Forest Ecology and Management 352 (2015) 1–2
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Editorial Introduction to the Changes in Global Forest Resources from 1990 to 2015 q
Understanding global forest resource change is more compli- that series – although this is the first time a large portion of the cated than one might think. This is true irregardless of whether technical analyses have been published in the peer-reviewed the assessment of change is done with ground-based measure- open literature. This volume was written by over 50 authors from ments, satellite image analysis, aerial imagery or some combina- some 25 countries from every continent and includes world tion of these approaches. National governments use a wide experts from many disciplines and institutional homes. Over variety of approaches in measuring, monitoring and regulating 75% of the authors are from organizations other than the Food their forests – and have access to widely divergent levels of and Agriculture Organization which organizes and leads the FRA national forest resource data. Despite the challenges that countries process. It is itself an evolutionary change in how the results dili- face – our awareness of the global role of forests in climate change, gently provided by 155 governments are aggregated and analyzed the importance of forest loss or gain and gaps in wood supply have to help us all understand the global forest resource and how it is over the past 60 years come largely from the Global Forest changing. Resources Assessment (FRA). Generally the results of FRA 2015 show positive trends – Too often the FRA is viewed solely for changes in forest area – increased knowledge about the resource, a slowing in the rate of particularly deforestation rates. While this is important, there are both forest area loss and carbon emissions from forests and many aspects of the forest resource and forest management that increasingly important actions taken by governments to improve are perhaps more important. These include indicators of stocking, sustainable forest management. designated management and ownership, sustainable forest man- The papers in this volume cover a broad range of topics – but agement and forest disturbance. What happens to the forest and still there is much more to explore from FRA 2015. We encourage how it is changing is far more than the conversion of forest land readers to look at these other sources for data and analysis of FRA to agriculture and other uses – the forest that remains as forest 2015 reporting. These include: is also often changing. Part of this comes from the activities of man – as it has been since man and forest first met. Part comes 1. The Forest Land Use Data Explorer. This online portal provides from a changing climate and the stress that this places on forests access to download FRA 2015 data, some of which has been that have adapted to site conditions that are no longer what they updated since this Special Issue was published. It also allows once were. Part of this change is also due to the fact that forests exploration of other natural resource data – including the agri- are generally always in some kind of change – whether from shifts cultural statistics kept by FAO – along with FRA 2015 data. in management, pest and disease, drought, fire, severe weather or 2. The FAO report: Global Forest Resources Assessment 2015: How some combination of these. Change is as much a part of the ecolog- are forests changing? This synthesis document represents FAO ical balance of forests as it is a critical element for foresters to summary reporting of key results from FRA 2015. It and the understand and manage. Desk Reference are available in all six official UN languages. The job governments do in monitoring and reporting on their 3. Global Forest Resources Assessment 2015 Desk Reference. This doc- forest resources is often complex. Multiple jurisdictions, changes ument provides summary tables for nearly all of the quantita- in monitoring and analysis related technologies and the availability tive variables reported in FRA 2015. It is designed to be of human and financial resources for monitoring and assessment downloaded, printed and used as a handy paper reference or a all impact how countries are able to monitor and manage their for- digital reference. ests. The countries reporting through the FRA account for nearly 4. Country Reports. Since the year 2000 Country Reports have 99% of the world’s forest area – and 91% of this area is reported been the primary source of data reported through the FRA. All in the top two quality tiers. 155 Country Reports are freely available online as are 79 Desk This volume reports forest change over the period 1990–2015. Studies that were produced for countries and territories that The Global Forest Resources Assessment has worked with govern- did not submit reports. Country reports cover nearly 99% of glo- ments since the mid-1940s to prepare and assemble a global view bal forest area. of how the world’s forests are changing. This volume is the latest in 5. Background documents, graphics and infographics are all avail- able on the FRA website (http://www.fao.org/forestry/fra/en).
q This article is part of a special issue entitled ‘‘Changes in Global Forest Resources The world has learned much about global forests and how they from 1990 to 2015’’. have changed over the last 25 years. We have discovered as well http://dx.doi.org/10.1016/j.foreco.2015.06.018 0378-1127/Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 2 Editorial / Forest Ecology and Management 352 (2015) 1–2 that the conditions for better forest management have also Greg Reams expanded during that time. This evolution is critical as total forest USDA Forest Service, National Office, 1601 North Kent Street, Suite 400, area declines, human populations and demand for forest products Arlington, VA 22209, USA continue to increase. We all have much to learn about how to meet these new challenges. Understanding the global resource is an Joberto de Freitas important part of this process. We believe this volume is one step Brazilian Forest Service, Ministry of Environment, SCEN, AV. L4, in that direction. Trecho 2, Bloco H, Brasília-DF 70818-900, Brazil
Kenneth MacDicken Available online 7 September 2015 Food and Agriculture Organization of the United Nations, Rome, Italy E-mail address: [email protected] Forest Ecology and Management 352 (2015) 3–8
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Global Forest Resources Assessment 2015: What, why and how? q
Kenneth G. MacDicken
Food and Agriculture Organization of the United Nations, Rome, Italy
article info abstract
Article history: This paper introduces a Special Issue of Forest Ecology and Management that includes a collection of ana- Received 10 November 2014 lytical results from the 2015 Global Forest Resources Assessment (FRA 2015) covering 25 years of forest Received in revised form 4 February 2015 change (1990–2015). FRA 2015 builds on a series of global assessments that began in 1948 and covers Accepted 5 February 2015 change in forest area and type, volume, biomass and carbon stocking, measures of sustainable forest Available online 7 September 2015 management, biodiversity and conservation, soil and water protective functions, wood production and a number of socio-economic variables. It covers 234 countries and territories with an emphasis on forest Keywords: resource change over a twenty-five year period (1990–2015) and also looks forward to anticipated forest Global Forest Resources Assessment 2015 change – both as government targets for forest area and projected change (to 2030) to global production FRA Global forest statistics and conservation forest area (to the year 2050). This paper describes important contributions of global Forest resource change forest resource estimates to forest management, the methods used in the collection and analysis of Forest change FRA 2015 data and provides links to additional information resources. It discusses some of the limitations of this global dataset, some of the steps taken to improve quality and the characteristics that make this type of global data most useful. While forest area change dominates public use of the FRA, the state of the forest resource and management is critical to understanding the ecological and social values of the forest and forestry. Country level reporting not only provides insights that are only possible through national reporting but also provides greater national-level understanding and discussion of forest resource change. The papers that follow in this Special Issue provide analyses of FRA 2015 data covering a wide range of topics related to sustainable forest management and forest change. Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction The first global assessment conducted by the Food and Agriculture Organization of the United Nations (FAO) was pub- 1.1. A short history of global forest resource data lished in 1948 when the main interest was well expressed in the first sentence of the report: ‘‘The whole world is suffering from We often take for granted our global knowledge of forest shortages of forest products’’ (FAO, 1948). resources. Yet it is only since the 1920s that humankind has had Global Forest Resources Assessments, coordinated by FAO, have any real understanding of the global forest resource. That knowl- been made at approximately five to ten year intervals since then. edge has changed the shape of how forests are viewed by the pub- The mandate for these assessments is found in the FAO lic – and it has influenced the investment of public and private Constitution, which states that ‘‘The Organization shall collect, money in forestry. analyze, interpret and disseminate information relating to nutri- Global information on the extent and quality of the forest tion, food and agriculture. In this Constitution, the term ‘agricul- resource did not exist until Rafael Zon and Sparhawk (1923) pro- ture’ and its derivatives include fisheries, marine products, duced the first comprehensive Global Forest Resources forestry and primary forestry products.’’ (Article I, Functions of Assessment in 1923. This ground-breaking work set the stage for the Organization, paragraph 1). all future global forest assessments and was a remarkable accom- The scope and content of global forest assessments have plishment in the aftermath of World War I. The assessment did not evolved over time to respond to changing information needs. include all countries and as a result reported world forest area as Studies of timber supply trends dominated the assessments just over 3 billion ha. through the 1960s, but from the 1980s onward they have included a wider range of forest benefits and functions. The challenges faced
q in global forest assessment begin with a persistent lack of reliable This article is part of a special issue entitled ‘‘Changes in Global Forest Resources from 1990 to 2015’’. source data to meet increasing demand for information. For E-mail address: [email protected] example, the 1992 Earth Summit in Rio de Janeiro initiated three http://dx.doi.org/10.1016/j.foreco.2015.02.006 0378-1127/Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 4 K.G. MacDicken / Forest Ecology and Management 352 (2015) 3–8 conventions (UN Framework Convention on Climate Change, FRA reports noted the rapid conversion of broadleaf tropical forest Convention on Biological Diversity and the UN Convention to into agricultural land. This helped prompt some 60 years of Combat Desertification) that each have expanded requirements increased investment by governments, companies, individuals, for countries to report on forest resources. Organizations and tech- donor agencies and civil society groups in improving forest man- nical professionals seek new global information through the FRA agement in the tropics. This investment has in turn contributed and this interest often translates into new areas of inquiry, despite to the reductions in tropical forest loss rates reported in Keenan efforts to keep the assessment focused on the forest resource. This et al. (2015) and FAO (2015). demand for information has been difficult for countries to meet in Forest stock losses due to long-term land use change, especially large part because the data often do not exist and resources for in the tropics, are an important part of greenhouse gas emissions additional data collection are scarce. (Settele et al., 2014). Forest area and growing stock changes Criticisms of FRA data have been primarily focused on detected through monitoring have provided improved understand- data-poor country reports, the lack of comparable long-term trend ing of forests in the global carbon balance – and much of the early data (Mather, 2005; Grainger, 2008; Harris et al., 2012) and work on this topic came from the FRA (Detwiler and Hall, 1988; assumptions that suggest remotely-sensed data are inherently Houghton, 2008). FRA data continues to be used in global estimates superior to forest statistics reported by sovereign nations of emissions from land use and land use change for the (Grainger, 2008; Harris et al., 2012; Hansen et al., 2013). While Intergovernmental Panel on Climate Change (IPCC) and climate the idea of long-term, high quality forest data collected using the change modelling (Smith et al., 2014; Petrescu et al., 2012). same methods across time, forest type and countries with highly Global reporting over time can help identify knowledge gaps divergent access to technical and financial resources is attractive, and highlight where improved information on forest resources is it is also most impractical. At the same time, the assumption that needed. The importance of field-based National Forest remote sensing provides clear, accurate and precise results for forest Inventories (NFI) has long been demonstrated through FRA report- change at the global scale is also tenuous. Recent attempts to report ing – both through the value of reported inventory results and the global forest change have made the mistake of characterizing tree identification of serious data gaps in countries where these inven- cover change from satellite imagery as forest change (Harris et al., tories do not yet exist. The FRA 2015 dataset adds value to NFI 2012; Hansen et al., 2013) without regard to the processes of natural results by providing a Tier system that integrates data age and regeneration and reforestation. Both of these studies have confused source classes. The need for updated field-based forest inventory the distinction between forest and woody horticultural crops and as has become increasingly important for climate change mitigation a result reflect tree canopy change, but not necessarily forest efforts such as the Reducing Emissions from Deforestation and change. Neither remote sensing nor country-based reporting pro- Degradation (REDD+) mechanism. vides perfect answers to forest resource change questions. An anal- The inclusion in FRA global reports of earth observing satellite ysis of how results from FRA 2015 and remote sensing studies data such as those obtained and derived from the Landsat sensor compare is found in Keenan et al. (2015). have become a useful adjunct to country reporting on forest extent Global Forest Resources Assessment (FRA) 2015 statistics and over time. The integration of Landsat in tracking forest cover analyses reported in this volume inherit many of the same change in the tropics (FRA 1980, 1990, 2000) has helped highlight strengths and weaknesses as the 1948 assessment, yet it is also a the global value of this unique dataset. At the same time the use of very different assessment in scope, transparency and quality. remote sensing in national forest inventories on which many FRA More national forest inventories were available for FRA 2015 than country reports are based has grown substantially (MacDicken for any other global assessment – 70% of them utilized remote et al., 2015). sensing for at least a portion of the inventory. In 1948, one hundred and one countries and territories reported – in 2015, this increased 2. Methods to 234 countries and territories. While public interest in forest change presently seems focused 2.1. Characteristics of FRA 2015 on deforestation, many of the world’s forests have changed in other important ways that are less visible to the public – for example FRA 2015 was organized around 21 key questions grouped into characteristics such as stocking density, species composition and eight topical categories: forest area and forest characteristics, pro- diameter distribution (Plumptre, 1996; Dallmeier and Comiskey, duction, protective functions and ecosystems services, biodiver- 1998; Coomes and Allen, 2007). Climate change is predicted to cre- sity/conservation, disturbance, measuring progress toward ate substantial shifts in tree species distribution and forest struc- sustainable forest management, economics/livelihoods and looking ture (Scheller and Mladenoff, 2005; Gustafson et al., 2010). These forward (www.fao.org/forestry/FRA2015/Methods). A total of 117 shifts may require even greater monitoring efforts to assess more variables are included, most of which covered the period 1990– rapid forest change in the future. At the same time, human popu- 2015 (Table 1). FRA 2015 included 37 variables that were not lations have nearly tripled from 1948 to 2015 and are predicted included in previous assessments. Countries submitted reports to continue increasing, putting greater pressure on remaining, between October 2013 and July 2014, including projected values accessible forests to provide goods and services for a growing for the 2015 reporting year. population. The majority of variables were reported for the years 1990, 2000, Understanding how global forest resources are changing is far 2005, 2010 and 2015. Future forest area targets were requested more complicated, and generally far more important than under- for the years 2020, 2030, and some variables were requested for standing forest area change alone. the latest available year when a specific date was likely to be unavailable or irrelevant (e.g., monitoring of forest management 1.2. How have FRA global datasets been used? plans stakeholder involvement). In addition to the quinquennial reports, annual values were reported for wood removals, total Information on the global state of forests drives policy and burned area and burned forest area. Annual forest area under inter- resource flows at global, regional and national levels. Forests today national forest management certification were provided by the – including extent, composition and structure, are in part a result Forest Stewardship Council (FSC) and Programme for the of the many years spent acting on reported characteristics and for- Endorsement of Forest Certification (PEFC). Projections of future est change. MacDicken (2014) highlights how, for example, past forest area were requested of countries for 2020 and 2030 and a K.G. MacDicken / Forest Ecology and Management 352 (2015) 3–8 5
Table 1 collection process and definitions (including additional details on Summary of FRA 2015 characteristics. the categories below), please see: http://www.fao.org/forestry/ Characteristic Values FRA2015/Methods. Proportion of forest area covered 98.8% by country reports 2.2. The primary analytical categories for FRA 2015 data analyses Proportion of forest area covered 1.2% by FAO desk studies 2.2.1. Global Number of questions 21 Global analyses of FRA 2015 data are possible for up to 234 Number of variables 117 Reporting periodsa 1990, 2000, 2005, 2010, 2015, 2020, countries and territories. The number of reports per variable and 2030, latest available year the number of variables reported per country differ widely. In gen- Proportion of variables covered 33% eral, country reports contain more data than desk studies. Missing by Tier categories values present a challenge in interpreting FRA data at the global Number of capacity building 22/591 workshops/participants level – particularly in cases where countries report on variables for some years and not others. Addressing missing values without a Reporting periods were variable-dependent (see online methods document for losing important information is difficult for this data set and there reporting years by variable). is no perfect solution. For FRA 2015 no missing values were filled in by FAO. Authors in this volume have chosen analytical approaches to handle missing values based on their judgement of the extent special study was conducted using a scenario-based model to project and nature of data gaps. possible forest change to the year 2050 (D’Annunzio et al., 2015). The dataset available online at (www.fao.org/forestry/ 2.2.2. Sub-regional FRA2015/dataset) contains quantitative data and Boolean expres- FRA 2010 primarily used five geographic regions to break down sions plus descriptive data covering data contributors, original global trends. FRA 2015 uses 12 sub-regions for finer-scale global data sources, methods and comments from FRA National analyses and provides for regional analysis using FRA-designated Correspondents. Country reports that contain complete country regions. Sub-regions are particularly important where intra- submissions can be found at www.fao.org/forestry/FRA2015/ regional trends are markedly variable – for example, the region of CountryReports. Most countries submitted their reports using North America includes Canada, Mexico, the United States and the an online data entry system (Forest Resources Information countries of Central America. In the sub-region of North America for- Management System – FRIMS) which included automated quality est area is increasing and the sub-region of Central America forest checks for use by National Correspondents and reviewers. Data area is generally decreasing. Similar trends are found in Asia when were extracted into Excel worksheets from the FRIMS for analysis aggregated at the regional scale. Use of the sub-regional scale pro- in Excel or specialized statistical software packages. vides greater analytical sensitivity than use of the regional scale. Countries were provided with pre-filled online reports that included data provided to FAO for FRA 2010 in order to improve 2.2.3. Climatic domains consistency and reduce the reporting burden. Countries were Climatic domains are used in FRA 2015 as a categorical variable encouraged to review these data, and the data from external in the analyses reported in the Special Issue. Because the FRA is not sources, and to revise them for previous years (1990–2010) if more spatially explicit, climatic domains at the national scale are defined recent or higher quality data were available. These updates can be by the dominant climatic domain per country. These domains were a source of confusion because they may result in different values assigned based on spatial analysis of the forest area in each domain for the same reporting year in two different assessments. per country using a forest distribution approximation from Hansen Grainger (2008) notes the difficulty in using FRA data for assessing et al. (2003) and domain distributions from Iremonger and Gerrand long-term trends in part because the values are adjusted by coun- (2011). These describe the following domains as aggregations of tries over time. Because the most recent reporting year for forest ecological zones: Tropical, Sub-tropical, Temperate, Boreal and area in each FRA is projected rather than measured, it is inevitable Polar. For the purposes of FRA 2015 the Polar zone was dropped that the measured values reported in a subsequent assessment will as forest area is de minimis and at the country/territory scale is be different from the projected values in the preceding assessment. restricted to Greenland and the Svalbard and Jan Mayen Islands. In addition, new inventories or remote sensing results or correction Because of the lack of spatial data in the FRA, the climatic domains of previous errors result in new values for previous reporting should not be perceived as precise delineations. A spatial analysis periods. of mapped forest by ecozone would differ from those presented While this Special Issue describes many of the most important in this volume because of the presence of multiple climatic zones changes in forest extent and quality over the period from 1990 within some large forest area countries (e.g., Canada, China, to 2015, it does not provide exhaustive analysis of many FRA vari- Australia, and the United States). However, analysis of predomi- ables. Additional FRA 2015 reports include a synthesis document nant climatic domains does provide a useful approach of discrimi- (www.fao.org/forestry/FRA2015/Synthesis) and a Desk Reference nating and understanding where forest area change occurs. that provides summary tables for nearly all of the tabular values in FRA 2015 (www.fao.org/forestry/FRA2015/Desk Reference). 2.2.4. Income categories Readers are encouraged to download and explore the data Gross National Income per capita was used as a categorical (www.fao.org/forestry/FRA2015/Database). This online database variable with four income categories defined by the World Bank also provides access to country data from related areas such as (http://data.worldbank.org/about/country-and-lending-groups): agriculture, demographics and others to allow analysis of FRA Low-income economies ($1045 or less), Lower-middle (US$1046– results together with non-forest resource data. All of the papers $4125), Upper-middle (US$4126–$12,745) and High income in this volume use the FRA 2015 data set as a primary source economies (US$12,746 or more). No adjustment of these categories and in some cases are supplemented with additional data from were made – although there were fifty-five countries or territories other sources. used in FRA 2015 (out of 234 countries and territories) that are Individual papers in this volume describe methods used for excluded in the World Bank categories. These countries/territories each paper. For general methods used in the FRA 2015 data represent 9.1 million ha of forest that is not included in the income 6 K.G. MacDicken / Forest Ecology and Management 352 (2015) 3–8 category-based analyses. Analyses by income category provide estimates of key FRA variables along with estimates of precision. unique insights into where forest is concentrated, where change The Tier designations provide a measure of relative confidence in is occurring and where the challenges for sustainable forest man- data at the variable level, even though measures of precision are agement are greatest. not reported. Sample-based remote-sensing values reported at regional, ecozone and global levels (FAO and JRC, 2012; FAO and 2.2.5. Country report vs. desk study JRC, 2014) provide added value in that the analysis contains calcu- While the FRA process is dependent on national reporting by lated levels of precision around the means. governments through their designated National Correspondents, not all countries/territories have forest or a National Correspondent. 3.1.2. Consistent definitions over time FAO received 155 country reports for FRA 2015 – representing Consistent definitions allow better comparisons over time and nearly 99% of total forest area. When country reports were not sub- make reported values more consistent across countries. One of mitted, FAO made estimates using desk studies based on available the differences between the assessments done prior to the year literature and expert estimates – a practice also used in previous 1980 is that they contained a variety of forest definitions. While assessments. Desk studies are analyses done by FAO staff and the pre-1980 definitions essentially defined forests as seen by consultants based on limited data sources, and are therefore sovereign states, they resulted in countries reporting to different are as a category less reliable than country reports. Desk study standards. By the year 2000 definitions of variables such as forest countries are clearly identified in country reports, the online area were stable across all countries and have not changed in the database (www.fao.org/forestry/FRA2015/database) and the Desk FRA since then. Other definitions have changed, as data limitations Reference (www.fao.org/forestry/FRA2015/Desk Reference). were demonstrated or needs or data sources changed (www.fao. org/forestry/FRA/2015/Historicalvariables). Variables included in 2.2.6. Quality tiers FRA 2015 were assembled (and for new variables, defined) through FRA 2015 used a set of tier categories similar to those used by extensive consultation with a wide range of experts and the Intergovernmental Panel on Climate Change (IPCC). Tiers were stakeholders. requested for all variables that potentially had more than one source of data. Tiers were defined by countries for each of the 3.1.3. Ease of interpretation included variables for both status (i.e. the most recent report) Given the complexity of forests and forest change, no single and trend (i.e. for two or more reporting periods). Countries were source of data tells a complete story. Even the definition of forest asked to assign a Tier value to each qualifying variable: Tier 1 in the FRA can be difficult to communicate. While the FRA defini- (expert estimate), Tier 2 (low intensity or incomplete surveys, tion of forest may on the surface appear to be a forest cover defini- older data) or Tier 3 (high reliability, recent sources with national tion it is actually a forest land use definition – land can be scope). Specific definitions for each tier were provided in the FRIMS temporarily devoid of tree cover and remain forest land for FRA following this general pattern and are available in the FRA country reporting purposes. This is an important difference between the reports online. Tier values were requested for status and trend for internationally accepted definition of forest used in the FRA com- about one-third of all FRA 2015 variables. pared to sources such as Global Forest Watch, which reports It is important to note that all country reports were indepen- changes in tree cover of all types. Data that are not easy to inter- dently peer-reviewed by FAO staff, partners in the Collaborative pret are less useful – which requires continuous efforts by FAO 1 Forest Resources Questionnaire (CFRQ) and external experts. and partners to provide easy access, clear definitions and analyses Peer-review comments were provided to National Correspondents to help inform interpretation. for inclusion and, where necessary, corrections of individual national reports were made before incorporation of data into the final FRA 3.1.4. Reasonable potential for practical use 2015 database. Many users seek FRA data that has practical use. While much is said about the value of FRA data for policy makers, it is only when 3. Discussion forest policy translates into appropriate changes in management practices or investment that positive improvements in forest man- 3.1. When are global forest resource data most useful? agement occur. This applies to forestry-related investments by governments, private companies, donors, NGOs or individuals. Global datasets are often less detailed and precise than national Making global and national-level forest information relevant – or sub-national datasets – this is also true for the FRA. Users have and easily accessible – to those who make investment decisions through stakeholder discussions, internal FRA evaluations and a can help improve decision-making and ultimately improve forest user survey noted the following desired characteristics for global management and use. forest resource assessments:
3.1.5. Process is part of decision-making 3.1.1. Known levels of precision FRA 2000 (FAO, 2001) noted that government users of FRA data Understanding the precision of reported values instils an appro- are most likely to be committed to improving it when they are also priate level of confidence in mean or summed values and allows responsible as producers of the information. Mather (2005) noted variance-based analyses. The FRA country reporting process does that while the user focus is often on FRA results, the process of not produce numbers with measures of variability around reported planning, data collection and reporting is a potentially significant values. This does not mean, however, that national data necessarily instrument of forest governance. Countries such as Brazil use FRA originate from a source without estimates of precision. Indeed, reporting periods to assemble and discuss data across government many countries use survey methods capable of generating units and in the process learn in ways that might not otherwise be possible (J. de Freitas, pers. comm.). Other countries, such as 1 CFRQ Partners share over 50% of FRA 2015 data to reduce country reporting Canada, Mexico and the United States collaborate with each other burdens and improve data consistency. Partner organizations are FAO, FOREST in how they report to the FRA to assure more consistent data at the EUROPE, UN Economic Commission for Europe, International Tropical Timber Organization, the Montreal Process and the Observatoire des Forêts d’Afrique continental scale and adapt some aspects of their data collection to Centrale. FRA definitions (B. Smith, pers. comm.). K.G. MacDicken / Forest Ecology and Management 352 (2015) 3–8 7
3.2. Challenges with the FRA data include assessments. Analyses of change over time are most reliably done within the 25 year coverage of FRA 2015 rather than across differ- Despite efforts since 1948 to improve reporting and data quality ent FRA reports. there remain constraints to the use of FRA data (FAO (1948, 2010), A summary of changes in data collection and definitions is found Grainger (2008), Harris et al. (2012)). The following section outli- at http://www.fao.org/forestry/FRA2015/Historicalvariablechange. nes some of the known limitations of the data collected for FRA Collectively these constraints seem exceptionally limiting – but 2015. this would be an incorrect conclusion for most purposes, particu- larly when examining change over a 25 year period. The FRA data 3.2.1. Incomplete country reporting point to important changes in global forest resources – not always The FRA 2015 questionnaire contains a diverse range of as precisely as some users would like, but of substantial quality requests. In most cases, countries are unable to complete the entire and usefulness. questionnaire for all years requested. Missing data complicates time series analysis, particularly those that relate to forest area 4. Conclusions numbers and requires caution in analysis and interpretation. This problem will persist in future assessments because – like optical Despite the known limitations of collecting and synthesizing satellite imagery in areas of perennial cloud cover – data in some information on the state, condition and trends of the world’s for- countries simply do not exist. ests there is immense value in the data collected and the analyses generated. Perhaps the best way to summarize the value of global 3.2.2. Inaccurate reporting forest resources information is to ask the question: Would forests Until FRA 2015, there was no way to assess reporting quality be different today had we not known how they have changed in without reading individual country reports. In 2015, the tier sys- recent times? The answer is yes. Not knowing would have led to tem described in this paper was introduced to allow easy assess- piecemeal attempts to focus actions by governments, donors, ment of timeliness and data source and to select country reports non-government organizations and private companies in improv- for analysis based on a threshold quality class per variable. ing forest management where they are needed most. The monetary However, missing documentation for some countries makes it dif- value of actions taken as a result of global knowledge of forest ficult to assess sources even with tiers assigned because the basis resources may never be precisely known, but it is clear that for tier selection is not provided. humanity and forest resources are both better off as a result of the hard work of all who have contributed to understanding 3.2.3. FRA data are not experimental change in world forest resources – including those who have dili- Some users are accustomed to experimental data that are well gently contributed to this volume. controlled. The FRA data come from a variety of national sources, including district forest offices, government registries, remote Acknowledgements sensing, national inventories and special studies. In some cases, these sources are combined to provide national statistics – statis- To the 285 FRA National Correspondents/Alternates and the tics that are generally provided without associated measures of thousands who supported them in collection of the FRA 2015 data precision. set – a most sincere thanks. This was a complex task often unap- preciated by those who seek perfection where perfection is gener- 3.2.4. Numbers do not always add up ally impossible! Likewise, the author acknowledges with gratitude Ideally, forest characteristics such as primary forest, other nat- the useful comments by reviewers and to those diligent FAO staff, urally regenerated forest and planted forest should add up to the consultants and CFRQ partners who cleaned and spent many long same number as total forest area. In some cases, they do and in hours analysing and interpreting data. Funding for this work was others, they do not-in part due to missing data for one or provided from the FAO Regular Program and extra-budgetary con- more category or the use of more than one source for related tributions from Canada, the European Union, Finland, Japan and variables. the United States.
