”. Compatible allocations (such as assets owned by various telecommunications providers) are already being shared and sharing allocations for other utilities such as telecommunications and electricity may decrease the impact of trees on utilities.
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2.9.3 Spatial requirements of trees
The lack of space for trees has been identified as a significant constraint for the implementation of street tree planting (Greater Sydney Commission 2018b, p 119). The above-ground and underground components of trees have different dimensions, different requirements and different impacts.
The above-ground parts of a tree are relatively straightforward and have predictable spatial requirements. A tree needs to expose its leaves to sunlight for photosynthesis and transpiration. Historically, overhead power lines and trees have clashed, but in new subdivisions electricity infrastructure is underground. At the time of planting, the tree will have no impacts on above-ground electrical assets (poles and wires, streetlights) as the canopy and trunk diameter are small. Any potential above-ground spatial conflicts are due to the size of the sapling – for example, a low branching (albeit small) canopy can impact on pedestrians, cyclists and vehicles. However, these are usually resolved as the tree grows.
Provided the tree is planted away from street lights and electrical pillars, the main above- ground conflict in Camden is between the canopy of a semi-mature or mature tree and the lifting arm of a waste collection truck (see 4.6.6 below).
The below-ground requirements of street trees are more complicated to determine mainly because research into the root systems of trees has traditionally involved destructive methods: that is, a tree must be dug up to examine its roots. This may change with the advent of ground-penetrating radar, but at the time of writing the technology is not sufficiently advanced to be definitive.
Tree roots have three main functions: to anchor the tree in the ground; to absorb water, nutrients and oxygen; and to store excess food (Roberts, John, Jackson, Nick, Smith, Mark 2015, p 40). Roots grow by extension and are opportunistic, but they are delicate and limited by density and pore size of the soil in which they grow. Roberts et al. cite Brady & Weil, R., R. (1999) as finding that soils with a bulk density exceeding 1.6g/cm3 limit root penetration (Roberts, John, Jackson, Nick, Smith, Mark 2015, p 19) and comment that 90% of the root plate will occur in the top metre of soil (Roberts, John, Jackson, Nick, Smith, Mark 2015, p 45) Moore goes further, suggesting that “[m]ost large trees have 95% of their roots growing near the soil surface, with the majority of their small absorbing roots concentrated in the surface 150–200 mm of soil” (Moore 2008, p 2), as shown in Figure 2.11.
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Figure 2.11: Typical root system of a tree in unrestricted soil Source: (Moore 2008, p 2).
Limited soil volume has been identified as the single biggest factor affecting the success of urban trees (Lindsey & Bassuk 1992, p 26). In their influential papers regarding soil volumes for mature urban trees, Lindsey and Bassuk propose a model for calculating the volume of soil required for a tree of a particular size (Lindsey & Bassuk 1992), (1991). The model uses variables such as the water-holding capacity of the soil, the leaf area of the tree and the predicted interval between rainfall events. By plugging variables into the equation, a soil volume is suggested that provides a guide for the designer and tree manager. These papers have been widely cited (DeGaetano & Hudson 2000; Moffat 1995; Plant 2002) and have been used to quantify volumes for street trees in Sydney (Hitchmough 1994; Leake, S. and Haege, E. 2014)
Required soil volumes depend on numerous factors, including the climate, soil type, tree size and species tolerance to drought. Suggested soil volumes for urban trees were summarised by Leake and Haege, who found that volumes for an 8m-canopy tree ranged from 9m3 to 34m3 (Leake, S. and Haege, E. 2014, pp 157–160). In an unencumbered 2m-wide planting strip, assuming that the roots occupy one metre of soil depth, this represents 4.5–17 linear metres.
2.9.4 Conflicts between trees and other infrastructure
The consequences of utilities failure are many: burst water pipes waste valuable water; leaking gas pipes pose an ignition hazard, affect air quality and impact respiratory health; and electricity outages in summer could be life-threatening to people vulnerable to heat stress. Given the preference for underground utilities in new subdivisions, the main conflict between utilities and street trees occurs at the surface or underground.
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The linear form of the street verge and the near-circular form of a root system set the scene for conflict. The limited soil volume not only impacts on the anchoring function of roots, but also the availability of water. Tree roots cause utilities to fail in two ways: either through root penetration into the pipe (in search of water and nutrients) or through the movement of pipes, known as heave (Mattheck, Breloer & Lonsdale 2009, p 90). McPherson & Peper 1996, p 146) found that roots searching for water will be drawn to the old clay and cement sewer and water pipes, because these materials lead to condensation on the outside of the pipe, and that roots will travel along the pipe until they find a joint to penetrate. However, the Dial Before You Dig plans indicate that newly installed sewer and water pipes are made of PVC. McPherson & Peper 1996, p 146) also found that PVC pipes are resistant to root penetration if the joints are properly constructed, suggesting that construction standards for the plumbing of PVC pipes could reduce the risk of root penetration.
The physical damage to pipes due to heave affects all piped utilities as well as structures (driveways, kerbs and footpaths). Forces acting on the tree roots due to wind or from the weight of the tree can impact on infrastructure. Figure 2.12 illustrates how a small wind force can create a bending moment that can crack a pipe.
Figure 2.12: Pipe failure due to wind throw Source: (Mattheck, Breloer & Lonsdale 2009, p 90).
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Trees planted over the top of a pipe have less pressure under wind force (Figure 2.13). If the pipe is deep enough to the withstand the weight of the tree, then the pipe is theoretically at less risk from root damage than if the tree is planted 1-2 metres away. For existing trees, Moore (2000) found that: "Tree roots are for the most part shallow and spreading, and it is perfectly sensible to tunnel under them without interfering with important root structures" (Moore 2000, p 14).
For designers of streets this is worthy of consideration, especially in relation to the increased temperatures already being experienced due to climate change. Moore has suggested that if there is water available, “warmer temperatures should see more rapid root growth so that when street trees are planted root systems should extend into the surrounding soil for the root plate and planting hole more rapidly” (Moore 2011, p 45).
Figure 2.13: Forces exerted on pipes beneath trees Source: (Mattheck, Breloer & Lonsdale 2009, p 94).
Other research suggests that inadequate soil volumes for roots not only stunt growth and lead to premature senescence, but are also more likely to damage pavements (Plant 2002, p 28). In one study that examined tree benefits and costs in two cities in California, it was found that hardscape repair costs accounted for 18% of total expenditure (in one city) and that this can be largely attributed to 50% of street trees being located in restricted sites (<1m x 1m)
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(McPherson & Simpson 2002, p 69). Another study found that across a number of North American cities, “[t]otal concrete and sewer repair costs average 25 per cent of total tree maintenance budgets” (McPherson & Peper 1996, p 154).
Another issue for urban and street trees is the risk of a tree falling in a storm or strong wind event. There are a number of reasons that semi-mature trees fail in storms and wind events, including “[i]nadequate, effective anchor root zones, waterlogged planting pits, [and] incorrectly shaped planting holes” (Kenyon 2002, p 39). In addition:
Poor nursery practices and resultant root deformities such as J roots, and root girdling have been shown to be the reason for many tree failures. Sometimes these root deformed trees fail within a five to ten year period, but other root deformed trees may not fail for twenty plus years. (Kenyon 2002, p 37)
However, this risk is being mitigated through improved nursery growing practices. The Australian Standard AS2303:2018 – Tree stock for nursery use, and the National Building Specification (www.natspec.com.au) have performance indicators for trees to ensure that trees provide their maximum landscape potential. However, there are cost implications to compliance and unless the specification for the supply of the trees requires compliance with the quality provisions of the Australian Standard, and this compliance is regulated by the certifying body, then the use of cheaper stock without quality control records is likely.
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3 Methodology
3.1 Introduction This section sets out the theoretical background for the research, the questions that the research seeks to address, and the methods used. A qualitative methodology has been devised to understand the barriers to street tree planting and to suggest policy and procedural changes that would assist in the implementation of tree-lined streets. The methodology includes interviews and a focus group with Camden Council officers involved in the design, certification and maintenance of streets as well as desktop mapping and ground truthing of map data.
3.2 Theoretical background Groat and Wang suggest that the root meaning of theory is contemplation from a distance (2013, p 124). Deadlines, financial planning, client negotiations and human resource management, being the day to day challenges facing the landscape architectural practitioner, interrupt the space for contemplation and leave little opportunity for distance. It is easy to overlook the role of theory in contemporary practice, but it is imperative not to. The landscape architectural body of knowledge needs continual development and advancement through evidence-based landscape architecture, defined by Brown and Corry as “the deliberate and explicit use of scholarly evidence in making decisions about the use and shaping of land” (2011, p 328). The theoretical foundation of this research is informed by an evaluation of the theory classifications of Deming and Swaffield (2011), Herrington (2016) and Groat and Wang (2013). These sources have all developed a broad classification of theories upon which landscape architectural research and architectural research can be based. There are a number of overlaps, and although the names are sometimes the same, the meanings are different. A summary of the theory classifications is shown in Table 3.1 below.
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Table 3.1: Classification of theories Deming and Swaffield Herrington (2016, p 3) Groat and Wang (2013, p (2011, p 30) 124) Instrumental: prediction, Normative: what should be control, practical action. Critical: challenges the Resistant: challenges the Normative: describes and status quo and stimulates status quo explains conventions change Interpretive: enhances Explanatory: why Explanatory: explains and understanding of meaning something is the way it is describes phenomena and context Design-Polemical: deontology in design expression
This research falls into the critical/ resistant/ normative class of theory. However, where Groat and Wang distinguish between theory and application (Groat & Wang 2013, p 123), Deming and Swaffield (2011) embed action within their theory classification. For the purpose of this methodology, Deming and Swaffield’s term “critical” theory has been adopted – through a street-tree focused reading of the government literature that applies to western Sydney, the research describes the conventions and seeks to challenge the status quo to engender change.
Conventions are the expression of a body of knowledge developed over a considerable period. As representations of collective knowledge and experience, they are valuable and should not be dismissed lightly. However, unless conventions can evolve to address new challenges, they can obstruct progress. They need to be continually tested against contemporary challenges and adjusted to suit. The conventions around street design are tested against the Greater Sydney Commission’s (GSC) Planning Priority W15 “Increasing urban tree canopy cover” (2018b, p 15) to determine the consequences of the conventions on streets.
Herrington describes infrastructure research from a theoretical position of “systems logic” and describes infrastructure as “the network of physical and bio-physical systems that facilitate the necessary operations of daily life” (Herrington 2016, p 232). “A system is an array of interrelated or interdependent elements that form a complex whole, and it has spatial and temporal boundaries that can be open, closed, or fluid.” (Herrington 2016, p 221). Applying
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this definition to streets, a street is a system with an array of interrelated physical elements (soils, footpath, underground and above-ground utilities, travel and parking road lanes, kerbs and driveways) and climatic factors (temperature, rainfall, solar exposure and winds)that form a complex whole with distinct spatial boundaries. The interrelationship of these elements contributes to the broad ecological and environmental impacts of urban development and has consequences for the social and physical wellbeing of the people that use the street.
3.3 Research strategies Swaffield and Deming define a research strategy as “the overall conceptual logic and motivation for an inquiry” (2011, p 35) and state that strategies are classified as being on two axes – the “relationship to theory” and the “epistemological assumptions”. They note that research within landscape architecture is complex, occupying a theoretical space drawn from science, the humanities and the arts, and classify nine research strategies on these two axes, as shown in Table 3.2.
Table 3.2: Classification of research strategies Inductive Reflexive Deductive Objective Description Modelling Experimentation Constructive Classification Interpretation Evaluation and diagnosis Subjective Engaged action Design projection Logical systems Source: (Swaffield & Deming 2011, p 37).
Adopting the matrix in Table 3.2, this research employs a hybrid strategy of ‘Description’ and ‘Evaluation and diagnosis’. Deming and Swaffield suggest that description is often the first stage of a research program (2011, p 65): it sets the scene and demonstrates that there really is an issue worthy of research. Description sits on the intersection of the inductive and objective nodes of the axes (see Table 3.2): objective, because the data is collected from secondary sources, and inductive, because the data creates the theoretical convention which is measured in the evaluation and diagnosis phase. The strategy of evaluation and diagnosis sits on the intersection of the deductive and constructive nodes of the axes: “in evaluation research theory is already accepted and embedded within the normative/critical standards or parameters used for measurement” (Deming, ME, Swaffield, S 2011, p 174).
The descriptive research strategy in this thesis is largely secondary source description, defined as “the use and summarization of observations or information that has been recorded by people other than the investigator” (Deming, ME, Swaffield, S 2011, p 71), but does include
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direct observation. It examines the planning objectives for street trees in the Western Sydney District as well as the regulatory context for the provision of infrastructure. Procedures (specifications and guidelines) and minimum requirements for street trees and grey infrastructure are reviewed to assess the feasibility of reallocating space in the street verge for trees. Methods include conducting a literature review; carrying out semi-structured interviews with council officers who are directly or indirectly involved in the implementation of streets; and direct observation.
With the issues described, the evaluation and diagnosis strategy projects the likely implications of policy and codes (conventions) on the physical outcome of the street to diagnose the barriers to street tree planting and to evaluate the likelihood of current practices achieving the strategic planning vision. Finally the research makes recommendations to address the barriers to street tree planting.
3.4 Research design The research design is a case study of a single local government area (LGA), Camden, within the Western Sydney District. “A case study is an empirical inquiry that investigates a contemporary phenomenon in depth and within its real-life context, especially when the boundaries between phenomenon and context are not clearly evident." (Yin 2009, p 18). The advantage of the case study method in this research is that it can describe, explain and test ideas to address a problem that affects a complex geographic area. The GSC’s Western District Plan pertains to an area that is extremely large; has numerous soil types (which affect both underground and above-ground infrastructure); contains eight different LGAs; includes many different community profiles; and has various land-use and transport options, including a planned airport. It is not feasible in the research degree framework to examine and describe the whole district, but an examination of the Camden LGA illustrates the barriers that exist in the other LGAs of the district and provides a useful case study of the Western Sydney District.
As Yin’s definition pertains to the social sciences, it is useful to consider a case study definition for landscape architecture: “A case study is a well-documented and systematic examination of the process, decision-making and outcomes of a project, which is undertaken for the purpose of informing future practice, policy, theory and / or education.” (Francis 2001, p 16). This case study does not review a single project, but instead uses the method to describe the problem and to illustrate alternatives. Groat and Wang (2013, pp. 418–419) suggest that there are five salient characteristics of a case study, listed in Table 3.3 with the corresponding Camden case study response.
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Table 3.3: Case study characteristics General case study characteristic Camden case study characteristic A focus on a single or multiple cases studied A review of the policies and procedures that in their real-life contexts apply to the whole LGA with a focus on two discrete areas within master-planned developments The capacity to explain causal links Explanation of the link between street conventions and the realisation (or otherwise) of tree-lined streets Theory development in the research design Critical study that illustrates and tests phase policies and practices Reliance on multiple sources of evidence Mapping, interviews and focus group The power to generalise theory Recommendations could be applied to the whole of New South Wales, and the theory could be generalised to any urban area. Source: (Groat & Wang 2013, pp 418–419).
Swaffield notes that it is common in landscape architecture to “undertake several smaller embedded case studies within a single overall study” (Swaffield 2017, p 132). He suggests that this allows for comparison across different geographic parts of a landscape, but in addition to a spatial comparison, it is equally true that smaller embedded case studies can allow for a temporal comparison – in this case, the design responses to conventions.
The Camden LGA case study examines in detail two small areas that demonstrate different approaches to street design and space allocation: one in Oran Park and one in Harrington Park. By choosing small areas, the role of guidelines, codes and individual decision-makers in the implementation of streets can be investigated and used to predict the likelihood of the GSC’s vision being realised. Inferences drawn from these cases inform design alternatives that could be used in the development of new controls for streets within the LGA and generalised to any urban area wishing to increase its urban forest.
Case study methods include mapping the existing tree canopy in old and new streets in the LGA using data collected from Camden Council, the NSW Office of Environment and Heritage, and Landcom, as well as from aerial photos and ground truthing of the map data. Semi- structured interviews with council officers assist to understand the barriers to street tree
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planting. Table 3.4 illustrates the questions, research strategy, methods and techniques to be employed in the research.
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Table 3.4: Research methodology matrix Main Research Question: How do we establish tree-lined streets in local access streets in new subdivisions in Western Sydney? Main Research Strategies: Description and Evaluation and Diagnosis Sub question Logic Research strategy Research method Research Technique What is the strategic vision for Western Review of legislation and strategic Sydney? Objective and inductive Description Literature review planning policy
Literature review; Why is this vision important? Objective and inductive Description semi-structured interviews Review of evidence-based literature.