3.2.5. FRA data are not spatially explicit Country reports may or may not have been compiled from spa- tially explicit data sources, but the data submitted to the FRA are References aggregated at the national level. This means that information regarding specific forest type or subnational distribution of forest Coomes, D.A., Allen, R.B., 2007. Mortality and tree-size distributions in natural resources is not reported. mixed-age forests. J. Ecol. 95, 27–40. Detwiler, R., Hall, C., 1988. Tropical forests and the global carbon cycle. Science 239, 42–47. 3.2.6. Expectations for long-term comparison Dallmeier, F., Comiskey, J.A. (Eds.), 1998. Forest Biodiversity in North, Central and FRA 2015 reports 25 years of forest change – which is the long- South America, and the Caribbean. UNESCO, Paris, 214 pp. FAO, 1948. Forest Resources of the World. Unasylva 2(4). Rome, Italy. est period covered by any of the FRA-related reports since 1948. FAO, 2001. Global Forest Resources Assessment 2000. Rome, Italy. While authors such as Grainger (2008 and 2014 expect data stan- FAO, 2010. Global Forest Resources Assessment 2000. Rome, Italy. dards, variables and methods to remain constant over long periods, FAO, 2015. Global Forest Resources Assessment 2015: How have the world’s forests the reality is that they do not. New inventories and remote sensing changed? Rome, Italy. FAO, JRC, 2012. Global forest land-use change 1990–2005. In: Lindquist, E.J., results provide new insights into past forest area and resource D’Annunzio, R., Gerrand, A., MacDicken, K., Achard, F., Beuchle, R., Brink, A., Eva, information. These updates mean that aggregated values for the H.D., Mayaux, P., San-Miguel-Ayanz, J., Stibig, H.-J. (Eds.). FAO Forestry Paper same reporting year are likely to change for many variables from No. 169. Food and Agriculture Organization of the United Nations and European Commission Joint Research Centre. Rome, FAO. one assessment to the next. FAO has noted that the values reported FAO, JRC, 2014. Global Forest Land-Use Change 1990–2010. An Update to FAO in one FRA cannot readily be compared with one another (FAO, Forestry Paper No. 169. UN Food and Agriculture Organization, Rome 2010) because of the changes in definitions and new information (Unpublished). Grainger, A., 2008. Difficulties in tracking the long-term global trend in tropical from national monitoring and assessments. It is important to note forest area. Proc. Natl. Acad. Sci. USA 105, 818–823. http://dx.doi.org/10.1073/ that FRA 2015 is no different in this regard from previous pnas.0703015105. 8 K.G. MacDicken / Forest Ecology and Management 352 (2015) 3–8
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Forest Ecology and Management
journal homepage: www.elsevier.com/locate/foreco
Review and synthesis Dynamics of global forest area: Results from the FAO Global Forest Resources Assessment 2015 q ⇑ Rodney J. Keenan a, , Gregory A. Reams b, Frédéric Achard c, Joberto V. de Freitas d, Alan Grainger e, Erik Lindquist f a School of Ecosystem and Forest Sciences, University of Melbourne, 221 Bouverie St, Carlton, Vic 3053, Australia b USDA Forest Service, National Office, 1601 North Kent Street, Suite 400, Arlington, VA 22209, USA c European Commission Joint Research Centre, Via Enrico Fermi 2749, I-21027 Ispra, VA, Italy d Brazilian Forest Service, Ministry of Environment, SCEN, AV. L4, Trecho 2, Bloco H, Brasília-DF 70818-900, Brazil e School of Geography, University of Leeds, Leeds LS2 9JT, UK f UN Food and Agriculture Organization, Viale delle Terme di Caracalla, 00153 Rome, Italy article info abstract
Article history: The area of land covered by forest and trees is an important indicator of environmental condition. This Received 7 January 2015 study presents and analyses results from the Global Forest Resources Assessment 2015 (FRA 2015) of Received in revised form 9 June 2015 the Food and Agriculture Organization of the United Nations. FRA 2015 was based on responses to sur- Accepted 9 June 2015 veys by individual countries using a common reporting framework, agreed definitions and reporting Available online 7 September 2015 standards. Results indicated that total forest area declined by 3%, from 4128 M ha in 1990 to 3999 M ha in 2015. The annual rate of net forest loss halved from 7.3 M ha yÀ1 in the 1990s to Keywords: 3.3 M ha yÀ1 between 2010 and 2015. Natural forest area declined from 3961 M ha to 3721 M ha between Forest 1990 and 2015, while planted forest (including rubber plantations) increased from 168 M ha to 278 M ha. Deforestation À1 Forest transition From 2010 to 2015, tropical forest area declined at a rate of 5.5 M ha y – only 58% of the rate in the À1 Land use 1990s – while temperate forest area expanded at a rate of 2.2 M ha y . Boreal and sub-tropical forest Land cover areas showed little net change. Forest area expanded in Europe, North America, the Caribbean, East Remote sensing Asia, and Western-Central Asia, but declined in Central America, South America, South and Southeast Asia and all three regions in Africa. Analysis indicates that, between 1990 and 2015, 13 tropical countries may have either passed through their forest transitions from net forest loss to net forest expansion, or continued along the path of forest expansion that follows these transitions. Comparing FRA 2015 statis- tics with the findings of global and pan-tropical remote-sensing forest area surveys was challenging, due to differences in assessment periods, the definitions of forest and remote sensing methods. More invest- ment in national and global forest monitoring is needed to provide better support for international ini- tiatives to increase sustainable forest management and reduce forest loss, particularly in tropical countries. Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
Contents
1. Introduction ...... 10 2. Methods ...... 10 3. Results...... 11 3.1. The distribution of forest area ...... 11 3.2. Global and regional trends in forest area ...... 11 3.3. Trends by climatic domain ...... 12 3.4. Trends by income category...... 12
q This article is part of a special issue entitled ‘‘Changes in Global Forest Resources from 1990 to 2015’’. ⇑ Corresponding author. E-mail addresses: [email protected] (R.J. Keenan), [email protected] (G.A. Reams), [email protected] (F. Achard), joberto.freitas@florestal.gov.br (J.V. de Freitas), [email protected] (A. Grainger), [email protected] (E. Lindquist). http://dx.doi.org/10.1016/j.foreco.2015.06.014 0378-1127/Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 10 R.J. Keenan et al. / Forest Ecology and Management 352 (2015) 9–20
3.5. National trends ...... 12 3.6. Data quality ...... 12 4. Analysis...... 13 4.1. The implications of FRA 2015 statistics for trends in deforestation...... 13 4.2. Implications for modeling human impacts on forests...... 13 4.3. Uncertainties about trends in forest area ...... 15 4.4. Comparison of the findings of FRA 2015 and remote sensing studies ...... 16 5. Conclusions...... 19 Acknowledgements ...... 19 Appendix A. Supplementary material ...... 19 References ...... 19
1. Introduction sections: Section 2 summarizes the methods used to estimate val- ues of FRA statistics; Section 3 provides an overview of FRA 2015 Reliable information on global trends in forest area is of great results; and Section 4 analyses these findings to assess their signif- help to international agencies, governments, non-governmental icance for our understanding of recent trends in global forest area organizations and the commercial sector when they make deci- and what has caused them. sions on policies and investment, and to scientists whose research also informs these decisions. The first global forest assessment was undertaken by the US Government early in the 20th Century (Zon, 2. Methods 1910; Zon and Sparhawk, 1923). However, regular global assess- ments had to wait until the Food and Agriculture Organization of FAO’s Global Forest Resources Assessments (FRAs) continue to the United Nations (FAO) was established in 1945. FAO published rely on the submission of national data by governments, but the statistics on global forest resources every five years from 1948 to methods used for this have changed over time. Sending question- 1963 in its World Forest Inventory series. It launched a new series naires to countries, the same method used for the World Forest of Forest Resources Assessments (FRAs) in 1980 that were initially Inventories, was found to have limitations. Since FRA 2005, FAO limited to the tropics (Lanly, 1981; FAO, 1982, 1993). Subsequent has devolved most statistical estimation to the National assessments for 1990, 2000, 2005 and 2010 have had global cover- Correspondents (NCs) who supply information on behalf of govern- age (FAO, 1995, 2001, 2006, 2010). ments, giving them instructions in detailed guidance documents Statistics contained in FRAs have supported decision making by on how to submit information using a common reporting frame- various international bodies. These include FAO itself, the UN work (e.g. FAO, 2013a,b). Framework Convention on Climate Change (UNFCCC), the The two main categories of tree cover for which statistics are Convention on Biological Diversity, the UN Convention to Combat reported in this paper are ‘forest’ and ‘other wooded land’. Since Desertification, and the UN Forum on Forests. Concerns in the FRA 2000, all countries in the world have been asked to use a com- UNFCCC about the role of forests in global climate change have mon definition of ‘forest’, as land of at least 0.5 ha covered by trees led to negotiations on a mechanism for Reducing Emissions from higher than 5 m and with a canopy cover of more than 10%, or by Deforestation and Degradation and the role of conservation, sus- trees able to reach these thresholds, and predominantly under for- tainable management of forests and enhancement of forest carbon est land use. This excludes land that is mainly under agricultural or stocks in developing countries (REDD+) (UNFCCC, 2014), and to the urban land uses. The FAO definition of ’forest’ is essentially a recent New York Declaration on Forests (UN, 2014). FRA statistics land-use based definition, and it differs from other definitions of have also been of value in many scientific studies, most recently forest which rely solely on the presence or absence of tree cover, on forest and agricultural land dynamics (Ausubel et al., 2012), dri- and from legal definitions based on topographic or other factors vers of deforestation (Hosonuma et al., 2012), environmental sus- (Lund, 1999, 2002). It includes areas of land that may be temporar- tainability (Arrow et al., 2012) and the carbon cycle (Le Quere ily unstocked with trees but are still intended for forestry or con- et al., 2009; Smith et al., 2014). servation use. It also combines natural forest and planted forest, Deforestation, particularly in the tropics, was a major concern the latter including intensively managed forest plantations. of FRAs 1980 and 1990 (Holmgren and Persson, 2002). As the ben- ’Other wooded land’ describes land of at least 0.5 ha that is covered efits expected from forests have increased over time, the focus of by trees higher than 5 m, and either the tree canopy cover is 5–10%, FRAs has diversified to assess the status and supply of a wider or the total cover of trees, shrubs and bushes exceeds 10% (FAO, range of forest ecosystem services. However, debate continues 2010). about the breadth of variables that should be assessed in FRAs, Three key questions asked in FRA 2015 that are relevant to for- given the limited resources made available to undertake the est area concern: assessments (Matthews and Grainger, 2002). FRAs rely heavily on information supplied by governments in response to FAO question- 1. The areas of forest and other wooded land. Forest area was also naires, and the lack of up to date and comprehensive national for- reported in the categories of primary forest, other naturally est inventories in developing countries on which these responses regenerated forest, and planted forest. are based has raised concerns about the accuracy of the resulting 2. The rate of forest expansion, which was subdivided, where pos- statistics on forest area change (Grainger, 2008). It has also led to sible, into the natural expansion of forest, and human-induced proposals for improving global forest monitoring for REDD+ by afforestation. making better use of satellite images (Baker et al., 2010; Grainger 3. The rate of forest loss. and Obersteiner, 2011). This paper presents and analyses the findings on global trends NCs were asked to submit responses to these and other ques- in forest area between 1990 and 2015 reported in the Global tions for the reporting years 1990, 2000, 2005, 2010 and 2015, Forest Resources Assessment 2015 (FRA 2015) (FAO, 2015; through tables in the online Forest Resources Information MacDicken, 2015). The remainder of the paper is in three main Management System (FAO, 2013a) for which standard templates R.J. Keenan et al. / Forest Ecology and Management 352 (2015) 9–20 11 were provided by FAO (2013b). To facilitate the reporting process, Ten countries – the Russian Federation, Brazil, Canada, the USA, FAO pre-filled the tables with data for 1990–2010 from FRA 2010 China, Democratic Republic of Congo, Australia, Indonesia, Peru (FAO, 2013a), a practice introduced in FRA 2010. If better estimates and India – account for 67% of total forest area. Six countries or ter- had since become available, NCs were instructed to update infor- ritories – Aruba, the Faroe Islands, Greenland, Guernsey, Malta and mation from previous years, using the interpolation and extrapola- Norfolk Island – reported zero forest cover, and there are no entries tion methods employed in previous FRAs. All values for 2015 were for ten other countries or territories which also have little forest estimated by NCs using extrapolation, generally based on a linear (Table S2)(FAO, 2015). projection from previous data. Further details on the methods used for FRA 2015 may be found in MacDicken (2015). FRA 2015 received responses from 155 countries, and 79 desk 3.2. Global and regional trends in forest area studies were conducted for the remaining countries and territories, giving information for a total of 234 individual countries and terri- Overall, there was a net decrease in global forest area of 3% tories. Data sources used by countries to report forest area between 1990 and 2015, from 4128 M ha to 3999 M ha, with nat- included official government statistics, ground-based forest and ural and human-induced deforestation being offset by increases vegetation inventories, remote sensing-based studies, published in forest area that had both natural and human causes (Table 1). and refereed studies, ’gray literature’ reports and expert opinion. The annual rate of net forest loss halved over the 25 year period, À1 À1 Countries were asked to report on the quality of their data for each falling from 7.3 M ha y in the 1990s to 4.6 M ha y between À1 À1 variable using a three tier system: Tier 1 data were considered the 2000 and 2005, and to 3.4 M ha y and 3.3 M ha y for 2005–10 least reliable and Tier 3 data the most reliable (MacDicken, 2015). and 2010–15, respectively (Table 4). While this reduced rate of Countries were classified into four climatic domains: Boreal, net forest loss is encouraging, it should not be regarded as equiva- Temperate, Subtropical and Tropical (FAO, 2013a). If a country’s lent to reduced rates of human-induced deforestation (see national boundaries encompassed more than one climatic domain, Section 4). the country was assigned to the domain occupying the largest for- Primary forest accounts for a third of total forest area (see est area of the country (Table S1). Countries were also divided into Morales et al., 2015), and increased slightly from 1200 M ha in 12 ‘sub-regions’, based on breakdowns of FAO regional groupings; 1990 to 1282 M ha in 2015, mainly because more countries sub- and into income categories according to the World Bank country mitted data for this statistic. Primary forest, which is regarded as lending group designation (MacDicken, 2015). undisturbed by human beings, is often reclassified as ’Other natu- The methods used for the analysis of FRA findings in Section 4 rally regenerated forest’ after disturbance, though entries for this are outlined in Supplementary Material. statistic are also incomplete, and it has changed little, from
3. Results Table 2 The trend in forest area from 1990 to 2015 by sub-region (K ha) (FAO, 2015). All totals This section provides an overview of the most important find- involve rounding. ings of FRA 2015 on trends in forest area between 1990 and 2015. Sub-region 1990 2000 2005 2010 2015 Central 26,995 23,448 22,193 21,010 20,250 3.1. The distribution of forest area America Caribbean 5,017 5,913 6,341 6,745 7,195 In 2015 forest covers 3999 M ha globally. This is equivalent to East Asia 209,198 226,815 241,841 250,504 257,047 East-Southern 319,785 300,273 291,712 282,519 274,886 31% of global land area, or 0.6 ha for every person on the planet. Africa A further 1204 M ha are covered by other wooded land (Table 1). Europe 994,271 1,002,302 1,004,147 1,013,572 1,015,482 Forty-four per cent of global forest area is found in countries North Africa 39,374 37,692 37,221 37,055 36,217 classified as tropical and another 8% is in sub-tropical countries. North 720,487 719,197 719,419 722,523 723,207 America Temperate countries account for 26% of global forest area and bor- Oceania 176,825 177,641 176,485 172,002 173,524 eal countries for 22% (Table 1). Europe (including the Russian South 930,814 890,817 868,611 852,133 842,011 Federation) has more forest than any other geographical America sub-region (25%), followed by South America (21%) and North South- 319,615 298,645 296,600 295,958 292,804 America (16%) (Table 2). Three quarters of all forest is in high Southeast Asia income and upper middle income countries, with just 25% of the West-Central 346,581 332,407 325,746 318,708 313,000 total in countries classified as having lower middle or low income Africa (Table 3). The proportion of other wooded land in the tropics (43%) West-Central 39,309 40,452 42,427 42,944 43,511 is similar to that for forest in the tropics, but there are proportion- Asia Total 4,128,269 4,055,602 4,032,743 4,015,673 3,999,134 ally greater areas of other wooded land in the sub-tropical and temperate domains (Table 1).
Table 1 Forest and other wooded land from 1990 to 2015 in different global climatic domains (K ha) (FAO, 2015). Note that domains are determined by country classification into a domain and all forests in the country are included in that domain. All totals involve rounding.
Forest area (K ha) Other wooded land area (K ha) Domain 1990 2000 2005 2010 2015 1990 2000 2005 2010 2015 Boreal (inc. polar) 1,219,309 1,219,820 1,218,856 1,224,873 1,224,452 121,212 117,735 119,590 121,999 121,187 Temperate 617,997 640,892 659,176 673,429 684,468 157,582 154,534 159,568 163,737 167,255 Sub tropical 325,421 324,777 323,912 319,613 320,057 150,132 149,090 151,391 150,602 399,094 Tropical 1,965,542 1,870,112 1,830,799 1,797,757 1,770,156 549,529 533,090 523,143 537,825 516,935 Grand total 4,128,269 4,055,602 4,032,743 4,015,673 3,999,134 978,454 954,448 953,692 974,163 1,204,471 12 R.J. Keenan et al. / Forest Ecology and Management 352 (2015) 9–20
Table 3 middle income countries declined at 0.14% yÀ1 in the 1990s, but The trend in forest area from 1990 to 2015 by country income category (K ha) (FAO, this halved to 0.07% yÀ1 in the 2000s, and between 2010 and 2015). Income categories are defined by Gross National Income per capita per year: 2015 it was relatively stable. In lower middle and low income low ($1045 or less), lower-middle (US$1046 to $4125), upper-middle (US$4126 to $12,745) and high (US$12,746 or more) (World Bank, 2013). All totals involve countries forest area continues to decline: both groups of countries rounding. exhibited high loss rates of about 0.6% yÀ1 in the 1990s, but while this rate has been maintained in low income countries it halved to Income level 1990 2000 2005 2010 2015 about 0.3% yÀ1 between 2000 and 2015 in lower middle income High 1,808,959 1,817,229 1,817,957 1,825,524 1,830,347 countries (Table 3). Upper middle 1,254,645 1,237,046 1,231,708 1,228,041 1,228,186 Lower middle 591,378 557,059 550,997 542,767 533,344 Low 464,070 435,090 422,921 410,211 398,135 3.5. National trends Unclassified 9,218 9,179 9,161 9,131 9,121 Total 4,128,269 4,055,602 4,032,743 4,015,673 3,999,134 At the national scale, net loss of forest area between 2010 and 2015 for countries in South America was dominated by Brazil (984 K ha yÀ1), but there were also significant net losses in Table 4 À1 À1 Net rates of change in the areas of forest and other wooded land from 1990 to 2015 in Paraguay (325 K ha y ), Argentina (297 K ha y ), Bolivia 1 1 different global climatic domains (M ha yÀ1)(FAO, 2015). (289 K ha yÀ ) and Peru (187 K ha yÀ )(Table S2). In South and Southeast Asia, the rate of net forest loss was greatest in 1990–00 2000–05 2005–10 2010–15 Indonesia (684 K ha yÀ1), followed by Myanmar, where the loss Forest rate of 546 K ha yÀ1 between 2010 and 2015 was 25% higher than Boreal (inc. polar) 0.051 À0.193 1.204 À0.084 Temperate 2.290 3.657 2.851 2.208 in the 1990s. In Africa, the greatest net losses in forest area À1 Sub tropical À0.064 À0.173 À0.860 0.089 between 2010 and 2015 were in Nigeria (410 K ha y ), Tanzania Tropical À9.543 À7.863 À6.608 À5.520 (372 K ha yÀ1), Zimbabwe (312 K ha yÀ1) and Democratic Grand total À7.267 À4.572 À3.414 À3.308 Republic of Congo (311 K ha yÀ1). Other wooded land The net rate of forest loss has significantly declined in some Boreal (inc. polar) À0.348 0.371 0.482 À0.162 countries. For example, in Brazil, the net loss rate between 2010 Temperate À0.305 1.007 0.834 0.704 and 2015 was only 40% of the rate in the 1990s. Indonesia’s net loss Sub tropical À0.104 0.460 À0.158 49.698 À1 Tropical À1.644 À1.989 2.936 À4.178 rate has also dropped by two thirds, from 1.9 M ha y in the 1990s Grand total À2.401 À0.151 4.094 46.062 to 684 K ha yÀ1 from 2010 to 2015, while the rate in Mexico has halved from 190 K ha yÀ1 in the 1990s to 92 K ha yÀ1 between 2010 and 2015. 2312 M ha to 2329 M ha between 1990 and 2015. Other wooded Other countries have reported a net rise in forest area between land area changed little between 1990 (979 M ha) and 2010 2010 and 2015. China has the highest rate of expansion À1 (974 M ha), but then rose sharply to 1204 M ha in 2015. A number (1.5 M ha y ), though this is only 63% of the corresponding rate of countries exhibited relatively sharp rises or declines in their in the 2000s. Forest area increased rapidly in the last five years À1 À1 areas of other wooded land between 2010 and 2015, probably aris- in Chile (301 K ha y ), the USA (275 K ha y ), the Philippines À1 À1 ing from difficulties faced in applying uniformly the percentage (240 K ha y ), Lao People’s Democratic Republic (189 K ha y ), À1 À1 tree cover thresholds in FAO’s definitions of forest and other India (178 K ha y ), Vietnam (129 K ha y ) and France 1 wooded land (Gabler et al., 2012). However, the main reason (113 K ha y ). There was a net increase in forest area of À1 appears to be a 165% rise in the area of sub-tropical other wooded 308 K ha y in Australia between 2010 and 2015 but, reflecting land from 151 M ha to 399 M ha (Table 1), following the report by the variability of climate in this country, this followed a net loss À1 Australia of an area of other wooded land in 2015 that is twice its of 563 K ha y in the 2000s, caused by a mixture of drought, fire forest area and virtually identical to this increment (Table S2). and human clearance. Half of global forest area is in sub-regions where forest cover is expanding: Europe, North America, the Caribbean, East Asia, and 3.6. Data quality West and Central Asia. The remainder is in sub-regions where for- est area continues to decline: Central America, South America, Estimates of about 60% of global forest area in 2015 are reported South and Southeast Asia and all three sub-regions in Africa. to be based on data of the highest (Tier 3) quality (Table 5). This is Oceania (dominated in area by Australian forests) showed periods supported by an analysis of data sources listed in FRA 2015 of gains and losses in forest area between 1990 and 2015 (Table 2). Country Reports for 99 tropical countries (Romijn et al., 2015), which implies that 54 countries now have good or very good capacities to monitor changes in forest area using remote sensing 3.3. Trends by climatic domain data. Comparison with the corresponding FRA 2005 Country Reports led to the conclusion that the proportion of total tropical Trends also vary by climatic domain (Table 1). Between 1990 forest area estimated using good or very good monitoring capacity and 2015 tropical forest area declined by 195 M ha from rose from 69% in 2005 to 83% in 2015. This reflected increased 1966 M ha to 1770 M ha, though the net rate of loss decreased over time, from 9.5 M ha yÀ1 in the 1990s to 7.2 M ha yÀ1 in the 2000s À1 and to 5.5 M ha y from 2010 to 2015. Over the 25 year period, Table 5 forest in temperate countries increased by 67 M ha, at an average The trend in global forest area classified by the quality of source data (Tier 1 is the of 2.7 M ha yÀ1, but forest in the sub-tropical and boreal domains lowest quality and Tier 3 the highest) (K ha) (FAO, 2015). Note that a small area was showed little change (Table 4). not classified. Quality tier 1990 2000 2005 2010 2015 3.4. Trends by income category 1 473,191 452,602 442,972 431,748 422,231 2 1,315,257 1,264,676 1,238,387 1,218,309 1,206,644 3 2,339,804 2,338,308 2,351,367 2,365,599 2,370,242 In high income countries, forest area showed a small increase of Total 4,128,252 4,055,586 4,032,726 4,015,656 3,999,117 about 0.05% yÀ1 over the 25 year period. Forest area in upper R.J. Keenan et al. / Forest Ecology and Management 352 (2015) 9–20 13 investment in forest inventory capacity in tropical and sub-tropical Our calculations show that natural forest area worldwide countries, mainly to support more robust estimates of greenhouse declined by 6% from 3961 M ha to 3721 M ha between 1990 and gas emissions from deforestation and forest degradation in antici- 2015 (Table 7). This was twice the percentage drop in forest area, pation of payments becoming available under the UNFCCC REDD+ and the net result of a 3% expansion of temperate natural forest, mechanism (Romijn et al., 2015). On the other hand, estimates for from 529 M ha to 546 M ha, and declines in natural forest in the 11% of global forest area in 2015 were based on data of the lowest other three climatic domains. In 142 tropical countries, the area (Tier 1) quality. For example, 79 countries or territories, compris- of natural forest declined by 11%, from 1935 M ha to 1713 M ha. ing 1.2% of global forest area, submitted no country reports and The decline in natural forest area worldwide was offset by a 66% so their statistics had to be estimated by less accurate desk studies rise in planted forest, from 168 M ha to 278 M ha (Table 7). (MacDicken, 2015). Furthermore, while the 12 countries which The change in natural forest area between any two time periods have a forest area of more than 5 M ha and data of Tier 1 quality will be the net effect of forest clearance and conversion to another only account for 9% of global forest area in 2015, they accounted land use (or deforestation) in some areas, natural forest losses for 20% of the net decline in global forest area from 1990 to through processes such as fire or drought and natural forest expan- 2015. Ten of these countries are in Africa (Table 6). sion elsewhere. The trend in forest area combines these processes with afforestation, in which forest is planted or regenerates natu- 4. Analysis rally on previously cleared land, e.g. as intensively managed plan- tations or restoration forests, and reforestation, in which trees are A key finding of FRA 2015 is that the net rate of loss of global planted or regenerate naturally on land already classified as forest forest area halved over the last 25 years. This and other findings (FAO, 2013a). So a report of no net loss in forest area does not mean are examined in this section to determine their robustness, and that the composition and structure of forest, its habitat value, or its what they reveal about relationships between human beings and supply of ecosystem services, have stayed the same. Converting an forests. area of natural forest into an intensively managed plantation of exotic tree species in the tropics, for example, will increase its tim- ber production potential but will generally reduce its biodiversity. 4.1. The implications of FRA 2015 statistics for trends in deforestation FRA 2015 includes statistics on the rate of ’deforestation’ but coverage is not comprehensive, as the table only includes reports To grasp the full meaning of FRA 2015 statistics on forest area from 48 countries. Our calculations on the dynamics of natural for- trends it is necessary to disaggregate them in two ways: by sepa- est show that the net rate of loss of natural forest halved, from rating natural forest from forest plantations, and by separating 11.5 M ha yÀ1 to 5.8 M ha yÀ1, between the 1990s and 2010–15 deforestation from afforestation. (Table 8). This replicated the sharp fall in the net rate of loss of for- Early FRAs listed areas of natural forest and forest plantations est (from 7.3 M ha yÀ1 to 3.3 M ha yÀ1) over the same period separately, but since FRA 2000 FAO has combined them in a single (Table 4). The vast majority of natural forest loss was in the tropics, statistic, called ’forest’ (Grainger, 2007). Natural forest generally where the rate of loss fell by 39%, from 10.4 M ha yÀ1 in the 1990s describes vegetation that evolved naturally in an area. Planted for- to 6.4 M ha yÀ1 from 2010 to 2015. In between these periods, it fell est includes both intensively managed forest plantations purposely to 9.1 M ha yÀ1 in 2000–05 and to 8.1 M ha yÀ1 in 2005–10. The established to give priority to wood production that are usually overall gross rate of loss of natural forest worldwide fell from composed of a single tree species and forests established for land 11.8 M ha yÀ1 to 7.2 M ha yÀ1, but continuing loss in the tropics conservation, coastal stabilization, biodiversity conservation or was offset by an almost fivefold rise in the rate of expansion of other purposes. Fortunately, the inclusion of separate figures for temperate natural forest, from 0.3 M ha yÀ1 to 1.4 M ha yÀ1. total forest area and planted forest area in FRA 2015 enabled us Planted forest area has increased in absolute terms and as a pro- to calculate natural forest area as the difference between the val- portion of total forest area, though the rate of expansion halved ues of these statistics (Table S3). FRA 2015, like FRA 2010, includes from 5.3 M ha yÀ1 in 2005–10 to 2.5 M ha yÀ1 in 2010–15 (Table 8). statistics on the areas of ’primary forest’ and ’other naturally regenerated forest’, but their coverage for early time periods was not comprehensive. The ’planted forest’ statistic, introduced in 4.2. Implications for modeling human impacts on forests FRA 2010, includes both forest plantations and rubber plantations, but not oil palm plantations and other agricultural plantations. So Changes in land cover and land use from forest to non-forest replacing an area of rubber plantation by an oil palm plantation have both natural causes, e.g. drought, fire, storms and disease, will suggest that there has been a reduction in forest plantation area and hence in forest area too.
Table 7 Table 6 Trends in natural forest area (calculated as total forest area minus planted forest area) Countries with forest areas greater than 5 M ha in 2015 and data of Tier 1 (lowest) and planted forest area from 1990 to 2015 by climatic domain (K ha) (calculated from quality (FAO, 2015). FAO, 2015). All totals involve rounding.
Country Forest area in 2015 (K ha) Year 1990 2000 2005 2010 2015 Democratic Republic of the Congo 152,578 Natural forest Boreal/polar 1,189,195 1,178,980 1,171,757 1,170,451 1,166,747 Angola 57,856 Bolivia 54,764 Temperate 529,131 531,922 534,774 538,836 545,759 Central African Republic 22,170 Sub-tropical 307,123 303,746 301,332 295,502 295,331 Sudan 19,210 Tropical 1,935,226 1,831,358 1,785,725 1,745,219 1,713,324 Madagascar 12,473 Total 3,960,676 3,846,005 3,793,590 3,750,008 3,721,160 Botswana 10,840 Planted forest Cote d’Ivoire 10,401 Boreal/polar 30,114 40,841 47,099 54,423 57,705 Nigeria 6,993 Temperate 88,866 108,971 124,402 134,593 138,709 Guinea 6,364 Sub-tropical 18,298 21,030 22,579 24,111 24,726 Somalia 6,363 Tropical 30,316 38,755 45,074 52,539 56,833 Democratic People’s Republic of Korea 5,031 Total 167,593 209,597 239,153 265,665 277,973 14 R.J. Keenan et al. / Forest Ecology and Management 352 (2015) 9–20
Table 8 Table 9 Rates of change in natural forest area (calculated as total forest area minus planted Mean rates of change in natural forest area in 2000–10 (K ha yÀ1) in countries with forest area) and planted forest area from 1990 to 2015 by climatic domain (K ha yÀ1) the highest mean rates of population growth in 2000–10 (K persons yÀ1) above (calculated from FAO, 2015). All totals involve rounding. 1000 K persons yÀ1.
Period 1990–00 2000–05 2005–10 2010–15 Rate of population Rate of forest area growth change Natural forest Boreal/polar À1.022 À1.445 À0.261 À0.741 India 16,336 3 Temperate 0.279 0.571 0.812 1.385 Nigeria 3,683 À625 Sub-tropical À0.338 À0.483 À1.166 À0.034 Indonesia 3,174 À1,002 Tropical À10.387 À9.127 À8.101 À6.379 Pakistan 2,932 À71 Total À11.467 À10.483 À8.716 À5.770 Ethiopia 2,107 À169 Brazil 2,071 À3,030 Planted forest Bangladesh 1,874 À4 Boreal/polar 1.073 1.252 1.465 0.657 Philippines 1,579 9 Temperate 2.011 3.086 2.038 0.823 Democratic Republic of the 1,524 À467 Sub-tropical 0.273 0.310 0.306 0.123 Congo Tropical 0.844 1.264 1.493 0.859 Mexico 1,401 À187 Total 4.200 5.911 5.302 2.462 Tanzania 1,095 À595 and human causes, e.g. clearance for agriculture, over-exploitative timber harvesting, the expansion of settlements, and infrastructure Research to model short-term relationships between deforesta- development. Changes to other land uses are linked to a complex tion rates and driving and controlling forces is complemented by and multi-faceted set of underlying driving forces, which include studies of long-term trends in forest area. The most prominent population growth, poverty, and government policies; and control- generic relationship involves a curve showing the switch from ling forces, such as technological development, rural to urban net forest loss to net forest expansion as a country develops. The migration, changes in cultural attitudes toward forests, and stron- actual turning point marks a country’s national forest transition ger incentives for conservation. (Mather, 1992; Rudel et al., 2005). Because the expansion of It was possible to use statistics from early FRAs in regression planted forest makes an important contribution to this switch, analysis across countries for the same time period to show positive the aggregated FRA statistic of forest area can be used to monitor correlations between the rate of tropical deforestation and key dri- such transitions. The forest transition model is consistent with vers (Lambin, 1997; Lambin et al., 2001). Indeed, modeling was the the low or negative rates of forest loss in higher income countries focus of 30% of all scientific studies that made substantive use of that are reported in FRA 2015 (Table 3). An inspection of national statistics in FRAs 1980–2005 (Grainger, 2008). Yet FAO actually trends in forest area in FRA 2015 also provides evidence that 13 used population growth rates to estimate deforestation rates in tropical countries were likely to have either passed through their FRA 1980 for countries for which reliable forest area change data national forest transitions between 1990 and 2015, or continued were lacking (Lanly, 1981) and, as demonstrated by Rudel and along the path of forest expansion that follows such transitions Roper (1997), some scientists who were unaware of this drew mis- (Table 10). These include such countries as India and Vietnam, leading conclusions about the significance of population growth as for which forest transitions have already been documented a driver. Subsequently, scientific analysis of drivers of forest (Mather, 2007). Forest transitions might also have occurred in six change has placed greater stress on national and sub-national other countries, such as Thailand, but these are more uncertain studies that rely on national data on changes in population and because of potential errors in statistics; uncertainty around the land use and land cover (e.g. Mena et al., 2006), and on turning point itself (Grainger, 2010); and other factors, e.g. the cross-sectional regression studies in which rates of deforestation apparent trend in Thailand’s forest area may have been influenced are estimated using pan-tropical satellite surveys, of the kind dis- cussed in Section 4.4 (e.g. DeFries et al., 2010). Nevertheless, FRA 2015 statistics may still be used in new scientific studies to check for any cross-sectional evidence for the driving and controlling Table 10 Trends in forest area in countries where a national forest transition (switch from net forces of forest change. forest loss to net forest expansion) between 1990 and 2015 is likely or possible (K ha). To anticipate such research, our analysis suggests that the find- ings of such studies are unlikely to be as categorical as those in the Country 1990 2000 2005 2010 2015 past. For example, a test of the 62 tropical countries that had a Transition likely mean rate of loss of natural forest above zero in 2000–10, and Burundi 289 198 181 253 276 Gambia 442 461 471 480 488 employing logarithmic transformations, resulted in a correlation Ghana 8,627 8,909 9,053 9,195 9,337 coefficient of r = 0.615 between Log10 (deforestation rate2000–10) Rwanda 318 344 385 446 480 and Log10 (population growth rate2000–10)(Fig. S1, Table S4). Bhutan 2,507 2,606 2,656 2,705 2,755 However, the relationship between the rate of change of natural India 63,939 65,390 67,709 69,790 70,682 forest area and the rate of population growth is now far more com- Laos 17,645 16,526 16,870 17,816 18,761 Philippines 6,555 7,027 7,074 6,840 8,040 plex than it was in the 1980s and 1990s, owing to the increasing Vietnam 9,363 11,727 13,077 14,128 14,773 dominance of controlling forces and drivers of forest expansion Cuba 2,058 2,435 2,697 2,932 3,200 over drivers of deforestation, the differential influences of urban Costa Rica 2,564 2,376 2,491 2,605 2,756 and rural populations (DeFries et al., 2010), and the effect of time Dominican Republic 1,105 1,486 1,652 1,817 1,983 lags. For example, for the five tropical countries with mean popu- Puerto Rico 287 450 463 479 496 lation growth rates of 2–4 million persons yÀ1 in 2000–10 (UN, Transition possible 2013), the rate of deforestation varied from 71 K ha yÀ1 Cape Verde 58 82 84 85 90 Cote D’Ivoire 10,222 10,328 10,405 10,403 10,401 À1 (Pakistan) to 3030 K ha y (Brazil), and natural forest area actually Sierra Leone 3,118 2,922 2,824 2,726 3,044 À1 rose at a rate of 43 K ha y in India, which had the highest popu- Malaysia 22,376 21,591 20,890 22,124 22,195 lation growth rate in the tropics (16.4 million persons yÀ1) Thailand 14,005 17,011 16,100 16,249 16,399 (Table 9). Trinidad and Tobago 241 234 230 226 368 R.J. Keenan et al. / Forest Ecology and Management 352 (2015) 9–20 15 by a change in the method used by its Royal Forest Department to between trends in different FRAs can establish mutual corrobora- analyse satellite images. tion, or shed light on associated uncertainties (Houghton, 2010). We examined global trends in natural forest, and trends for a sam- 4.3. Uncertainties about trends in forest area ple of 90 tropical countries in 1990, and how the shape of each trend varied. By 2015, creation of new states had increased the size One way to determine the robustness of forest area statistics of this sample to 93 countries, through the emergence of Eritrea, reported in FRAs is to examine the quality of the latest individual South Sudan and Timor-Leste (Table S5). The set of countries used estimates of national forest area. In FRA 2005 and earlier reports for long-term comparison corresponds to the set used in FRA 1990 specific information was listed in tables in the FRA Main Report (FAO, 1993), and includes Mexico, Nepal and Pakistan, which in on the dates and types of the original estimates used to calculate FRA 2015 are allocated to the sub-tropical climatic domain. the values of statistics, e.g. whether these estimates were recent Sometimes, differences between trends in successive FRAs can or, say, 20 years old, and whether they were based on satellite or be traced to national factors, but on other occasions they reflect airborne remote sensing measurements or on ’expert estimates’. changes in overall FRA methods. For example, the FRA 1990 value The type of measurement (or lack of it) indicated the accuracy of of natural forest area in the tropics in 1990 was 170 M ha lower each data point. The likely error involved in projecting it forward than the value for the same year in FRA 2000, reflecting a switch to the latest common FRA reporting year (2015 in the case of from non-linear projection and interpolation methods in FRA FRA 2015), using the interpolation and extrapolation methods 1990 to linear methods in FRA 2000 (Fig. 1, Table 11). After this described in Section 2, could be inferred from the date of the esti- mate and hence the length of the projection (Grainger, 2008). Table 11 In FRA 2015, the quality of the latest survey estimate is reported Trends in tropical forest area and natural forest area (90 countries) and global forest by countries in terms of Tier quality rankings (from 1, poorer qual- area in Forest Resources Assessments (FRAs) 1990–2015 (M ha). ity to 3, higher quality) (Table 5). In the template provided for Date FRA 1990 FRA 2000 FRA 2005 FRA 2010 FRA 2015 national forest area reports by FAO, Tier 3 was defined as ‘‘Data Tropical sources: either recent (610 years ago) National Forest Inventory Forest area or remote sensing, with ground truthing, or programme for 1980 1,928 repeated compatible NFIs’’; Tier 2 as ‘‘Data sources: full cover map- 1990 1,800 1,989 1,978 2,085 2,022 ping/remote sensing or old NFI (>10 years ago)’’; and Tier 1 as 2000 1,866 1,861 1,972 1,923 ‘‘Other’’ (FAO, 2013b). The evidence on which these rankings were 2005 1,803 1,929 1,872 2010 1,887 1,847 based will be published in the individual FRA 2015 Country 2015 1,819 Reports, but these reports could not be used for analysis in this Natural forest area study. 1980 1,920 We therefore focused instead on examining the uncertainties 1990 1,756 1,926 1,949 2,058 1,995 associated with the aggregate trends in forest area from 1990 to 2000 1,799 1,829 1,934 1,888 2015 that were reported in FRA 2015, by analyzing them in the 2005 1,768 1,885 1,841 context of trends for the same period reported in earlier FRAs. 2010 1,837 1,799 2015 1,767 Since each FRA is undertaken independently, FAO prefers not to estimate change by comparing, say, the estimate of global forest Global forest area area in 2015 published in FRA 2015, with the estimate of global 1990 3,963 4,077 4,168 4,128 forest area in 2005 published in FRA 2005. Instead, each FRA has 2000 3,870 3,989 4,085 4,056 2005 3,952 4,061 4,033 presented new historical trends, e.g. from 1990 to 2015 in FRA 2010 4,033 4,015 2015, that are consistent with the estimate for the latest reporting 2015 3,999 year, i.e. 2015 in the case of FRA 2015. Analyzing the relationships
Fig. 1. Trends in tropical natural forest area 1980–2015 in Forest Resources Assessments (FRAs) 1990–2015. 16 R.J. Keenan et al. / Forest Ecology and Management 352 (2015) 9–20
Fig. 2. Trends in global forest area 1990–2015 in Forest Resources Assessments (FRAs) 2000–2015. disjunction, in FRA 2005 the value of natural forest area in 1990 left as pre-filled. We found that, out of a sample of 93 tropical only rose by 23 M ha over the value in FRA 2000 (Grainger, countries, in FRA 2010 41 countries had used the same statistics 2008), and this relatively small increment is interesting because for 1990–2005 as in FRA 2005, while in FRA 2015 47 countries from FRA 2005 onwards NCs had more autonomy to make their had repeated the estimates for 1990–2010 used in FRA 2010. In reports than in earlier FRAs. The increasing trend continued in contrast, in FRA 2005, the last report before prefilling was intro- FRA 2010, in which natural forest area for 1990 rose by 109 M ha duced, only 10 tropical countries had used the same statistics for to 2058 M ha. In FRA 2015, however, this trend was reversed, with 1990–2000 as in FRA 2000 (Table S6). The 47 countries that did natural forest area in the tropics for 1990 actually falling by not change the prefilled figures in 2015 accounted for 32% of total 63 M ha to 1995 M ha – though this value is still higher than the natural forest area in the sample of 93 countries in 2015 corresponding estimate in FRA 2005. A similar deflation is seen (569 M ha), an area 33% larger than that of the 41 prefilling coun- in consecutive trends in global forest area (Fig. 2). Whether this ’de- tries in FRA 2010 (428 M ha). When all FRA 2015 Country Reports flationary’ phenomenon is the result of a greater accuracy of indi- become available, further scientific studies could explore this effect vidual FRA 2015 estimates, or of other factors, requires further in more detail, and undertake a deeper statistical analysis of the study. To show how national circumstances can play a role, e.g. uncertainties associated with FRA 2015 trends than was possible deflation was also visible between tropical forest area trends in in this paper. FRA 2005 and FRA 2000 (Table 11). A major reason for this was the reclassification of 90% of forest plantations in India as natural 4.4. Comparison of the findings of FRA 2015 and remote sensing forests, which inflated natural forest area but not overall forest studies area (Grainger, 2010). If FRA 1990 statistics are excluded, as an outlier, the decline of Another way to evaluate the findings of FRAs is to compare 228 M ha in tropical natural forest area between 1990 and 2015, them with the findings of global remote sensing surveys. A funda- calculated from FRA 2015 statistics (Fig. 1), is 73% greater than mental issue for FRAs is that individual countries undertake their the 132 M ha range of area estimates of tropical natural forest in forest inventories at different times and frequencies, according to the year 1990 in FRAs 2000–2015 (Table 11). However, the their own measurement cycles and the availability of funding. 129 M ha decline in global forest area over the same period is only Errors can therefore arise when relatively rudimentary methods 63% of the 205 M ha range of estimates for global forest area in are used in FRAs to adjust estimates of forest area based on the 1990 in FRAs 2000–2015 (Fig. 2), and so could be within the limits results of these national surveys to a common reporting year, e.g. of error for the trend as a whole, tending to support Mather’s 2015 in FRA 2015, and to estimate rates of forest area change (2005) conclusions about historic uncertainties in the trend in glo- (see Section 3). Since remote sensing satellites collect data every bal forest area. year for every part of the Earth’s surface, it is possible, in principle, A second feature of successive trends that is apparent in Fig. 1 is to use these data to measure global and pan-tropical forest areas in that while trends in FRAs 1980–2005 were generally parallel to one specific years and the rate at which they changed between these another, in FRA 2010, and more markedly in FRA 2015, forest area years. In practice, for areas with high cloud cover, or subject to declines less rapidly after 2005. On the one hand, this reflects the other technical issues associated with image processing, it may recent reduction in the rate of deforestation, noted above. mean that remotely sensed images are a compilation of images However, it might also have been influenced by FAO staff ‘‘prefill- from around a target year. In this section we compare FRA 2015 ing’’ the 1990, 2000, 2005, 2010 values of the forest area statistics findings with the results of global remote sensing surveys. We look in FRA 2015 with those from FRA 2010. As was the case in FRA in turn at estimates of forest area and forest area change, and at 2010, countries were not obliged to fill in all the years in the data- their limitations. base using the same set of data and the same forward and back- While there are general similarities between FRA and global ward projection methods. Instead, values for the most recent remote sensing estimates, differences between them can be years could be estimated separately and figures for previous years explained by a combination of five main factors. First, the R.J. Keenan et al. / Forest Ecology and Management 352 (2015) 9–20 17 limitations of FRA statistics, in terms of data quality and consis- as the FRA 2015 figure for all tropical forest, which was based on tency between countries, which are well documented (Grainger, a threshold tree cover of 10%. 2008; Hansen et al., 2013). Second, variation in the methods used Global or pan-tropical remote sensing studies of forests include to estimate forest area, e.g. FRA main reports involve the aggrega- surveys undertaken outside the FRA process, and those undertaken tion of national statistics reported by countries, while global within the FRA process itself. To provide an alternative common remote sensing surveys may employ sampling methods or compre- picture of forest cover FAO has, since 1990, commissioned hensive (‘‘wall to wall’’) mapping. Each method has its own large-scale uniform Remote Sensing Surveys (RSS) to complement strengths and limitations. Third, difficulties in using remote sens- the national statistics listed in the FRA main reports. The results of ing techniques to correctly determine percent tree cover for low these RSS have generally been presented in parallel with data sup- tree cover densities, i.e. below 30%. Fourth, differences in the set plied by countries. Thus, the findings of RSS 2000 were included as of countries covered by estimates. a chapter in the FRA 2000 Main Report (FAO, 2001). FAO commis- The fifth factor, which will have a major impact on the analysis sioned two recent RSS in partnership with the Joint Research in this section, is the use of different definitions of ’forest’. Lund Centre of the European Commission. These surveys, which were (2014) lists over 1500 different operational definitions of the term based on a global sample of satellite imagery, were designed to ‘forest’ and over 200 different definitions of the term ‘tree’. Some of provide consistent and comparable estimates of tree cover and for- these are land cover based (e.g. biophysical) definitions while est land-use from 1990 to 2010 at global and regional scales, to others are land use based definitions. The FRAs employ a land use complement the increasing number of national statistics in FRA definition, which means that they can include areas designated main reports that are based on national remote sensing surveys. for forestry or conservation that are temporarily unstocked with The first, ‘RSS 2010’ (FAO and JRC, 2012), was undertaken as part trees (see Section 2). Most remote sensing studies, on the other of the FRA 2010 process, but completed and published after the hand, use a land cover definition (Magdon et al., 2014), because Main Report. The second, here called ‘RSS 2015’ (FAO and JRC, land use cannot be determined by remote sensing alone. 2014), was part of the FRA 2015 process and extended the Definitions of forest also vary in the minimum threshold of per- time-series for the same sample sites to 2010. centage tree cover which they require before an area of land can According to FRA 2015, global forest area declined from be defined as forest. Consequently, the use of different definitions 4128 M ha in 1990 to 3999 M ha in 2015 (Table 1). In the earliest can lead to very different estimates of forest area in remote sensing remote sensing survey at this scale, Hansen et al. (2010) found that estimates. This is illustrated by Hansen et al. (2013), who divided global forest area declined from 3269 M ha to 3168 M ha between world land area into four ‘‘tree cover’’ classes – 0–25%, 26–50%, 2000 and 2005 (Table 12). The absolute values of area in 2000 and 51–75% and 76–100% – when they undertook wall to wall mapping 2005 were much lower than those in FRA 2015. One possible rea- using Landsat images. They found that in the tropics, the 76–100% son for this was that Hansen et al. (2010) only mapped areas with tree cover class, which broadly corresponds with tropical moist tree cover above 25%, whereas FRA 2015 used a 10% threshold; forest, covered 1324 M ha in the year 2000, while the area above another reason was that they used coarse (0.5 km) resolution 25% tree cover, 2094 M ha, was of the same order of magnitude MODIS images, which may not detect small areas of forest. The
Table 12 Estimates of global and pan-tropical forest area 1990–2015 based on satellite data, compared with FRA 2015 findings (M ha).