Review of statutory requirements; Literature review; review of guides and codes; What is required to achieve it? Objective and inductive Description semi-structured interviews review of common practice Semi-structured What are the barriers? Constructive and deductive Evaluation and diagnosis interviews What will happen if the business as usual approach continues? Objective and inductive Evaluation and diagnosis Mapping Mapping What could happen if the approach changes to a tree-focused one? Constructive and deductive Evaluation and diagnosis Scenario planning Workshop; mapping
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3.5 Case study methodology This research is concerned with the Western Sydney District (also called the Western Parkland City), which is comprised of the LGAs of Wollondilly, Penrith, Liverpool, Hawkesbury, Fairfield, Campbelltown, Camden and the Blue Mountains.
Table 3.5 shows the area size and SEPP growth centres, if any, for each of the eight LGAs of the Western Sydney District. Table 3.6 shows population projections for the LGAs.
Table 3.5: Western Parkland City LGA area size and SEPP growth centres, 2016 LGA Area (km2) SEPP (Sydney Region Growth Centres) Blue Mountains 1430 n/a Camden 206 South West Growth Sector Oran Park and Turner Rd; Camden Growth Centres Campbelltown 312 Campbelltown Growth Centres Fairfield 102 n/a Hawkesbury 2793 Hawkesbury Growth Centres Liverpool 306 Liverpool Growth Centres Penrith 405 n/a Wollondilly 2560 n/a Source: author generated from NSW Office of Local Government and SEPP SRGC Table 3.6: Population projections for Western Parkland City LGAs LGA Population Density Population Density Population 2016 2016* 2031 2031* Increase Blue 81,550 54 82,850 63 118% Mountains Camden 80,600 380 179,850 1090 287% Campbelltown 163,600 503 205,200 747 148% Fairfield 205,150 1949 210,550 2223 114% Hawkesbury 72,700 23 75,850 30 132% Liverpool 213,050 668 289,000 1082 162% Penrith 204,100 484 242,650 669 138% Wollondilly 49,100 19 61,850 28 150% * Number of people per kilometre
(NSW Government Department of Planning and Environment 2016)
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The problems examined in this research apply to all eight LGAs of the Western Sydney District, but the scope of this research is limited to the detailed examination of one LGA only. The criteria established for selecting an LGA are set out in Table 3.7, and Table 3.8 shows the results of applying the criteria to the LGAs of the Western Sydney District.
Table 3.7: Criteria for selection of the local government area for the case study Criterion Measure Area of land small enough to make in-depth < 500km2 analysis feasible within the duration and scope of the thesis Area of land large enough to be > 200km2 representative of the issues being analysed Greenfield sites zoned for development Presence of land subject to SEPP (Sydney Region Growth Centres) Significant increased population density Projected increase to 2036 greater than 1.5 times 2016 population Potential conflict of interest Researcher working within the LGA* * The author works in landscape architectural practice in the Sydney Region. To avoid any potential conflicts of interest, any LGA the author was working in at the time of selection (January to March 2018) was immediately ruled out.
Table 3.8: Application of the selection criteria to Western Parkland City local government areas Blue Mountains Camden Campbelltown Fairfield Hawkesbury Liverpool Penrith Wollondilly
200km2 < Area < 500km2 • • • •
Greenfield sites (SEPP) • • • • Population density increase >1.5 • • • Free of potential conflict of interest • • • •
This matrix narrowed the selection to Camden or Liverpool. Although the impacts of development are being experienced by both LGAs, three factors left Camden as the preferred option:
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- The projected population increase for Camden between 2016 and 2036 is greater than that for Liverpool and likely to have a greater impact on the character of the LGA. - Liverpool is the site of a new international airport with a greater proportion of land in the LGA being zoned for transport rather than residential zoning and airport restrictions likely to impact on the urban forest within the area. - Camden has a council landscape architect who was amenable to the research. - The case study aims to demonstrate the effect of current controls on the likelihood of achieving tree-lined streets. The methods for evaluation included: - conducting semi-structured interviews with key members of council staff about the barriers to establishing street trees; - establishing a rubric that measures the definition of a tree-lined street; - comparing two to three streets in Harrington Park and Oran Park to provide a real- world comparison in controls.
3.6 Mapping methodology The mapping process compared streets in an older established area that has tree-lined streets (Harrington Park) to streets in a newly developed area (Oran Park). The resultant maps illustrate the different factors in the two areas including:
- lot sizes, house sizes and private open space; - driveway widths (in the verge); - footpaths; - areas for waste collection; - utilities layouts; - projected tree canopy in the street reserve.
The data required for the mapping included:
- street and lot layouts; - existing tree canopy in streets; - existing tree species in streets; - utilities layouts; - layouts and widths of footpaths, verges and driveways.
Maps were created from layers from different data sets sourced from various agencies. Table 3.9: Map layers indicates layers and the source of the data.
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Table 3.9: Map layers Map items Data type Source Lots Cadastral Council GIS Streets Road centrelines Council GIS Houses Figure ground footprints NearMap Kerbs (Oran Park) Cad linework Landcom-issued design drawings Kerbs (Harrington Park) GIS digitisation NearMap Street trees GIS digitisation NearMap Driveways GIS digitisation NearMap Utilities Cad linework DBYD
The purpose of the maps is to demonstrate the likely canopy percentage once the existing street trees have grown to their full mature size; and to demonstrate the likelihood of achieving tree-lined streets (as defined by the GSC) that contribute to the green grid. Maps are a snapshot in time, with the following limitations: - The maps are based on data provided by Camden Council, Landcom, NearMap and Dial Before You Dig. The Dial Before You Dig and Landcom data is in pdf format and has been exported to Adobe Illustrator and then to AutoCAD in order to use it within the mapping. This process may have resulted in some data loss, but maps were ground truthed for accuracy (above-ground infrastructure and surface pits only). - Projected canopy cover is based on each tree achieving the average maximum size for that species. Street trees are constrained and may not reach their full potential. - Footpath and kerb information for Harrington Park was interpolated from aerial photography and ground-truthed. - Driveways for both Oran Park and Harrington Park were interpolated from aerial photography and ground-truthed.
3.7 Camden LGA – a brief history
3.7.1 Introduction
With a projected increase in population between 2016 and 2036 of 287%, Camden is increasing faster than any LGA in the Western Sydney District (NSW Planning and Environment 2016c). The corresponding development to house and service the growing population is resulting in an area undergoing rapid change to its character. The agricultural land-use
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patterns are giving way to suburban land-use patterns, with impacts on the road networks, built form, vegetation and landform.
3.7.2 History
The land now designated as the Camden LGA has been continuously occupied by the Dharug, Tharawal and Gundungarra nations since before Europeans arrived; in 2016 2.5% of Camden’s population identified as Aboriginal or Torres Strait Islander (Australian Bureau of Statistics 2016). Fire was used by Aboriginal people for various reasons, including to create patchwork or mosaic vegetation patterns, (Benson, D. and Howell, J. 1990, p 15). The land now occupied by Mt Annan Botanic Garden was significant as a meeting place for Aboriginal people (Frances Bodkin, personal communication, 11 April 2019).
Camden was identified as agricultural land by early settlers in the Australian colony. The Sydney colony was short of livestock because in 1788, only 5 months after arriving, the only cattle escaped into the bush and were lost. In 1795, Aborigines told of a herd grazing 60km south of Sydney in the area now known as Cowpastures (Atkinson 1988, p 8). Together with the gentle topography, fertile soils and regular water, the woodland landscape would have attracted the colonising settlers to the area. “From the earliest years white men wrote about the Camden landscape almost as a work of art, well defined, vivid and various, satisfying all the aesthetic notions of the day.” (Atkinson 1988, p 26)
In The Biggest Estate on Earth, Bill Gammage cites an early European correspondent writing of the Cowpastures that now form part of Camden:
Henry Waterhouse wrote in 1804: “I am at a loss to describe the face of the country otherways than as a beautiful park, totally divested of underwood, interspersed with plains, with rich, luxuriant grass; but, for want of feeding off, rank, except where recently burnt. This is the part where the cattle that have strayed have constantly fed – of course, their own selection.” (Gammage 2011, pp 281–282)
Gammage goes onto to describe the “grass templates” created through burning of the landscape and says: "No wonder settlers took such country so quickly. Grass templates were farms without fences." (Gammage 2011, p 282). It is not surprising then that when John Macarthur was granted 5000 acres of land to raise sheep, he chose the area around Camden. Within five years other settlers followed (Atkinson 1988, p 10). For white Australia, Camden is one of the oldest settlements and there are still numerous reminders of the early days of the
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colony, including the farmland at Camden Park; the homestead at Harrington Park; the suburb names of Camden, Wivenhoe and Gledswood; and road names such as Cowpasture Road.
3.7.3 Geology and soils
Providing structure, nutrients, water and oxygen, soils are critical for the success of urban street trees. “Knowledge of soils management has always been considered important in rural environments. It is just as important, or even more, to understand and manage soils in an urban environment for sustainable environmental management.” (Hazelton & Murphy op. 2011, p 5). Camden is located on the Cumberland Plain of the Sydney Basin and its landscape is a product of a combination of natural and human-induced features. The east coast of Australia has a geology consisting of layers of ancient folded rocks overlain with layers of sandstone and shale. The Sydney Basin is bordered by plateaus to the north, west and south; and to the east by the Pacific Ocean.
The Cumberland Plain’s gentle undulating topography is a result of the underlying Wianamatta Shale geology. Camden’s soils are derived from Wianamatta Shales overlaying the Narrabeen Group which in turn overlay the Lachlan Belt. Soils of the Cumberland Plain are more fertile than the skeletal soils derived from sandstone, hence the attraction of the early agricultural settlers (see 3.7.2 above).
Figure 3.1 shows the soils of Camden mapped using data from the NSW Government data portal. When compared to Hawkesbury sandstone, Wianamatta Shale-derived soils are “the more fertile loamy or clay soils [that] retain more moisture and have lightly higher nutrient levels” (Benson, D. and Howell, J. 1990, p 9). However, the NSW Government soil landscape mapping and reports (NSW Department of Planning, Industry and Environment) suggest that much of Camden has soils with a low available water-holding capacity. Table 3.10 shows properties of soil types found in Camden LGA.
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Figure 3.1: Map of soil types in Camden Local Government Area Source: author generated map from NSW Office of Environment and Heritage dataset
Table 3.10: Properties of Soils found in in Camden LGA Soil type (by main AWHC 1 Typical Tern mapping location) depth Blacktown Low – Moderate >1m 10–20% Luddenham High <1m 20–25% Monkey Creek Low >1m 10–15% Picton Moderate >1m 15–20 % Richmond Low >1m 10–15% South Creek Low <1m 10–15% Theresa Park Low <1m 10–15% 1.AWHC: available water-holding capacity Source: NSW Office of Environment and Heritage dataset
The Blacktown Soil that occupies the majority of Camden LGA is described in the Soil Landscape Report as being capable of sustaining regular cultivation (NSW Department of
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Planning, Industry and Environment 2013a, p 38). The other important soils of Camden vary in their fertility, salinity and tendency to water logging. However, the soils of Camden are capable of sustaining regular cultivation (NSW Department of Planning, Industry and Environment 2013b; NSW Department of Planning, Industry and Environment 2013c; NSW Department of Planning, Industry and Environment 2013d)
3.7.4 Vegetation communities
Vegetation communities of the Camden LGA are part of the Cumberland Plain Woodland group (Benson, D. and Howell, J. 1990, p 72). Tozer notes that the vegetation of the Cumberland Plain differs from the surrounding sandstone communities, with differences among species, composition and structure, and cites the NSW National Parks and Wildlife Service as finding that less than 5% of Cumberland Plain Woodland was intact in 1997 (Tozer 2003, p 3).
In Camden the vegetation communities are characterised by Eucalyptus trees (E. moluccana, E. crebra and E. tereticornis) with an understorey dominated by grasses.
3.7.5 Climate
The climate of Camden is influenced by its distance from the coast as well as its location in the Sydney Basin. The BOM climate statistics (http://www.bom.gov.au/climate/data/) indicate that Camden experiences higher average summer temperatures and lower average winter temperatures than Sydney Harbour (Camden Airport Weather Station compared with Observatory Hill Weather Station) and lower rainfall. Camden has an average summer temperature of 29°C and average summer rainfall of 77mm per month.
3.7.6 Heat Island
The NSW Urban Heat Vulnerability Index was mapped in 2015 to show areas of Sydney that are vulnerable to extreme heat. Although this data is not current and does not reflect the 2019 cadastral data for Camden, it provides useful information showing the link between heat vulnerability and urban development.
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Figure 3.2: Heat Vulnerability Index for Camden Local Government Area Vulnerability scale 0–5, where 1 = a combination of low exposure, low sensitivity and/or high adaptive capacity and 5 = a combination of high exposure, high sensitivity and/or low adaptive capacity, Source: author generated map from NSW Office of Environment and Heritage dataset
Data sourced from Camden Council and the NSW Office of Environment and Heritage were used to generate a map showing the urban heat in the Camden area (Figure 3.2), Which shows that heat vulnerability increases with urban development and newly developed areas with large areas of dark surfaces and few trees are particularly vulnerable to the effects of heat.
Comparisons between long term temperature data from the Bureau of Meteorology for Camden Airport and Observatory Hill shows that the coast has a moderating effect on Sydney’s eastern urban areas. (www.bom.gov.au/climate/). Sydney is a geographic basin surrounded on the north and south by plateaux and mountains to the west. The coastal breeze that cools eastern Sydney and disperses air pollution does not extend inland to the Camden LGA and consequently temperatures tend to be hotter in Summer and air pollution higher.
3.7.7 Population statistics
The 2016 Australian census found that there were 25,008 households in the Camden LGA housed in 26,190 private dwellings of which 24,132 were separate houses. Of these, 15,789 houses had four bedrooms or more. The average number of people per household in Camden
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was 3.1. The census also found that Camden is a car-dependent community. Some 72.9% of Camden residents have two or more vehicles registered to their address, as compared to 50.8% for the whole of New South Wales; 70.3% of residents drive to work as compared with 57.8% of the whole of New South Wales (Australian Bureau of Statistics 2016).
3.7.8 Camden organisational structure
As a local government entity, Camden Council is composed of elected officials who are supported by an administration. There are nine elected officials who represent three geographic wards. The administration of Council is described in the 2019 Adaptive Organisational Framework (available from https://www.camden.nsw.gov.au/council/about- us/organisational-structure/) which shows that that administration is organised into five departments: Community Assets; Sport, Community and Activation; Planning and Environment; Customer and Corporate Strategy; and Finance. Each of these is managed by a director who answers to the General Manager of Council.
The departments responsible for street trees and the implementation of policies and strategies that pertain to streets include designers, engineers, planners and arboricultural maintenance staff. These staff work in Community Assets and Planning and Environment. All participants in this research were selected from these departments.
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4 Findings
4.1 Introduction This section describes the findings of the research into street trees in the Camden Local Government Area (LGA). It describes the findings from the review of the relevant planning controls, interviews, mapping process and focus group and then summarises the barriers and opportunities referenced by the interviewees and participants.
4.2 Planning controls
4.2.1 Application of SEPP, the Camden LEP and Development Control Plans
State Environmental Planning Policy (Sydney Region Growth Centres) 2006 (SEPP SRGC) applies to land in Camden known as the South West Growth Centres (Figure 4.1 shows the location of this land in grey). Of relevance to street trees is the aim “to enable the establishment of vibrant, sustainable and liveable neighbourhoods that provide for community well-being and high quality local amenity” (SEPP SRGC cl 2(d)) , as well as the minimum size of lots in subdivisions with detached dwellings being 300m2 (SEPP SRGC cl 4.1A(1)(a)).
The Camden Local Environmental Plan 2010 (Camden LEP) makes provision for the development of land in Camden, including land in urban release areas. One of its aims is “to ensure Camden retains its valued traditional qualities, character and scenic landscapes while providing for sustainable urban growth” (Camden LEP cl 1.2(2)(a). Of particular significance for street trees is the LEP’s specification of minimum lot sizes (in the accompanying LEP Lot Size Map)
Minimum dimensions for lots are set out in the four separate Development Control Plans (DCPs) that apply to land in Camden LGA. These are Camden Development Control Plan, 2019; Oran Park Development Control Plan, 2007; Turner Road Precinct Development Control Plan, 2018; and Growth Centre Precincts Development Control Plan, 2016 (refer to Figure 4.1 for the location of land where the various controls apply). The specific DCPs that apply to Growth Areas are controlled by the NSW Department of Planning, Industry and Environment (formerly known as the Department of Planning and Environment) and are discussed in turn below.