Source 1990 2000 2005 2010 Forest definition Method Global forest area FRA 2015 4,128 4,056 4,033 3,999 >10% canopy, >5 m height, land use Compilation of national statistics Hansen et al. (2010) – 3,269 3,168 – >25% canopy, >5 m height, tree cover Wall to wall 500 m resolution MODIS images plus sample of Landsat images Hansen et al. (2013) – 4,145 – – >25% canopy, >5 m height, tree cover Wall to wall 30 m resolution Landsat images Gong et al. (2013) – – – 3,730 Presence of tree cover > 15% Wall to wall 30 m resolution Landsat images RSS 2010 3,860 3,820 3,790 – >10% canopy, >5 m height, land use >13,000 102 km2 blocks in Landsat images RSS 2015 4,000 3,950 – 3,890 >10% canopy, >5 m height, land use >13,000 102 km2 blocks in Landsat images Tropical forest area FRA 2015 1,966 1,870 1,831 1,798 >10% canopy, >5 m height, land use Compilation of national statistics Hansen et al. (2010) – 1,870 – – >25% canopy, >5 m height, tree cover Wall to wall 500 m resolution MODIS images plus sample of Landsat images Hansen et al. (2013) – 2,094 – – >25% canopy, >5 m height, tree cover Wall to wall 30 m resolution Landsat images RSS 2000 – 1,571 – – >10% canopy, land use Sample of 117 Landsat images RSS 2010 1,730 1,670 1,620 – >10% canopy, >5 m height, land use >13,000 102 km2 blocks in Landsat images RSS 2015 1,860 1,790 – 1,730 >10% canopy, >5 m height, land use >13,000 102 km2 blocks in Landsat images Achard et al. (2014) 1,635 1,574 – 1,514 >30% canopy in 3 ha MMU, tree cover 4000 102 km2 blocks in Landsat images Tropical moist forest area Achard et al. (2002) 1,150 – – – >40% canopy, tree cover Wall to wall 1 km resolution AVHRR images then a sample of 100 Landsat images Mayaux et al. (2005) – 1,094 – – Various, tree cover Wall to wall 1 km resolution SPOT-4 Hansen et al. (2010) – 1,156 – – >25% canopy, >5 m height, tree cover Wall to wall 500 m resolution MODIS images plus sample of Landsat images Kim et al. (2015) – – – 1,240 >30% canopy, 35 countries only Wall to wall 30 m resolution Landsat images Achard et al. (2014) 1,043 1,004 – 972 >30% canopy in 3 ha MMU, tree cover 4000 102 km2 blocks in Landsat images
Notes. Hansen et al. (2010) study estimated gross loss from 2000 to 2005. RSS 2010 study estimated loss from 2000 to 2005. Achard et al. (2014) study does not include Mexico. – = not assessed. MMU = Minimum Mapping Unit. 18 R.J. Keenan et al. / Forest Ecology and Management 352 (2015) 9–20 second factor seems to have been influential, because when Table 13 Hansen et al. (2013) used medium (30 m) resolution Landsat Trends in pan-tropical forest area change rates 1990–2015 based on satellite data, compared with FRA 2015 findings (M ha yÀ1). For notes on forest definitions and images (again assuming at least 25% tree cover) they found that methods see Table 12. global forest area in the year 2000 was 4145 M ha, which was only 89 M ha above the FRA 2015 estimate for 2000 of 4056 M ha. Source 1990s 2000–05 2000–10 Hansen et al. (2013) did not attach any error bars to their esti- Tropical forest mates, but the errors involved in measuring global forest area in FRA 2015 À9.5 À7.9 À6.6 Hansen et al. (2010) – 9.5 – this way are clear from the range represented by the two Hansen À Hansen et al. (2013) ––À8.5 et al. estimates, and another estimate of 3730 M ha for global forest Achard et al. (2014) À8.0 – À7.6 area in 2009 that was also based on Landsat imagery, but with a RSS 2000 À8.3 – – 15% tree cover threshold (Gong et al., 2013). RSS 2010 À5.7 À9.1 – RSS 2010 reported a drop in global forest area from 3820 M ha Tropical moist forest to 3790 M ha between 2000 and 2005 (FAO and JRC, 2012), but RSS Achard et al. (2002) À5.8 – – 2015 reported higher area values and but the same rate of loss, Hansen and DeFries (2004) À7.2 – – Hansen et al. (2010) – À5.4 – from 3950 M ha to 3890 M ha between 2000 and 2010 (FAO and Achard et al. (2014) À4.8 – À4.1 JRC, 2014). The relative proximity of these five global surveys to Kim et al. (2015) À4.0 À7.0 À6.6 the FRA 2015 trend is interesting, given that the two RSS used over 13,000 10 km  10 km sampling blocks within Landsat images, while the other three surveys used wall to wall sets of Landsat 1150 M ha in 1990 and 1116 M ha in 1997 (Achard et al., 2002); images (Hansen et al., 2013; Gong et al., 2013) or MODIS images 1094 M ha (Mayaux et al., 2005) and 1156 M ha (Hansen et al., (Hansen et al., 2010). 2010) in 2000; and 1257 M ha in 2010 (Kim et al., 2015). The high Another set of remote sensing surveys can be used to evaluate value of the last of these studies was remarkable, as it was based the report in FRA 2015 that between 1990 and 2015 tropical forest on wall to wall mapping using Landsat images, and referred to only area in 142 countries declined by 10% from 1966 M ha to 34 countries and to all forest with more than 30% tree cover. 1770 M ha (Table 1). One estimate of 1870 M ha for all tropical for- Another set of measurements, based this time on samples of est area in the year 2000 (Hansen et al., 2010) is identical to the Landsat images, did show a decline, from 1043 M ha in 1990, to FRA 2015 figure for that year, and the RSS 2015 trend may also 1004 M ha in 2000 and 972 M ha in 2010 (Achard et al., 2014). not be significantly different from the FRA 2015 trend: A more challenging task is to substantiate key findings of FRA 1860 M ha, 1790 M ha and 1730 M ha for 1990, 2000 and 2010 2015 that between the 1990s and 2010–15 the net rates of loss À1 respectively (FAO and JRC, 2014). On the other hand, the RSS of all forest and tropical forest halved, falling from 7.3 M ha y À1 À1 À1 2010 estimate of 1620 M ha for 2005 (FAO and JRC, 2012) and esti- to 3.3 M ha y , and from 9.5 M ha y to 5.5 M ha y , respectively mates by Achard et al. (2014) of 1635 M ha, 1574 M ha and 1514 M (Table 4). One reason for this difficulty is that estimates of forest for 1990, 2000 and 2010, respectively, are much lower (Table 12). area loss are affected by differences between land use and land These latter figures resulted from using the same sampling method cover definitions. For example, most forest clearance in the tropics as RSS 2010 (4000 sample blocks in the tropics), but with a land involves a change in land use, e.g. to agriculture, and the customary cover definition instead of a land use definition. Interestingly, the forest management practice is selective logging, which does not Achard et al. (2014) figure for 2000 is almost identical to the esti- involve forest clearance. In temperate and boreal forests, on the mate of 1571 M ha for all tropical forest in 2000 by RSS 2000 (FAO, other hand, clear-felling is a common forest management practice. 2001), which employed a different (two-stage stratified random) This results in a temporary loss of tree cover but does not lead to a design for sampling Landsat images. change in land use. Hansen et al.’s (2010) measurement of ’gross The accuracy of estimates of all tropical forest area is con- global forest loss’, which equated forest with tree cover above À1 strained by uncertainty about the distribution of open ’savanna’ 25%, concluded that 20.2 M ha y was lost between 2000 and woodlands in dry areas, which are extensive in Africa, Australia 2005. This was much higher than the corresponding rate in FRA À1 and Latin America (Bodart et al., 2013; Beuchle et al., 2015). 2015. However, only 47% of this loss (9.5 M ha y ) occurred in À1 Open woodlands were thought to contribute 734 M ha, or 38%, to the tropics, while the remaining 53% (10.7 M ha y ) occurred in the estimate of 1935 M ha for tropical natural forest area in 1980 temperate and boreal forests, as a result of logging, fire and insect (FAO, 1982). Yet owing to their low commercial importance they outbreaks. Hansen et al.’s (2010) method involved taking samples are often not assessed by field surveys, or surveyed regularly by of Landsat images to estimate the rate of forest loss. When Hansen governments. Measuring their area using remote sensing is also et al. (2013) used the more elaborate approach of classifying wall difficult, even with Landsat images (Lambin, 1999). Estimates of to wall Landsat images they found that temperate and boreal for- the area of the even lower tree cover category of ’other wooded ests now accounted for just 38% of global gross forest cover loss À1 land’ also vary, e.g. the estimate by Achard et al. (2014) of of 19.2 M ha y between 2000 and 2012, and this was offset by À1 975 M ha for other wooded land in 2010 is 81% higher than the forest gain of 6.7 M ha y . RSS 2010 used the same 10% tree cover 538 M ha reported in FRA 2015. This discrepancy is partly threshold used for the FRA main report statistics, but its estimate À1 explained by the fact that the remotely-sensed class of other of 14.7 M ha y for the rate of global net forest loss between wooded land may include areas of low density tree cover that 2000 and 2010 was also higher than the corresponding estimate would be classified as ’forest’ in FRA Main Report statistics. in FRA 2010 (FAO and JRC, 2012). Coulston et al. (2013) shed fur- Indeed, RSS 2010 showed that differences between regional forest ther light on this issue by showing that estimates of forest land area estimates in FRA 2015 and RSS 2010 estimates rose as the use extent and forest land cover extent in the southeastern USA extent of drylands in a region increased (FAO and JRC, 2012). were not correlated; that estimates of net change based on forest Tropical moist forests – which comprise all closed forests in the land cover and forest land use were only modestly correlated; humid tropics – are easier to map using satellite data, though they and that net forest land use change estimates were independent are often hidden from satellite sensors by clouds. They were the of gross forest cover loss. They suggested that changes in forest initial focus of global remote sensing forest surveys, yet it is diffi- cover are more indicative of a change in forest land use in the trop- cult to conclude that tropical moist forest area has declined signif- ics than in areas, such as the southeastern USA, where forest regen- icantly by looking at the time series of available estimates, i.e. eration commonly follows harvesting and disturbance. R.J. Keenan et al. / Forest Ecology and Management 352 (2015) 9–20 19
A sufficient number of estimates of deforestation rates for trop- policy outcomes. For example, FRA 2015 estimates of forest area ical moist forest are available for comparison with estimates of include natural forest and planted forest, and a reduction in net tropical forest area loss in FRA 2015. These estimates tend to be forest loss (which could result from a combination of a loss of nat- lower, not higher, than corresponding estimates of tropical forest ural forest and a gain in planted forest) is not the same as a reduc- loss in FRA 2015, not least because they refer to a subset of tropical tion in deforestation. forests. Thus, estimates of forest loss for the 1990s include The quality of data on which FRA 2015 statistics are based is 5.8MhayÀ1, based on samples of Landsat images (Achard et al. considered to be higher than those in earlier FRAs, with National (2002); and 7.2 M ha yÀ1, offset by forest gain of 1.2 M ha yÀ1, Correspondents reporting that about 60% of global forest area in using 8 km resolution images (Hansen and DeFries, 2004) 2015 has been estimated using the highest quality data. (Table 13). The declining trend in FRA 2015 was supported by However, the amount of forest reported using the poorest data Hansen et al.’s (2010) estimate for 2000–05 of 5.4 M ha yÀ1, and quality (Tier 1) is still 11%, indicating that a number of countries estimates by Achard et al. (2014) of 4.8 M ha yÀ1 between 1990 used out-of-date or incomplete national assessments. and 2000 and 4.1 M ha yÀ1 between 2000 and 2010. On the other Independent pan-tropical and global remote-sensing surveys hand, another set of integrated estimates found that the net rate exhibited differences in estimates of global and tropical forest area of forest loss in 34 humid tropical countries, based on wall to wall and dynamics, both with FRA 2015 and with each other, because of mapping using Landsat images, rose from 4.0 M ha yÀ1 in the 1990s differences in definitions and in measurement methods. This vari- to 7.0 M ha yÀ1 in 2000–05, and then declined to 6.1 ha yÀ1 in ation between studies suggests the need for policy makers to 2005–10 (Kim et al., 2015). understand differences between estimates of forest area derived Fewer estimates of forest loss are available for all tropical forest. using different methods and based on different definitions when These include 8.3 M ha yÀ1 in the 1990s in RSS 2000 (FAO, 2001), establishing policies and targets to reduce deforestation rates 9.5MhayÀ1 between 2000 and 2005 (Hansen et al., 2010), and and increase forest area. 8.5MhayÀ1 between 2000 and 2012 (Hansen et al., 2013). The Increased investment over the last 10 years has improved combined time series is understandably closer in value to the cor- national forest monitoring capacity in developing countries, in responding FRA estimates than the time series for tropical moist considerable part to prepare to implement arrangements for the forest, and supports Kim et al.’s (2015) claim that tropical defor- REDD+ mechanism of the UN Framework Convention on Climate estation peaked after 2000. Further support is provided by RSS Change. This investment needs to be sustained, and expanded to 2010, which estimated that net tropical forest loss rose from include key African and Latin American countries with currently 5.7MhayÀ1 in the 1990s to 9.1 M ha yÀ1 in 2000–05 (FAO and deficient inventory systems. A comprehensive monitoring JRC, 2012). However, Achard et al. (2014) found only a slight drop approach that integrates remotely-sensed data of sufficiently high from 8.0 M ha yÀ1 in the 1990s to 7.6 M ha yÀ1 from 2000 to 2010, resolution with field measurements and observations could pro- which supports the FRA 2015 trend. vide a sound basis for assessing forest-related greenhouse gas Overall, the findings of remote sensing studies provide some dynamics and for supporting sustainable forest management at a support for FRA 2015 findings, especially on trends in global forest range of scales. area and tropical forest area. However, it is difficult to generalize, because there are considerable differences between the findings Acknowledgements of remote sensing studies, owing to differences in assessment peri- ods, the definitions of forest, remote sensing methods, and country We would like to acknowledge the efforts of the National coverage. Correspondents from each country and territory in collecting and presenting data for the 2015 Global Forest Resource Assessment and the UN FAO staff involved in reviewing and collating data. 5. Conclusions This analysis was completed while RJK was undertaking a Special Study Program from the University of Melbourne at CATIE in The results of the latest Global Forest Resources Assessment of Costa Rica and the London School of Economics and Political the Food and Agriculture Organization of the United Nations (FAO) Science. He would like to acknowledge the support and hospitality indicate that between 1990 and 2015 total forest area declined by provide by those institutions. Other authors would like to acknowl- 3%, from 4128 M ha to 3999 M ha, and the annual rate of net forest edge the support of their respective host institutions. We also À1 À1 loss halved from 7.3 M ha y in the 1990s to 3.3 M ha y between thank two anonymous referees for helpful comments and 2010 and 2015. Loss of forest area was largely in the tropics, from suggestions. 1966 M ha in 1990 to 1770 M ha in 2015, while temperate forest expanded from 618 M ha to 684 M ha over the same period. Net Appendix A. Supplementary material tropical forest loss over the last five years was dominated in South America by Brazil (984 K ha yÀ1), in Asia by Indonesia Supplementary data associated with this article can be found, in (684 K ha yÀ1), and in Africa by Nigeria (410 K ha yÀ1). However, the online version, at http://dx.doi.org/10.1016/j.foreco.2015.06. the Brazilian and Indonesian loss rates were only about 40% of 014. the corresponding rates in the 1990s. Forest area expanded between 2010 and 2015 by 1.5 M ha yÀ1 in China, and at rates of 301 K ha yÀ1, 275 K ha yÀ1 and 240 K ha yÀ1 in Chile, the USA and References the Philippines, respectively. Between 1990 and 2015, thirteen Achard, F., Eva, H.D., Stibig, H.-J., Mayaux, P., Gallego, J., Richards, T., Malingreau, J.- tropical countries may have either experienced national forest P., 2002. Determination of deforestation rates of the world’s humid tropical transitions from net forest loss to net forest gain, or continued forests. Science 297, 999–1002. along the path of forest expansion that follows such transitions. Achard, F., Beuchle, R., Mayaux, P., Stibig, H.-J., Bodart, C., Brink, A., Donnay, F., Lupi, A., Carboni, S., Desclee, B., Donnay, F., Eva, H.D., Lupi, A., Rasi, R., Seliher, R., Forest transitions may be in progress in another six countries. Simonetti, D., 2014. Determination of tropical deforestation rates and related While the results of FRA 2015 are likely to be used extensively carbon losses from 1990 to 2010. Glob. Change Biol. 20, 2540–2554. for research and policy formulation, as with previous FRAs, careful Arrow, K.J., Dasgupta, P., Goulder, L.H., Mumford, K.J., Oleson, K., 2012. Sustainability and the measurement of wealth. Environ. Dev. Econ. 17, 317–353. interpretation will be needed to ensure that the statistics are used Ausubel, J.H., Wernick, I.K., Waggoner, P.E., 2012. Peak farmland and the prospect in ways that are consistent with scientific terminology and desired for land sparing. Popul. Dev. Rev. 38 (S), 217–238. 20 R.J. Keenan et al. / Forest Ecology and Management 352 (2015) 9–20
Baker, D.J., Richards, G., Grainger, A., Brown, S., DeFries, R., Gonzalez, P., Held, A., Houghton, R.A., 2010. How well do we know the flux of CO2 from land-use change? Kellndorfer, J., Ndunda, P., Ojima, D., Skrovseth, P.-E., Souza, C., Stolle, F., 2010. Tellus B 62, 337–351. Achieving forest carbon information with higher certainty: a five step strategy. Kim, D.-H., Sexton, J.O., Townshend, J.R., 2015. Accelerated deforestation in the Environ. Sci. Policy 13, 249–260. humid tropics from the 1990s to the 2000s. Geophys. Res. Lett. 2014GL062777. Beuchle, R., Grecchi, R.C., Shimabukuro, Y.E., Seliger, R., Eva, H.D., Sano, E., Achard, F., http://dx.doi.org/10.1002/2014GL062777. 2015. Land cover changes in the Brazilian Cerrado and Caatinga biomes from Lambin, E.F., 1997. Modelling and monitoring land-cover change processes in 1990 to 2010 based on a systematic remote sensing sampling approach. Appl. tropical regions. Prog. Phys. Geogr. 21, 375–393. Geogr. 58, 116–127. Lambin, E.F., 1999. Monitoring forest degradation in tropical regions by remote Bodart, C., Brink, A., Donnay, F., Lupi, A., Mayaux, P., Achard, F., 2013. Continental sensing: some methodological issues. Glob. Ecol. Biogeogr. Lett. 8, 191–198. estimates of forest cover and forest cover changes in the dry ecosystems of Lambin, E., Turner, B., Geist, H., Agbola, S.B., Angelsen, A., Bruce, J.W., Coomes, O.T., Africa for the period 1990–2000. J. Biogeogr. 40, 1036–1047. Dirzo, R., Fischer, G., Folke, C., George, P.S., Homewood, K., Imbernon, J., Coulston, J.W., Reams, G.A., Wear, D.N., Brewer, C.K., 2013. An analysis of forest land Leemans, R., Lin, X., 2001. The causes of land-use and land-cover change: use, forest land cover and change at policy-relevant scales. Forestry 87 (2), 267– moving beyond the myths. Glob. Environ. Change 11, 261–269. 276. Lanly, J.P. (Ed.), 1981. Tropical Forest Resources Assessment Project (GEMS): DeFries, R.S., Rudel, T., Uriarte, M., Hansen, M., 2010. Deforestation driven by urban Tropical Africa, Tropical Asia, Tropical America, vol. 4. UN Food and Agriculture population growth and agricultural trade in the 21st-century. Nat. Geosci. 3, Organization/UN Environment Programme, Rome. 178–181. Le Quere, C., Raupach, M.R., Canadell, J.G., Marland, G., 2009. Trends in the sources FAO, 1982. Tropical Forest Resources. FAO Forestry Paper No. 30. UN Food and and sinks of carbon dioxide. Nat. Geosci. 2, 831–836. Agriculture Organization, Rome. Lund, H.G., 1999. A ’forest’ by any other name.... Environ. Sci. Policy 2, 125–133. FAO, 1993. Forest Resources Assessment 1990: Tropical Countries. FAO Forestry Lund, H.G., 2002. When is a forest not a forest? J. For. 100, 21–28. Paper No. 112. UN Food and Agriculture Organization, Rome. Lund, H.G., 2014. Definitions of Forest, Deforestation, Reforestation and FAO, 1995. Forest Resources Assessment 1990: Global Synthesis. FAO Forestry Paper Afforestation. Forest Information Services, Gainesville, VA,
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Changes in forest production, biomass and carbon: Results from the 2015 UN FAO Global Forest Resource Assessment q ⇑ Michael Köhl a, , Rodel Lasco b, Miguel Cifuentes c, Örjan Jonsson d, Kari T. Korhonen e, Philip Mundhenk a, Jose de Jesus Navar f, Graham Stinson g a University of Hamburg, Center for Wood Sciences, World Forestry, Leuschnerstrasse 91, 21031 Hamburg, Germany b World Agroforestry Centre (ICRAF), Calabarzon, Philippines c CATIE, 7170 Cartago, Turrialba 30501, Costa Rica d FAO, Forestry Department, viale delle Terme di Caracalla, 00100 Rome, Italy e Natural Resources Institute Finland (Luke), Yliopistokatu 6, 80101 Joensuu, Finland f CIIDIR-IPN Unidad Durango, Sigma No. 119, Fraccionamiento 20 de Noviembre 11, Durango, Dgo, Mexico C.P. 34220, Mexico g Natural Resources Canada, National Forest Inventory, 506 Burnside Road West, Victoria, BC V8Z 1M5, Canada article info abstract
Article history: Forests are important sources of livelihoods to millions of people and contribute to national economic Received 19 December 2014 development of many countries. In addition, they are vital sources and sinks of carbon and contribute Received in revised form 25 May 2015 to the rate of climate change. The UN Food and Agriculture Organization has been collecting and present- Accepted 26 May 2015 ing data on global forest resources and forest cover since 1948. This paper builds on data from FAO’s 2015 Available online 7 September 2015 Global Forest Resource Assessment (FRA) and presents information on growing stock, biomass, carbon stock, wood removals, and changes of forest area primarily designated for production and multiple use Keywords: of the world’s forests. Forest Resources Assessment 2015 Between 1990 and 2015, the total growing stock volume has increased in East Asia, Caribbean, Western Removals Wood fuel and Central Asia, North America, Europe (including the Russian Federation), and Oceania with the highest Production area relative increase in East Asia and the Caribbean. In all other subregions the total growing stock volume Carbon decreased. North and Central America, Europe and Asia report forest C stock increases while South Growing stock America and Africa report strong decreases and Oceania reports stable forest C stocks. The annual rate of decrease of forest C stock weakened between 1990 and 2015. The total volume of annual wood removals including woodfuel removals increased between 1990 and 2011, but shows a remarkable decline during the 2008–2009 economic crisis. Forest areas designated for production purposes differ considerably between subregions. The percent- age of production area out of total forest area ranges between 16 percent in South America and 53 per- cent in Europe. Globally about one quarter of the forest area is designated to multiple use forestry. The balance between biomass growth and removals shows considerable sub-regional differences and related implications for the sustainable use of forests. Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction countries. In addition, they are vital sources and sinks of carbon (C) and contribute to the rate of climate change. Forests are important sources of livelihoods to millions of peo- Forest ecosystems cover roughly one third of the global land ple and contribute to national economic development of many area and are among the most biologically rich and genetically diverse ecosystems on earth. They contribute to soil formation and water regulation and are estimated to provide direct employ- q This article is part of a special issue entitled ‘‘Changes in Global Forest Resources ment to at least 10 million people, apart from being a source of from 1990 to 2015’’. livelihoods to millions more (FAO, 2010). It is estimated that about ⇑ Corresponding author. 410 million people are highly dependent on forests for subsistence E-mail addresses: [email protected] (M. Köhl), [email protected] and income, and 1.6 billion people depend on forest goods and ser- (R. Lasco), [email protected] (M. Cifuentes), [email protected] vices for some part of their livelihoods (Munang et al., 2011). Wood (Ö. Jonsson), kari.t.korhonen@luke.fi (K.T. Korhonen), Philip.mundhenk@uni- hamburg.de (P. Mundhenk), [email protected] (J. de Jesus Navar), Graham.Stinson@ and manufactured forest products add more than $450 billion to nrcan-rncan.gc.ca (G. Stinson). the world market economy annually, and the annual value of http://dx.doi.org/10.1016/j.foreco.2015.05.036 0378-1127/Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). internationally traded forest products is between $150 billion and 2000, 2005, 2010 and 2015). As expected, there were significantly $200 billion. more missing values for dead wood, litter and soil C stocks. Since 1948, the FAO has been conducting the Global Forest We made estimates for missing values in order to evaluate Resources Assessments (FRA) which are now produced every five sub-regional and global totals. Missing values were categorized years. It aims to provide a consistent approach to describing the in two main classes: (1) at least one value was reported but time world’s forests and how they are changing. FRA has become a series is incomplete, and (2) no value was reported for any year. major source of information on global forests for policy making In order to have complete time series for countries that had and for the development of international programs and initiatives. reported C stock for at least one year, estimates were made by mul- In this paper we report on the results of FRA 2015 on the state and tiplying forest area for the missing years by C stock density trends of forest production, biomass and carbon. Specifically, we (Mg C haÀ1) for the closest year reported. Sub-regional mean C analyze the latest trend in growing stock, biomass, carbon, wood stock densities were then calculated. In order to make estimates removals, production and multiple use forest area changes. for countries that did not report any value, the sub-regional C stock density was multiplied by forest area for the corresponding miss- 2. Methods ing year. No country in East Asia reported on C in litter, so the sub-regional average of South and Southeast Asia was used FRA 2015 provides reports on 234 countries and territories, of instead. No country in Central America reported on C in soil, so which 155 come from country reports prepared by national corre- sub-regional average from Caribbean was used instead. Most coun- spondents nominated by government agencies responsible for for- tries reported soil C to the specified common soil depth of 30 cm. A estry. The remainder comes from desk studies, which since FRA few countries used other soil depths, but this was not adjusted for 2000 have been used to provide estimated values for forest statis- because it does not affect the trend over time as the same soil tics in countries which have not provided a country report. While depth was used for all reporting years. the number of desk studies is high, in total they represent only 0.5% of global forest area. Data for this study were kindly made 2.3. Wood removals available by FAO. FRA 2015 utilizes a questionnaire approach to collect forest Wood removals have been reported in the FRA since 2000. related national statistics. The data collection process for FRA Before 2000, FRA utilized the attribute ‘‘Production’’, which is more 2015 was undertaken collaboratively with Forest Europe, or less synonymous to removals. Wood removals refer to the total Montréal Process, International Tropical Timber Organization and volume that is actually removed from forests and does not include l’ Observatoire des Forêts d’Afrique Centrale using a Collaborative the volume of cut trees, logs and logging residuals left in the forest. Forest Resources Questionnaire (CFRQ) and the data were reported Thus, the volume classified as wood removals is generally smaller in the Forest Resources Information Management System (FRIMS) than the volume of fellings. However, in rare situations the volume hosted by FAO in Rome. This information collection process is of removals can exceed the volume of fellings, such as when har- not a sample based survey and thus does not permit the applica- vesting operations are utilized to remove timber from fellings in tion of probability based procedures for estimating sampling errors earlier periods or trees killed or damaged by natural causes. and confidence intervals. Data submission is not mandatory and Wood removed from the forests is either used for energy produc- the individual countries are responsible for reporting comprehen- tion or as raw material for the production of goods. The term sive, up-to date, reliable and representative data. For further ‘‘woodfuel removals’’ is used for the wood removed for energy pro- details on the collection and validation of national data for FRA duction purposes, regardless whether for industrial, commercial or 2015 see MacDicken (2015). domestic use, the term ‘‘industrial roundwood removals ’’ describes the wood removed (volume of roundwood over bark) 2.1. Growing stock for production of goods and services other than energy production (wood fuel) (FAO, 2010). 184 out of 234 countries and territories reported the growing For the period from 1990 to 2011 countries were provided stock volume estimates for the reference year 2015. These coun- annual data on wood removals from FAOSTAT and were asked to tries and territories represent 93.5% of the global forest area. For check and correct whenever necessary. A total of 171 countries pro- some countries, growing stock data were reported for 2015, but vided information for 1990. The number of countries that reported missing for some of the other reporting years. We made the follow- information on wood removals consistently increased over time, ing estimations to get global and sub-regional estimates for grow- with 196 countries provided information for 2011. The global forest ing stock in 2015. First, in order to have complete time series for area covered by the reporting increase from 92 percent in 1990 to countries that had reported growing stock for at least one year, 98 percent in 2011. Adjustments for missing data were not applied estimates were made by multiplying forest area for the missing because wood removals are driven by human interventions that years by growing stock density (m3 haÀ1) for the closest year cannot be approximated using simple imputations. reported. Sub-regional growing stock densities were then calcu- lated. Secondly, estimates were made for countries that did not 2.4. Production and multiple use forest area changes report any value by multiplying the sub-regional mean growing stock density by forest area for the country and reporting year in The FRA reporting categories differentiate between question. The estimated data for these latter countries were not considered in our trend analyses. production forest, which is the forest area designated primarily for production of wood, fiber, bioenergy and/or non-wood forest 2.2. Biomass and carbon products and multiple use forest, which is the forest area designated for more Most Country Reports included reporting on carbon (C) stocks, than one purpose and where none of these alone is considered but not all included complete reporting. A total of 173 countries as the predominant designated function. representing 98% of the global forest area reported biomass C stocks (Fig. 1). Of these, 167 countries representing 84% of the glo- The multiple use concept applied in FRA does not imply that bal forest area reported a complete time series (including 1990, multiple use forests take into account all of forest functions (A) Biomass (B) Dead wood Percent of area with repor ng Percent of countries repor ng Percent of area with repor ng Percent of countries repor ng 100% 100% 100% 100%
80% 80% 80% 80%
60% 60% 60% 60%
40% 40% 40% 40%
20% 20% 20% 20%
0% 0% 0% 0% Europe North and South Africa Asia Oceania World Europe North and South Africa Asia Oceania World Central America Central America America America
(C) Li er (D) Soil Percent of area with repor ng Percent of countries repor ng Percent of area with repor ng Percent of countries repor ng 100% 100% 100% 100%
80% 80% 80% 80%
60% 60% 60% 60%
40% 40% 40% 40%
20% 20% 20% 20%
0% 0% 0% 0% Europe North and South Africa Asia Oceania World Europe North and South Africa Asia Oceania World Central America Central America America America
Fig. 1. National reporting on forest C stocks in FRA 2015 Country Reports. simultaneously. But these forests are managed to serve more than stock in 1990. Between years 1990 and 2000 the global growing a single primary designated function. stock volume was slightly decreasing, thereafter slightly increas- The ‘‘primary designated function’’ refers to the primary func- ing. Between 1990 and 2015, the total growing stock volume has tion or management objective assigned to a management unit increased in 6 out of the 12 subregions: East Asia, Caribbean, either by legal prescription, documented decision of the Western and Central Asia, North America, Europe, and Oceania landowner/manager, or evidence provided by documented studies (Fig. 2). In relative terms, highest increase took place in East Asia of forest management practices and customary use. No adjust- and the Caribbean, over 40% in both subregions. The increase of ments were made for non-responses. growing stock volume in the Caribbean subregion is explained by the increase of forest area by almost 50% between the years 1990 2.5. Categories and 2015. In East Asia, both forest area and mean stocking per hec- tare increased. In absolute terms, the increase was highest in North 3 3 Results are presented for three different stratification America (7.1 billion m ) and Europe (10.9 billion m ). In both of categories: these sub-regions, the increase of growing stock volume is explained by increased mean stocking per hectare (Table 2). (1). Domains (Boreal, Temperate, Subtropics, Tropics) Between 1990 and 2015, the growing stock volume decreased (2). Subregions (Caribbean, North America, Central America, in 6 sub-regions: Central America, Eastern and Southern Africa, South America, Northern Africa, Western and Central South and Southeast Asia, Northern Africa, Western and Central Africa, Eastern and Southern Africa, Europe, Western and Africa, and South America. In relative terms, the highest decrease Central Asia, East Asia, South and Southeast Asia, Oceania) took place in Central America (16.1%) and Eastern and Southern (3). Income groups (see Table 1). Africa (12.6%). In absolute terms, the largest decrease took place in South America (10,843 million m3). For further details see MacDicken (2015). The average forest growing stock per hectare in 2015 varies by sub-regions from less than 60 m3 haÀ1 in Eastern and Southern Africa and North Africa to more than 200 m3 haÀ1 in Oceania 3. Results (Table 2). Between 1990 and 2015 the average growing stock increased in most of the sub-regions and clearly decreased only 3.1. Growing stock and biomass in South and Southeast Asia. Very slight decrease is observed also in the Caribbean sub-region and North Africa. In most of those The total global growing stock estimate is 530.5 billion m3 for sub-regions where total growing stock volume decreased, the 2015. This is 3.6 billion m3 (0.7%) more than the total growing decrease has been primarily caused by loss in the forest area, not Table 1 by degradation or shifts from older to younger age class distribu- Income groups as defined by the World Bank (Source: http://data.worldbank.org/ tions caused by natural disturbance or harvesting (Fig. 3). Two about/country-and-lending-groups). sub-regions, South & South-East Asia and North-Africa show Income group Index GNI per Capita decrease both in mean stocking and forest area. In North-Africa Low income economies L 6US$ 1.045 both these changes are nominal, whereas in South & South-East Lower middle income economies LM US$ 1.046 to US$ 4.125 Asia both the decrease in forest area and decrease in mean stocking Upper middle income economies UM US$ 4.126 to 12.745 are remarkable leading a clear decrease in total growing stock High income economies H PUS$ 12.746 (Fig. 2). In 4 sub-regions, Central America, South America, Fig. 2. Volume of growing stock (million m3) 1990–2015 by sub-regions.
Table 2 Western & Central Africa and Eastern & Southern Africa the forest 3 Mean volume (m /ha) of growing stock in forest from 1990 to 2015 by sub-regions. area change is negative but mean stocking positive. In all these Only countries that have reported both forest area and growing stock volume sub-regions, the increase in mean stocking is too low to fully com- included for each reporting year. pensate the decrease in forest area, leading to decrease in total Subregion Year growing stock. The positive trend in mean stocking may be caused 1990 2000 2005 2010 2015 by plantations in these sub-regions. In 5 sub-regions, North Caribbean 78.8 86.7 89.3 78.1 78.0 America, East Asia, Europe, Oceania, Western & Central Asia both Central America 141.7 140.6 140.5 139.9 158.5 the forest area and mean stocking trends are positive. Naturally, East Asia 76.8 82.4 84.2 88.5 90.8 the total growing stock has increased in these sub-regions. Eastern and Southern Africa 56.2 56.1 56.5 56.8 57.2 Caribbean is the only sub-region where the mean stocking has Europe 104.3 107.4 109.2 111.2 112.9 North America 112.6 115.7 121.4 124.4 128.1 decreased and forest area increased. The changes in mean stocking Northern Africa 59.2 61.7 58.2 58.0 58.3 is nominal and therefore the total growing stock has slightly Oceania 194.2 196.4 197.9 200.0 201.7 increased in the Caribbean sub-region (Fig. 2). South America 172.8 174.4 175.0 176.1 178.2 South and Southeast Asia 102.8 105.1 102.9 100.9 98.5 Western and Central Africa 191.5 193.0 193.8 194.7 195.5 3.2. Carbon Western and Central Asia 68.6 70.6 70.0 71.8 73.7
Forest C stocks declined by 13.6 Pg C between 1990 and 2015 (Fig. 4). Most of this decline occurred in living biomass. The global trend in dead wood & litter C stocks was driven by increases in 20 Europe and North America, where these stocks are the largest C.America (Fig. 5) and where natural disturbances transfer large quantities 15 N. America E.Asia of C from living to dead pools (e.g. Kurz et al., 2008). The global trend in soil C stocks is one of weakening decline (the short-lived 10 Europe gain during 2000–2005 is likely an artifact of the approach we used Oceania to fill in missing data; few countries reported soil C stock trends S.America 5 W&C.Asia W&C.Africa and most of these used Tier 1 (least reliable) methods). North E&S. Africa N.Africa 0 and Central America, Europe and Asia report total forest C stock Caribbean -80000 -60000 -40000 -20000 0 20000 40000 60000 increases while South America and Africa report strong decreases S&SE.Asia-5 and Oceania reports stable forest C stocks. The rate of forest C stock decline decreased from 0.84 Pg C yearÀ1 during 1990–2000 to À1 -10 0.34 Pg C year during 2010–2015. Forest C stock densities vary sub-regionally, with the highest reported densities in Western and Central Africa, and the lowest Fig. 3. Change in mean volume (y-axis, m3/ha) vs. change in forest area (x-axis, densities in Western and Central Asia (Fig. 5). The highest biomass 1000 hectares) from 1990 to 2015 by sub-regions. C densities were reported in tropical sub-regions, chiefly South (a) Biomass (b) Dead wood & li er 6 0.8 Europe 4 0.6 2 0.4 North & Central 0 America 0.2 South America -2 0 -4 Africa Pg C Pg C -0.2 -6 Asia -0.4 -8 Oceania -10 -0.6 -12 -0.8 World -14 -1 1990 2000 2005 2010 2015 1990 2000 2005 2010 2015 (c) Soil (d) Total 3 10
2 5 1 0 0
-1 -5 Pg C Pg C -2 -10 -3 -15 -4
-5 -20 1990 2000 2005 2010 2015 1990 2000 2005 2010 2015
Fig. 4. Forest carbon stock changes since 1990 (1 Pg = 1015 g = 1 billion tons).
200 200
180 Biomass 180 Dead wood 160 160 Li er 140 Soil 140 120 120 -1
100 100 Pg C
80 Mg C ha 80
60 60
40 40
20 20
0 0 Europe Europe WORLD Oceania Oceania East Asia East Asia Caribbean Caribbean South America South America North America North America Northern Africa Northern Africa Central America Central America Western and Central Asia Western and Central Asia South and Southeast Asia South and Southeast Asia Western and Central Africa Western and Central Africa Eastern and Southern Africa Eastern and Southern Africa
Fig. 5. Forest C stocks and C stock densities in global forest sub-regions, 2015.
America (122.4 Mg C haÀ1) and Western and Central Africa 3.3. Wood removals (120.6 Mg C haÀ1). The highest dead wood and litter C densities were reported in North America (12.1 and 29.5 Mg C haÀ1, respec- The total volume of annual wood removals increased from tively). The highest soil C densities were reported in Europe 2.75 billion m3 to around 3.0 billion m3 from 1990 to 2011 as (94.6 Mg C haÀ1), a sub-region that is dominated by the extremely reported. Fig. 6 presents the development of wood removals for large forest area in the Russian Federation, making Europe the (a) countries that reported for all points in time and (b) the data sub-region most dominated by forests of the boreal biome. Forest provided for a specific point in time, which includes countries that C stocks are largest in Europe, South America and North America missed reporting for one or more reporting periods. The similarity because these sub-regions host the largest forest areas (26%, 22% in the shape of both curves and their pronounced difference in and 16% of the world’s forest area, respectively). 1993 suggest that non-response was mainly a problem in the time Fig. 6. Wood removals between 1990 and 2011. period from 1990 to 1992. The development of annual wood With reference to domains, the total volume of woodfuel removals over time was not continuous. Between 1990 and 1993 removals shows the same ranking as wood removals: they are the total volume of timber declined, followed by a constant highest in the Tropics, followed by the Temperate, Boreal and increase until 2005. In 2008 and 2009 a reduction was recorded, Subtropics domain. A relatively continuous growth is observed in coincident with the global economic crisis. In 2010 and 2011 the the Tropics, while moderate changes are found for the other total volume of wood removals recovered to the levels reported domains (Fig. 8). for the period 2005 to 2007 for both the countries that reported Fig. 9 gives a more detailed picture. Wood removals were in every year and for all countries that reported (Fig. 6). highest in North America, Western and Central Asia and South Woodfuel removals show a different development but it should and Southeast Asia and lowest in the Caribbean, Central be noted that woodfuel statistics maintained by FAO is largely America, Western and Central Africa, East Asia, and Oceania. based on estimation methods (Whiteman et al., 2002). For 80% of Compared with the figures on forest areas mainly designated the reported volume the woodfuel removals were estimated for for production, as presented in Fig. 11, reveals substantial differ- the year 2011 compared with 84% for the year 2000, over time data ences in area related utilization rates in the sub-regions. Europe is improving and share of estimates decrease for historical data as takes an intermediate position in the total volume of wood national data becomes available. They increased almost continu- removals, but reported the largest amount of areas primarily des- ously between 1990 and 2011, starting at 1134 million m3 in ignated for production. In contrast, North America realizes most 1990 and reaching 1343 million m3 in 2011 (Fig. 7). wood production in multiple use forests (Fig. 13). In Western Wood removals are highest in the Tropics and lowest in the and Central Asia the level of wood removals is high while only Subtropics. The global decline in 2008 and 2009 (Fig. 6) can only a relatively small forest area is primarily designated for produc- be observed in the Boreal and Temperate domains (Fig. 8). While tion forest or multiple use. For most subregions wood removals the total volume of wood removals shows a notable increase in increased over time. South America shows a decline between the Tropics, it remains constant in the Subtropics. In the Boreal 1997 and 2000. In Europe a pronounced decline between 1995 domain a clear decline between 1990 and 1996 is followed by a and 1996 is followed by a recovery until 2007. Both subregions, recovery until 2005. The wood removals in the temperate domain North America and Europe show a downturn in 2007 and 2008, fluctuated between 1990 and 2007 before the economic crisis of coincident with the economic crisis, while other sub-regions did 2008. not indicate any reduction.
Fig. 7. Woodfuel removals between 1990 and 2011. Fig. 8. Wood removals (above) and Woodfuel removals (below) by domains 1990–2011.
Woodfuel removals are highest in South and Southeast Asia. increasing, with the largest increase in South and Southeast Asia. Western and Central Africa, Eastern and Southern Africa, South At least in Europe the increase is likely driven by the increasing America, and Europe take a central position, in all other subregions demand for renewable energies. The EU Renewable Energy woodfuel removals are low. In Eastern and Southern Africa, Europe, Directive (EU, 2009) requires the EU to fulfill at least 20% of its total and South and Southeast Asia woodfuel removals are consistently energy needs with renewables by 2020, which should be achieved Fig. 9. Wood removals (above) and Woodfuel removals (below) by sub-region 1990–2011. through the attainment of individual national targets. All EU coun- wood removals are slightly higher than for the low income group. tries must also ensure that at least 10% of their transport fuels In the low and lower middle income group wood removals come from renewable sources by 2020. increased over time, while in the upper middle and high income A comparison of wood removals with income groups shows a groups substantial fluctuations can be observed. In the high mixed pattern (Fig. 10). The level of wood removals increased with income group a depression during the first seven years of the income groups except for the upper middle income group, where reporting period is followed by an increase and a relatively steady Fig. 10. Wood removals (above) and Woodfuel removals (below) by income group 1990–2011. state since 2005. The same pattern is found for the high income development patterns differ. Woodfuel removals decrease from group, except for the decline in 2007 and 2008. 1990 to 2001 in the upper middle income group followed by a pro- Woodfuel removals are highest in the low middle income nounced increase between 2004 and 2005 and a slight decrease group, followed by the low income group. In both groups wood from 2005 to 2011. A downturn between 1991 and 1996 can be removals are increasing over time. The level of woodfuel removals observed in the upper income group with a subsequent small fluc- is comparable in upper middle and high income group, but the tuation after 1998. In some countries, wood removals from trees Fig. 11. Area of production forests by sub-region. outside of forests (i.e. other lands with tree cover) may be consid- Assigning the area of forests mainly used for production to erable, but here we make no distinctions between woodfuel income levels gives a relatively uniform picture; most of the forest removals from forests versus harvesting trees outside of forests. area designated for production is found in higher income countries (Fig. 12). Production forests in low income countries is roughly 3.4. Production and multiple use forest area changes 100 million hectares while more than 600 million hectares are des- ignated primarily for production in areas with high income. The In 2015, 190 countries representing 97 percent of the global for- trends over time indicate only minor differences. est area reported on production forest area. The number of coun- About 26 percent or 1.049 million hectares of the total forest tries reporting on multiple use forest area is smaller (183 area are primarily designated for multiple use. Between 1990 countries or 95 percent of the global forest area). There are marked and 2015 the area of forests designated for multiple use differences between sub-regions in the designation of forest areas decreased in North America, Western and Central Africa, Europe for production purposes (Fig. 11). In Europe more than 500 million and South and Southeast Asia, while in South America and East hectares or 52 percent of forests are designated primarily for pro- Asia an increase can be seen. In Eastern and Southern Africa the duction, a number that is significantly larger than in other decline between 1990 and 2010 could be reversed, so that in sub-regions. In the Caribbean, Central American, Northern 2015 more areas are designated to multiple use forestry than in African, Western and Central Asian and Oceania sub-regions the 1990 (Fig. 13). area of production forests is smaller than 20 million hectares. In the remaining sub-regions the respective areas range between 4. Discussion 60 million and 120 million hectares. In Western and Central Africa 30 percent of the total forest area are designated as produc- The results presented are based on the best information that tion forest and in Eastern and Southern Africa 22.3 percent, in countries can provide. Even so, the quality and reliability of indi- North America 16.7 percent, in South America 16.2, in Western vidual figures varies considerably because not all countries have and Central Asia 23.3, in East Asia 44.5, and in South and well established forest inventory and monitoring programs. The Southeast Asia 45.7 percent. number of countries providing data for the different information Fig. 11 presents the development over time for the total of the groups requested by the questionnaire varies and thus response reporting countries (bars) and the countries that reported in all rates show differences between reporting years, sub-regions and years (lines). In Africa the area of production forests decreased over attributes. The data are weakest for trend analysis, just as they time, which could be caused by the general reduction of forested were in previous FRA (Marklund and Schoene, 2006; MacDicken, area. In North and South America as well as in South and 2015). Where changes are driven by biophysical processes, such Southeastern Asia and Oceania the area of forests primarily desig- as climate, site index or soil carbon, statistical interpolation for fill- nated for production increased since 1990. In East Asia a decline ing missing values might be an appropriate measure to increase from 1990 to 2005 was followed by a slight increase until 2015. data completeness. Where developments are mainly a result of In Europe there is a pronounced decrease between 1990 and human interventions (e.g. wood removals, land-use change, forest 2000, followed by a steady state in 2005, 2010 and 2015. The management), spatial and temporal changes are subject to com- decrease could be a result of European activities for an increase plex interrelations of a variety of agents. In these situations it is of areas mainly designated for conservation and protection, such not advisable to fill data gaps by interpolation or other probability as the EU Habitat Directive on the protection of natural habitats based approaches. Therefore we undertook gap filling for missing and of wild flora and fauna (EU, 1992). growing stock, biomass and carbon stock data, but not for wood Fig. 12. Production forest area by income 1990–2015.
Fig. 13. Multiple use forest by sub-region 1990–2015. removals or forest areas designated to specific uses. Some diagnos- the overall global BCEF of 0.91 in the FRA 2015 data set is almost tics reveal problematic national reporting data and it is tempting to identical to the 0.92 in FRA 2010 (FAO, 2010). Considering the apply corrections to these data before analyzing them. For exam- diversity of national circumstances in the more than 200 countries ple, biomass conversion and expansion factors (BCEF) implied by reporting, it is expected that some of the data will look strange. the growing stock and biomass C stock data reported by countries Overall, however, the data appear to be plausible and they are use- do not all appear to be reasonable (Fig. 14). But the largest coun- ful for the purposes of sub-regional and global assessment. tries that are most influential on sub-regional and global means Between 1990 and 2015, the total growing stock volume has and totals appear to have reasonable implied BCEF values, and increased in East Asia, Caribbean, Western and Central Asia, 3.50 600
3.00
500 2.50
2.00 400 1.50
1.00 300
0.50 Biomass conversion & expansion factor FRA 2015 0.00 200 FRA 2010 0 100 200 300 400 500 600 700 800 900 Live biomass carbon stock (Pg C) Forest area reported for 2015 (million ha) FRA 2005
Pan et al. 2011 Fig. 14. Biomass conversion and expansion factors (BCEF) derived from country 100 reports, calculated as above-ground biomass C stock (t C) converted to biomass Pan / Saatchi stock (t) assuming 0.5 t C per t biomass and divided by growing stock (m3). The derived BCEF for three countries exceeds 3.50. Houghton et al. 2009 0 1990 2000 2005 2010 2015 North America, Europe (including the Russian Federation), and Oceania with the highest relative increase in East Asia and the Fig. 15. Global forest carbon stocks in live biomass carbon stocks (including above- Caribbean. In all other subregions the total growing stock volume and below-ground) reported in this paper compared with previous FRA (Marklund decreased. North and Central America, Europe and Asia report for- and Schoene, 2006; FAO, 2010) and peer-reviewed scientific papers. est C stock increases while South America and Africa report strong decreases and Oceania reports stable forest C stocks. The global importance of uncertainty about tropical forest biomass C stock annual rate of forest C stock decline decreased between 1990 densities to the estimation of global forest biomass C stocks. It also and 2015. suggests that the tropical forest biomass C densities used by Pan On a first glance the decrease of global carbon stocks and the et al. (2011) to estimate the global forest C sink may be high. The simultaneous increase of global growing stocks appear contradic- uncertainty bars for circa 2000 are taken from Houghton et al. tory. However, the carbon decrease found in the FRA 2015 data is (2009), and one might argue now that the upper end of this range mainly driven by the decreases in South America and Western can be brought down. and Central Africa. Here the carbon densities of forests are highest The importance of forest C estimates relates, of course, to the in the world and thus reductions of growing stock have a higher need to better understand the contribution of forests to the global impact on forest carbon balances than in other sub-regions. C cycle. Global cumulative anthropogenic emissions of carbon
Increases of growing stock in other sub-regions cannot compensate dioxide (CO2) will reach about 535 ± 55 Pg C for 1870–2013, of for the carbon losses in South America and Western and Central which about 30% is from land use change (145 ± 50 Pg C) (Le Africa. Quéré et al., 2014). Only a portion of these emissions remains in Just how large the C stock densities are in tropical forests the atmosphere, however, because the world’s oceans and terres- remains in some dispute and this is an important dispute. We must trial ecosystems act as important CO2 sinks. Le Quéré et al. know tropical forest C densities in order to know the greenhouse (2014) estimated that the global terrestrial CO2 sink is gas impacts of tropical deforestation (Houghton et al., 2009). Pan 2.7 ± 0.9 Pg C yearÀ1. This estimate was calculated using the resid- et al. (2011) report live biomass C stock densities (including ual of other, better known fluxes. Its actual size and location above- and below-ground live biomass) of 134.5 t C haÀ1 while remains highly uncertain. Using forest inventory data and Saatchi et al. (2011) report 100.5 t C haÀ1. The FRA 2015 biomass long-term ecosystem studies, the total C sink in established forests C stock densities reported for tropical sub-regions range around globally has been calculated to be 2.4 ± 0.4 Pg C year–1 for the per- the Saatchi et al. estimate, the highest being South America at iod 1990–2007 (Pan et al., 2011). Pan et al. also calculated that 122.4 t C haÀ1 and the lowest being Eastern & Southern Africa at tropical forest land-use changes contributed a source of 69.5 t C haÀ1. Fig. 15 shows that global forest biomass C stocks 1.3 ± 0.7 Pg C year–1 during this same period. Together, these fluxes reported in FRA 2015 are quite consistent with those reported in comprise a net global forest sink of 1.1 ± 0.8 Pg C year–1. previous FRA (FAO, 2010; Marklund and Schoene, 2006) but sub- Carbon budgets of terrestrial and forest ecosystems have also stantially lower than those reported by Pan et al. (2011). If the been investigated at the sub-regional and national scales. For Pan et al. estimates are based on over-estimates of tropical forest South Asia, the annual net carbon flux from land-use change was biomass C stocks, then this would explain the discrepancy. The À0.014 ± 0.050 Pg C yearÀ1 in 2000–2009 largely as a result of tree data point labeled ‘‘Pan/Saatchi’’ in Fig. 15 shows the value we plantation establishment (Patra et al., 2013). In North America, net get by adding boreal and temperate forest biomass C stock esti- ecosystem exchange (NEE) for a 7-year period (ca. 2000–2006) mates reported by Pan et al. with a tropical forest biomass C stock was estimated to be a À0.327 ± 0.252 Pg C yearÀ1 sink (Hayes calculated as the tropical forest area from Pan et al. multiplied by et al., 2012). These sinks are counteracted by the C source estimated the tropical forest biomass C stock density estimated by Saatchi for the Other Lands sector of 0.218 Pg C yearÀ1, where much of the et al. The positioning of this point on the y-axis (298.4 Pg C) is forest and crop products are assumed to be returned to the atmo- approximate because we applied the mean tropical forest biomass sphere. The terrestrial C balance of East Asia during 1990–2009 C density reported in Saatchi et al. to the forest area categorized as using three different approaches are: À0.293 ± 0.033 Pg C yearÀ1 tropical in Pan et al., which are not exactly the same study areas. from inventory–remote sensing model–data fusion approach, This crude calculation is, however, sufficient to demonstrate the À0.413 ± 0.141 Pg C yrÀ1 (not considering biofuel emissions) or À0.224 ± 0.141 Pg C yearÀ1 (considering biofuel emissions) for C Countries 100% cycle models, and À0.270 ± 0.507 Pg C yearÀ1 for atmospheric inverse models (Piao et al., 2012). The net balance of tropical forest biomes globally has been esti- mated to be 0.2 ± 0.4 Pg C yearÀ1 (not significantly different from zero) over both periods 1990–1999 and 2000–2005 (Malhi, 50% 2010). There were also a number of estimates at the national and sub-regional levels including for: tropical Pacific islands (Donato et al., 2012), China (Wei et al., 2014; Guo et al., 2010; Ren et al.,
2011; Tan et al., 2011; Liu et al., 2012; Lun et al., 2012), Australia 0% (Haverd et al., 2013), Russia (Dolman et al., 2012), Canada (Stinson et al., 2011), and the USA (Peckham et al., 2012).
If the world’s forests are acting as net sinks for atmospheric CO2, Change in forest area then how can global and sub-regional forest C stocks be in decline? Fig. 16 shows the net global forest C sink calculated by Pan et al. -50% alongside the forest C stock changes reported in FRA 2010 and FRA 2015. Federici et al. (2015) used the FRA 2015 data to estimate that À1 forests were a net source of CO2 emissions of 1.47 Gt CO2 year -100% -100% -50% 0% 50% 100% in the period 1991–2015 (1.47 Gt CO2 ⁄ 12/44 = 0.40 Pg C), so the answer may lie in the FRA 2015 data. Like data reported for previ- Change in biomass carbon density ous FRA, these data have some peculiarities (Marklund and Fig. 17. Country-level forest area and carbon density changes between 1990 and Schoene, 2006). The quality and reliability of individual figures 2015. reported by countries varies considerably with many of the reported data having lower tiers (less reliable). For example, only FRA 2015 data, the average C density of the world’s forests 5% of countries representing 9% of the forest area provided Tier 3 increased by 0.6% between 1990 and 2005 and by 0.1% between data for soil carbon stocks. But the discrepancy between the sink 2005 and 2015. Pan et al. reported a 2.0% increase in forest C den- reported by Pan et al. (2011) and the C stock loss calculated from sity between 1990 and 2007, including a 22.5% increase in tropical FRA 2015 data is not entirely caused by problems in the FRA data. forests that are recovering from past deforestation and logging, and First, not all CO2 taken up by forests is sequestered in forest ecosys- a 5.0% increase in tropical intact forests. Permanent sample plots in tem C pools. Some is transferred laterally out of the forest and tropical intact forests are few, but they indicate that these forests sequestered or emitted back into the atmosphere elsewhere. 9 3 are accumulating biomass and C (Baker et al., 2004; Phillips Global wood removals in 2005 totaled 3.0 Â 10 m , which et al., 2008; Lewis et al., 2009). Pan et al. estimate that tropical À1 amounts to roughly 0.3 Pg C year . Cole et al. (2007) conserva- intact forests are accumulating C at a rate of 1.1 Pg C yearÀ1.In À1 tively estimate that 1.9 Pg C year are transferred from terrestrial contrast, the FRA 2015 data only report an accumulation of ecosystems to inland waters, but only a portion of this is trans- 0.1 Pg C yearÀ1 in these forests. This difference accounts for the ferred from forests. majority of the discrepancy between Pan et al. and FRA in The second reason for the apparent discrepancy between Pan Fig. 16. Considering our discussion of tropical biomass C stock den- et al.’s sinks and FRA’s reported C stock losses arises from differ- sities, above, and the equally large (and important) uncertainties ences in how tropical forest C dynamics are estimated and about dead wood, litter and soil C stocks and stock changes, much reported. Many countries rely on Intergovernmental Panel on work remains to be done to refine our knowledge of the world’s Climate Change (IPCC) default expansion factors (IPCC, 2003)to forest C stocks and fluxes. calculate their C stocks for FRA, or they only have an estimate of The total volume of annual wood removals including woodfuel forest C stocks from one point in time, which was used by them removals increased between 1990 and 2011. Wood removals show (or us, see Section 2.2) to calculate C stock density and apply to a remarkable decline in 2009, but recovered until 2011. Forest the forest areas in the other years to calculate C stocks for those areas designated for production purposes differ considerably years. Fig. 17 shows these countries clustered along the vertical, between subregions (16.2 percent in South American and 52 per- zero percent change in biomass C density axis. According to the cent in Europe). Globally about one quarter of the forest area is
2.5 designated to multiple use forestry.