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Figure 4.1: Camden Council land where Camden Development Control Plan applies Source: (Camden Council 2019a, p 6).
Figure 4.2: Land to which Schedules in the Camden Development Control Plan apply Source: (Camden Council 2019a, p 128).
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4.2.2 Camden Development Control Plan 2019
The Camden Development Control Plan 2019 (Camden DCP) has controls that apply to all land other than land designated as a Growth Centre in SEPP SRGC. It is structured in two sections: general land-use controls; and controls that apply to land release areas (LRAs) (see Figure 4.2). The main section containing the general land-use controls is further divided into parts that describe objectives and controls for development. Section 3: General Subdivision Controls sets out controls for, among other things, lot dimensions, public open space, street network and street trees.
The street tree controls in this section are:
1. Street trees are to be provided on all streets and must:
a. be used consistently to distinguish between public and private spaces and between different classes of street within the street hierarchy;
b. minimise risk to utilities and services and minimise ongoing water consumption;
c. be durable and suited to the street environment and include endemic species;
d. maintain adequate lines of sight for vehicles and pedestrians, especially around driveways and street corners;
e. be suitably located away from waste collection areas to accommodate servicing;
f. provide appropriate shade;
g. provide an attractive and interesting landscape character without blocking the potential for street surveillance; and
h. ensure street tree design and species selection complement and define the neighbourhood area, ecological linkages, street hierarchy, precinct entries, significant intersections, items of environmental heritage, heritage conservation areas and significant view lines.
(Camden Council 2019a, p 141)
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Street sections are not included in the main body of the Camden DCP, but the objective for Section 3.2.6 Street Trees is to “Ensure trees are planted to enhance the local environment.” (Camden Council 2019a, p 142) This section then lists controls that apply to street tree planting such as providing appropriate shade. If implemented, would ensure that streets are tree-lined and shaded – that the vision of the high-quality environment articulated in strategic policies is realized. However, this section is not specific and refers to Appendix B of the DCP that states:
“The selection and placement of street trees should have regard to the following criteria:
a. Power/Gas/Water/Sewer/Cable Services and Easements.
b. Not planted within 3m of a Sydney Water access shaft.
c. Positioning of street lights.
d. Pruning and shaping adaptability of selected trees.
e. Driveways & bus stop placements.
f. Frontages/setbacks.
g. Lateral spread of branches.
h. Road verge widths.
i. Waste services collections.
j. Pedestrian & vehicle vision. Trees must not be planted closer than 10-metres from road corners or intersections;
k. Existing amenity;
l. Above ground services and easements;
Footpaths and cycleways – (Street trees must not be planted less than 1 metre away from a concrete footpath/cycleway or other concrete structures.”
(Camden Council 2019a, p 594)
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4.2.3 Oran Park Precinct Development Control Plan 2007 and Turner Road Precinct Development Control Plan 2018
The DCPs for the Oran Park and Turner Road Precincts were prepared by the NSW Department of Planning and Environment with duplicate objectives and vision for the streets, and so are treated here as identical.
The DCPs state:
Street trees are required on all streets. Street planting is to: – be used consistently to distinguish between public and private spaces and between different classes of street within the street hierarchy, – minimise risk to utilities and services, – be durable and suited to the street environment and include endemic species, – maintain adequate lines of sight for vehicles and pedestrians, especially around driveways and street corners, – provide appropriate shade, and – provide an attractive and interesting landscape character without blocking the potential for street surveillance." (NSW Planning and Environment 2016a, p 23), (NSW Planning and Environment 2018, p 23)
The Oran Park Precinct and Turner Road Precinct DCPs do not specify a distance between trees but do include an indicative plan that shows a tree per lot. The DCPs also allow for trees to be planted in the carriageway, allowing for three vehicles, driveways and waste bins.
The DCPs also state:
Any proposal for street tree planting within the road reserve (i.e. carriageway and footpath) is to include appropriate detailed design that addresses access and maneuverability of heavy vehicles, street sweepers and cars, the impact of the root system on the carriageway, ongoing maintenance of the tree and carriageway, and the relationship with future driveway access points. It must also address any adverse impact on available on-street parking, especially in higher density areas. (NSW Planning and Environment 2016a, p 23)
The Block and Lot Layout sections of the DCPs nominate minimum lot widths classified according to the density that SEPP SRGC aims to achieve (NSW Planning and Environment 2016a, p 82); (NSW Planning and Environment 2018, p 74). These allow for minimum
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frontages for front-loaded lots (lots with driveways at the front) of 12.5m, 9m and 7m depending on the location. Camden’s waste collection also requires a 3m zone for bins (see 4.6.6 below). Figure 4.3 shows the space left over for a street tree if the minimum lot size, waste collection allocation and driveway width are adopted.
Figure 4.3: Minimum lot sizes in Oran Park Precinct and Turner Road Precinct Source: author, compiled from Oran Park Precinct DCP, Turner Road Precinct DCP and Camden Council Access Driveways Specification 4.2.4 Growth Centre Precincts Development Control Plan 2016
The Growth Centre Precincts DCP is different from the other DCPs that apply to land designated under SEPP SRGC. Its structure is more closely aligned to the Camden DCP than the Oran Park and Turner Road Precinct DCPs. However, it has the same lot frontages as shown in Figure 4.3 for the Oran Park and Turner Road Precincts (NSW Planning and Environment 2016b, p 41).
4.3 Interviews An ethics approval through the UNSW Human Research Ethics Team was granted (HC190223) for one to one interviews with Council officers and a focus group discussion. The aim of the interviews and focus group was to explore the barriers and opportunities for street tree planting. Roles in Council that have an impact on the implementation of street trees were identified by Council’s landscape architect.
Fourteen council officers were invited to participate in the research and eleven were interviewed between June and November 2019 (see Appendix 1 for the Participation forms and project description). Participants were suggested by Camden Council’s landscape architect and represented staff involved in the planning, design, certification and maintenance of streets and street trees. Council staff interviewed included people in the following roles:
- Team Leader for Landscape Design;
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- Coordinator for the LEP Review; - Urban and Tree Officers; - Team Leader for Engineering Certification; - Team Leader Design; - Manager of Assets and Design Services; - Team Leader Traffic and Road Safety; - Strategic Planner Land Use Planning; - Team Leader of the Development Application Assessment Team.
The interviews were semi-structured and included a mix of open and closed questions (see Appendices 2-8). Questions were tailored to the specific role, so varied across the interviews (refer to Appendices). The interviews were transcribed, issued to the interviewees for accuracy review and then de-identified. Interviews were initially coded by reading and re- reading them to identify themes that may illustrate barriers and challenges as well as the interviewee’s general attitude towards street trees and the GSC requirement to install them. These themes assisted in developing the focus group structure by ensuring that the discussions, questions and exercises offered a mechanism to further explore the barriers and opportunities. Following the focus group, interview codes were reviewed to ensure that themes accurately reflected the views of research participants.
Figure 4.4: Coding word cloud for the interview transcripts Source: author generated from NVivo analysis
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Figure 4.4 shows the word cloud visualisation resulting from a word frequency query of the interview transcripts (excluding the questioner’s questions and commentary). It shows that “driveway” was the most frequently used word in the interviews.
Eight preliminary themes were identified in the coding of the interviews: 1. There is in-principle support for street trees in Camden. 2. New development in Camden is controlled by four DCPs that are not always consistent. 3. There are inconsistencies in the Camden DCP between the main parts and the Schedules that apply to the LRAs. 4. The lack of surface area in the street reserve for trees is a bigger constraint than underground utilities. 5. The Camden Council Engineering Design Specification (Camden Council 2017) is a key document for design and certification of the streets. 6. The Austroads guide to road design (Austroads 2015) has a significant impact on the installation of street trees, but there is a lack of clear guidance around its application. 7. Staged construction and certification in subdivisions puts pressure on the realisation of tree-lined streets. 8. Heat is increasing as an issue for the Camden LGA.
4.4 Case study mapping Two small cases were mapped to explore the possibilities for tree-lined streets in planned subdivisions. The two cases are in Oran Park and Harrington Park; see Figure 4.5 for the context of the two suburbs within the Camden LGA.
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Figure 4.5: Aerial map of Camden local government area showing location Oran Park and Harrington Park Source: author from NearMap aerial (05.11.18) accessed 29.10.19
4.4.1 Background to the cases
Oran Park is being developed jointly by Landcom (the NSW Government’s land and property development organisation) and the Greenfields Development Company. The homes in the subject streets of Oran Park are detached single-family dwellings under the Torrens title system (meaning that title in the land is registered to individual owners). Harrington Park was developed by Harrington Estates using a community title model (meaning that the home- owner buys into the community rather than owning a specific lot, and has access to community-owned assets such as community clubs, but they are responsible for the upkeep of their own lot). Harrington Estates describes Harrington Park as being on rolling hills with plenty of space (Harrington Estates 2019). The dwellings in the subject streets in Harrington Park are also detached single-family houses. In this section, references to Oran Park and Harrington Park refer to the areas comprising the subject streets of the case studies and not to the entire suburbs.
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Figure 4.6(a) shows the case study area within Oran Park as comprising a section of McCormack Street, Holdsworth Street and Lawler Drive; and Figure 4.6(b) shows the case study area in Harrington Park: a section of Kensington Drive, George Bransby Circuit and Crain Court.
(a) (b)
Figure 4.6: Aerial views of the case study areas: (a) Oran Park and (b) Harrington Park Source: Author generated image from NearMap aerial (05.11.18) accessed 29.10.19
4.4.2 Case Study Measurements
Table 4.1 shows the spatial data derived from the mapping and ground truthing of the two case study areas. The cases have several factors in common, including development type (residential), overall area (occupying approximately 3.5ha), and a similar ratio of road reserve area to lot area (approximately 1:3). However, the average lot size in Harrington Park is significantly larger than in Oran Park (642m2 and 432m2 respectively), meaning that there are 40 lots in Harrington Park compared to Oran Park’s 60 lots. This limits the comparison between lot frontages and driveway widths, but lot size is a contributing factor to the implementation of tree-lined streets and frontages are a direct result of lot size.
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Table 4.1: Statistical dimensions of the case study areas
Oran Park Harrington Park Overall area 35,044m2 34,844m2 Combined lot area 26,494m2 25,644m2 Lot area as percentage of overall area 75.6% 73.6% Number of lots 60 40 Average lot size 432m2 642m2 Median lot size 449m2 623m2 Combined street area 8,550 m2 9,200m2 Street area as percentage of overall area 24.4% 26.4% Average house footprint 253m2 250m2 Median house footprint 259m2 250m2 Average private landscape area (including soft 179m2 392m2 and hardscape) Source: author generated data from GIS mapping
Noteworthy is the relationship between average lot size and house footprint. Although the average lot size in Harrington Park is nearly 50% larger than in Oran Park, the difference in the average footprint of the house is insignificant (250m2 and 253m2 respectively). That is, the houses in Oran Park occupy a larger portion of the lot and the available open space for front and back yards is reduced. Figure 4.7(a) shows a house with the median lot size in Oran Park. Located in Holdsworth Street, this house has a lot size of 449m2 and house footprint size of 286m2. The available space for the front and back garden, including the driveway and bin storage, is 163m2. The front garden depth ranges from 3–5.5m and the back from 2–6m. Figure 4.7(b) shows a house with the median lot size in Harrington Park. Located in Crain Circuit, the lot size is 623m2 and the house has a footprint of 281m2. The front garden depth ranges from 4.5–6m and the back from 4.5–6.5m. There is also a side garden that ranges from 5–7m wide. The 342m2 garden area allows for tree planting in the front, rear and side gardens.
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(a) Oran Park (b) Harrington Park
Figure 4.7: Houses representing the median lot size in (a) Oran Park and (b) Harrington Park Source: author generated image from NearMap aerial (05.11.18) accessed 29.10.19 with cadastral information from GIS
Table 4.2: Dimensions of frontages and driveways in the case study areas Oran Park Harrington Park Average frontage width 14.69m 19m Median frontage width 15m 19m Average driveway width 4.49m 4.69m Median driveway width 4.5m 5m Waste allocation 3m 3m Average available frontage for tree planting 7.2m 11.31m Source: author generated data from GIS
Table 4.2 shows average and median lot frontages and driveway widths. Once the 3m waste allocation is included, Oran Park has an average frontage width of 7.2m for tree planting. With 7–8m canopy trees being common on Camden, in theory this is enough room to accommodate a tree outside each house lot. However, if the space is irregular and piecemeal, then achieving a tree-lined street is more difficult.
By plotting the location of the existing street trees on the maps, projecting them to their maximum projected canopy and then measuring the canopy as a proportion of the overall area, it is possible to measure the potential canopy against the Draft Urban Tree Canopy Guide
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(Draft UTCG) target of 40% (Government Architect New South Wales 2018, p. 9). There is a significant difference in canopy area of the street trees as a proportion of the subject and street area in the two cases. Even though the average lot width and driveway width shows that trees should be able to be accommodated in streets in Oran Park, the potential canopy in this area falls short of the 40% target. With wider lot frontages, the average available frontage space for trees in the Harrington Park case is 11.31m after driveways and waste allocations, showing it is possible to meet the 40% target for the street area.
Table 4.3: Projected maximum street tree canopy in the case study areas Oran Park Harrington Park Combined canopy of street trees 2,148m2 3,660m2 Canopy as a percentage of total area 6.13% 14.57% Canopy as a percentage of street area 25.12% 40.62%
4.5 Focus group process Camden Council staff who participated in the interviews (see section 4.3 above) were asked to participate in a follow-up focus group. The focus group had three primary aims:
- to explore the meaning of ‘tree-lined street’; - to articulate the barriers to street tree planting experienced by different teams; and - to explore alternative layouts for local streets.
Of the eleven interviewees, eight were able to attend the focus group. Two additional participants who had been unavailable for an interview, joined the focus group. Despite the change in attendees, the final ten participants represented previously identified roles that have an impact on the implementation of street trees. The final ten participants represented council staff from the arboricultural team, landscape and urban design, engineering (drainage, design and certification) and strategic planning.
The focus group was conducted on 5 November 2019 in Camden Council offices and was facilitated by the author (Christina Silk), with Professor Linda Corkery observing.
An introduction delivered by Tim Vyse, a senior landscape architect from Camden Council, described Council’s interest in the research and the progress of the City Deals process. Mr Vyse described the collaboration between the eight councils of the Western Parkland City and Blacktown City Council and their shared aim to prepare coordinated urban design guidelines with an accompanying engineering specification that will enable the implementation of the guidelines.
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As most of the participants had previously been introduced to the research, the author’s description of the background to the research was brief, emphasising the relevance of the focus group to the research and the structure of the thesis (for the benefit of the additional two participants). Throughout the focus group the two case studies of Oran Park and Harrington Park were referred to.
An analysis of the Oran Park site to illustrate the projected urban canopy revealed that the urban canopy of the three blocks – as currently planted and assuming the trees reach their maximum potential size – will be only 7% coverage. This was presented to the group primarily to illustrate that the lot sizes in Oran Park indicate that the private open space is too small for large trees and therefore unlikely to contribute to the area’s canopy; and also to show that the current approach to street tree planting is neither meeting the urban canopy target of 40% of the site area, nor 40% of the street area.
Preliminary themes derived from the interviews (see 4.3 above) were outlined to the participants. A round-table discussion of the themes identified a range of barriers to tree-lined streets:
- The space allocated for waste bins and the area that needs to be kept free so that the arm of the truck can swing impact on the space available for new trees and have forced the removal of mature trees. - Driveways occupy a large area of the street verge because of their width and their frequency (aligned to narrow frontages). - Lots are narrower than in the past which necessitates more servicing; that is, more utilities crossing the verge to enter the lots and more stormwater discharge pipes to the gutter. - There are insufficient controls in the Camden DCP to encourage tree planting, but numerous controls that discourage tree planting. - The application of the Austroads guidelines and design standards for road design (e.g. Austroads 2015, 2018) is a barrier to street tree planting. - Utilities are generally not in shared allocations and therefore perceived (by the group) to be an inefficient use of space. - To encourage walking, footpaths in new developments are 1.5m (1.2m in past developments). - Verges are being built to the minimum permissible width to maximise housing density. - Driveway locations are not being set at the subdivision stage.
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- Some residents do not value trees and are “too ready to pull them out”.