2.0 Pan et al. 2011 FRA 2010 5. Conclusions and recommendations 1.5 FRA 2015 1.0 The FRA provides comprehensive information on the current
-1 state and trends of the global forest resources. Over time it has 0.5 become a frequently cited information source, which is used for
Pg C yr a wide scope of applications from scientific studies to international 0.0 negotiations for political decision making. When utilizing and -0.5 interpreting the data on growing stock, carbon, removals and areas designated for production and multiple-use, it should be taken into -1.0 consideration that data have been made available by countries and -1.5 thus are subject to various assessment schemes and differ with 1990 to 99 2000 to 05 2005 to 10 2010 to 15 respect to data quality and reliability. We strongly recommend the restriction of analyses to sub-regions as the smallest units of Fig. 16. Global net forest ecosystem C sink calculated by Pan et al. (2011) for the periods 1990–1999 and 2000–2007 shown alongside forest C stock changes reference and to consult additional information on data reliability reported in FRA 2010 and FRA 2015 for the corresponding and more recent periods. when information on the country level is referenced. Recent international efforts to streamline global forest report- contemporary North American carbon balance among terrestrial biosphere ing and strengthen collaboration among international reporting models, atmospheric inversions, and a new approach for estimating net ecosystem exchange from inventory-based data. Glob. Change Biol. 18, 1282– processes (e.g. NRCan, 2012) have resulted in better alignment of 1299. http://dx.doi.org/10.1111/j.1365-2486.2011.02627.x. international data reporting requirements, reduced reporting bur- Houghton, R.A., Hall, F.G., Goetz, S.J., 2009. The importance of biomass in the global den and increased consistency of reporting. The most tangible carbon cycle. J. Geophys. Res. – Biogeo. 114. IPCC, 2003. Good Practice Guidance for Land Use, Land-Use Change and Forestry. In: example of this is the development of the Collaborative Forest Penman, J., et al. (Ed.). Institute for Global Environmental Strategies, Hayama. Resources Questionnaire, created by six international organiza-
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Forest Ecology and Management
journal homepage: www.elsevier.com/locate/foreco
Protective functions and ecosystem services of global forests in the past quarter-century q ⇑ Satoru Miura a, , Michael Amacher b, Thomas Hofer c, Jesús San-Miguel-Ayanz d, Ernawati e, Richard Thackway f a Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan b Logan Forestry Sciences Lab, Rocky Mountain Research Station, US Forest Service, 860 N 1200 E, Logan, UT 84321, USA c Watershed Management and Mountains, Forestry Department, Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, Rome 00153, Italy d Unit Forest Resources and Climate, DG Joint Research Centre, European Commission, Via Fermi 2749, I-21027 Ispra, Italy e Data and Information of Forest Management Unit and Land Preparation at Forestry, Ministry of Forestry, Block VII Floor V, Indonesia f Planning and Environmental Management, School of Geography, University of Queensland, Brisbane St Lucia, QLD 4072, Australia article info abstract
Article history: The world’s forests provide fundamental protection of soil and water resources as well as multiple Received 5 December 2014 ecosystem services and cultural or spiritual values. We summarized the FRA 2015 data for protective Received in revised form 22 March 2015 functions and ecosystem services, and analyzed increasing or decreasing trends of protective areas. Accepted 24 March 2015 The global forest area managed for protection of soil and water was 1.002 billion ha as of 2015, which Available online 7 September 2015 was 25.1% of all global forested areas. Protective forests have increased by 0.181 billion ha over the past 25 years mainly because more countries are now reporting protective forest areas (139 in 2015 vs 114 in Keywords: 1990). However, average percentage of designated for protective forests did not change significantly from Sustainable forest management 1990 to 2015. Global forest area managed for ecosystem services is also now at 25.4% of global total forest Multiple functions Forest conservation area and has changed little over the past 25 years. Among the twelve categories of protective forests, Ecosystem value flood control, public recreation, and cultural services increased both in terms of percentage of total forest Criteria area and the number of reporting countries. Public awareness of the importance of forest resources for Indicator functions and services other than production continues to increase as evidenced by the increase of pro- tective forest designations and reporting in many countries. Percentages of total forest area designated for both protective forests and ecosystem services show a dual-peak distribution of numbers of countries concentrated at 0% and 100%. This suggests a socio-economic influence for the designations. We exam- ined five case study countries (Australia, Canada, China, Kenya, and Russia). The most dramatic changes in the past 25 years have been in China where protective forests for soil and water resources increased from about 12% to 28% of forest area. The Russian Federation has also increased percentages of forest area devoted to soil and water resource protection and delivery of ecosystem services. Australia is now report- ing in more protective forest categories whereas Kenya and Canada changed little. These five countries have their own classification of forest functions and recalculation methods of reporting for FRA 2015 were different. This demonstrates the difficulty in establishing a universal common designation scheme for multi-functions of forest. Production of more accurate assessments by further improvements in the reporting framework and data quality would help advance the value of FRA as the unique global database for forest functions integrated between forest ecosystems and social sciences. Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction as cultural or spiritual values. The Food and Agriculture Organization (FAO) of the United Nations reported in Global The world’s forests provide fundamental protection of soil and Forest Resources Assessment (FRA) 2010 that 8% of the world’s for- water resources and provide multiple ecosystem services as well ests had been primarily designated for protection of soil and water (FAO, 2010b). The public awareness of these forest functions has
q been growing over last few decades (WHO, 2005; Collaborative This article is part of a special issue entitled ‘‘Changes in Global Forest Resources Partnership on Forests, 2014). The Earth Summit (United Nations from 1990 to 2015’’. ⇑ Corresponding author. Tel.: +81 3 5841 8636; fax: +81 3 5841 8193. Conference on Environment and Development, UNCED) in Rio de E-mail address: [email protected] (S. Miura). Janeiro in 1992 was a turning point in this awareness trend. The http://dx.doi.org/10.1016/j.foreco.2015.03.039 0378-1127/Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 36 S. Miura et al. / Forest Ecology and Management 352 (2015) 35–46 conference spurred people to promote a variety of activities for attention and importance. FAO (2008) conducted an interesting sustainable forest management. Chapter 11 of Agenda 21 practical experience of compensation mechanisms for water ser- (‘‘Combating Deforestation’’) is particularly relevant in this vices provided by forests in Central America and the Caribbean, context. In the summary of this chapter, Keating (1993) writes: however its calculation remains a challenge (FAO, 2004b). Recent ‘‘forests are a source of timber, firewood and other goals. They also advances in Clean Development Mechanism (CDM) and Reducing play an important role in soil and water conservation, maintaining Emissions from Deforestation and Forest Degradation (REDD) in a healthy atmosphere and maintaining biological diversity of the 2000s under the UN Framework Convention on Climate plants and animals...there is an urgent need to conserve and plant Change (UNFCCC) also require a reliable reporting of objective for- forests in developed and developing countries to maintain or ests (REDD Research and Development Center, 2012). Demand for restore the ecological balance, and to provide for human needs’’. reporting multiple functions of forests has increased in importance It is generally accepted that forests and trees, in undisturbed based on these rising social concerns in the field of environmental form, provide the greatest vegetative protection against erosion economics. from rain, wind, and coastal waves (Broadhead and Leslie, 2007; FRA, the only statistical forest database covering the whole Hamilton, 2008). Accordingly, they also significantly contribute globe, has attempted to assess the extent of protective forests in to the reduction of downstream sedimentation (Fu, 1989). The root the world. The inclusion in FRA of the protective function of forests system of the trees creates increased soil strength (Greenwood gradually developed in parallel with the increasing importance for et al., 2004; Reubens et al., 2007). Forests and trees contribute to the global community assigned to this function. FRA first intro- the preservation of a good soil structure thanks to the protection duced a concept of ‘protective function’ of forest as non-wood ben- against splash erosion (provided the litter layer and the understory efits in FRA 1990 only for developed countries (FAO, 1995) and vegetation are maintained) and maintenance of robust biological made the first comprehensive report of protective functions of for- activity in the soil (Binkley and Fisher, 2013). In this context, for- est in FRA 2005 as ‘‘More than 300 million hectares of forests are ests and trees also contribute to the mitigation of risks of shallow designated for soil and water conservation’’ (FAO, 2006a). In the landslides. However, deep-rooted mass movements triggered by report of FRA 2015, FAO created separate main categories for pro- tectonic events cannot be prevented by forests and trees tective functions and selected ecosystem services since 1990 (FAO, (Hamilton, 1986; Government of Japan, 2002; Dolidon et al., 2009). 2012). An initial evaluation of the status and trend of forest protec- Clean water is becoming more recognized as one of the most tive functions over the past twenty-five years can provide the basis important environmental services provided by forests and trees for further detailed analysis of the importance of these forest func- (FAO, 2013). At least one third of the world’s largest cities draw a tions to the international forestry community and other related significant proportion of their drinking water from forested areas environmental sciences. (FAO, 2013). It is also well established that forests play a crucial In this paper we analyze the FRA reported data in two main cat- role in the hydrological cycle. Forests influence the amount of egories of protective functions and selected ecosystem services. In water available and regulate surface and groundwater flows while addition, we analyze the status and trend data in several protective maintaining high water quality (Aust and Blinn, 2004; Hamilton, forest sub-categories. We tested the effects of sub-regional, 2008). Forests and trees contribute to the reduction of water- latitude-affected climatic, and socio-economic differences and related risks such as floods and droughts and help prevent deserti- temporal changes on the main category and sub-category protec- fication and salinization (FAO, 2013). However, there is sufficient tive forest variables according the FRA reporting framework scientific evidence that forests are not able to prevent or even (FAO, 2014a). The trend analyses are based on percentages of total reduce medium to large scale floods (FAO and CIFOR, 2005; forest area or total land area and not on absolute forest area. We Hofer and Messerli, 2006; Hamilton, 2008). Policy makers have also discuss, as case studies, the status and trend of protective for- voiced concern about the effectiveness and limitation of these reg- ests in selected countries located in different regions and climatic ulating and provisioning services of forests (Cubbage et al., 2007; domains. Finally, we discuss key findings and future recommenda- Collaborative Partnership on Forests, 2014). tion to FRA for improving the reporting of protective functions and In the context of climate change and the resulting increased ecosystem services. incidence of natural hazards, the soil and water protection function of forests and trees is becoming increasingly important. For the 2. Methods maintenance and sustainability of this function, forest manage- ment through a watershed (landscape) approach is very important 2.1. Data source and compilation (Kammerbauer and Ardon, 1999; Postel and Thompson, 2005). Watershed management includes the management of all available The FRA 2015 dataset (http://www.fao.org/forestry/fra/fra2015/ natural resources (including forests) in a comprehensive way and en/) is described by MacDicken (2015). We used FRA 2015 data makes the link between natural resources management and the submitted by countries in response to the question ‘‘How much improvement of livelihoods. It provides a framework to organize forest area is managed for protection of soil and water and ecosys- different land-uses (forestry, pasture, agriculture) in an integrated tem services?’’ way (Turner, 1989). Watershed management contributes to the There are two main categories and ten sub-categories of protec- reduction of risks of natural hazards, such as landslides and local tive forests designated for specific purposes of providing protection floods, and creates local resilience against climate change as well against events that damage forest resources as well as for provid- as adaptation options (FAO, 2006b, 2007). ing various types of ecosystem services. The main categories are The soil and water protection function of forests and trees offers protective forests for soil and water resources and protective for- significant scope for the establishment of payment for ecosystem ests for delivery of ecosystem services. Within the soil and water services (PES) schemes. PES has been developing rapidly under resource protection category are protective forests for the sub- the framework of the Convention of Biological Diversity (CBD) sup- categories of (1) clean water, (2) coastal stabilization (3) desertifi- ported by Millennium Ecosystem Assessment and environmental cation control, (4) avalanche control, (5) erosion and flood control, economics (ex. Costanza et al., 1997; Kumar, 2010). In the context and (6) other control. Within the ecosystem services category are of large economic losses by floods and sediment disasters, the cal- protective forests for the sub-categories of (1) public recreation, culation of ecosystem values of services related to soil and water (2) carbon storage, (3) cultural services, and (4) other services protection provided by forests and trees is getting increased (excluding Table 6 for conservation of biodiversity). S. Miura et al. / Forest Ecology and Management 352 (2015) 35–46 37
2.2. Data analysis subtropical domain), Canada (North and Central American region, boreal domain), China (Asian region, temperate domain), Kenya Protective forest area data are reported in kilohectare (kha) (African region, tropical domain), and the Russian Federation units for each country that provides such information. These area (Europe region, boreal domain). Russia is a special case, geograph- data range more than six orders of magnitude because of the large ically. It is included in the global region of Europe in the FRA data- variation in land area and forest areas within a country and are base, but because it stretches across a wide longitudinal area, it non-normally distributed. To compare protective forest areas also includes large land area in Asia. All five countries report data among countries of such large size variability, area data were cal- quality in the tier 2 or 3 reliability categories. Thus, countries with culated as percentages of total land area (remains invariant over the least reliable data tier were excluded from these detailed case total 25-y reporting period) for each country and as percentages studies. of total forest area (which may change over reporting period). This enabled us to avoid too much influence by a few large coun- 3. Results tries. Protective forest areas were also calculated on a per capita basis. Expressing the protective forest area data as a % of total land 3.1. Protective forests for soil and water resources area or forest area basis allows for comparisons among countries of vastly different sizes and has the added advantage of producing a Globally, the Earth has about 3.999 billion ha of forest area as of more normal data distribution. We referred to sum of areas of main the 2015 report year, a decline of about 0.129 billion ha since 1990 or sub-categories of protective forests and its proportion to total (Fig. 1 top). Of this total forest area, as of 2015, about 1.002 bil- forest area or land area in those cases where we need to clarify lion ha (25.1% of global total forest area) has been designated by the absolute status of protective forests. the various countries and territories for the protection of soil and Statistical data analysis for this paper was generated using SAS water resources, an increase of 0.181 billion ha since 1990. At least software, version 9.4 of the SAS System (Ó 2013, SAS Institute Inc., part of the increase is due to more countries reporting protective Cary, NC, USA). The SAS generalized linear mixed model (GLIMMIX) forests (114 in 1990 vs 139 in 2015 out of 234 recognized countries software was used to test for differences among global sub-regions and territories) (Table 1 and Fig. 1 top). In percentage terms, global (northern Africa, eastern and southern Africa, western and central forest area has still declined (Keenan et al., 2015) from 32.3% of Africa, western and central Asia, east Asia, south and southeast total land area in 1990 to 31.3% of total land area in 2015 (Fig. 1 Asia, Europe, Caribbean, Central America, North America, South bottom). On the other hand, protective forest area remained fairly America, and Oceania), climatic domains (polar, boreal, temperate, constant over the same time interval with a mean of 35.9% of total subtropical, and tropical), income level (low, low middle, high mid- forest area (Table 2 and Fig. 1 bottom). Values of the percentage for dle, and high), and report years (1990, 2000, 2005, 2010, and 2015) each country showed a U-shaped histogram polarized to 0 or 100% for each protective forest sub-category with the data expressed in terms of % of total land area, % of forest area, and on a per capita basis. Normal distribution of the residuals was tested using the Global total forest and protected forest areas Pearson graphs panel. The Tukey option was used to test for statis- 4.5e+6 240 tically significant differences among the least-square computed 4.0e+6 220 means. Because the various forest area categories were expressed 3.5e+6 in terms of ratios (% of land area, % of forest area, per capita), any 200 Total forest area countries with blank values for the denominator values (land area, 3.0e+6 Total protective forest area 180 forest area, or population) result in an undefined ratio. These were 2.5e+6 Countries reporting forest area omitted from the data analysis. Some countries report 0 values in Countries reporting protective forest area 160 the various protective forest categories. Since these are real data 2.0e+6 140 entries, these were included in the data analysis. Forest area, kha 1.5e+6
Income level classification for testing protective forest differ- Nbr reporting countries 1.0e+6 120 ences among income class is from the 2013 World Bank dataset and is based on per capita annual income (MacDicken, 2015). 5.0e+5 100 Income classes are low ($1035 USD or less), lower middle ($103 1990 1995 2000 2005 2010 2015 6–$4085 USD), upper middle ($4086–$12,615 USD), and high Report year ($12,616 or more). We acknowledge that there is considerable variation in data 45 quality from all the reporting countries. FAO has addressed this problem by data quality tiers to all the main category data from each reporting country (MacDicken, 2015). Two types of tier eval- 40 uation were introduced. One is status of reliability of data acquisi- tion and the other is reported trend over 5 report years. Tier 1 data 35 are the least reliable, tier 2 data are considered moderately reliable, while tier 3 data are considered the most reliable. Countries were asked to assign tier values for each of the main protective forest Forest area, % 30 categories (soil and water resources and ecosystem services) in Total forest area, % of total land area the country reports, which were independently peer-reviewed by Protective forest area, % of forest area FAO staff, partners and external experts (MacDicken, 2015). We 25 used the tier data of status and we summarized the number of 1990 1995 2000 2005 2010 2015 countries in each tier category by domain. Report year To provide detailed examples of the reporting of protective for- Fig. 1. Global forest area, forest area designated for protection of soil and water est data into the FRA database, we selected five large area case resources, and numbers of reporting countries by report year (top). Mean ± std err study countries to represent a cross-section of the major global global forest area as % of total land area and mean ± std err soil and water protective regions and climatic domains. These are Australia (Oceania region, forest area as % of forest area by report year (bottom). 38 S. Miura et al. / Forest Ecology and Management 352 (2015) 35–46
Table 1 Summary of number of reporting countries in each protective forest main category and sub-category for each report year. Nbr > 0 = number of reporting countries with forest area great than 0 in each category or sub-category.
Report year Soil and water Clean water Coastal Desert control Avalanche Flood control Other control stabilization control Total Nbr > 0 Total Nbr > 0 Total Nbr > 0 Total Nbr > 0 Total Nbr > 0 Total Nbr > 0 Total Nbr > 0 (a) Protective forests for Number of reporting countries 1990 114 90 47 15 56 14 60 10 68 3 55 20 47 5 2000 120 98 50 19 59 16 59 10 68 3 56 22 49 8 2005 124 102 50 19 61 17 61 10 69 3 57 23 49 7 2010 134 113 61 30 68 25 62 10 71 4 63 28 55 12 2015 139 117 62 32 70 27 64 12 74 6 67 32 58 15
Report year Ecosystem services Public recreation Carbon storage Cultural services Other services Forest area Total Nbr > 0 Total Nbr > 0 Total Nbr > 0 Total Nbr > 0 Total Nbr > 0 Total Nbr > 0 (b) Protective forests for Number of reporting countries 1990 64 44 51 25 42 3 42 11 37 7 234 224 2000 67 47 54 30 44 4 45 13 38 8 234 224 2005 73 54 59 36 45 6 47 15 41 11 234 224 2010 79 61 63 40 47 6 51 19 45 17 234 224 2015 83 65 65 42 48 10 51 19 45 17 234 224
Table 2 200 Global mean ± std err protective forests (as % of total land area and % of forest area) by category and sub-category for all report years (1990–2015) and proportions of land and forest area in each category and sub-category as of 2015 (e.g., Total ha for protection of soil and water resources/total global land area or forest area in 150 ha  100). Total hectares were obtained by summing the corresponding hectares for all reporting countries. 100 Protective forest Mean ± std Proportion Mean ± std Proportion category or sub- err (% of of land area err (% of of forest category total land in 2015 (%) forest area) area in 2015 area) (%) 50 Number of countries Soil and water 8.67 ± 0.14 7.85 35.92 ± 0.38 25.06 resources Clean water 1.14 ± 0.13 0.551 3.42 ± 0.26 1.761 0 Coastal 0.23 ± 0.03 0.210 0.83 ± 0.08 0.671 0 102030405060708090100 stabilization Protective forests for soil and water resources, Desertification 0.19 ± 0.00 0.041 3.61 ± 0.09 0.132 % of forest area control Avalanche 0.04 ± 0.00 0.001 0.36 ± 0.01 0.004 control 200 Flood control 1.46 ± 0.07 0.186 5.10 ± 0.33 0.596 Other control 0.98 ± 0.09 1.948 3.13 ± 0.26 6.221 Ecosystem 7.52 ± 0.12 7.97 29.82 ± 0.60 25.45 150 services Public 1.14 ± 0.08 0.728 4.28 ± 0.19 2.324 recreation 100 Carbon storage 0.60 ± 0.08 0.098 2.63 ± 0.68 0.313 Cultural 0.56 ± 0.09 1.771 1.94 ± 0.26 5.656 services Other services 0.69 ± 0.23 1.267 1.97 ± 0.66 4.047 50 Number of countries
0 (Fig. 2). The number of countries reporting a median value around 0 102030405060708090100 50% was very small. The U-shaped double peak distribution pattern Protective forests for ecosystem services, did not change through 25 years. % of forest area Neither main category of protective forests (for protection of soil and water resources (Fig. 3) or for delivery of ecosystem ser- Fig. 2. Histogram distribution of numbers of countries reporting protective forests for soil and water resources as % of total forest area (top) and protective forests for vices (Fig. 4)) showed significant trends over the reporting time delivery of ecosystem services as % of total forest area (bottom). Number of interval (1990–2015) when expressed as a % of total forest area. countries were summed for all five report years. Sub-category trends in Figs. 3 and 4 are described below under the various sub-category headings. No significant differences among global sub-regions for soil and forest area as a % of forest area. Polar countries (only two territo- water protective forest area were observed when expressed either ries, Greenland (Denmark) and Svalbard and Jan Mayen Islands as a % of land area or as a % of forest area because of the large vari- (Norway), are classified as polar) did not report any forest area. ation across countries within a region. Similarly, there were no sig- Per capita protective forest area was also calculated and tested nificant differences among the climatic domains for protective for significant differences among global sub-regions. None were S. Miura et al. / Forest Ecology and Management 352 (2015) 35–46 39
Global protective forest area sub-category) among soil and water protection sub-categories 100 1(Table ). These forests in this category are found in all the sub- Soil and water resources Clean water regions except for Central America and North Africa, and most Coastal stabilization abundant in the European region, where 2.7% of the forest area is Desertification control Avalanche control primarily designated for water protection. Among them, Japan Flood control has designated 24–37% of its forest land area for delivery of clean 10 Other control water from 1990 until 2015 (Table 3). Uruguay ranks second at 20–34% for the same time interval. The most noticeable changes in the reporting period from 1990 to 2015 occur in Europe, Oceania and South America. In Europe, there was a sharp increase 1 in forest for water protection in Russian Federation (from 4.1% in 1990 to 6.3% as of 2015); a small decrease in this forest protection category occurs in Bulgaria. In Oceania, forests designated for water protection were 0.5% in 1990, which increased to 4.8% initi- Protective forest area, % of land 0.1 ated by sharp increase in Wallis and Futuna Islands and that of 1990 1995 2000 2005 2010 2015 newly designated forests by Australia, New Zealand and Tonga in Report year 2010. On the other hand, in South America, forest area in this cat- egory showed a decreasing trend because of a substantial decrease Fig. 3. Mean ± std err global protective forest area (as % of forest area) for soil and from 34% to 20% by Uruguay, and recent small designations in 2000 water resources (main category) and for sub-categories of clean water, coastal stabilization, desertification control, avalanche control, flood control, and other by French Guiana (2%), and Venezuela (0%). control by report year. 3.1.2. Coastal stabilization About 0.83% of global forest area has been primarily designated Global protective forest area for coastal stabilization (Table 2). Significant temporal increase of 100 percentage to total forest area (P < 0.001) was observed (Fig. 3) Ecosystem services and the percentage of Caribbean sub-region was significant higher Public recreation Carbon storage than that of South America in 1990 and 2000 (P < 0.001) but was Cultural services not significant in the most recent ten years due to the increase of Other services 10 percentage forest area in South American countries. Few countries in the regions suffering disasters by cyclones, hurricanes, and typhoons, such as Cuba and Jamaica in Caribbean or Bangladesh in South Asia have primarily designated forests for coastal stabilization. Globally, Cuba with its long coastal length 1 has the highest percentage of forest area devoted to coastal stabi- lization (18–19%) (Table 3). Lithuania ranks second at about 8%.
Protective forest area, % of land Table 3 0.1 Countries with the highest percentages of forest area in each of the protective forest 1990 1995 2000 2005 2010 2015 and ecosystem services main and sub-categories. Report year Protective forest Countries with highest % of forest area (report Fig. 4. Mean ± std err global protective forest area (as % of forest area) for delivery category or sub-category % of forest area in year) of ecosystem services (main category) and for sub-categories of public recreation, protective forest carbon storage, cultural services, and other services by report year. category Soil and water resources Austria, Burundi, All at 100% (most to all found. Similarly, no significant differences among income class for Burkina Faso, Bhutan, reporting years) Isle of Man, Jamaica, soil and water protective forest area were found either as a % of Kenya, Libya, Morocco, land area, % of forest area, or on a per capita basis. Thus, neither Martinique, Mayotte, sub-regions, climatic domain, nor income class can account for Saint Pierre & the variation in protective forest area among countries at the main Miquelon, Thailand, category level. Tajikistan, Tunisia, Yemen Relationships between soil and water protective forest area (as Clean water Japan 24–37% (1990–2015) % of forest area or on a per capita basis) and a select group of other Coastal stabilization Cuba 18–19% (2000–2015) FRA database variables were explored. No relationships were found Desertification control Uzbekistan 80% (1990–2015) between protective forests (% of forest area) and production forest Avalanche control Tajikstan 14% (1990–2015) Flood control Timor-Leste 32% (1990–2015) area, cumulative forest area damaged by outbreaks (e.g., diseases, Other control United States 61–68% (1990–2015) insects, severe weather), or forest areas with management plans. Ecosystem services Belgium, Bhutan, Isle of All at 100% (most to all On a per capita basis, no relationships were found between protec- Man, Iceland, Jamaica, reporting years) tive forests and non-wood forest products, forest revenue, or public Kenya, Martinique, expenditures on forests. Mayotte, United States Public recreation Saint Lucia 29–31% (1990–2015) Carbon storage Saint Pierre & 100% (2015) 3.1.1. Clean water Miquelon Approximately 3.4% of global forest area has been primarily Cultural services Australia 35% (2015) designated for the protection of clean water (Table 2). The number Other services Australia 59% (2010), 39% (2015) of countries reporting more than 0 ha in this sub-category was 32, See the 2nd and 3rd ranked and subsequent countries in the ‘Country sorted’ which was the one of two largest (along with the flood control sheet of the supplemental table. 40 S. Miura et al. / Forest Ecology and Management 352 (2015) 35–46