Participants were then asked to review three slides of the Oran Park subject site and to discuss which best achieved the intent of planning controls: the existing street trees with the maximum projected canopy size (Figure 4.8) or trees in regular rows –first with 8m street trees at 8m centres (that is, with no regard for driveways) (Figure 4.9), the second with a 12m tree located on the prolongation1 of each property boundary (Figure 4.10).
Figure 4.8: Oran Park area showing existing trees with projected maximum canopy Source: Author generated image from NearMap aerial (05.11.18) accessed 29.10.19 and landscape design from JMD drawings issued by Landcom
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Figure 4.9: Oran Park area showing 8m trees in regular rows Source: Author generated image from NearMap aerial (05.11.18) accessed 29.10.19
Figure 4.10: Oran Park area showing 12m trees in regular rows Source: Author generated image from NearMap aerial (05.11.18) accessed 29.10.19
Although a clear vision for the streets was not articulated by the focus group, there appeared to be unanimous agreement that the existing situation (Figure 4.8) did not meet the expectations of individual participants. The 8m layout (Figure 4.9) was not examined in detail
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– there appeared to be a general consensus that the driveway locations could not be ignored. However, the 12m trees on the prolongation of the boundaries (Figure 4.10) generated discussion around the benefits of this approach as well as the difficulty of locating electricity pillars (which are usually located on the prolongation of the boundary within 600mm of the boundary) and street lights.
A brief presentation to compare the maximum potential canopy of the subject sites was followed by a discussion of the factors that contributed to the streetscapes and the street trees in the verges. Of note:
- Verges (from lot boundary to back of kerb) are typically wider in Harrington Park than in Oran Park. - Oran Park lots are owned under Torrens title, whereas the development in Harrington Park is community title. - The arboricultural team has come under pressure to remove trees in Harrington Park to facilitate waste management services. - Lot sizes in Oran Park are typically much smaller than in Harrington Park – areas mentioned by participants were 300m2 for Oran Park and 800m2 for Harrington Park.
Participants were then issued three base plans at 1:200 scale – two of these were streets in Oran Park showing 3.5m verges and property boundaries, but without dwellings or driveways. The third plan showed the same, but with the verge increased to 4.5m. Participants formed into small groups of two, each of which was issued drawing materials and tree templates and asked to draw their ideal street. Tree templates, to quickly draw trees at an accurate size and layout, were designed and laser cut from perspex for the purpose of the focus group. Three templates (Figure 4.11) were issued with the following dimensions:
- 4m diameter canopy trees at 4m, 6m and 8m centres; - 8m diameter canopy at 8m centres; - 12m diameter canopy at 12m centres.
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Figure 4.11: Tree templates issued to small groups within the focus group Source: author
Participants were asked to collaborate within their small groups to draw the ideal street for the purpose of illustrating what council officers would ideally like to see in new developments in Camden. Four drawings were produced – refer to Figure 4.12 to Figure 4.15.
Figure 4.12: Focus group ideal street for Group 1
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Figure 4.13: Focus group ideal street for Group 2
Figure 4.14: Focus group ideal street for Group 3
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Figure 4.15: Focus group ideal street for Group 4
4.5.1 Definition of a tree-lined street
Although a definition was not articulated in words, the ideal plans created indicate a consensus among the focus group participants that tree-lined streets have a contiguous canopy. They are not necessarily formal avenues and can include trees of different sizes depending on the space available. Ideal plans varied, but generally were based on the 12m canopy template (no participant used the 4m template for the primary tree planting, only for ancillary planting) suggesting that the ideal tree-lined street is composed of large-canopy shade trees spaced to create a shaded verge.
4.5.2 Barriers
It was noteworthy that participants mentioned their experience of barriers at numerous stages in the lifespan of a development – from planning (development controls and consent conditions) through the construction process (builders damaging trees that were installed in the subdivision stage), residents’ perceptions of trees (the value of trees in the street and the concern over damage to property) and finally to the Council’s operation and maintenance of streets (garbage removal, tree maintenance, footpath and kerb maintenance).
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4.5.3 Alternatives
Although there was some frustration expressed amongst participants that control over the future development of the LGA has been diminished by NSW Government regulation and policy, there was enthusiasm for finding alternative solutions that would accommodate street tree planting and tree-lined streets.
Some participants suggested that front gardens should have an easement over the boundary that was reserved for either electricity (allowing more room in the verge for trees) or for tree planting (removing trees from the verge altogether). One participant in the focus group suggested that during the community consultation for Council’s LEP review, a question was put to the community that asked whether there is community support for requiring residents to plant trees in their gardens and that this question was met with a negative response from the community.
One idea that has been tested in Oran Park, is planting trees in the parking lane. This has been successful in streets such as Hazelbank Road, Wollstonecraft (see Figure 2.8), but the limited space for parking in Camden and the Engineering Specification’s suggested spacing of trees at 18m centres (Camden Council 2017, p 92) results in isolated trees in limited soil volumes.
4.5.4 Research themes
The qualitative research themes were refined following the focus group discussions:
1. There is support for street trees in Camden but barriers to planting at the implementation stage are numerous. 2. The controls in the DCPs that apply to Camden do not aid in the implementation of tree-lined streets and may hinder street tree planting. 3. The number and width of driveways and the space required for waste collection are the biggest constraints on tree planting. 4. The Camden Council Engineering Design Specification (Camden Council 2017) is a key document that assists in the design and certification of streets and the implementation of tree-lined streets. 5. Austroads guidelines and design standards for road design (e.g. Austroads 2015, 2018) have a significant impact on the installation of street trees, but their application in local urban streets is unclear. 6. Staged construction and certification in subdivisions puts pressure on the realisation of tree-lined streets.
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7. Community education about the value of trees, their role in mitigating urban heat and the different species in Camden may assist in gaining community support for tree-lined streets. 8. A “business as usual” approach to streets will not achieve Planning Priority W15: “Increasing urban canopy and green grid connections” (Greater Sydney Commission 2018b, p 119).
4.6 Factors affecting the potential for tree-lined streets
4.6.1 Government support for trees
All participants of the interviews and focus group indicated that they understood the importance of street trees as well as the planning priorities of the Greater Sydney Commission and Camden Council’s requirements to implement those priorities. There appeared to be consensus that although the inclusion of trees was supported in principle, in practice there were too many factors that took priority over trees. One participant suggested that “what we look at is what’s left there for the tree”.
4.6.2 Planning controls and processes
Numerous participants expressed disquiet that Camden is subject to four separate Development Control Plans (Camden DCP, Oran Park Precinct DCP, Turner Road Precinct DCP and Camden Growth Centre Precincts DCP – see section 4.2 above) which were prepared and adopted on different dates and consequently have different priorities, inconsistent guidance and varying development characters.
In addition, the historical planning process for land release areas, which involved landowners and developers providing an indicative layout plan with self-determined road hierarchies and widths, has impacted on the road network of Camden. Inconsistent designs for streets are a barrier to implementing tree-lined streets as there can be spatial discrepancies in the street network and sometimes within one street that crosses developments. The recently published 2019 Camden DCP (Camden Council 2019a) attempts to reconcile planning controls in the Camden LGA with the Oran Park DCP in order to provide consistent development guidance and character for Camden.
4.6.3 Austroads Guide
Austroads is a member-based organisation for road managers in Australia and New Zealand. It publishes a 15-part suite of documents collectively known as The Guide to Road Design (Austroads Guide) that includes parts on geometric design; intersection, crossings and
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roundabout design; road drainage; and the roadside environment. Consistency across the national road network is valued as a means to provide drivers with visual cues that increase safety on the roads: "a road whose features tell the driver what type of road it is and therefore what can be expected in terms of the elements of the design." (Austroads 2015b, p 12) . The Austroads Guide has been adopted by state governments throughout Australia and New Zealand to ensure that roads are safe for all users and consistent in their design. Nevertheless, it is not statutory and the preface states: “This Guide is produced by Austroads as a general guide. Its application is discretionary.” (Austroads 2015b, p 0). the Guide moves away from rigid design limits as the basis for achieving these goals, and promotes the concept of 'context-sensitive design'." (Austroads 2015b, p 11).
The Austroads Guide is intended to apply “across the range of road categories, from major roads to local roads, but does not address urban local-access roads” (Austroads 2015b, p 3). Urban local-access roads are not defined in the glossary, but given that the tables through the different parts of the Austroads Guide use 60km/hr and a traffic volume of 750 vehicles per day as the lowest category of road, it can be inferred that streets designed for maximum speeds of 50km/hr with a low volume of traffic are urban local-access roads. A study of US crash data and urban canopy found that in urban areas "increased tree canopy coverage was significantly associated with fewer crashes." (Marshall, Coppola & Golombek 2018, p 140).
The application of Austroads design guidelines was mentioned by five of the eleven participants as being a constraint that prevents the implementation of tree-lined streets. Some Camden Council interviewees working in the Community Assets team felt that the use of the Austroads Guide was discretionary, but comments from interviewees in the Planning and Environment team who either write conditions of consent for planning approvals or certify subdivisions, suggested that compliance with Austroads is mandatory.
Interviewees suggested that in relation to street trees, the most challenging part of the Austroads Guide is the requirement for roads to have a clear zone, which “is the area adjacent to the traffic lane that should be kept free from features that would be potentially hazardous to errant vehicles” (Austroads 2018, p 13). Features hazardous to an errant vehicle include trees with a trunk diameter of 100mm or more (Austroads 2018, p 23). Austroads identifies trees with a diameter of over 70-100mm as hazardous to an errant vehicle (Austroads 2015a, p 27, Austroads 2018, p 23). However, Wolf and Bratton (2006) suggest that this is a rule of thumb from the American Association of State Highway and Transportation Officials and cites
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Ziegler as finding that fatal accidents in the US that involve trees are usually associated with trees with a diameter of 500mm or more (Wolf & Bratton 2006, p 171).
Clear zones are a dimensioned offset from the edge of the travelling lane. Their width depends on a number of factors, including the design speed of the road and the anticipated number of cars. Table 4.1 of Part 6 of the Austroads Guide indicates that on a flat road with an anticipated average daily traffic of 750 vehicles or less and a design speed of 60km/hr or less, the clear zone is 3m. (Austroads 2018, p 15). This zone needs to be either kept clear of hazards of protected by a barrier of some form that keeps cars on the road.
One interviewee commented on the use of roll kerbs and barrier kerbs in regard to the clear zone. Table C12.2 of Part 6 (Austroads 2018, p 251) defines barrier kerbs as being near-vertical kerbs that are 150mm high, which are limited to use in high-speed environments. However, the interviewee suggested that in a low speed environment, a barrier kerb should eliminate the need for a clear zone: “The whole point of a barrier kerb is that it deflects traffic at slower speed”. The same interviewee also noted that as the clear zone is measured from the edge of the travelling lane, parked cars are within the clear zone.
One participant suggested that if Austroads is referenced in a development consent then it must be complied with. This was queried with a statutory planner who indicated that Austroads is included in conditions of consent as it is referenced in the engineering specification.
4.6.4 Engineering specifications
The Camden Council Engineering Design Specification (Engineering Spec) outlines Council’s minimum design standard for the subdivisions in the Camden LGA (Camden Council 2017, p 14). The Engineering Spec ensures uniformity across subdivisions and states that departures from the specifications are generally not permitted but that Council will consider alternatives that have been demonstrated to be fit for purpose. (Camden Council 2017, p 16).
The Engineering Spec states that if there are inconsistencies between standards, then the relevant section of the Camden DCP applies (Camden Council 2017, p 27). “If there are any differences in practice between the RMS [Roads and Maritime Services] supplements and other RMS complementary material, the RMS supplements will apply.” (Camden Council 2017, p 16). As the Austroads Guide is an RMS supplement, it can be inferred that its provisions are obligatory in Camden.
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For road design, the Engineering Spec is intended to be read in conjunction with the Austroads Guide (Camden Council 2017, p 23). The road design section sets out the verge width and kerb type for roads not described by the relevant DCP.
Of particular interest is the section on street trees (Section 5.3.2) that states: “Street trees spacing of 18 metres apart (from main stem to main stem) should be considered as a standard guide for installation numbers requirements.” (Camden Council 2017, p 92).
The specification for spacing of street trees set out in the Engineering Spec (see section 2.3.x above) was cited by one participant as being important in the review and certification process. Although the Engineering Spec defers to DCPs, it was cited by focus group participants and interviewees as being the pre-eminent standard that determines street tree placement.
4.6.5 Staged construction
Several interviewees and participants commented on staging of development as being a challenge in the implementation of tree-lined streets. There are four types of staging that affect streets:
- New subdivisions abut and extend existing suburbs that may have been subject to different planning and street design regulations. - Different DCPs within the LGA sometimes have different widths to roads that connect the two areas and different land release areas in the Camden DCP have different road widths. - New subdivisions are staged across the suburbs (e.g. a developer will concentrate construction on a few streets that are released to the market before the next section commences). - Elements within the subdivision are also staged across the construction period.
Staging elements across the construction period refers to the process where the developer delivers a completed subdivision with lot layouts, utilities and all work within the road reserve to achieve subdivision occupation. This generally means that the footpaths and street trees are implemented prior to the lots being handed over to the owners and their builders. Several interviewees noted that street trees are sometimes lost and not replaced once the builders take possession of the house site.
As noted in Section 4.2 Planning controls (above), there are four DCPs that apply to Camden. Although there is an attempt to harmonise them, they are regulated by two different authorities (NSW Department of Planning and Camden Council), so the harmonisation process
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is ongoing. One interviewee stated: “It is a really frustrating thing that we do have different sizes [of streets] between all the DCPs”. Table 4.4 demonstrates the range of inconsistencies across the street network by showing the planning controls from the Engineering Spec and the DCPs. It should be noted that the specifications for different areas set out in the Schedules to the Camden DCP 2019 resulted from the historical inclusion of land release areas in the Camden DCP; however, most of the areas to which these Schedules pertain have been fully developed at the time of writing. One of the objectives for Camden DCP 2019 is to address these discrepancies. It should also be noted that with the exception of Emerald Hills, all the verge widths specified in the Land Release Area Schedules are wider than the 3.5m minimum of the Growth Centres.
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Table 4.4: Local street controls comparison
Planning control Road type Carriage- Footway Path width Road Kerb Type document way width width reserve Engineering Access 7ma 8.0m total 1.2m one 15.0m Roll Specification road or inclusive of side
place both sides Camden DCP Local 7.2m 4.4m to 1.4m one 16m Not Schedule access each side side specified Elderslie road Camden DCP Primary 8m 4m to each 1.2m to 16m Not Schedule Spring access side each side specified Farm road Camden DCP Local 8m min.b 4m to each 1.2m to 16m Not Schedule street with sideb each side specified Manooka Valley parking bay Camden DCP Access 6m 10m to 1.2m 16m Not Schedule road or both sidesc specified Harrington Grove place Camden DCP Local 5m 4.25m to 1.2m to 14.5m Not Schedule street each side each side specified Camden Lakeside Camden DCP Local road 9m 3.5m to 1.2m to 16m Roll Schedule each side each side Emerald Hills City Growth Primary 9m 3.5m to 1.2m to 16m Not Centres DCP local street each side each side specified Oran Park DCP Local 7.4m 3.5m to 1.2m one 14.4m Rolld street each side side Turner Road DCP Local 7.4m 3.5m to 1.2m one 14.4m Rolld street each side side
Source: (Camden Council 2017; Camden Council 2019a; NSW Planning and Environment 2018; NSW Planning and Environment 2016b; NSW Planning and Environment 2016a). Notes:
a. Connecting road or cul-de- sac up to 200m. b. Manooka Valley: carriageway is increased by 4m where parking bays are present and verge is decreased accordingly. c. Harrington Grove: either 5m to each side, or 6m one side and 4m the other. d. Oran Park and Turner Road: barrier kerb is permitted if carriageway is increased by 200mm.
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4.6.6 Waste collection requirements
A number of interviewees mentioned waste collection requirements as having a significant negative affect on tree-lined streets as the space required for waste collection further constrains the already limited space of the street. Camden Council’s Waste Management Guideline refers to the Camden DCP and specifies the requirements for the collection of waste from subdivisions. Waste is collected weekly and “each dwelling must allow for the storage and presentation of 3 (three) 240L bins” (Camden Council 2019d, 4.2.1). This equates to an footprint of 3m x 900mm located adjacent to the kerb. The guideline states that “collection will not occur from lot driveways” (Camden Council 2019d, 4.1(h)), meaning that in addition to the space in the verge required for a driveway, a dedicated zone for waste is also required for each lot. The truck requires a clear area of 2.4m (horizontal) x 4.5m (vertical) and the guideline indicates that “removal of specific street trees may be required to ensure servicing can occur” (Camden Council 2019d, 4.1(h)). If complied with, this vertical clearance means that eight metre canopy street trees cannot be planted within four metres of the bins.
4.6.7 Camden Council specifications for access driveways
The Council’s Design and Construction Specification: Access Driveways (Camden Council 2019b) (Access Driveway Specification) nominates the minimum requirements for driveways across the public land of the street verge. It applies to urban residential, rural residential and industrial and commercial driveways. For single-family detached dwellings, all Camden DCPs include a control to set back the front façade of the house by 4.5m and the garage a further metre behind. The purpose of the control is to ensure that streets are not dominated by garages, but are instead characterised by articulated facades (NSW Planning and Environment 2016a; NSW Planning and Environment 2016b; Camden Council 2019a). The Access Driveway Specification permits a driveway over the verge of equal width to the garage door, rather than widening to the garage door once the property boundary has been crossed.
Table 4.5: Driveway widths across public land Garage Single Double Triple Minimum Maximum Minimum Maximum Minimum Maximum Width 3m 4m 4m 5.5m 4m 6.5m Source: Camden Council (2019b, p 9).
The application for a new driveway across the verge is through an online application form. When constructing a driveway, the concrete reinforcement must be inspected by a council engineer, but as this occurs during the construction period, the final certification is self-
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certified. If a tree is in the way of the driveway location, a non-standard application is used that requires the applicant to replace the tree. However, this replacement does not always occur. A number of interviewees commented that trees being removed for driveway construction was a significant factor in losing street trees. One interviewee stated: “If you remove a tree, they might say you need to replant it, but that is often when you lose the trees, when the driveways go in.”
Throughout the consultation process driveways were raised as an issue that affects tree-lined streets by participants in both the interviews and focus group. Although all the DCPs that apply to Camden aim to reduce the dominance of garages in the street by setting them back behind the house façade, the narrow lot frontages permissible in the LEP and DCPs result in driveways being prominent in many residential streets.
Participants noted that there is a development trend to reduce carriageway widths, however, there were varying opinions regarding the impact of this on driveway widths. One interviewee (from an engineering background) suggested that driveways need to be of a certain width so that cars can turn onto the driveway without needing to swing onto the wrong side of the road. Another (also from an engineering background) suggested that in low volume local access streets, swinging out into the middle of the road to turn onto a driveway was acceptable.
This suggests turning paths are not the reason for the varying width of the driveways. If a vehicle can turn onto a four metre driveway, then the carriageway width is not the reason for wider driveways. Instead, the driveway widths appear to be determined by garage size and the desire for off-street parking. Carriageway widths do impact on-street parking, but in low volume, local access streets, it is possible (and desirable from a pedestrian safety perspective) to slow vehicles down so that they can negotiate parked cars. Figure 4.16 shows on-street car parking in a narrow street in Spring Farm (a subdivision in the southern part of Camden LGA). It is worth noting that the cars utilize the full width of the roll kerb. The Oran Park and Turner Road DCPs distinguish between streets with roll kerbs and barrier kerbs. In streets with barrier kerbs, the DCP control specifies the carriageway to be 200mm wider than if a roll kerb is used.
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Figure 4.16: Cilento Street, Spring Farm Source: author
As well as the width, the permissible location of the driveway is specified in the Access Driveway Specification. There are minimum offsets to drainage and pram ramps (Camden Council 2019b, p 3) as well as to light poles and electrical pillars (Camden Council 2019b, p 4). Once these are complied with, the driveway can go anywhere on the frontage. It is worth noting that although the online application for driveways asks whether the proposed driveway necessitates tree removal or relocation, the Specification cites Council’s Tree Preservation Order that defines a tree as being 3m or more in height; 100mm diameter trunk at 1m above the ground; or with a spread of 3m or more (Camden Council 2015, p 6). The Camden DCP requires street trees to be planted at a minimum size of 75l (most species are approximately 2- 2.5m tall at this pot size), so newly planted street trees are unlikely to meet the definition of a tree. Some participants suggested that there is an entitlement to place your driveway wherever you like and although the driveway application requires the applicant to replace a street tree if affected by the driveway, interviewees noted that the certification check list does not include the replacement of trees.
The location of the driveway is also linked to the kerb type. Roll kerbs are used so that the home-owners can place their driveway in any place on the frontage at any width (providing the Specification is complied with). Roll kerbs allow a vehicle to roll over them and on streets with narrow carriageways, participants indicated that residents park over the kerb. This is not permitted by Camden Council, but is an unintended consequence of roll kerbs. Cars parking on the verge was identified in the findings as a barrier to tree-lined streets as there have been instances across the LGA where trees have been damaged and destroyed by cars parked partially or fully on the verge (see Figure 4.17).
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(a) Romney Street, Narellan (b) Lorimer Crescent, Narellan Figure 4.17: Car Parking on the Verge Source: author
Temporal staging of the development, where the streets and verges are completed at the subdivision stage and the homes built later, was highlighted by many participants as a reason that roll kerbs were preferred. If a barrier kerb was installed, the home owner would need to cut into the kerb and rebuild a section of the carriageway. This leads to damage to the road surface which may shorten the life span for the surface due to water ingress at the joints and as the carriageway is patched, an inconsistent finish. However, by mandating the location and width of the driveway, the construction staging could change so that the subdivision developer could deliver the driveway as well as the kerb, carriageway, footpath and utilities. This negates the need for the roll kerb and could facilitate the use of barrier kerbs.
The area of the road reserve (boundary to boundary) shown in Figure 4.19 is 1210m2 and if an 8m tree were located as shown, this would equate to a canopy of 553m2 or 45.7%. Not only does this increase the urban canopy in this area, it exceeds the canopy target for a suburban street.
There is some hope amongst participants that the Western Sydney City Deal’s process currently underway to create a common Street Design Guidelines (WSSDG) and Harmonised Engineering Specification will resolve some of the issues around street trees and the conflicting requirements of other street elements. A risk identified by interviewees for Council and individuals certifiers is the absence of an alternate standard that can be applied to streets (in place of Austroads and Streets Opening Coordination Council). 1
.1 At the date of writing, a commercial in confidence first draft of the Urban Design Guidelines has been distributed to the City Deals Urban Design Working Group and the Engineering Specification Working
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However, some interviewees had some doubt that the common guidelines will be adopted in full by Camden Council. It was suggested that there may be resistance to common design guidelines because of the perceptions that Camden’s specific character will be diminished and that a generic character across Western Sydney will dominate. Embedding tree-focused amendments in the DCP would complement the City Deals common guidelines, but if they are not adopted by Council, the DCP amendments would assist in achieving the planning priorities for Camden that involve street trees.
4.6.8 Lot Sizes
The interviews and focus group found that narrow lot frontages were a barrier to tree planting. Table 3.2 of Camden DCP permits lots between 300m2 and 450m2 to have a frontage of 9m. A front-loaded 9m frontage with 3m allocation for waste collection and the minimum driveway width (see Action 3 below) cannot support a street tree with a spread of 8m if the waste collection specification is complied with.
The findings suggest that it is the combination of driveway width, waste collection space and lot frontages that impact on street trees. Mapping found that in the verge adjacent to 12.5m lots it is possible to fit a tree on the boundary, a 4m wide driveway and to comply with the provisions of the Waste Guidelines. However, it requires careful placement of the driveway. Figure 4.18 shows a detailed section of the Oran Park subject area. These 12.5m and 15m lot frontages are larger than the minimum 9m frontage permitted. The random placement of the driveways means that if 8m trees were planted on the prolongation of the boundary, 80% of the 12.5m lots (four or five lots) would be non-compliant as the trees would eventually grow over the waste area.
Group have met with a draft specification anticipated in late 2019/ early 2020. As these documents are commercial in confidence, they have not been sighted and do not form part of this research.
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Figure 4.18: 8m tree on the prolongation of the boundary - random driveways Rectangles indicate conflicts between driveways, waste and trees Source: author
Figure 4.19 shows the detailed area of Oran Park (as shown in Figure 4.18) but with 4m wide driveways set at a consistent position offset from the boundary by 1m. Driveways are located on the western side of the property and therefore shaded by the tree helping to reduce the absorption of heat and the subsequent heat island effect. All waste areas comply with the lifting arm requirement, and in spite of the two lot widths, a tree-lined street would be realized here making this street contribute fully to the realization of the strategic vision of a Parkland City.
Figure 4.19: 8m tree on the prolongation of the boundary - 4m driveways in consistent position Source: author
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Three tree sizes were tested to confirm whether the driveway and waste specifications could be complied with. Figure 4.20(a) shows a large tree with a 16m spread planted on the prolongation of the boundary of every second lot. Using this size tree it is possible to create a tree-lined street with 9m frontages. However, the trees would need to be very large with a clear trunk of 4-4.5m to ensure that the lifting arm of the garbage truck could operate. A tree of this size would most likely have root conflicts with underground utilities.
Figure 4.20(b) shows a medium tree with an 8m spread planted on the prolongation of the boundary of each lot. This is the goldilocks tree – large enough to create a shaded, tree-lined street, but not so large that the root system is likely to damage underground utilities. However, the spread of the canopy is likely to extend into the airspace for waste collection, meaning that in the future, council arborists will come under pressure to remove the trees.
Figure 4.20(c) shows a small tree planted on the prolongation of the boundary of each lot. This is not ideal as the tree will not provide shade to the footpath and verge (let alone the carriageway). A 3m waste collection area cannot be accommodated in this verge as the canopy will obstruct the lifting arm.
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a) 16m tree canopies extend over all waste collection spaces
b) 8m tree canopies partially extend over all waste collection spaces
c) 5m canopies partially extend over all waste collection spaces
Figure 4.20: Tree size comparison on a 9m lot frontage a) 16m trees, b) 8m trees, c) 5m trees Source: Author
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Assuming a minimum driveway width of 4m and waste area of 3m, the minimum lot width that can accommodate 8m trees is 11.75m (see Figure 4.21). This allows the driveway to be offset from the boundary by 750mm to accommodate an electricity pillar (if required).
Figure 4.21: Minimum lot frontage to accommodate trees, driveways and waste All waste collection areas are open from canopy Source: author
4.6.9 Community perceptions
The focus group suggested that there are community perceptions that impact on trees. These include perceptions of tree sizes obtained from generic online sources and perceptions about the value of trees. One participant suggested that residents sometimes over-estimate the size that a particular species is likely to attain in Camden because a generic internet search has revealed its maximum size in its ideal habitat and ideal soil volume. It was suggested that some residents have become concerned about future damage to their property caused by tree root heave or falling branches, and consequently the value of their home. This has led to residents removing trees when they are small or resisting Council’s attempts to plant trees. One participant suggested that residents seem to view the verge as an extension of their property and that this perceived ownership empowered them to remove street trees from the verge to facilitate other functions such as parking.
There was also a feeling that biodiversity certification and the biobanking scheme indicates that trees are not valued by state government. Biodiversity certification and biobanking are processes established and regulated under the Threatened Species Conservation Act 1995 (NSW). “The process identifies areas that can be developed after they are certified and
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measures to offset the impacts of development” (NSW Government 29.11.18). Some participants felt that biobanking leads to conflicting ideas about the value of trees with individuals asking why the tree in their verge is so important when large tracts of urban bushland are being removed elsewhere.
4.6.10 Pace of development
A theme that was identified by all interviewees was that the rapidity of development in Camden results in difficulties in resourcing the planning, implementation, certification and maintenance of Council’s assets. For street trees, the added complication in implementing an ordered street tree plan is that trees require a lead time measured in growing seasons, not weeks. There may be an agreement that a certain species will be planted in a certain street, but if the trees are not available at the appropriate size at the time of planting, then the species will be changed to meet the construction and certification program.
This sometimes leads to outcomes that were not intended by Council, the developer or the designer.
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5 Discussion Trees provide numerous services to the community, to the climate, to animals and even to other vegetation. The NSW Government recognises these benefits, as do Camden Council and all the participants in the interviews and focus group. The benefits of urban trees have been documented in the literature review, and it is worth reiterating that there are economic, health and ecosystem benefits that urban trees provide, one of which is mitigation of urban heat. The Greater Sydney Commission has enacted a planning priority to increase urban canopy in the Western Sydney District and the urban heat already being experienced there is, on its own, a compelling reason to do so. Increasing the urban canopy is not just about achieving a number. The point is not to tick a box, but instead to ensure that urban canopy benefits are maximised and available to all. Urban trees in parks and similar public open space can assist with increasing the overall urban canopy, but most new houses do not abut public parks and will not experience the benefits of shade from these trees. All land needs to contribute to urban canopy increases, but the dominant development model in Camden suggests that private open space is unlikely to offer a significant contribution.
Streets are a critical land resource that must be exploited to the full potential for infrastructure delivery and this includes urban canopy. A large proportion of a resident’s time is spent in moving between home and a public destination; given the predominant development model of single-family, detached houses, most of the residents of western Sydney suburbs will start or finish their journey in a local street. Local access streets could support an important part of the urban forest. In addition to the climate benefits provided by all urban trees, tree-lined streets could shade houses and the heat-absorbing surfaces of the street, give scale to the street and shelter footpaths too. Although this research commenced with a view that a quantitative methodology would “prove” that trees and utilities could be accommodated in the street, as the research proceeded it became apparent that the problem is political as well as technical.
There is broadly expressed political support to incorporate street trees in new residential subdivisions. The policy review in Chapter 2 indicates political support for trees at all levels of government: at the federal level through the City Deals program being managed by the Commonwealth Department of Infrastructure, Transport, Cities and Regional Development; at the state level through the Greater Sydney Commission and its vision for a connected parkland city with an increased urban canopy and through the exhibition of the Government Architect New South Wales’ Draft Urban Tree Canopy Guide (2018) and associated procedures; and at
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the local level in Camden Council through the draft Local Strategic Planning Statement. However, this investigation has found that while the vision is clearly articulated in policy, the procedures for achieving tree-lined streets have not been resolved.
Four actions that could be adopted to implement tree-lined streets in the Western Sydney Region are:
1. Create a state environmental planning policy for urban trees. 2. Amend development control plans to embed street tree controls throughout the plans. 3. Mandate the location and width of driveways in new subdivisions. 4. Create a Camden-wide street tree master plan.
A new SEPP for urban trees would apply to the whole of NSW and could be replicated in other jurisdictions. The other actions that apply specifically to Camden could also be replicated in other states and LGAs. Together these actions would ensure that future streets would be lined with trees. But the actions are completely independent of one another and each in isolation will assist in the implementation of tree-lined streets across NSW. The actions are discussed in sections 5.2–5.5 below, but first it is worth commenting upon the process that arrived at these recommendations.
5.1 A Discussion of the Findings Camden Council’s landscape architect, Tim Vyse, nominated council staff involved in decision- making about street trees for participation in the interviews and focus group. These nominees were all from the Planning and Environment team and the Community Assets team. The council officers who took part in the research were all well-informed and cognisant of the importance of street trees and the challenges in establishing them in new subdivisions. Although all participants indicated support for trees, they expressed misgivings that Council have been divested of control of the processes that affect street trees by policies and processes at the state level. Examples included the Greater Sydney Commission’s population projections for Camden, and two SEPPs, namely State Environmental Planning Policy (Exempt and Complying Development Codes) 2008 and State Environmental Planning Policy (Sydney Region Growth Centres) 2006. They also identified procedural barriers to street tree planting including the application of Austroads (in the absence of any other agreed standard), the location and width of driveways and the space required for waste collection. Other barriers included the value placed on trees by residents and builders.
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In the focus group design exercise, council officers were asked to draw or design the ideal street tree configuration. No further instruction was given, but the participants could select one of three plans on which to apply the configuration:
- two that reflected areas of Oran Park as a true representation of the street (accurate lot, street and verge widths); and - one that showed an accurate plan of the lots and carriageway but with a widened verge (4.5m wide).
All participants chose the plans with a true representation of Oran Park (3.5m verge) and all produced designs with large canopy trees (Figure 4.13 - Figure 4.16). The designs demonstrated the desire for tree-lined streets and the layout of the trees infer that tree-lined streets have a contiguous canopy of medium to large trees.
The barriers identified in the interviews and focus group discussion pertained to the whole of the LGA. The two areas in Oran Park and Harrington Park that were investigated and mapped not only demonstrate the benefits of tree-lined streets, but also the real-world effect of the barriers identified by participants.