However, many island countries have not always primarily desig- allowed countries to report a forest area of ‘other control’ by sub- nated forests for that function. The other 26 countries designated tracting the sum of forest area of sub-categories from the forest less than 10% of total forest area to protect against coastal erosion. area of the soil and water protection main category. More than half Among them, Russia designated 24.3 mil. ha (3.0% of total forest of all countries reported an identical number of the ratio of the area) forests for coastal stabilization, which occupied 90.5% of glo- sum of forest area of sub-categories to the forest area of soil and bal total forest area in this sub-category as of 2015. However, water protection main category. Thus, many countries reported Russia has not shown an increasing trend in coastal forest protec- the ‘other control’ sub-category by means of data subtraction. tion in terms of percentage of total forest area. Other relatively small countries in the Caribbean, South and Southeast Asia regions 3.2. Protective forests for ecosystem services and other European countries have contributed increased percent- ages of total forest area to coastal stabilization. Globally, as of 2015, about 1.018 billion ha of forest (25.4% of global total forest area) has been designated for ecosystem ser- 3.1.3. Desertification control vices, which is almost the same percentage as global protective for- Relatively few countries have protective forests designated for est area for soil and water resources (Table 2). Forest area devoted desertification control. All are in arid regions mainly in parts of to ecosystem services has continuously increased over the past Africa and in central Asia. About 3.6% of global forest area in the 25 years mainly because of the increasing number of reporting form of protective forests has been used to check the advance of countries (Table 1) and because of a few countries with distinct desertification with no significant trend since 1990 (Table 2 and net increase of forest area for ecosystem services (e.g. China, Fig. 3). Uzbekistan, an arid region country in central Asia, has the Russia, and Ecuador). Of this total forest area managed for ecosys- highest areal extent of forest land designated to arrest the process tem services, about 48.5% as of 2015 (0.493 billion ha) has been of desertification (80%) (Table 3). Some other arid region countries primarily designated for sub-category of public recreation, carbon designate at least 10% or more of their forests to control desertifi- storage, spiritual/cultural services, and the other services. The cation (e.g., Mauritius, Mauritania, Oman, Sudan, and Tajikstan). average percentage of forest area managed for ecosystem services Neither regions nor domains were significantly different regardless has not changed from around 29.8 ± 0.6% during this period of expressing protective forests for desertification control as % of (Table 2). However, the proportion of accumulated forest areas land area, % of forest area, or on a per capita basis. primarily designated for delivery of ecosystem services sub- categories was 4.5% in 1990, and then distinctly increased up to 3.1.4. Avalanche control 12.3% as of 2015. This increase is about two times larger than the About 0.36% of global forest area is primarily designated for increase in the proportion of accumulated forest areas primarily avalanche control (Table 2). Tajikstan, a mountainous country also designated for protection of soil and water. in central Asia, has designated 14% of its forests for avalanche con- Canada and United States of America in North America are the trol to protect villages and transportation corridors (Table 3). top two countries that have the largest forest areas designated Switzerland, another mountainous country, ranks second at about for ecosystem services. Canada designates 93% of its total forest 7%. Other countries that designate forests for avalanche control use area and the United States of America designates 100% of its forests less than 0.1% of their forests for that purpose. Obviously, the need for ecosystem services as of 2015. These two countries also desig- for this category of protected forests depends largely on the clima- nate high percentages for protective forests of soil and water tology, that is, presence of large and deep layers of snow cover and (Canada, 91%; USA, 61–68%). Another eight countries also desig- the topography of the countries. The designation of a forest under nate more than 90% for both two main categories. As a natural con- this category depends also on the potential avalanche risk to pop- sequence, almost all forests for both categories overlap. A ulations and human assets. This is thus a very specific category of definition modification of removing the definitive adverb ‘primar- protected forests that is present in very few regions and countries ily’ shifts these countries designation percentages from one end of in the world and has changed little during these 25 years (Fig. 2). the percentage scale to the other. Thus, the primary designation issue remains a difficult problem for tracking changes through 3.1.5. Flood control time. The global mean of percentage of forest area managed for ero- Percentages of total forest area designated for ecosystem ser- sion and flood protection has been the largest of ca. 5.1% among vices have not shown significant differences in terms of global this primarily designated sub-category of protection of soil and regions, climatic domains, or time. Other variables in the FRA data- water (Table 2). Global protective forests designated for erosion set such as production forest area, cumulative forest area damaged and flood protection have increased three times from ca. 7.0 mil. ha by outbreaks of insects or disease, or forest areas with manage- (0.17% of global total forest area of 20 countries) in 1990 to ment plans, and economic value data on a per capita basis did 23.8 mil. ha (0.6% of 32 countries) as of 2015 (Fig. 2). The flood con- not have any statistical relationship with forest areas designated trol and clean water protection sub-categories have the largest for ecosystem services also expressed on a per capita basis. number of reporting countries (32) (Table 1). This rapid increase Changing trends also did not any relationships with any of the was due to the increase in Russia in 1990s and is also due to the above variables. increase of reporting countries in the 2000s. Countries in temper- ate to sub-tropical and tropical domains designated larger forest 3.2.1. Public recreation area for erosion and flood control, such as Timor-Leste (32%) About 4.3% of global forest area is primarily designated for pub- (Table 3), Austria (30%) and Switzerland (28%) as of 2015. lic recreation (Table 2). Forests devoted for public recreation are Tajikistan, a semi-arid country, also designated a high percentage located in all the regions and sub-regions except North America. of forest area (25%) for erosion and flood control. The number of reporting countries for this sub-category has been increasing for 25 years, and it was the largest among ecosystem 3.1.6. Other control services sub-categories (42 countries reporting more than 0 ha About 3.1% of global forest area has been primarily designated out of 65 total reporting countries as of 2015) (Table 1). Most of for other controls within the protective forest soil and water con- protective forests for public recreation are located in South trol category (Table 2). No overall global trend in protective forests America (43%), Oceania (33%) and Europe (20%) as of 2015. South for other control has been observed (Fig. 2). We note that FAO America, Oceania and Central America were sub-regions which S. Miura et al. / Forest Ecology and Management 352 (2015) 35–46 41 rapidly expanding its recreational forests. Among all the countries, of soil and water and ecosystem services and cultural and spiritual Saint Lucia has designated the highest percentage of its forest area values for all 5 reporting years. Thus, areas of protective forests for public recreation (29–31%) (Table 3). Australia is next highest at change are linked with total forest area. Kenya had decreased for- 21–25% (2010–2015). Forest areas in North America are unques- est area in 1990s due to degazettement of forestland to open up tionably used for public recreation. However, this reported data areas for agricultural land (FAO, 2014e). Since 2000, there is an situation is because of the ‘primarily designated’ constraint for increase in forest area both in gazetted and non-gazetted areas sub-categories. due to rehabilitation of degraded forest, especially through carbon credit schemes (Ministry of Environment, Water And Natural 3.2.2. Carbon storage Resources, 2014), not reaching, however, the values of 1990. No About 1.3% of global forest area was designated for carbon stor- sub-division was made of the different protection objectives. age in 1990 and this has increased to 5.3% as of 2015 (Fig. 4). Saint Pierre and Miquelon, a self-governing French-aligned territory off 3.3.2. China (Asia) the coast of Newfoundland, Canada, designated 100% of its forests China has dramatically expanded its protective forests over the for carbon storage – the only country or territory to so designate past 25 years from 18 mil. ha to 58 mil. ha as of 2015 (Fig. 5). The thus far (Table 3). Iceland is next highest at 28–37% for 2000– proportion of protective forests to total forest area increased from 2015. The increasing trend is a very positive development for glo- 12% in 1990 to 28% as of 2015, which is also associated with the bal forests to have an increased role in sequestering more carbon in increase in total forest area (Fig. 5). This incredible increase con- the future (Fig. 4). However, very few (ten) countries, which was tributed a percentage increase in the proportion of protective for- the smallest number among four sub-categories of ecosystem ser- ests for soil and water resources in East Asia compared to a global vices, reported forest area of more than 0 ha for carbon storage as no percentage change. of 2015 (Table 1). The total global forest area in this sub-category According to the national report on sustainable forest manage- was 12.5 mil. ha (0.3% of global total forest area). Carbon storage ment in China (State Forestry Administration, 2013), areas suffer- has been by far the smallest primarily designated sub-category of ing from soil erosion at the end of 1990s extended to 356 mil. ha ecosystem services (Table 2). Because of the limited dataset, it is and the amount of annual soil losses amounted to 5 billion tons. difficult to produce a robust statistical analysis. Water erosion covered 165 mil. ha, and wind erosion damaged 191 mil. ha. The degradation of forests in China had continued for 3.2.3. Cultural services several decades until 1990s, owing to rapid population growth Forests are an important cultural service resource for many coupled with the over-exploitation of forest resources, and subse- countries. About 1.9% of global forest area is primarily designated quent cultivation on steep slopes (Wenhua, 2004). This caused for cultural services (Table 2). The forests in this category are dis- serious frequent natural hazards and disasters and produced vast tributed in all regions of the globe, except for the African continent. human and economic loss. The Chinese government launched a Most protected forest for cultural services are located in South America (48%) and North America (32%) as of 2015. The most noticeable increase in protected forest areas for cultural services Protective forest functions and services in China occurred in South America, from approximately 11 mil. ha (2.1% 30 30 of total forest area) in 1990 to 108 mil. ha (16.0%) as of 2015. 25 25 This sharp increase was driven by a significant enlargement of cul- tural services areas in Brazil (2–21%), which correspond to approx- 20 20 imately 97% of the protected areas in the region. Likewise, most of 15 15 the protected areas in the region of North America are in the USA (21.0% of total forest area) and Canada (2.0%) where figures have 10 10
been fairly stable since the 1990s. Significant protected areas for % of land area % of forest area Total forest area, cultural services are also present in Oceania (35% of Australia), Protective forests, 5 Soil and water resources 5 Total forest area which contributes 19.3% as of 2015 to the global figure for this cat- 0 0 egory. Australia began using the primary designation of forests for cultural services in 2000 as the first country in the region to do so. 2.5 Europe (0.6% of global total forest area) and Asia (1.5%) has con- tributed to this sub-category in small percentages. The largest glo- 2.0 bal total forest area (5.7%, 226 mil. ha) designated for cultural 1.5 services among four sub-categories is a consequence of the contri- butions by a few large countries. 1.0 % of forest area
3.2.4. Other services Protective forests, 0.5 About 2.0% of global forest area has been designated by coun- 0.0 tries for delivery of other (unspecified) services (Table 2). No over- all global trend has been observed in the past 25 years (Fig. 4). As of 1990 1995 2000 2005 2010 2015 2015, Australia now has the highest percentage of forest area Report year devoted to protective forests for other services (Table 3 and discus- Ecosystem services Public recreation sion below). Cultural services Other services 3.3. Case study countries Fig. 5. Mean ± std err protective forest area (as % of forest area) for soil and water 3.3.1. Kenya (Africa) resources (main category – top) and for ecosystem services (main category) and subcategories of public recreation, cultural services, and other services (bottom) for Forest area of Kenya occupies only 7.8% (4.4 mil. ha) of total China by report year. Note: China did not report data in any sub-categories under land area as of 2015 and 70% of land area is grassland (FAO, protective forests for soil and water resources or for C storage under ecosystem 2014e). Kenya has designated all forest areas for the protection services. 42 S. Miura et al. / Forest Ecology and Management 352 (2015) 35–46 series of top-to-bottom afforestation projects and implemented comprises forests for clean water protection, coastal stabilization, natural forest conservation projects, and increased shelter forests and flood control (Fig. 6). While small change occurred in area des- associated with total forest area (State Forestry Administration, ignated for coastal stabilization, protective forests for clean water 2013). This caused a major annual increase in forested areas from increased from 4.1% (33 mil. ha) to 6.3% (52 mil. ha) in the period. 0.27% (1970s–90s) to 3.27% (6.2 mil. ha/y, 1999–2008) of land area. The most notable increase in the allocation of protective forests is Areas of shelter forests have reached 83.1 mil. ha in late 2000s, evidenced for erosion and flood protection; the forest area in this occupying 45.8% of forest area and 8.7% of total national land. category grew from 0.2% (1.6 mil. ha) in 1990 to 1.3% (10.4 mil. ha) Greater parts of shelter forests are for water supply conservation as of 2015 (Fig. 6). Forest designated for the protection of ecosys- forest (30.6 mil. ha) and water and soil conservation forest tem services, cultural and spiritual values increased from 9.1% (43.7 mil. ha), whereas 3.0 mil. ha are for windbreak and sand- (74 mil. ha) in 1990 to 13.4% (109 mil. ha) as of 2015 (Fig. 6). It is fixing forest. Although the area of shelter forests for arid and interesting to note that the forest designated for public recreation semi-arid region is not large, it is apparent that many forests are has significantly decreased in the period 1990–2000. In any case, a explicitly managed to control desertification in China, but were slight change of percentage for a sub-category in Russia strongly not reported in FRA 2015. China stated that it did not report affects any increase or decrease in trend for Europe and even influ- sub-categories of protection of soil and water because of difficul- ences the entire global forest assessment as we can see for clean ties of translation between the designation system of FAO and that water or flood control. of China own (FAO, 2014d). 3.3.4. Canada (Americas) Canada has reported all publicly owned forests as designated 3.3.3. Russian Federation (Europe) for protection of soil and water (FAO, 2014c). At 347 mil. ha Russian territory spreads over the most northern part of the (2015 report year), Canada ranks 3rd globally (behind Russia and north hemisphere. Thus most Russian forests are located in the Brazil) in terms of total forested land area (38% of total land area boreal domain (88%) (FAO, 2014f). About 50% of land area is cov- in Canada is forested). Despite ranking 3rd in total forest area, ered by forest (815 mil. ha, the world’s largest) as of 2015. Russia Canada leads all nations in terms of total forest area designated designated forests by its own classification system, as four main for protection of soil and water resources (317 mil. ha as of categories: protected forests (2.2%), protective forests (24%), oper- 2015). Canada reported protective forest area in both main cate- ational forests (50.9%) and reserve forests (22.9%) in 2013 (FAO, gories – soil and water protection (91.4% of forested land area in 2014f). Protected forests (18 mil. ha) and protective forests all report years) and ecosystem services (93.4% of forest area in (215 mil. ha) correspond to FRA protective forests and conserva- all report years). Canada only reported protective forest areas in tion forests for biodiversity (main category 6). Russia reclassified the cultural services sub-category (about 2% of forest areas). and divided these two national categories of forests to adapt FRA definitions of protective forests for soil and water (FAO, 2014f). 3.3.5. Australia (Oceania) According to the new FRA 2015 dataset, forests designated for Australia (2015 report year) has a total forested land area of the protection of soil and water have increased from 7.3% 124 mil. ha (16% of total land area) and ranks 7th behind China (59 mil. ha) in 1990 to 10.6% (86 mil. ha) as of 2015 (Fig. 6). and Congo. It has reported protective forest area in the two main However, Russia did not show the details of the calculation in categories – soil and water protection (23.9% of total forest area the country report (FAO, 2014f). The area under this category as of 2015) and ecosystem services (98.4%) (Fig. 7). Australia is one of the largest dry continent in the world. Most of Australia’s Protective forest functions and services in Russia land area is classified as rangelands, which encompass some 75% 12 (570 mil. ha) of the continent. One third of the continent has extre- mely low and variable stream-flow compared to other continents 10 and large areas of the arid hinterland produce almost no run-off. Soil and water resources 8 Clean water For these reasons, Australia’s population is concentrated within Coastal stabilization 100 km from the coast and much of Australia’s drier hinterland is 6 Desertification control Avalanche control minimally managed. Flood control 4 Other control Public forest excluded from wood harvesting is 29 mil. ha as of 2015. Public forest comprised almost entirely native forest % of forest area
Protective forests, 2 includes forests managed for soil and water protection and ecosys- 0 tem services, which has remained relatively stable in these report-
16 ing period (SOFR, 2013). Australia’s forest area designated primarily for protective functions include various public nature 14 Ecosystem services Public recreation conservation reserves. Not all sub-categories of soil and water pro- 12 Carbon storage tection or ecosystem services have been included in any reporting 10 Cultural services Other services year. Though Australia operates indeed dune protection program 8 for coast care, integrated package for desertification control and 6 managements for erosion and flood controls, it has not provided
% of forest area 4
Protective forests, nationally inconsistent information for these functions (FAO, 2 2014b). 0 Ownership of forests affects designation of protective forests in 199019952000200520102015 Australia. Importantly, forest areas in public nature conservation Report year reserves are ‘managed primarily for protective functions’, which includes the conservation of biodiversity as well as protection of soil Fig. 6. Mean ± std err protective forest area (as % of forest area) for soil and water and water values. It is worth noting that, across most of Australia’s resources (main category); for sub-categories of clean water, coastal stabilization, forest management jurisdictions, the preservation of soil and water desertification control, avalanche control, flood control, and other control (top); for ecosystem services (main category); and subcategories of public recreation, C is usually one of several forest management objectives included in storage, cultural services, and other services (bottom) for Russia by report year. the management of multiple-use public forests. S. Miura et al. / Forest Ecology and Management 352 (2015) 35–46 43
Protective forest functions and services distribution although we could not clarify the exact reason. A gov- in Australia ernment could hesitate to designate or increase protective forests 30 in such a situation. For instance, stakeholders of forests in the coun- try which has a regulation against production activities may hesitate 25 Soil and water resources to designate protective forests. In the opposite case, they have no Clean water reason to hesitate to designate 100% of their forests as protective for- 20 Other control ests. Historical development of forest ownership may also influence 15 this situation such as in Canada or Australia. For example, in Australia, significant proportions of multiple-use forests are informal 10 reserves where wood harvesting is not permitted. In addition, differ- ences among state-based jurisdiction rules in Australia could be % of forest area
Protective forests, 5 obstacles to adjust a unified reclassification of multiple-use forests within one country. Such possible political considerations influenc- 0 ing the designation of protective forests are apparent from country reports for FRA 2015 and other country reports from the Montreal 100 Process for four countries, China, Russia, Canada and Australia. Those countries reports are indispensable sources of understanding 80 Ecosystem services the multiple functions of forests in each country. Public recreation Although we could not find by SAS GLIMMIX analysis any clear 60 Cultural services Other services factor affecting percentages of forest area designated for protective 40 functions on a global basis, dramatic change has occurred in China. This Chinese case is not necessary a special case. Excess deforesta-
% of forest area tion has brought about decline of societies (Perlin, 1989). This could
Protective forests, 20 happen to other developing countries by rapid increase of its pop- 0 ulation. A relevant lesson for forest management is how we can set a level of protective functions of forests to maintain sustainable 1990 1995 2000 2005 2010 2015 forest management to prevent severe erosion and sediment trans- Report year port disasters for food production and social infrastructure. The current reporting of FRA for protective functions or delivery Fig. 7. Mean ± std err protective forest area (as % of forest area) for soil and water of ecosystem services requires designation of forest areas by gov- resources (main category); for sub-categories of clean water and other control (top); for ecosystem services (main category); and subcategories of public ernments. No information about the effectiveness of forest protec- recreation, cultural services, and other services (bottom) for Australia by report tive functions is provided. In the case study of China, one of the year. Note: Australia did not report data for protective forests for soil and water current concerns is a verification of actual functioning or effective- resources (or any of the sub-categories) prior to 2010. Australia did not report data ness of increasing protective forests. There are now two challenges in the coastal stabilization, desertification control, avalanche control, flood control, in this regard – demonstrating prevention of forest degradation by or C storage sub-categories. encroaching sand dunes by means of shelter belts, and not demon- 4. Discussion strating its effects (Wang et al., 2010; Yu et al., 2006). Detecting actual change of functions and services could be the next challenge 4.1. Global trends of protective forests and selected ecosystem services for China to fully utilize FRA. If a future FRA report challenges countries to assess forest protective functioning with measureable Despite a net loss of global forest area over the past 25 years, variables, this could fill this knowledge gap. To cite a case, a global forest area devoted to protection of soil and water resources has review of relationships between thinning or clear cutting and increased by 22%, mostly due to an increase in reporting countries. water yield (Bosch and Hewlett, 1982) should be a good example. Some sub-categories such as clean water, flood control, public We can introduce such relationships between forest managements recreation and cultural services showed clear increased trends and various kinds of functions into FRA reporting. both in terms of percentage of total forest area (Figs. 3 and 4) and the number of reporting countries (Table 1). These global 4.2. FRA definitions and reporting multiple functions trends provide evidence for the continuing increase of public awareness of multiple functions of forests. Various fronts of inter- We found both improvement and problems in the reporting national cooperation for sustainable forest management, such as variables of ‘‘Topic III: Protective functions and selective ecosystem regional initiatives (ITTO, FE, MP1 etc.), UNFF2, criteria and indicator services’’ in FRA 2015. The improvement was a modification of def- development (Raison et al., 2001; Diaz-Balteiro and Romero, 2008) inition by removing the word ‘primarily designated’ for the two and forest certification (Rametsteiner and Simula, 2003; van main categories (5.1 Protection of soil and water, 5.2 Ecosystem Kooten et al., 2005) have initiated the current trend associated with services, cultural or spiritual values). This likely produced reported UNFCCC and CBD. However, globally, there have been no significant data that was a more accurate reflection of forest protection classi- changes in the average of percentages forest area designated for pro- fications around the world. The main problem was an insufficient tective forests or ecosystem services. In addition, dual-peak end framework for reporting functions of forests. Before we discuss this member distributions of percentages of protective forests or ecosys- in detail, we describe the change of definition in recent FRA. tem services were far from a common one peak natural distribution Changes in the past few decades to FRA by FAO have paralleled around a mean. A designation of a forest for protective or ecosystem the global trend of increasing the importance of multiple functions services purposes could introduce some regulation of productive for- of forests other than production. FAO first introduced a concept of est use. Some political regulations or measures likely affect this protective forests for soil and water in FRA 1990 (FAO, 1995). However, FRA had not advanced the concept of protective forests as reporting items in subsequent reporting years of 1995 and 1 International Tropical Timber Organization, Forest Europe and Montreal Process. 2000 (FAO, 1997, 2000, 2001). Then, in FRA 2005, it adopted a per- 2 United Nations Forum on Forests. centage of protective forests as a reporting variable (FAO, 2004a). 44 S. Miura et al. / Forest Ecology and Management 352 (2015) 35–46
Percentage forest area in FRA 2005 was divided into six exclusive of FE, introduced general principles to designate protective func- categories of functions; (1) Production, (2) Protection of soil and tions with legal basis, long-term commitment and explicit designa- water, (3) Conservation of biodiversity, (4) Social services, (5) tion of biodiversity, landscape, specific natural element or Multiple purpose, (6) None or unknown function. Category 1 protective function of forest and other wooded land (MCPFE, through 4 was applicable if a forest is primarily designated as 2003). This exclusive designation rule for protective functions is one of four functions. Otherwise, category 5 or 6 was assigned. similar to the definition of FRA 2005 (FAO, 2004a). This kind of des- All the forest area must be within one of six categories and the ignation scheme was intended to be shared internationally in early sum of percentages of all six categories must add up to 100%. 2000’s. However, FE also could not completely overcome the prob- Using this definition in FRA 2010 (FAO, 2010a), the United States lem of overlapping designation for protective forests. FE had to of America did not report in the category of ‘primarily function acknowledge that there exists overlapping designations of indica- as’ and no primarily designated protective forests were reported tors 5.1 Protective forests of FE – soil, water and other ecosystem for the North American sub-region. Reasons how and why this functions and 5.2 Protective Forest – infrastructure and managed was done were described in the main report of FRA 2010 (FAO, natural resources in 2011 (MCPFE, 2011). Thus, we can say that 2010b). there still exists potential to further develop the framework of This potentially-misleading definition was modified in FRA definitions for reporting multiple forest functions to establish 2015. The word ‘primarily’ designated was not used for the two long-term robust variables as a whole forestry sector. Tracing main categories of protection of soil and water and selected and examining details of recalculation formulas and comments ecosystem services and was applied only to sub-categories. In con- for the three Tables 4–6 of FRA 2015 would be a good start. We sequence, the global level of protective forests as a proportion of could learn from the diversity of the methods and original defini- total forest area abruptly jumped to 25.1% in FRA 2015 from 8% tions for designation of protective forests in each country as we in FRA 2010. Sum of forest area of primarily designated sub-cate- illustrated with the five case study countries. On the other hand, gories of protection forest in 2010 was 369 mil. ha (9.2% of total movement of developing tools for sustainable forest management forest area) in FRA 2015 report. This shows a fairly good correspon- is a sweeping trend of forestry sector. Regional initiatives such as dence to 8% in FRA 2010 report considering that each country was ITTO, FE, MP have lead the establishment of criteria and indicators allowed and encouraged to make a retroactive modified report in (McDonald and Lane, 2004). Strengthening collaborations with previous reporting years of 1990 to 2010. those activities would also be another effective solution for this The problem of ‘primarily’ designated for protective forests for issue. The beginning of such international collaboration has been soil and water has been resolved as described above for the two seen in the partnership activities of the Collaborative Forest main categories. However, the overall strategy of how FRA reflects Resources Questionnaire (MacDicken, 2015) for FRA 2015. The multiple functions of forests still lacks consistency and harmoniza- overall strategy of FRA for reporting multiple forest functions tion across reporting periods. Ecosystem services of forests are should be reconciled and improved. divided into conservation of biodiversity (FRA 2015, Table 6) and other services (FRA 2015, Table 5b) (FAO, 2014a). Carbon storage 4.3. Data quality or sequestration is assigned a sub-category of selective ecosystem services, though biomass carbon and below ground carbon are These are largely qualitative designations that while providing a reported within the main category of production (FRA 2015, guide to overall data quality, do not facilitate a more quantitative Table 3e). In the meantime, there is an opinion such as that of assessment of data reporting errors. For protective forests for soil China (FAO, 2014d) and Russia (FAO, 2014f) that all forests make and water resources, tier 1 countries (least reliable data quality) a significant contribution to carbon storage or sequestration outnumber tier 3 countries (most reliable data quality) by a large because every forest provides a function of carbon sequestration margin (Table 4). For example, there are twice as many tier 1 coun- to some extent. Variables reporting multiple functions in FRA tries in the protective forests for soil and water category as there 2005 and 2010 showed a clear stance of FAO to report the multiple are tier 3 countries. Only about 59% of all countries have tier des- functionality of forests within a table even if it introduced a new ignations for the soil and water resources protective forests cate- problem as described above. However, in FRA 2015, FAO separated gory. Only 35% of all countries have assigned data quality tiers in a part of forest functions into three different tables (4. production, the ecosystem services delivery category. For future editions of 5. protection, 6. biological conservation). Thus, the FAO approach FRA, we recommend a renewed emphasis on encouraging coun- to understand multiple forest functions was still developing. tries in the lowest tier 1 to take steps to move to tier 2 and tier 2 Forest Europe (FE), the pan-European political process for the countries to move to tier 3. In the current FRA reporting cycle, only sustainable management of the continent’s forests, has also been about 18% of reporting countries are in tier 3 for the protective for- facing to this kind of dilemma of designation between a primary est category and only about 13% are in tier 3 for the ecosystem ser- function and multi-functionality of forest. MCPFE, the predecessor vices category.
Table 4 Numbers of countries (% of total countries) in each data reliability tier for the main protective forest categories of soil and water resources and ecosystem services. Tier 1 = least reliable data quality, tier 2 = moderately reliable data quality, tier 3 = most reliable data quality.
Domain Soil and water resources Ecosystem services Tier 1 Tier 2 Tier 3 No tier Tier 1 Tier 2 Tier 3 No tier Number of countries in each tier category Polar 1 (0.4) 0 (0) 1 (0.4) 0 (0) 1 (0.4) 0 (0) 1 (0.4) 0 (0) Boreal 2 (0.9) 1 (0.4) 3 (1.3) 1 (0.4) 1 (0.4) 1 (0.4) 3 (1.3) 2 (0.9) Temperate 8 (3.4) 5 (2.1) 21 (9.0) 13 (5.6) 5 (2.1) 7 (3.0) 15 (6.4) 20 (8.5) Sub-tropical 14 (6.0) 2 (0.9) 5 (2.1) 15 (6.4) 8 (3.4) 2 (0.9) 3 (1.3) 23 (9.8) Tropical 45 (19.2) 16 (6.8) 13 (5.6) 68 (29.1) 17 (7.3) 10 (4.3) 8 (3.4) 107 (45.7) Total 70 (29.9) 24 (10.3) 43 (18.4) 97 (41.5) 32 (13.7 20 (8.5) 30 (12.8) 152 (65.0) Grand total (tiers 1 + 2 + 3) 137 (58.5) 82 (35.0) S. Miura et al. / Forest Ecology and Management 352 (2015) 35–46 45
All but 10 countries and territories report forest area greater Appendix A. Supplementary material than 0 ha. Half the world’s countries now report some forest area (>0 ha) for protection of soil and water resources (117 in 2015) Supplementary data associated with this article can be found, in (Table 1). Only about a quarter of all countries (28%) have actual the online version, at http://dx.doi.org/10.1016/j.foreco.2015.03. forest area (>0 ha) reported for ecosystem service delivery. In all 039. the protective forest and ecosystem service sub-categories, the number of reporting countries is a minor fraction of all possible reporting countries. It ranges from as few as 6 countries with pro- tective forest areas designated for avalanche control in 2015 to 42 References countries reporting forest area for public recreation in 2015. Aust, W.M., Blinn, C.R., 2004. Forestry best management practices for timber Because of the low numbers of reporting countries with hectares harvesting and site preparation in the eastern United States: an overview of >0 in each of the sub-categories, both the total forest area and per- water quality and productivity research during the past 20 years (1982–2002). centages of forest area designated as protective forests remains Water Air Soil Pollut. Focus 4, 5–36. http://dx.doi.org/10.1023/ B:WAFO.0000012828.33069.f6. small on a total global basis. There is opportunity for expansion Binkley, D., Fisher, R., 2013. Ecology and Management of Forest Soils, fourth ed. in many of these protective forest sub-categories. Wiley-Blackwell, Hoboken, 362 pp. Bosch, J.M., Hewlett, J.D., 1982. A review of catchment experiments to determine the effect of vegetation changes on water yield and evapotranspiration. J. 5. Conclusions Hydrol. 55 (1), 3–23. Broadhead, J., Leslie, R., 2007. Coastal protection in the aftermath of the Indian Ocean tsunami: what role for forests and trees? In: Proceedings of an FAO FRA was originally founded to build a global inventory of forest Regional Technical Workshop, Khao Lak, Thailand, 28–31 August 2006, FAO, resources as the name implies. The global community has come to Thailand. Collaborative Partnership on Forests. SFM and the Multiple Functions of Forests. expect FRA to report forest functions and services other than forest
Government of Japan, 2002. International Expert Meeting on Forests and Water, Post, W.M., Kwon, K.C., 2000. Soil carbon sequestration and land-use change: Shiga. Proceedings of the meeting. Tokyo. 361 p. processes and potential. Glob. Change Biol. 6, 317–327. http://dx.doi.org/ Greenwood, J.R., Norris, J.E., Wint, J., Greenwood, J.R., Norris, J.E., Wint, J., 2004. 10.1046/j.1365-2486.2000.00308.x. Assessing the contribution of vegetation to slope stability. Proc. ICE – Geotech. Postel, S.L., Thompson, B.H., 2005. Watershed protection: capturing the benefits of Eng. 157, 199–207. http://dx.doi.org/10.1680/geng.2004.157.4.199. nature’s water supply services. Natl. Resour. Forum 29, 98–108. http:// Hamilton, L.S. 1986. Towards clarifying the appropriate mandate in forestry for dx.doi.org/10.1111/j.1477-8947.2005.00119.x. watershed rehabilitation and management. East-West Environment and Policy Raison, R.J., Flinn, D.W., Brown, A.G., 2001. Application of criteria and indicators to Institute, Reprint No 94, East-West Center, Honolulu. 51 p. support sustainable forest management: some key issues. In: ‘Criteria and Hamilton, L.S. 2008. Forests and water – a thematic study prepared in the Indicators for Sustainable Forest Management’. IUFRO Research Series No. 7, framework of the Global Forest Resources Assessment 2005. Forestry Paper CABI, Wallingford, pp. 5–18. doi: http://dx.doi.org/10.1079/9780851993928. #155. Rome, Italy. 78 p. 0005. Hofer, T., Messerli, B., 2006. Floods in Bangladesh – History, Dynamics and Rametsteiner, E., Simula, M., 2003. Forest certification—an instrument to promote Rethinking the Role of the Himalayas. United Nations University Press, Tokyo, sustainable forest management? J. Environ. Manage. 67, 87–98. http:// 468 p. dx.doi.org/10.1016/S0301-4797(02)00191-3. Kammerbauer, J., Ardon, C., 1999. Land use dynamics and landscape change pattern REDD Research and Development Center, 2012. REDD-plus cookbook – How to in a typical watershed in the hillside region of central Honduras. Agric. Ecosyst. measure and monitor forest carbon. In: Hirata, Y., Takao, G., Sato, T., Toriyama, J. Environ. 75, 93–100. http://dx.doi.org/10.1016/S0167-8809(99)00071-7. (Eds.), Forestry and Forest Products Research Institute, Japan, 151pp. Keating, M., 1993. The Earth Summit’s Agenda for Change – A Plain Language Reubens, B., Poesen, J., Danjon, F., Geudens, G., Muys, B., 2007. The role of fine and Version of Agenda 21 and the Other Rio Agreements. Published by the Centre coarse roots in shallow slope stability and soil erosion control with a focus on for Our Common Future, Geneva, 35 p. root system architecture: a review. Trees 21, 385–402. http://dx.doi.org/ Keenan, R.J., Reams, G.A., Achard, F., de Freitas, J., Grainger, A., Lindquist, E., 2015. 10.1007/s00468-007-0132-4. Dynamics of Global Forest Area: Results from the FAO Global Forest Resources SOFR (Montreal Process Implementation Group for Australia and National Forest Assessment 2015. Forest Ecol. Manage. 352, 9–20. Inventory Steering Committee), 2013. Australia’s State of the Forests Report. Kirilenko, A.P., Sedjo, R.A., 2007. Climate change impacts on forestry. Proc. Natl. Acad. Canberra: ABARES; 2013.