It is worth noting that a limitation of the mapping is that the canopy measurements are for the projected maximum size that can reasonably be anticipated in Camden. In Harrington Park, where the trees are semi-mature, the maps confidently predict the canopy benefits. In Oran Park, were the trees are newly planted, the maps assume that all trees currently planted grow to their mature size. The species are hardy and there is a reasonable expectation that the trees will grow in the increasingly hot dry climate of Camden. Thus the findings of the canopy measurements ere on the side of optimism.
The maps show that the State Government’s 40% urban canopy cover target is unlikely to be achieved in the two study areas. However, what was interesting is that in Harrington Park the target is achieved as a percentage of the street area (40.62%) and that given the size of the lots, the target could be achieved across the whole area if the residents chose to plant trees. This is markedly different from Oran Park, where the anticipated canopy cover of the streets is 25.12% of the street area, and the lot areas are unlikely to support trees even if residents were to plant them.
The ground truthing for the maps was undertaken during three site visits in late Spring in 2019. The highest temperature experienced on a ground-truthing visit was 33 degrees (24th October 2019). Even though this visit was in spring, the heat made walking in the full sun very
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uncomfortable. However, in Harrington Park the benefits of the urban canopy were experienced: the streets felt cool and comfortable to walk along; the habitat provided by the exotic trees was evidenced in the sighting of numerous birds including red-rumped parrots, galahs and crested pigeons; the houses, driveways and garages receded so that as a pedestrian the dominant focus was the trees. At the time of writing (10th January 2020) the Bureau of Meteorology records that Camden has experienced 23 days over 30°C since the start of summer (1st December 2019). Of these 11 days were over 35°C and four days over 40°C.
It is worth noting that both Oran Park and Harrington Park are exemplary for urban design outcomes. Both Oran Park and Harrington Park have developers that are committed to planting street trees, both have exceeded the minimum road widths and neither has lots at the minimum lot size. As such, this research has examined some of the best examples of residential development in Camden. In spite of this, these two examples, combined with the qualitative research (interviews and focus-group), illustrate the challenges faced in the implementation of policy due to conflicting procedures that generally do not favour street trees.
One of the interviewees commented that in the preparation of development controls, planners need to be prescriptive enough to prevent low quality outcomes, but not so prescriptive to preclude innovative, high quality outcomes. The Actions outlined below are not intended to mandate numbers or locations of trees, but instead are intended to elevate the status of trees in the planning process.
5.2 Action One: create a new SEPP for urban trees At present in New South Wales, two SEPPs are in place that apply to vegetation in urban areas: State Environmental Planning Policy No 19—Bushland in Urban Areas, which states in cl 2 that it aims “to protect and preserve bushland within” specified urban areas; and State Environmental Planning Policy (Vegetation in Non-Rural Areas) 2017, which states in cl 3(a) that it aims “to protect the biodiversity values of trees and other vegetation in non-rural areas of the State”. These SEPPs were put in place to protect urban vegetation and bushland, but they also outline mechanisms to clear the bushland and allow for offset planting. The protections are concerned with preservation or replacement of existing trees and vegetation, but they do not apply to new trees or provide a mechanism to create an urban forest. This could be addressed in a new state environmental planning policy – SEPP: Urban Trees.
The objective of the proposed SEPP: Urban Trees is to cultivate an urban forest that provides ongoing ecosystem services to people living in urban areas. It would complement the urban
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vegetation and bushland SEPPs, but with an emphasis on creation rather than preservation or replacement.
Several participants in the research commented on the community value attributed to trees. Comments included that trees are divisive; that there are more instances of residents wanting to remove trees than to plant them; or, that there is a lack of education about trees leading to fears that trees will become problematic. The EP+A Act requires that prior to a SEPP being made, the Planning Minister must take steps “to publicise an explanation of the intended effect of the proposed instrument” (s 3.30(1)(a)). Although politically risky, the creation of SEPP: Urban Trees would generate an informed public discussion about the value of the urban forest and the benefits that trees bring. The policy will require that planning authorities ensure that new trees can be planted. It would not require home owners to plant trees in their gardens, but it would require that space is provided that could support a tree. It would therefore necessitate amendments to SEPP (Exempt and Complying Development Codes) 2008 to increase the minimum landscape area and minimum landscape dimensions in residential lots so that trees could be accommodated.
In terms of street trees, the proposed SEPP could also reinvest planning authority in local government. The council would act as the coordinator to ensure that space allocations for utilities are resolved in the planning and design phase. This could force a resolution to the problem of underground space conflicts and street trees by enabling Councils to mandate shared trenches (when safe to do so) and also to look at alternative locations such as placing utilities in parking lanes or carriageways of low speed, low volume streets.
The public health impact of urban heat is a compelling argument for increasing tree canopy cover. Increasing temperatures and extreme heat events throughout the state will soon implicate urban heat as a state significant issue. Sydney’s landform exacerbates urban heat in Western Sydney. So why create SEPP: Urban Trees? Why not SEPP: Urban Heat?
All urban areas benefit from a thriving urban forest and mitigation of heat is not the only benefit. If Sydney loses its urban forest, then objectives across numerous policies will be affected: liveability, social connectedness and equality are all influenced by the urban forest. The political will is evidenced by programs such as the NSW Government’s 5 million trees for a greener Sydney by 2030 and the 40% canopy cover targeted by both e Greater Sydney Commission and the Government Architect’s Office. The mapping shows that the current development model of detached houses on small lots largely confines urban trees to public space including streets. The comparison between Harrington Park and Oran Park indicates
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that the size of house footprint is not affected by the size of the lot – the footprint size is almost the same in both areas despite the difference in the lot size (see Figure 4.8 above). What is affected by lot size is the area for soft landscaping and gardens
SEPP: Urban Trees would also assist with mitigation of urban heat and the provision of other benefits of trees such as liveability. More importantly, perhaps, SEPP: Urban Trees would change the way that trees are viewed by all players in the development of new subdivisions, that is, planning authorities, developers and residents.
5.3 Action Two: amend the Development Control Plans There is a clear political will within Camden Council to incorporate street trees in all streets in new subdivisions. Some council officers who participated in this research were cautiously optimistic that the City Deals process would improve provisions for street trees, but others appeared more pessimistic and suggested that decreased lot sizes, lot frontages and street widths will not allow for street trees.
One mechanism that Camden Council does have complete ownership of is the Camden Development Control Plan. In common with the other DCPs that apply in Camden, Camden DCP requires street trees in local streets in new subdivisions. However, the list of criteria that needs to be considered in the design of street tree placement (see section 4.2.2 above) reads as a list of reasons not to plant; and the implication is that street trees have less value than non-living infrastructure. Unlike other forms of infrastructure in the street, street trees are designated inessential.
This list of factors to be considered allows developers to use discretion that could be to the detriment of the community and environment. Discretion in planning and construction does not lead to consistent outcomes and this is evidenced in recent high-profile controversial high rise projects: Mascot Towers and the Opal Tower (where residents have been evacuated and prevented from returning to their homes due to dangerous structural defects) have both demonstrated what can go wrong when discretion is applied in the building industry in NSW.
In the absence of controls that streets can be certified against, Appendix B of the Camden DCP leads to streets without any trees or with insufficient trees to be defined as tree-lined, in short it weakens the implementation of the strategic vision for a Parkland City and an increase in urban canopy. Figure 5.1 illustrates the result in one street in Elderslie.
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Figure 5.1: McLucas Circuit, Elderslie Source: author
The prominence of street trees in the minds of all involved in the development of new neighbourhoods would be elevated through the incorporation of street-tree focused objectives and controls that could be embedded throughout the Camden DCP.
Camden DCP starts by setting out its general objectives with reference to principles for development. Although the current objectives (a)–(j) are specific to Camden (Camden Council 2019a, p 7), adding a new objective which refers to the Sydney Regional and District Plans would assist Council to control development and ensure that it occurs in a way that gives effect to the plans and fulfils Council’s obligation to the community. This new objective (k) could be worded as follows:
k. The Directions, Planning Priorities and Actions of the Sydney Regional and District Plans are given effect in all new development in Camden LGA.
The findings in relation to minimum lot size showed that the minimum lot width to accommodate the ideal tree size of 8m canopy is 11.75m (see section 4.6.8 above). The current minimum width of 9m for a lot between 300m2 and 450m2 in Table 3-2 of the Camden DCP should therefore be amended to 11.75m (no change is required for lots of 450m2 or greater, as the minimum of 15m already exceeds this width).
Embedding requirements for street trees throughout the DCP would mean including them in all clauses that pertain to lot frontages, driveways, street networks and block locations. For example, cl3.3.2 controlling street block sizes could be amended to include a new street tree objective:
c. To facilitate the implementation of tree-lined streets.
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The street network cl 3.2.4 has similar objectives that currently exclude street trees; objective (a) of this clause could be amended by the insertion of the word “tree-lined”, thus:
a. Provide a hierarchy of interconnected tree-lined streets that provides safe, convenient and legible access within and beyond the Camden LGA.
Controls for the street verge similarly exclude street trees. The control that pertains to the landscape of the street verge could be amended to include a new requirement (in bold) as follows:
8. Civil and/or landscape plans must be provided. The plans must:
a. Indicate the location and species of the street trees (refer to Council’s Street Tree Master Plan). Trees are generally to be on the prolongation of the boundary.
Cl 3.2.5, which indicates additional controls for the street network in urban release areas, includes street trees in the objectives, but could be strengthened with a minor amendment, namely, the addition of “tree-lined” into objective (a), thus:
a. Provide a hierarchy of interconnected tree-lined streets that provides safe, convenient and legible access within and beyond the Camden LGA.
An action that could produce consistency across the road network (see section 4.6.3 above) and an increase in tree planting is to prescribe absolute widths for the road reserve, carriageway, verges and footpaths. This would require a collaboration with utilities companies to ensure that sufficient space is allocated for the different utilities and street trees, to elevate street trees to an equal status with utilities.
Bus stops, street lights and access pits that are deemed incompatible with street trees will still impact on tree-lined streets, but if street trees and an increased urban canopy were included as a principle of the DCP, then instead of a default position where trees are immediately deleted from the design, innovative ways to accommodate trees, elements and utilities will be developed.
Prescribing the width of the road reserve, verges and carriageways is outside the scope of this research, but it is worth noting that Camden’s Engineering Specification has a minimum verge width for access roads (16m reserve) of 4m (Camden Council 2017, p 28). The DCP states that street trees cannot be planted within 1m of a concrete structure (Camden Council 2019a, p 594), meaning that a minimum 2m wide zone for a tree is required in a verge with a footpath. A verge would need to be a minimum of 3.8m from boundary to back of kerb. The current
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verge width in the planning documents are shown in Table 4.4 above. If a developer were to comply with the DCP for a 3.5m verge with a footpath there would be no trees (see Figure 5.2).
(a) Existing minimum verge (b) Proposed minimum verge Figure 5.2: Typical street section comparison Source: author
The final section of the Camden DCP that refers to street trees is Appendix B – Landscape Design Principles and Submission Requirements. The long list of criteria for selection and placement of street trees, which functions as a list of reasons not to plant a tree (see 4.2.2 above), could be simply rewritten to say:
Street trees must be planted on the prolongation of the boundary 1m behind the kerb in accordance with Camden’s Street Tree Master Plan. Trees may be omitted where a streetlight is required.
These proposed amendments are not intended to be exhaustive – there are many opportunities to reinforce the importance of street trees throughout the DCP (including for driveways see section 5.4 below). However the examples demonstrate an approach that would require all players and decision makers to consider trees at the outset of the development process rather than considering them for the space left over. Trees would be considered as essential infrastructure.
Although development in Camden that is part of the South West Growth Centre Precinct is not controlled by Camden Council, Council is currently collaborating with State Government to
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prepare a new Growth Centre Precinct DCP. Therefore, there is an opportunity to integrate the recommendations into the new Growth Centres DCP as well as amending the existing Camden DCP.
5.4 Action Three: mandate driveway locations and widths The literature review and findings describe the spatial requirements of the many elements on the verge and this investigation found different factors affecting trees along the length of the street and across the width of the street. The size and frequency along the street is affected by a combination of driveway widths, driveway locations, waste collection space and lot sizes. The spatial allocation for a street tree across the width of the verge is impacted by the combination of the overall available space, structures such as footpaths and kerbs, and the application of the Austroads clear zone.
Camden is a car-dependent community and every dwelling is required to provide at least one off-street car parking space. Given the limited public transport options and the geographic distance of Camden from Sydney’s central business districts, this is understandable and not in question. What is in question is the access driveway that crosses the public space of the verge.
The Access Driveway Specification specifies the minimum and maximum permissible width of driveways. As discussed in section 4.6.7 above, provided a driveway is within the permissible range, the actual width is at the discretion of the applicant. The DCP indicates the permissible widths of the garage and this research found that the driveway width across the verge correlates with the garage door width. This action suggests mandating the width of the driveway across the public land of the verge not within the private property and residents could still opt to widen the driveway within private property.
This research found that although there is no definition for a tree-lined street, an 8m canopy tree spaced on the prolongation of the boundary provides canopy benefits without impacting on all other elements within the street. The layouts in Section 4.6.8 (above) indicate that the verge adjacent to a 9m lot frontage cannot accommodate an 8m canopy tree, a driveway and waste collection space. If the lot frontage minimum was amended to 11.75m (2.75m wider than the current minimum – see Action 2 above), the verge could accommodate a 4m driveway, 3m waste collection space and an 8m canopy tree, but only if these spaces are coordinated at the scale of the street. If tree-lined streets (and an increase in urban canopy) are to be realized, then nothing can be left to chance in the limited space of the street block.
Controlling the width of the driveway could be achieved by amending the Access Driveway Specification to restrict the maximum width across the verge to 4m. The location of the
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driveways, trees and waste allocation space would be shown on the landscape and civil drawings that form the subdivision application and the consent should not permit alterations without Council consent.
Space across the verge is a limiting factor for street trees. Increasing the width of the verge from the 3.5m minimum would provide more space for trees, but due to the cost of land may be resisted by developers. However, mandating the location of the driveway removes some of the competition for space on the verge by negating the need for roll kerbs: in particular illegal parking on the verge and the Austroads clear zone.
Although some participants questioned the impact of roll kerbs on street trees, roll kerbs do facilitate vehicles parking on the verge (albeit illegally), which compacts soil and constrains the growth of street trees. Although a car could still use the driveway to access parking on the verge, replacing roll kerbs with barrier kerbs reduces ambiguity in the street and therefore reduces the risk of street trees being unintentionally damaged by cars on the verge.
Barrier kerbs would also facilitate implementation of street trees by removing the clear zone provision for local access streets. The Austroads clear zone has been described in Section 4.6.3 above, and to summarise, clear zones allow an errant vehicle to leave the road and not encounter an infrangible object. In high speed roads where the consequence of a vehicle leaving the carriageway is serious injury or death, a flush crossover that does not deflect the vehicle back into oncoming traffic is necessary. If, however an infrangible object cannot be removed from the clear zone, then the preference is to deflect vehicles using a barrier. In low speed roads, such as local access streets where pedestrians and cycles are more likely to be present on the verge, a barrier kerb can help protect the general population by deflecting the vehicle without causing injury to the occupants of the vehicle.
This research found that roll kerbs are used so that driveways not installed at the subdivision stage, can be installed without affecting the kerb or carriageway. By mandating the location and width of the driveway, barrier kerbs could be installed. Regardless of the whether the driveway is installed at subdivision or later by the house builder, the crossovers would be installed by the developer negating the need for a roll kerb and consequently providing more space for street trees.
The subdivision developer is responsible for the infrastructure within the verge that serves the community. This includes utilities, light poles, foot paths and street trees. They are also responsible for electricity pillars and utilities stubs that service individual lots. It would be
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preferable if responsibility was extended to providing driveways and therefore all lot-servicing infrastructure that passes through public land.
The Oran DCP indicated that where barrier kerbs are used, the carriageway need to be increased by 200mm. This would be addressed in the DCP amendments described above.
5.5 Action Four: create a Camden-wide street tree master plan At the time of writing, Camden does not have a street tree master plan (STMP). The research did not examine a reason for this, but it is likely to be the result of the historical DCP process (land release area developers approaching Council with plans that are appended to the DCP as schedules) combined with the rapid development of the LGA and the resourcing requirements for Council to regulate the development. However, a short-term action in the Draft Local Strategic Planning Statement is to develop a Street and Public Tree Masterplan (Camden Council 2019c, p 67) and this is a positive step towards the implementation of the canopy targets and the implementation of tree-lined streets.
There are many compelling reasons to develop an STMP for Camden, such as: improving allocation of financial and human resources in relation to street trees; increasing the urban canopy; controlling the character of the LGA as it develops; ensuring that street trees and other infrastructure are able to co-exist; and implementing the GSC’s Planning Priority for tree- lined streets.
An STMP can assist in ensuring that the appropriate tree species of an appropriate size for planting are available at local nurseries, which will be able to access the STMP to plan for the supply of species as land is released for development. As well as benefiting the community and the LGA, in that the desired and agreed character for the streets can be implemented, it also benefits the local economy – many of the wholesale nurseries with capacity to deliver the trees in the numbers and quality required are located in the Western District of Sydney. Developers and Council benefit from more certainty in the process.
The process to develop an STMP would necessitate an inventory of the existing trees, including the juvenile street trees, in the Camden LGA, which could be held within the Council’s current geographic information system (GIS) department so that it can be continually updated. Creating and maintaining the tree inventory would allow planning for canopy trees and increase the probability of achieving the canopy targets (see section 2.3.10 above). It would also assist with planning for maintenance and replacement of infrastructure. Importantly it would also enable Council to proactively control the public space in the streets of new subdivisions rather than reacting to developer proposals.
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The tree inventory would also allow Council to measure the existing canopy and project the likelihood of achieving both Planning Priority W15 and the 40% canopy target (see section 2.3.8 above). The inventory process would involve both GIS mapping (using aerial photography, Office of Environment and Heritage data sets and the design drawings of recent developments) and ground truthing. This would enable a more rigorous inventory than using the OEH data sets alone and would empower Council to defend their statistics that demonstrate support and/ or compliance with the Planning Priority to increase the urban canopy.
An STMP would identify species that are likely to grow to their full potential in an environment experiencing the effects of climate change, including periodic drought and increasing temperatures. By assessing trees that are growing well in the current climate, arborists will be able to predict species that will grow well in hotter, drier climates. One arborist within Council suggested that the average life span of a street tree in the Camden LGA is currently 30–50 years (C. Stevens, personal communication, 25 June 2019). The canopy areas mapped in this investigation assume that the trees already planted in Oran Park and Harrington Park will reach their mature canopy size. The effects of climate change currently being experienced and the projected changes to the climate of western Sydney mean that this may not be the case and it is important that an STMP research species now for their longevity in a harsher climate if Camden is to increase the urban canopy and meet canopy targets.
An STMP would explore the cultural and ecological benefits of tree species that will help reinforce the character of the Camden LGA. Perhaps the most important benefit of an LGA- wide STMP would come from a well-articulated vision for the streets. This vision could describe the historic and evolving character of Camden and the value that Council and the community place on that character. In much of Camden the historic pastoral character of discrete villages in a rural landscape is being replaced by suburban development. Tree-lined streets that provide a physical and visual link to the landscape will help to ensure that the suburban character remains an asset to the community.
Finally, an STMP would demonstrate Council’s commitment to implementing the GSC priorities and meeting the urban canopy targets. It will help elevate the status of trees in the minds of all stakeholders and encourage people to value trees. The vision articulated in the Sydney Regional Plan is that in the future, green infrastructure “will be valued for its economic, social and environmental benefits." (Greater Sydney Commission (2018a, p 6). Hopefully this is true – it is certainly not guaranteed.
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6 Conclusion
6.1 Research outcomes There is an ethical imperative to ensure that new housing is safe and fulfils the rights of people to live healthy, long lives. In Australia codes such as the National Construction Code are in place to ensure that life-threatening or life-shortening risks are mitigated or avoided. The construction industry has numerous players with varied agendas, but we like to think that laws and policies designed to protect us and provide for our future needs are supported by effective procedures that ensure the public good trumps the agendas of individuals or corporations.
Australia lacks the political will and leadership to address climate change and is already experiencing extreme weather in the form of heat waves and prolonged drought. At the time of writing every state in Australia is experiencing bush fires and this fire season and the states of Queensland, New South Wales and Victoria are experiencing an unprecedented fire season with millions of hectares of land burnt since its premature start in August 2019. Parts of South Australia, Tasmania and Western Australia have also already had severe bushfires. Air pollution and heat-related impacts of climate change have been identified by the Australian Medical Association as having significant health and economic costs.
Despite the impacts of climate change, Australia is still considered a desirable place to live and the population is projected to increase steadily. Population projections for Sydney have guided the most recent iteration of the Sydney Regional Plan, which is the first to be enshrined in legislation. This plan projects that the Western Sydney District’s population will more than double from 2016 to 2056 (Greater Sydney Commission 2018a, p 16). In Sydney, population growth has been embraced by building in the hottest, driest parts of the Sydney basin, with 1.5 million people projected to live in western Sydney. Of the eight LGAS in the Western Parkland City, the LGA with the biggest projected population increase is Camden.
Camden’s bucolic character is being transformed into a near-contiguous subdivision. Agricultural land is being retained in the identified Metropolitan Rural Land (Greater Sydney Commission 2018b, p 6), but in the areas zoned for residential development, developers are offering detached single-family homes on small lots. The character is changing, and the new character is still in formation.
This research sought to reveal the barriers to street tree planting and to identify the policies, procedures and specifications that could be amended to address those barriers. The qualitative approach involved consultation with Camden Council officers in the form of face-to-
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face interviews and a focus group to identify the barriers to street tree planting. Two areas of Camden were mapped to review the approaches to street tree planting and the likelihood of meeting the NSW Government’s urban canopy target of 40% of the area. The findings showed that although there is political support for street trees, without amendments to policy and procedures the planning priorities to increase the urban canopy and create tree-lined street will fail.
Some council officers expressed misgivings about the efficacy of local procedures and controls given the need to accommodate such a large population. Camden Council cannot stop development, but it can shape it and effect a public domain character that is an asset to the community.
Of the four actions that this research is recommending, Actions Two, Three and Four are in the control of Camden Council.
1. Action Two: Amend the Camden Development Control Plan Embedding tree-focused language throughout the Camden DCP would elevate the status of trees in the development process so that their importance cannot be overlooked. Amendments include adding visionary statements (objectives) regarding implementing the regional and district plan’s priorities; amending controls to include trees so that they are considered in all decisions; and specific changes such as prescribing set widths for road reserves rather than minimum widths.
Collectively these amendments to the DCP would increase the prominence of street trees as essential rather than desirable infrastructure. Land release area and subdivision applications could be measured against tree-focused principles to ensure that developers are able to meet their social and environmental obligations.
2. Action Three: Mandate the location and width of driveways Spatial constraints on the ground surface of the verge were identified by participants as the largest obstacle to street tree planting. Mandating the location and width of driveways would address a number of problems, including the staging of the construction (when trees are lost); ensuring that waste collection is provided for; and removing the need for roll kerbs (which enable illegal parking on the verge to the detriment of trees) so that barrier kerbs (which negate the need for clear zones) could be installed.
3. Action Four: Create a Camden-wide Street Tree Master Plan
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A street tree master plan would assist in the implementation of tree-lined streets and an increase in the urban canopy. An inventory of existing trees would allow arborists to review which species are likely to thrive in a changing climate; and would provide a baseline measurement so that the target for canopy cover could be met. Growing an urban forest takes many years and decisions made now can have far reaching consequences. An STMP places control of the urban forest in the hands of Council. It could also be used as an education tool so that residents are informed about the trees growing in their area.
The fourth recommendation is outside Camden Council’s scope, as creation of SEPPs are the responsibility of the NSW Government:
4. Action One: Create a new SEPP: Urban Trees This policy would complement SEPP: Urban Bushland and SEPP: Vegetation in Non- Rural Areas that both seek to protect existing trees and vegetation. SEPP: Urban Trees would focus on creating a future urban forest by ensuring that trees are provided for in all new development. As it would apply to the whole of New South Wales, it would have benefits for regional towns and for the cities.
Any of the four recommendations alone would improve the chances of implementing tree- lined streets and meeting the urban canopy targets. However, mandating driveway locations and widths is the single action with the most beneficial consequences as this would coordinate space for trees and waste collection; reduce ambiguity in the street regarding on-street parking; assist with safety by enabling vehicle deflecting barriers; and therefore allow for the implementation of tree-lined streets.
It is worth noting that a new SEPP would apply to all of NSW and could also be modelled in other jurisdictions. The barriers to street tree planting identified in Camden are not localised to Camden but are common to many new developments in Sydney and in the rest of Australia. The actions suggested above could be generalised to other jurisdictions: a new SEPP would apply to all of NSW and could also be modelled in other states and territories in Australia as well as international jurisdictions; the changes to the DCP, the recommendations for the implementation of a street tree masterplan and the positive effects of mandating driveway widths and locations are all actions that could be applied by other local authorities to increase urban canopy.
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6.2 Further research Many gaps in the knowledge came to light in the course of the research. This research did not investigate the horticultural appropriateness of different species, not did it comment on the use of exotic or indigenous trees. Potential research in this area could examine the idea that the root systems of native trees are incompatible with non‐living infrastructure.
Anecdotal evidence from the author’s professional practice suggests that Councils tend to shy away from large native trees and in particular Eucalypts, but it could be argued that there is a case for smaller Eucalypts in streets that reinforce a unique Australian character. Shade is an important ecosystem service that street trees provide, and research to determine the efficacy of the seemingly lighter Eucalyptus canopy would be a valuable addition to the body of knowledge around street trees.
One participant noted that the trees in Kensington Drive, Harrington Park that were described in this research are (at the time writing) being considered for tree removal due to a conflict with waste trucks. Many streets in Sydney have trees in the verges and carriageways and waste removal services operate around them. Camden’s use of a side lifting arm should be reviewed against the benefits of trees. Trucks with a rear mechanism are more labour intensive, but further research would reveal the cost implications and benefits of using a different waste collection mechanism.
One theme that resulted from the qualitative research was that many members of the community have negative perceptions of trees. With the bushfire emergency in NSW and much of Camden being designated bushfire prone land, there is an imperative to educate the community about the values and benefits of trees. Understanding fire behaviour and the place of urban trees in fires will be important to ensuring that the policy responses to the current bushfire season do not exacerbate urban heat and increase the pace of climate change.
6.3 Final thoughts When this research began, the goal was to find empirical evidence that it is possible to accommodate street trees and non‐living infrastructure in a typical local street. The initial thoughts regarding methodology was that if the conflict between underground utilities and street trees were resolved, then it would be easy to implement tree‐lined streets. There was an idea that addressing each control item in the Camden DCP that needs to be considered before planting a tree (and therefore the list of reasons not to plant a tree) could convince council decision‐makers that it is possible to have it all. However, it quickly became apparent that there is immense support for street trees and the reasons for precluding them are not
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solely technical. What impedes the implementation of the Planning Priority W15 (Greater Sydney Commission 2018b, p 119) is the status of street trees as non-essential infrastructure. Despite the many benefits that street trees provide, as one participant stated, they are only allocated the space that is left over.
However, the personal and political will expressed in the policies and through the views of participants suggests that it is feasible to create beautiful tree-lined streets in new subdivisions. They just need to be planned for. It is likely that there will be resistance to the mandating of driveway locations, but there are many non-negotiable development and construction standards that are accepted. There are also examples in Camden LGA that demonstrate that many developers see the value of trees.
Re-writing procedures that support the implementation of tree-lined streets would give effect to the Greater Sydney Commission’s planning priorities. This would assist Camden Council to meet its legal obligations to the state government but also its ethical obligations to its constituents both present and future.
Figure 6.1: Royal George Drive, Harrington Park
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8 Appendices 1 Ethics participation template
2 Camden Council Interview Questions: Landscape Architect
3 Camden Council Interview Questions: Engineers
4 Camden Council Interview Questions: Planners #1
5 Camden Council Interview Questions: Planners #2
6 Camden Council Interview Questions: Planners #3
7 Camden Council Interview Questions: Arborists
8 Camden Council Interview Questions: Traffic and Road Safety
Christina Silk
Appendix 1. Ethics participation template
Christina Silk
Faculty of the Built Environment
PARTICIPANT INFORMATION STATEMENT AND CONSENT FORM Camden Council Urban Infrastructure; The Interface between Street Trees and the Built Environment Linda Corkery
1. What is the research study about? You are invited to take part in this research study. The research study aims to predict the probability of success of the Greater Sydney Commission’s objective to increase urban canopy by implementing tree-lined streets in the Western Parkland City. You have been invited because Camden Council are supporting the research by providing access to resources and staff within Council.
2. Who is conducting this research? The study is being carried out by the following researchers: Professor Linda Corkery and Christina Silk, Landscape Architecture Program, Faculty of Built Environment. Research Funder: This research is being funded by Landcom.
3. Inclusion/Exclusion Criteria Before you decide to participate in this research study, we need to ensure that it is ok for you to take part. The research study is looking to recruit people who meet the following criteria: • Staff member of Camden Council working in the engineering, strategic planning or landscape and urban tree teams.
4. Do I have to take part in this research study? Participation in this research study is voluntary. If you do not want to take part, you do not have to. If you decide to take part and later change your mind, you are free to withdraw from the study at any stage.
If you decide you want to take part in the research study, you will be asked to: • Read the information carefully (ask questions if necessary); • Sign and return the consent form if you decide to participate in the study; • Take a copy of this form with you to keep.
5. What does participation in this research require, and are there any risks involved? Participation in an interview and a workshop • If you decide to take part in the research study, you will be asked to participate in a face to face interview. You will be asked questions about the way that underground services are planned for and located in street verges. It should take approximately one hour to complete. To ensure we collect the responses accurately, we seek your permission to digitally record the interview using an audio application on a phone. If you would like to participate but do not wish to be recorded, you will need to discuss the options for your participation with the research team, but it is anticipated that notes can be taken during the interview. The audio recording will include your role in Council but will not include any personal information. • Following the interview, you will be asked to take part in a cross-disciplinary collaborative workshop. This will explore opportunities for different disciplines to collaborate and coordinate street trees in streets in new developments. It will also examine challenges that the participants identify to understand whether there is a process that can overcome these challenges. We will ask all participants for their permission to record the workshop. If you would like to be de- identified in the recording and subsequent transcription, please discuss with the research team.
If you decide to take part in the research study, the research team will ask you to consider the following questions and discussion topics: • What is the process to decide the allocation of underground space in street verges in masterplanned developments such as Oran Park?
HC Number: 190223 Page 1 of 5 Version dated: Participant Group:
Faculty of the Built Environment
PARTICIPANT INFORMATION STATEMENT AND CONSENT FORM Camden Council Urban Infrastructure; The Interface between Street Trees and the Built Environment Linda Corkery
• How does this differ to the process in streets developed by Council? • How does Council use the Streets Opening Coordination Council Guide to decide on the allocation of underground space? • A discussion of the risks to Council, to work health and safety and to the community if underground services are disrupted by tree roots. • How are tree root and services conflicts managed? • How does the Austroads design guide inform street design? Do the sight line provisions apply? • How do Council apply the provisions of the Greater Sydney Commission in their decision making processes for street design? • What are the impacts of SEPP Sydney Region Growth Centres (2006) on the design and implementation of streets? • How are newly planted trees maintained in masterplanned developments and in Council streets? • What are the other barriers to tree planting in streets in Camden?
It should take approximately an hour to complete the interview and one to two hours to participate in the workshop.
If you experience discomfort or feelings of distress while participating in the research and you require support, you can stop participating at any time. You can also tell a member of the research team and they will provide you with assistance.
6. What are the possible benefits to participation? We hope to use information we get from this research study to inform Council’s decision making processes around street design and implementation which will assist Council in meet the planning requirements of the Greater Sydney Commission.
7. What will happen to information about me? By signing the consent form you consent to the research team collecting and using the information that you provide in response to the interview questions for the research study. This data will be kept for 5 years (in accordance with UNSW protocol) after the project’s publication. We will store the data at the office of Professor Linda Corkery (paper) or on UNSW OneDrive (digital and audio files). The information you provide will only be used for the purpose of understanding the potential barriers to street tree planting and to inform alternative planning and design approaches. You can elect to have the date de-identified so as not to be attributable specifically to you.
The information you provide is personal information for the purposes of the Privacy and Personal Information Protection Act 1998 (NSW). You have the right of access to personal information held about you by the University, the right to request correction and amendment of it, and the right to make a complaint about a breach of the Information Protection Principles as contained in the PPIP Act. Further information on how the University protects personal information is available in the UNSW Privacy Management Plan.
8. How and when will I find out what the results of the research study are? The research team intend to publish and report the results of the research study in a variety of ways. All information published will be done in a way that will not identify you. If you would like to receive a copy of the results you can let the research team know by including your details in the space provided in the consent form.
HC Number: 190223 Page 2 of 5 Version dated: Participant Group:
Faculty of the Built Environment
PARTICIPANT INFORMATION STATEMENT AND CONSENT FORM Camden Council Urban Infrastructure; The Interface between Street Trees and the Built Environment Linda Corkery
9. What if I want to withdraw from the research study? If you do consent to participate, you may withdraw at any time. You can do so by completing the ‘Withdrawal of Consent Form’ which is provided at the end of this document. Alternatively, you can ring the research team and tell them you no longer want to participate. Your decision not to participate or to withdraw from the study will not affect your relationship with UNSW Sydney or Landcom. If you decide to leave the research study, the researchers will not collect additional information from you. Any identifiable information about you collected from the interview will be withdrawn from the research project. If you decide to participate in the workshop, your comments along with other participants will be recorded during the group discussions. Because of the way in which the group discussions are recorded, the research team will not be able to withdraw or destroy individual participant responses.
10. What should I do if I have further questions about my involvement in the research study? The person you may need to contact will depend on the nature of your query. If you require further information regarding this study or if you have any problems which may be related to your involvement in the study, you can contact the following member/s of the research team:
Research Team Contact Details Name Linda Corkery Position Chief Investigator Telephone 9385 6613 Email [email protected]
What if I have a complaint or any concerns about the research study? If you have a complaint regarding any aspect of the study or the way it is being conducted, please contact the UNSW Human Ethics Coordinator:
Complaints Contact Position UNSW Human Research Ethics Coordinator Telephone + 61 2 9385 6222 Email [email protected] HC Reference HC190223 Number
HC Number: 190223 Page 3 of 5 Version dated: Participant Group:
Faculty of the Built Environment
PARTICIPANT INFORMATION STATEMENT AND CONSENT FORM Camden Council Urban Infrastructure; The Interface between Street Trees and the Built Environment Linda Corkery
Consent Form – Participant providing own consent
Declaration by the participant
I am willing to participate in the interview; I am willing to participate in the workshop; I understand I am being asked to provide consent to participate in this research study; I have read the Participant Information Sheet or someone has read it to me in a language that I understand; I understand the purposes, study tasks and risks of the research described in the study; I understand that the research team will audio/video record the interviews; I agree to be recorded for this purpose. I provide my consent for the information collected from me to be used for the purpose of this research study only. I have had an opportunity to ask questions and I am satisfied with the answers I have received; I freely agree to participate in this research study as described and understand that I am free to withdraw at any time during the study and withdrawal will not affect my relationship with any of the named organisations and/or research team members; I would like to receive a copy of the study results via email or post, I have provided my details below and ask that they be used for this purpose only;
Name: ______
Address: ______
Email Address: ______
I understand that I will be given a signed copy of this document to keep; Participant Signature Name of Participant (please print) Signature of Research Participant Date Declaration by Researcher* I have given a verbal explanation of the research study, its study activities and risks and I believe that the participant has understood that explanation.
Researcher Signature* Name of Researcher (please print) Signature of Researcher
Date
+An appropriately qualified member of the research team must provide the explanation of, and information concerning the research study.
Note: All parties signing the consent section must date their own signature.
HC Number: 190223 Page 4 of 5 Version dated: Participant Group:
Faculty of the Built Environment
PARTICIPANT INFORMATION STATEMENT AND CONSENT FORM Camden Council Urban Infrastructure; The Interface between Street Trees and the Built Environment Linda Corkery
Form for Withdrawal of Participation
I wish to WITHDRAW my consent to participate in this research study described above and understand that such withdrawal WILL NOT affect my relationship with The University of New South Wales, Landcom. In withdrawing my consent I would like any information which I have provided for the purpose of this research study withdrawn.
Participant Signature Name of Participant (please print) Signature of Research Participant Date
The section for Withdrawal of Participation should be forwarded to: CI Name: Professor Linda Corkery Email: [email protected] Phone: 9385 6613 Postal Address: Red Centre Building, University Mall, Kensington NSW 2033
HC Number: 190223 Page 5 of 5 Version dated: Participant Group:
Appendix 2. Camden Council Interview Questions: Landscape Architect
I have some questions for you, but these are to get our conversation started. I am hoping that you will suggest other areas that I need to look at if you think there are important considerations that have not been mentioned.
The questions are loosely grouped around policy, design and planning, responsibilities, and implementation.
1. Can you describe your position and role in Council? 2. How does your work feed into / inform the LEP review? 3. For the design of streets in new developments, how do you ensure that trees are planted as per the DCP? 4. How do Council apply the provisions of the Greater Sydney Commission in their decision processes? 5. How do you coordinate internally to ensure that conflicts between services and trees are managed? 6. What is the internal Council process to decide the allocation of underground space in street verges in masterplanned developments such as Oran Park? 7. How does this differ to the process in streets developed by Council? 8. In your experience, do the guidelines of the SOCC prevent street tree planting in Camden? 9. How does the Austroads design guide inform street design? Do their roadside gudielines impact on street trees in Camden? 10. Do resident perceptions of trees affect decisions around trees in new developments? In established streets? 11. What strategies are Camden looking at to encourage walking in streets? 12. What are the barriers to walking in streets? 13. What are the impacts of SEPP Sydney Region Growth Centres (2006) on the design and implementation of streets? 14. The DCP shows trees in street sections, but doesn’t generally state a requirement for them (except in the industrial section). Is this a problem when negotiating with developers? 15. The Engineering Spec has a requirement for trees at 18m centres, but refers to the DCP as taking precedence. But, the DCP doesn’t give numbers of spacings. Is this something that could be incorporated into the DCP?
Christina Silk
16. Do you think it is feasible that Engineering Spec could be amended to give the same weight to street trees as to other elements in the street? 17. Who provides the principles and design direction for policy in Council? 18. What is the best position / role in Council to champion street trees and get real outcomes? 19. What are the other barriers to tree planting in streets in Camden?
Is there anything else that you think impacts on street trees?
Are you happy for me to give you a follow-up call if anything needs clarification?
Christina Silk
Appendix 3. Camden Council Interview Questions: Engineers
I have some questions for you, but these are to get our conversation started. I am hoping that you will suggest other areas that I need to look at if you think there are important considerations that I need to look at.
The questions are loosely grouped around design and planning, responsibilities, implementation and maintenance.
1. Can you describe your position and role in Council? 2. How does your work feed into / inform the LEP review? 3. How does the Austroads design guide inform street design? Do the sight line provisions apply? 4. Can you describe the governance of the street verge and the utilities located within it? 5. How does Council use the Streets Opening Coordination Council Guide to decide on the allocation of underground space? 6. Is Council able to negotiate with utilities providers? 7. If there is a conflict between utilities, which ones take priority? 8. Is there a ranking system for infrastructure (ie electricity takes precedence, then telecommunications, then…) or are all utilities considered equal? 9. What is the size of the different utilities in streets in Camden? 10. How are tree root and utilities conflicts managed? 11. Do utilities companies typically lay conduits for future needs? 12. Would it be feasible (from an engineering perspective) to show the broad utility routes in streets in the DCP? Eg to indicate which side of the street utilities are laid out. 13. A discussion of the risks to Council, to work health and safety and to the community if underground utilities are disrupted by tree roots. 14. What is the process to decide the allocation of underground space in street verges in masterplanned developments such as Oran Park? 15. How does this differ to the process in streets developed by Council? 16. Is it conceivable that some utilities could be laid under the carriageway in local (low volume) streets? 17. In the Engineering Specification, there are references in Section 2.7 to shared trenches, with a call to utilise shared trenches “where possible”. What are the barriers to shared trenches? 18. Is it Council’s GIS system that coordinates utilities in the verge? 19. Does Council’s Engineering Specification apply to the entire LGA including the Growth Centres? 20. What is the process to put the Specification together?
Christina Silk
21. Who sets the principles for the Specification? 22. Why do Council use roll kerbs? 23. Is the use of hinged joints (Tripstop) making an impact on the integrity of footpaths? Is Council measuring this? 24. Is there a maximum width of vehicle crossovers for detached dwellings or does it vary according to the development area? 25. What are the minimum requirements for garbage collection? Concrete pad? 26. Do you think it is feasible to include street trees in the next Specification?
Is there anything else that you think impacts on street trees?
Are you happy for me to give you a follow-up call if anything needs clarification?
Christina Silk
Appendix 4. Camden Council Interview Questions: Planners #1
I have some questions for you, but these are to get our conversation started. I am hoping that you will suggest other areas that I need to look at if you think there are important considerations that have not been mentioned.
The questions are loosely grouped around policy, design and planning, responsibilities, and implementation.
1. Can you describe your position and role in Council? 2. Can you talk me through the process within Council to prepare the LEP review? 3. The LSPS Guideline for Councils mentions that the purpose of the LSPS is to give effect to the Regional and District Plans. How do you apply the provisions of the Greater Sydney Commission in their decision processes? Particularly in reference to walkability and tree-lined streets. 4. To what extent do the GSC priorities infiltrate the detailed design of streets and public space? 5. Who decides on the principles of the planning documents? General Manager? Counsellors? 6. What are the impacts of SEPP Sydney Region Growth Centres (2006) on the design and implementation of streets? Does the LSPS apply to the Growth Centres area? 7. How are Council addressing increasing urban heat and air quality in the planning process? The LSPS report talks about both UH and infrastructure – are there specific actions planned for street trees? 8. Does Council have a definition for walkability? 9. Are tree-lined streets considered social infrastructure? 10. In the LSPS report to Council, there is a reference to a Green and Blue Grid Analysis. Has this commenced? 11. Is Council able to negotiate with utilities providers so that infrastructure is coordinated in the planning documents? Or is this beyond the scope of the planning process? 12. Would it be feasible (from a planning perspective) to show the broad utility routes in streets in the DCP? EG to indicate which side of the street utilities are laid out. 13. When assessing a DCP, in the event of a conflict who decides what takes precedence? EG if there is insufficient space in the verge for trees and utilities, is there a negotiation that can take place that could provide for both? 14. Who provides the street sections in the DCPs that show trees in the section? 15. How are other development-specific controls in the DCP designed (eg colours of roofs, driveway materials – Harrington Grove)
Christina Silk
16. In regards to the DCP, how do you compel developers to include street trees as per the sections and plans?
Is there anything else that you think impacts on street trees?
Are you happy for me to give you a follow-up call if anything needs clarification?
Christina Silk
Appendix 5. Camden Council Interview Questions: Planners #2
I have some questions for you, but these are to get our conversation started. I am hoping that you will suggest other areas that I need to look at if you think there are important considerations that have not been mentioned.
The questions are generic and I am not seeking information about the SWGC ILP, only the mechanisms to control the placement, frequency and type of street tree.
1. Can you describe your position and role in Council? 2. Can you talk me through the process to prepare the Growth Centres DCP? 3. In terms of controls such as setbacks and road widths, how closely aligned will the SWGC DCP be with the 2019 Camden DCP? 4. How do the provisions of the Greater Sydney Commission filter through to the DCP? 5. To what extent do the GSC priorities infiltrate the detailed design of streets and public space? 6. What are the impacts of SEPP Sydney Region Growth Centres (2006) on the design and implementation of streets? 7. Is there anything in the Growth Centres SEPP that precludes the installation of street trees? 8. Who provides the street sections in the DCPs that show trees in the section? 9. Would it be feasible (from a planning perspective) to show the broad utility routes in streets in the DCP? EG to indicate which side of the street utilities are laid out. 10. Is Council able to negotiate with utilities providers so that infrastructure is coordinated in the planning documents? Or is this beyond the scope of the planning process? 11. How are Council addressing increasing urban heat and air quality in the planning process? 12. Will the Camden DCP control to have a minimum of 2 car spaces in a 3 bedroom house apply to the SWGC? (Section 4.2.10 of Camden DCP) 13. The 2016 SWGC DCP has a control that street trees need to be one per lot or a maximum of 10m centres (Section 3.3.1.20). Will this be in the amended DCP?
Is there anything else that you think impacts on street trees?
Are you happy for me to give you a follow-up call if anything needs clarification?
Christina Silk
Appendix 6. Camden Council Interview Questions: Planners #3
I have some questions for you, but these are to get our conversation started. I am hoping that you will suggest other areas that I need to look at if you think there are important considerations that have not been mentioned.
1. Can you describe your position and role in Council? 2. Can you describe the process of assessing a subdivision DA? 3. Does that process differ between Growth Areas and the rest of the LGA? 4. When assessing a DA, in the event of a conflict who decides what takes precedence? EG if there is insufficient space in the verge for trees and utilities, is there a negotiation that can take place that could provide for both? 5. To what extent do you see that the GSC priorities infiltrate the detailed design of streets and public space? 6. When assessing a DA, how do you apply the provisions of the Greater Sydney Commission? 7. Do you have a view on the staging of the implementation of street trees in new subdivisions? Do you think it is better for the trees to go in prior to the subdivision certificate being issued, or would it be preferable to use a bond (or other instrument) and get the developer to return once the driveways are installed? 8. Do you think that it is feasible to mandate the location of the driveways at the subdivision stage so that the street trees are not relocated by builders/ residents? 9. In regards to CDC, if the DCP states that a property can only have a single or double garage, is it easy for the resident to increase this to a double/ triple garage? 10. If there is contradictory advice or requirements (from the various authorities), what is the process to negotiate an outcome? 11. Does Austroads apply to all roads in Camden? 12. When the DCP shows minimum street widths, do many developers increase from the minimum? 13. If the DCP showed trees in plan (at a specific interval), do you think that Council could compel developers to install them? Or are there always competing priorities that would mean that trees aren’t necessarily installed?
Is there anything else that you think impacts on street trees?
Are you happy for me to give you a follow-up call if anything needs clarification?
Christina Silk
Appendix 7. Camden Council Interview Questions: Arborists
I have some questions for you, but these are to get our conversation started. I am hoping that you will suggest other areas that I need to look at if you think there are important considerations that have not been mentioned.
The questions are loosely grouped around design and planning, responsibilities, implementation and maintenance.
1. Can you describe your position and role in Council? 2. How does your work feed into / inform the LEP review? 3. What is the policy concerning street trees and the design of streets in Camden Council? 4. How do Council apply the provisions of the Greater Sydney Commission in their decision processes? 5. How do you think residents perceive trees? 6. Do resident perceptions of trees affect decisions around trees in new developments? In established streets? 7. The various DCPs have street sections with large trees in the streets – how do these get regulated in the design process? What role do you have? 8. What is the process to decide the allocation of underground space in street verges in masterplanned developments such as Oran Park or Gregory Hills? 9. How does this differ to the process in streets developed by Council? 10. How does Council use the Streets Opening Coordination Council Guide to decide on the allocation of underground space? 11. A discussion of the risks to Council, to work health and safety and to the community if underground utilities are disrupted by tree roots. 12. How are tree root and utilities conflicts managed? 13. Does Council have a separate budget to rectify damage to infrastructure from street trees? 14. What about damage to street trees by infrastructure? 15. What proportion of the tree budget goes to rectifying damage? 16. What are the other barriers to tree planting in streets in Camden? 17. How are newly planted trees maintained in masterplanned developments and in Council streets? 18. What is the anticipated average lifespan for a street tree planted in Camden this year? Is this consistent with trees planted in the past?
Christina Silk
Appendix 8. Camden Council Interview Questions: Traffic and Road Safety
I have some questions for you, but these are to get our conversation started. I am hoping that you will suggest other areas that I need to look at if you think there are important considerations that I need to look at.
1. Can you describe your position and role in Council? 2. Can we discuss Austroads and its application in Camden? a. How does the Austroads design guide inform street design? Can you describe the provisions that apply to intersection design? b. Austroads Part 1 says that it does not apply to local-access roads in urban areas (P1, section 1.3). Is there an alternative guide or do Councils have discretion to determine street and intersection design? c. Are there different requirements in the Growth Centres and the rest of Camden? 3. Do roll kerbs contribute to safety? 4. Trees in parking lanes a. Do you have a view on these in terms of safety? b. In terms of damage to carriageways? 5. Are there any studies or papers that you would recommend in terms of road safety and trees? Do you use any statistics for road accidents and trees in your role? 6. Can we discuss driveway widths? a. the requirement to have minimum widths depending on the garage width. b. Turning circles from narrow roads. 7. Do you know why the DCP requires 2 car spaces on the property for a 3-bedroom house?
Is there anything else that you think impacts on street trees?
Are you happy for me to give you a follow-up call if anything needs clarification?
Christina Silk