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Forest Ecology and Management
journal homepage: www.elsevier.com/locate/foreco
Global progress toward sustainable forest management q ⇑ Kenneth G. MacDicken a, , Phosiso Sola b, John E. Hall c, Cesar Sabogal a, Martin Tadoum d, Carlos de Wasseige e a Food and Agriculture Organization of the United Nations, Rome, Italy b Center for International Forestry Research, Nairobi, Kenya c Natural Resources Canada, Ottawa, Canada d Central African Forest Commission, Yaounde, Cameroon e Observatory for Forests of Central Africa, Yaounde, Cameroon article info abstract
Article history: Sustainable forest management (SFM) is many things to many people – yet a common thread is the pro- Received 10 December 2014 duction of forest goods and services for the present and future generations. The promise of sustainability Received in revised form 4 February 2015 is rooted in the two premises; first that ecosystems have the potential to renew themselves and second Accepted 5 February 2015 that economic activities and social perceptions or values that define human interaction with the environ- Available online 7 September 2015 ment are choices that can be modified to ensure the long term productivity and health of the ecosystem. SFM addresses a great challenge in matching the increasing demands of a growing human population Keywords: while maintaining ecological functions of healthy forest ecosystems. This paper does not seek to define Sustainable forest management SFM, but rather provides analyses of key indicators for the national-scale enabling environment to gain SFM Forest policy a global insight into progress in implementing enabling and implementing SFM at the national and opera- Forest management planning tional levels. Analyses of the Global Forest Resources Assessment 2015 (FRA) country report data are used National forest inventory to provide insights into the current state of progress in implementing the enabling conditions for SFM. Forest certification Over 2.17 billion ha of the world’s forest area are predicted by governments to remain in permanent for- est land use, of which some 1.1 billion ha are covered by all of the SFM tools investigated in FRA 2015. At the global scale, SFM-related policies and regulations are reported to be in place on 97% of global forest area. While the number of countries with national forest inventories has increased over that past ten years from 48 to 112, only 37% of forests in low income countries are covered by forest inventories. Forest management planning and monitoring of plans has increased substantially as has forest manage- ment certification, which exceeded a total of over 430 million ha in 2014. However, 90% of internationally verified certification is in the boreal and temperate climatic domains – only 6% of permanent forests in the tropical domain have been certified as of 2014. Results show that more work is needed to expand the extent and depth of work on establishing the enabling conditions that support SFM over the long term and suggests where those needs are greatest. Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction and protect the environment. However, the challenge is to manage the forest’s regenerative capacity in a way that produces benefits Forests cover some 30% of the world’s land area (Keenan et al., now without compromising future benefits and choices. This idea 2015) and it is difficult to think of individuals that do not depend is at the core of most views of SFM. Recognition that the produc- on forest products and services in some form on a regular basis. tion and protection functions of forests must be sustained by In addition a large number of people depend on forests for at least sound management practice is not new. From the earliest times, part of their livelihood and well-being (EC, 2003; FAO, 2006; Jacek thoughtful people have encouraged the wise use of forests. et al., 2005; UNFF, 2007). Emperor Da Yu was the first Chinese emperor of the Xia Dynasty Forests can make significant contributions to the economy and (21st century BC) to pay special attention to the sustainable man- provide multiple products and services that support livelihoods agement of natural resources and forests (Anonymous). In seven- teenth century Europe, Evelyn (1664) and Colbert (1669 as
q reported in Brown, 1883) noted the negative influence of forest This article is part of a special issue entitled ‘‘Changes in Global Forest Resources from 1990 to 2015’’. over-utilization on sustained provision of forest goods and ser- ⇑ Corresponding author. vices. The tax accountant von Carlowitz (1713) describes how E-mail address: [email protected] (K.G. MacDicken). http://dx.doi.org/10.1016/j.foreco.2015.02.005 0378-1127/Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 48 K.G. MacDicken et al. / Forest Ecology and Management 352 (2015) 47–56
Saxonian forest regulation was used as an important principle of Operational scale progress toward SFM forest management in the early 18th century. Hartig (1795) described sustainable yield based on the quantity of increasing What is the area of forest under a forest management plan and timber volume which was an important step in the quantitative how is this monitored? regulation of harvest volumes. In the early 20th century, Gifford How are stakeholders involved in management decisions for Pinchot recognized that clear and convincing evidence was needed publicly-owned forests? to demonstrate that sustainable forest management would return What is the area of forest under one or more independently a profit. He also noted that sustainable forestry was not possible verified forest certification schemes? without the consent and active participation of the public (Schmithüsen, 2013). Zon and Sparhawk (1923) demonstrated 2. Methods how globally available data on forest resources provides profes- sionals and the public with information vital to effective strategies The methods, definitions and approaches used in FRA 2015 are for sustaining forest values. They also note the gaps in this data discussed and referenced in greater detail in MacDicken (2015) that constrain management – some of which remain unfilled in and www.fao.org/forestry/FRA/2015/Methods. FRA 2015 data were the early 21st century. The Global Forest Resources Assessment extracted from the Forest Resources Information System (FRIMS) as (FRA) was created to provide a continuing assessment of forest described in www.fao.org/forestry/fra2015. All data used in this resources and how they are changing (MacDicken, 2015). paper except international forest management certification was SFM has been encouraged as an important guiding principle in provided by countries or through desk studies carried out by FAO. managing forests (ITTO, 2006; EC, 2003). The concept provides Other than for international certification, country reports from gov- guidance on how to manage forests to provide for today’s needs ernment-appointed National Correspondents contributed data (as best as possible) and not compromise (i.e. reduce) the options representing some 99% of global forest area. International certifica- of future generations (Forest Principles, UN Rio, 1992). The tools tion data was provided by the Forest Stewardship Council (FSC) and available for encouraging SFM begin with policy and regulations the Programme for Endorsement of Forest Certification (PEFC) for that support those who are practicing forest management. They July in each of the reporting years1. Enabling environment-related also include inventories, monitoring, forest management data were collected on policies, legislation and regulations support- certification, stakeholder involvement and forest management ing SFM, presence of a national stakeholder platform and the types plans. Where there is a clear understanding of the ecological of forest resource monitoring information and progress reporting circumstances of the forests being managed an appropriate available. Progress at the operational level was measured as forest regulatory framework can establish the enabling conditions for area under Forest Management Plans (FMP), including an assessment SFM. of how the content of these plans are monitored and how frequently Criteria and indicators (C&I) of SFM have been developed and if stakeholder inputs are required and the extent of both interna- through the work of many actors – including governments, research tional and domestic forest management certification. Statistical organizations, non-governmental organizations and private com- summaries and analyses were done for all variables using Microsoft panies (MCPFE, 2001; Prabhu et al., 1998). This includes work by Excel and Systat (Ver. 13) and relationships described by national countries involved in the Montréal Process (MP), FOREST EUROPE income category, climatic domain and sub-region (see MacDicken, (FE), the International Tropical Timber Organization (ITTO) and 2015). Reported values were clustered into four nested categories: the Food and Agriculture Organization (FAO). These C&I are used legal framework, national data reporting, management planning to define SFM and to measure and report progress towards its and stakeholder involvement plus certified forest area. implementation (Canadian Council of Forest Ministers, 2008). These international and regional initiatives and research efforts have made good progress in using science, commerce and social 3. Results and discussion values to devise their indicators. Supportive national legal, policy and institutional frameworks can make SFM practices cost-effective 3.1. When do the conditions exist to enable sustainable forest and when effectively applied encourage the practices needed for management? SFM (Keeton and Crow, 2009; FAO, 2010; Lovrc et al., 2010). Forest management certification provides independent, third-party It depends on where you set the threshold – if the presence of a verification of adherence to a defined set of management standards regulatory framework is deemed adequate, then the conditions that promote and measure SFM (CEPI, 2006). exist when policies and regulations are in place. The most rigorous The main focus of this paper is to present factors that are set of enabling conditions includes the legal framework, national needed for and provide support to long-term sustainable forest data reporting, the availability of quality forest inventory data, management. By presenting a sub-set of data relevant to SFM management planning, effective stakeholder involvement and derived from the Global Forest Resources Assessment 2015 regular monitoring and reporting. Measuring and reporting these (www.fao.org/forestry/fra) the reader is provided with information data at the national scale and sharing the results through the that can help determine where and how much progress is being FRA is an important step in understanding progress to SFM and made towards establishing and maintaining the enabling where it or is not occurring. conditions for SFM. FRA 2015 was designed in part to provide this Using the SFM related data collected through FRA 2015, it is 2 information by asking questions under two broad categories: possible to begin with the area of permanent forest land and Enabling environment (national scale): evaluate how much forest land is covered by successive indicators. Fig. 1 presents this progression of the application of these ‘‘SFM What forest policy and regulatory framework exists to support implementation of sustainable forest management? 1 July was used as a mid-point for the annual data and is important because Is there a national platform that promotes stakeholder partic- monthly certification values change throughout the year as additional forest area is ipation in forest policy development? certified or previously certified forest are decertified. 2 Permanent forest land is defined in FRA 2015 as the area of state-owned forest What is the forest area intended to be in permanent forest land designated to remain permanently as forest (i.e. the permanent forest estate) plus an use now and how has it changed over time? estimate by governments of the portion of privately-owned forest expected to remain How is progress toward SFM measured and reported? permanently in forest land use. K.G. MacDicken et al. / Forest Ecology and Management 352 (2015) 47–56 49
Fig. 2. The area of permanent forest use as modified by other elements of the SFM enabling environment by climatic domain: (A) Permanent forest use; (B) Policies; Fig. 1. The area of permanent forest use as modified by other elements of the SFM (C) Legislation; (D) Stakeholder platform; (E) Forest inventory; (F) National enabling environment: (A) Permanent forest use; (B) Policies; (C) Legislation; (D) reporting; (G) Forest management plans; (H) Soil and water conservation; (I) Stakeholder platfor; (E) Forest inventory; (F) National reporting; (G) Forest High conservation value forest; (J) Social engagement; (K–M) Stakeholder involve- management plans; (H) Soil and water conservation; (I) High conservation value ment in operational planning, operations and review. forest; (J) Social engagement; (K–M) Stakeholder involvement in operational planning, operations and review. tools’’. It begins from the left, showing how forest area changes with 3.2. Legal framework the level and presence of enabling conditions for SFM. Moving from left to right the area of permanent forest subject to each of the 3.2.1. Permanent forest land indicators listed on the horizontal axis is given. This reduction is The area of permanent forest land indicates the area of forest based on the global extent of supportive legal, data availability, likely to remain as forest, including both the permanent forest management planning and stakeholder involvement in operations. estate and privately owned forest land expected by governments In those countries with permanent forest, some 98% of permanent to remain in forest land use (see www.fao.org/forestry/FRA2015/ forest land is covered by policies, laws and regulations in support Terms and Definitions for additional details). The permanent forest of SFM. This indicates a broad intention on the part of governments estate is state-owned and is mandated to remain as forest. The to support SFM into the future on some 2.2 billion ha (55% of global term permanent forest land is used to describe the sum of govern- forest area in 2015). When all of the SFM tools are included, the area ment estimates of non-state owned land intended to remain in decreases to 1.11 billion ha globally. permanent forest use plus the permanent forest estate. The intent When examining the application of each of the SFM tools to the to retain these areas as forest is the starting point for forest area forest by climatic domain (Fig. 2), all domains experience a that is managed sustainably – they are in principle those forest decrease in area as the number of SFM tools applied increases lands for which a commitment has been made to sustaining forest (from left to right on the x axis). Overall the temperate domain values well into the future. shows the least decrease in forest area as the number of SFM tools In 1990 the area reported as permanent forest estate was 1.4 increases, followed by the boreal, tropical and sub-tropical domain billion ha (FRA 2010) or 34% of total forest area while in by 2010 in order. It can be noted that each decrease identifies a need to this went to 1.7 billion or 43% of total forest area (as assessed in increase investment required to apply a given tool(s). FRA 2015). The total amount of forest land intended to be perma- The area under FMP in the Boreal domain drops by nearly 200 nent forest was 2.17 billion ha or 54% of total forest area in 2010. million ha once soil and water conservation objectives are included The difference between these two numbers comes from private as requirement in forest management plans. In the tropical forest lands intended to remain in forest. Fig. 3 shows the dis- domain, the permanent forest area covered by inventories is 309 tribution of permanent forest area by income category – of which million ha less than the area covered by legal frameworks support- some 82% is in upper middle and high income countries. Privately- ing SFM. The tropical domain area that does not include national owned forest is important in sustaining future forest area in the reporting, nor management plans nor stakeholder involvement high, upper middle and lower middle income category and of drops this by an additional 123 million ha. In the subtropics only almost no importance in low income countries where state 14% of permanent forest area is covered by forest reporting, ownership dominates. management plans and stakeholder involvement in operations. This difference between domains illustrates the need for greater 3.2.2. Policies and legislation supporting SFM investment in forest reporting, management planning and The practice of sustainable forest management is enhanced by stakeholder involvement in operations if the area of SFM is to be the effective application of a national legal, policy and institutional increased. framework. Countries that had either policies and or legislation The following discussion covers each of the SFM related that support sustainable forest management cover 99% of global indicators measured through the FRA with analyses by one or more forest area (Table 1). This is an increase in the area reported in of the categorical variables: climatic domain, national income FRA 2010 which reported coverage of about 70% of global forest category or sub-region. area under forest policy and legislation. Countries reporting only 50 K.G. MacDicken et al. / Forest Ecology and Management 352 (2015) 47–56
Table 2 Proportion of forest area covered by policies and or legislation supporting SFM by region and sub-region.
Region Sub region % of countries in the % forests in the sub-region sub-region Africa Eastern and 90 95 Southern Africa Northern Africa 86 100 West and Central 92 93 Africa Regional total 90 94 Asia East Asia 100 100 South and 100 100 Southeast Asia West and Central 58 78 Fig. 3. Permanent forest land by income category and ownership type. Asia Regional total 79 99 Central and Central America 100 100 legislation at national level in 2015 cover 97% of global forest area. North America Caribbean 43 90 Most policies and legislation were at the national level, although North America 80 100 Regional total 59 100 more than half of the countries had also invested in provincial and local level policies/regulations covering about 80% of the forest Europe Europe 88 100 area. This demonstrates the degree with which devolution and Oceania Oceania 33 97 decentralisation of regulatory framework for forest management South America South America 93 100 has occurred. There were no major differences in the proportion of countries and forests covered in terms of presence of policies versus legisla- tion (Table 2). The presence of policies and legislation were sharply skewed to the national level, particularly in the Caribean, Central America, Europe, South and Southeast Asia and West Central Asia where the proportion of countries investing in subnational policies and or legislation was well below 50%. More than 90% of the countries in Africa indicated they had policies and/or legislation supporting SFM covering 94% of the forests in the region. Each sub-region had more than 90% of the forests covered by policies and/or legislation except for West and Central Asia that was just below 80%. Analysis by climatic domain revealed no difference in the degree of SFM-supportive policy and legislation across domains. Fig. 4. Forest area covered by policies supporting SFM by income category and level Presence of legislation and or policies did not vary significantly of decentralization. across income groups. The geopolitical analysis revealed that coun- tries in the lower income categories invested more in national level and success of these platforms certainly varies substantially. In policies while higher income category countries investing in SFM part the inclusion of stakeholders is the result of widespread pro- policies across all levels of governance (Fig. 4). motion of stakeholder participation in forest policy development (FAO, 2009). Stakeholder engagement can help mitigate conflicts, 3.2.3. National stakeholder platforms enhance cooperation across stakeholder groups and improve the FRA 2015 defined national stakeholder platforms (NSP) as the quality of national forest policy – although it can be a difficult presence of a recognized procedure that a broad range of stake- and complex process to implement effectively (FAO, 2009). The holders can use to inform the national policy process through their functionality of reported NSPs was not investigated but their pres- opinions, suggestions and analysis. Significant progress has been ence is a positive starting point for most countries. made in allowing or encouraging stakeholder inputs into forest policy processes – countries indicated that 94% of global forest area is covered by national stakeholder platforms, although the extent 3.3. Data availability and reporting
3.3.1. Measuring the forest resource Table 1 Policies/Regulations supporting SFM at different geopolitical scales. Forest resource change measurement generally includes forest characteristics such as species composition, area, age class, volume Scale Policies Legislation Both policies and per hectare growth rates and site class. This forest inventory data legislation provides essential information as an early step towards national- Forest % of total Forest % of total Forest % of total scale planning and support of SFM policies, regulations and area forest area area forest area forest (000 ha) (000 ha) area (000 ha) area practices. There has been a remarkable and recent increase in the area of National 3,919,285 99 3,857,743 97 3,857,427 97 forest for which National Forest Inventories (NFI) have been under- Regional 2,639,784 67 2,209,200 56 2,196,123 55 Provincial/ 3,225,986 81 3,347,715 84 3,185,833 80 taken. In 2010, less than 50 countries reported having an NFI. As of State 2014, 112 countries were conducting forest inventories that cover Local 3,177,901 80 3,343,715 84 3,113,346 78 3,242,197,000 ha or 81% of the total global forest area. Over 70 countries received support for either national forest inventories K.G. MacDicken et al. / Forest Ecology and Management 352 (2015) 47–56 51 or national forest monitoring programs for climate change Table 3 mitigation purposes or both.3 Forest Inventory coverage by sub-region. Geographically the degree of NFI coverage varies across Sub-region % of sub- Area of sub- Total forest Area sub-regions with most of the world’s forest area (77%) in region area region area of sub- inventoried as sub-regions with high levels of NFI coverage (Table 3). Four percent with forest inventoried region % of global inventory (000 ha) (000 ha) forest area of the world’s forest were in sub-regions with lower (40–79%) NFI coverage. West and Central Africa have coverage of only 10% of Sub-regions with (80% or more NFI coverage) Central America 90 76,614 86,290 1.9 sub-regional forest area, presenting a significant challenge to East Asia 93 239,509 257,047 6 future governments to enhance forest management based on Europe 97 993,878 1,015,482 24.9 NFI data. Considering the importance of the forests in these North America 100 655,789 657,167 16.5 sub-regions to the well-being of people and the biodiversity found Oceania 96 166,863 173,376 4.2 there, these data support the need for strategic investment in those South America 80 678,096 842,132 17.1 South and 80 234,374 292,804 5.9 sub-regions most lacking in NFI coverage – particularly countries Southeast Asia in West and Central Africa. Total 3,045,123 3,324,298 77 There was a very strong relationship between national income Sub-regions with (40–79% NFI coverage) and forest area covered by forest inventory – as national income Caribbean 48 3530 7328 0.1 increases, so does the proportion of forest area covered by a East and Southern 49 126,317 274,866 3.2 national forest inventory (NFI) (Table 4). High income countries Africa North Africa 53 19,651 36,217 0.5 reported 98% of the forest area covered by national forest inven- West and Central 50 19,898 39,711 0.5 tories. Low income countries had national inventories covering Asia 37% of the forest area within this grouping suggesting this should Total 169,396 358,122 4 be considered as a priority group of countries for additional NFI Sub-region with <40% NFI coverage investment due to the highest annual forest loss rates (À0.6%) West and Central 10 32,678 312,997 0.8 reported for any income category (Keenan et al., 2015) and a lack Africa of reliable inventory data on forest change.
3.3.2. Forest inventory characteristics Nearly all NFI used ground plots (96%) with repeated inven- Table 4 tories conducted or planned on some 94% of the total inventoried Income grouping and national forest inventory. area (Table 5). The use of aerial imagery or remotely sensed imagery is reported on some 70% of inventoried land of which Income % of forest area Area with inventory Total area of forest 29% was sample based, 19% was full coverage and 22% utilized both category with NFI (000 ha) (000 ha) sampling approaches. High 98 1,807,621 1,830,480 Upper 80 985,556 1,224,998 middle 3.3.3. National forest resource reporting Lower 55 290,440 532,705 In many cases knowing the characteristics of the forest resource middle Low 37 146,809 398,135 and how it is changing is of little value unless this information is shared through reporting. Countries were asked to describe how they report national forest data from among three choices; criteria and indicator (C&I) reporting, periodic state of the forest reports Table 5 and ‘‘other’’ reports that describe some aspect(s) of the forest at NFI characteristics as percentage of total NFI area. the national level. The least helpful in determining progress to Inventory/sampling type % of total area under NFI SFM are reports in the ‘‘other’’ category. National periodic state Continuous forest inventory 36 of the forest type reports can be more helpful providing data Periodic forest inventory 10 needed in determining progress to SFM by providing consistent Combination of continuous and periodic 48 details about the forest resource over time. C&I reports are Single inventory event 6 purposefully designed to provide comprehensive information on Ground plots used 96 social, economic and environmental aspects of a nation’s forest Permanent ground plots 37 that, when considered together over time, can provide insight into Temporary ground plots 8 Both permanent and ground plots 51 that country’s progress towards SFM. No use of ground plots 4 The data show a significant commitment by countries to report Aerial imagery or remote sensing used 70 on their forests. Most countries (60%) use a periodic state-of-the- Sample based 29 forest type of report, globally covering 89% of forest area Full coverage 19 (Table 6). Criteria and indicator reports were drafted by 86 coun- Combination of sample and full coverage 22 tries that together covered 77% of total forest area and sixty-nine countries used ‘‘other’’ report formats mostly in combination with the other reporting types. the 22% of the global forest area that was not the subject of C&I There were 41 countries that produced all three types of report, reporting is located within 107 countries, many of which have little representing 67% of global forest area. It is important to note that or no forest area. The 11% of the global forest area not having per- iodic state of the forest reporting was within 77 countries and the 3 NFI support has included Algeria, Angola, Bangladesh, Brazil, Cameroon, Comoros 28% of the global forest area not reported within ‘‘other’’ reports Island, Congo, Costa Rica, Ethiopia, Gambia, Guatemala, Honduras, Kenya, Kyrgyzstan, were found across 124 countries. No reports were produced by Lebanon, Nicaragua, Panama, Paraguay, Peru, Philippines, Tanzania, Uruguay, Viet 38 nations that represented 5% of the global forest area. Nam, Zambia (Source: National Forest Monitoring Programme, FAO). UN REDD has provided country support for forest monitoring in 58 countries (I. Jonckheere, pers. Nearly all of the forest area in the high, upper middle and lower com.). middle income countries were covered by C&I reporting (Table 7). 52 K.G. MacDicken et al. / Forest Ecology and Management 352 (2015) 47–56
Table 6 Forest reporting types by number of countries and global forest area coverage.
Report type Number of % countries % of global forest Area reported (n = 193) countries with report area covered (000 ha) C&I 86 44 77 3,077,951 State of 116 60 88 3,519,677 forest ‘‘Other’’ 69 39 71 2,847,485
Table 7 Forest area reported through C&I reporting by income category.
Income category # Countries /# Of Area of income % of income in group countries category that is category area with no in unreported that is reporting category (000 ha) unreported High 12 62 5895 0.3 Upper middle 7 48 5062 0.4 Lower middle 4 40 4508 0.8 Low 4 30 168,260 42.3
The low income category contains 30 countries and accounts for 10% of global forest area. Four of the 30 low income countries do Fig. 5. Proportion of forest area covered by forest management plans by sub-region. not report on 168.2 million ha representing 42% of the forest area Low, medium and high labels are categories of relative proportion covered by FMP. in this income group. Combined with the lack of NFI coverage among low income countries there is a clear opportunity for countries to improve their capacity to manage their forests in the similar globally, but varied substantially by climatic domain. The long-term with better quality inventory and reporting. boreal domain without Russia showed low proportions of the domain with FMP for production and conservation in large part because Canada did not classify forest as production and con- 3.4. Forest management planning servation for FRA reporting, but included most of its forest area as multiple use. Some countries, such as Canada, reported only In the 1953 World Forest Inventory some 27% of forests in use total area with FMP without separate values for production and (considered equivalent to the FRA definition of production forests) conservation. were covered with working plans. In 2010 the equivalent propor- The presence of an FMP does not guarantee that the plans are tion was 70% percent of forests with management plans in 2010 implemented effectively, however the presence of a FMP is a posi- - a dramatic increase. The total area under Forest Management tive step in establishing the enabling conditions for SFM. Likewise, Plan (FMP) in 2010 was 2.1 billion ha or 52% of the total forest area the absence of FMP does not prevent the successful long-term, (Table 8). An important change since the 1950s is the significant sustainable forest management – for example, multi-generational increase in forest with management plans for conservation pur- family management of private forest occurs without a written poses. In 2010 the area with management plans for production management plan. Monitoring of FMP implementation by and conservation purposes were nearly equal. governments is an important means of improving compliance with Geographically, most forests in Europe, Asia, North and Central plans. Forty percent of FMPs were monitored annually in the America were reported to be covered by a FMP (Fig. 5) while South tropical climatic domain, followed by boreal (38%) and temperate America and Africa had the least coverage (<30% of sub-regional (32%) domains (Fig. 6). Only 22 percent of FMPs were monitored forest area). annually in the subtropical domain. This represents a high fre- The boreal and temperate domains reported high proportions of quency of monitoring events – for example, FMP in the tropics area under FMP (87% and 63% respectively) in contrast with the FMPs were reported on average to be monitored once every tropical and subtropical domains both of which had 28% under 2.5 years. In reality many governments with limited resources FMP (Table 8). Values for the boreal domain were also provided are unable to meet this monitoring schedule: 29% of countries with without Russia because Russia reports 100% of its forest under FMP reported no monitoring of the plans and some governments FMP while the rest of the boreal domain averages 63%. The total with planned monitoring intervals are unable to financially area reported with FMPs for production and conservation was very support the mandated frequencies.
Table 8 Forest area with FMP by climatic domain.
Domain Forest with FMP FMP for production FMP for conservation Area (000 ha) % of domain forest area Area (000 ha) % of domain forest area Area (000 ha) % of domain forest area Tropical 509,761 28.2 191,267 10.6 203,787 11.3 Temperate 424,971 63.1 175,516 26.1 209,428 31.1 Boreal 1,073,801 87.7 442,734 36.1 401,497 32.8 Boreal without Russia 258,656 63.1 21,243 5.2 7,852 1.9 Sub-tropical 91,131 28.5 36,505 11.4 28,678 8.9 Total 2,099,664 846,021 843,391 K.G. MacDicken et al. / Forest Ecology and Management 352 (2015) 47–56 53
70 social considerations/community involvement and high con- servation value forests (HCVF) (Table 9). 60 The components required in FMP vary substantially by country (Fig. 7). All of North America and most of Asia require soil and 50 water, social considerations and HCVF delineation while Europe, South America, Africa and Oceania have countries with varying 40 requirements.
30 3.5. How are stakeholders involved in the management decision making stages for public forests? 20 % of FMP monitored annually % of FMP 10 Stakeholder inputs into operational decision making for public forests is part of criteria and indicator schemes for SFM
0 (Montréal Process, 2009; ITTO, 2005). Stakeholder inputs can help Tropical SubTropical Temperate Boreal mitigate conflicts, enhance communication and cooperation across Climatic domain stakeholder groups, improve the quality of forest operations and contribute to nation forest policy – although it can be a difficult Fig. 6. Average proportion of forest management plans monitored annually by and complex process (Beckley et al., 1995). Fig. 2 demonstrates climatic domain (bars are the standard error of the mean). that stakeholders have the opportunity to provide inputs into management decisions in all climatic domains on approximately Table 9 the same forest area covered by FMP with requirements for Required components in forest management plans. stakeholder inputs. Stakeholders were allowed to be involved in the planning, operations and review of between 85% and 95% of Requirement Does requirement exist? forest area under management plans in all climatic domains. The Yes (million No (million extent to which these opportunities are used by stakeholders is ha) ha) not easily measured and was not measured in FRA 2015. Soil and water management 2698 1066 Social considerations/community 3526 253 involvement 3.6. Forest certification High conservation value forest delineation 3500 251 Criteria and indicators used for SFM and for forest management Countries reported on whether soil and water management, certification are closely connected (ITTO, 2007; Rametsteiner and social considerations/community involvement, or high con- Simula, 2003) – and forest certification is a reasonable indicator servation value forest delineation were required as part of FMP. of trends in SFM, independent of the other indicators reported Just over two-thirds of forest area with FMP required soil and water in this paper. International forest certification is not limited management as part of the plan, while over 90% of FMPs require to the Forest Stewardship Council (FSC) and Programme for
Fig. 7. Countries with required inclusion of soil and water management, stakeholder inputs and high conservation value forest designations in forest management plans. 54 K.G. MacDicken et al. / Forest Ecology and Management 352 (2015) 47–56
and 2014, although taking place at differing rates (Fig. 8). As of 2014 over 436 million ha of forest land were certified in these two schemes, although Fernholz and Kraxner (2012) estimated that there was double certification between schemes on about 1.7% of the area certified as of 2011, most of which was in Europe. Global growth has been uneven when viewed by income cate- gory and climatic domain. International forest certification has always been most extensive in the high income category countries (Fig. 9), where 88% of the growth in certified area has occurred. Ten percent of the total area change (2000–2014) was in upper middle income countries, with only two percent change in the lower mid- Fig. 8. Change in internationally certified forest area (2000–2014). dle income countries. There has been a slow decline in certified for- est area in low income category countries (from 315,000 ha in Endorsement of Forest Certification (PEFC), but these two systems 2002 to 255,000 in 2014). dominate in terms of the area covered and are the only two inter- International certification was by far the highest in boreal and national systems reported in the FRA (CEPI, 2006; Walter, 2008). In temperate domain countries – 90% of all internationally certified most cases, forest management certification is voluntary and is forest area. Historically they also account for the most rapid and often driven by company or investor policy as a means of accessing sporadic growth in certified area (Fig. 10). As of 2014 certification forest product markets that require third-party certification. in the tropical domain accounted for only 6% of the total certified forest spread across 38 countries.
3.6.1. International forest management certification The total area of internationally certified forest (PEFC and FSC) 3.6.2. Domestic certification systems went from approximately 13.8 million ha in 2000 to 437.5 million Ten countries reported the use of a domestic certification sys- ha in 2014 (Fig. 8) representing an annual average increase of some tem in 2012, compared with just three in 2000 (Canada, 30 M ha. Guadalupe and Tajikisatan). The area included in domestic Growth in internationally certified forest management has been schemes peaked in 2008 at around 90 million ha (Fig. 11), followed continuous for both certification schemes between the years 2000 by a decline that may be attributed to domestic schemes
(A) Forest Stewardship Council (B) Programme for Endorsement of Forest Cer fica on
Fig. 9. Forest certification by income category.
Fig. 10. Changes in area of forest management certification by climatic domain. K.G. MacDicken et al. / Forest Ecology and Management 352 (2015) 47–56 55
The state of the enabling environment for SFM and progress made at the operational level demonstrates commitment to sustainable forest management by governments, industry and communities. At the same time further investment in addressing these limitations is clearly needed to promote and support SFM – particularly in low income forest countries and in large parts of the tropical climatic domain. Overall, the evidence shows a trend favourable to SFM globally that will help ensure forests remain a valued part of our common future.
Acknowledgements
The authors express their gratitude to FAO, CIFOR, Natural Resources Canada, COMIFAC and OFAC for the support of authors in the writing of this paper and to the very useful comments of reviewers. Additional thanks are given to the Programme for Endorsement of Forest Certification (PEFC) and the Forest Fig. 11. Forest area covered by domestic forest management certification. Stewardship Council (FSC) for providing the annual values used for international certification. A special thanks to Sara Maulo, converting to international standards. Use of the sum of interna- Caterina Boitani and Erik Lindquist for help with data checking, tional and domestic certification areas is not recommended as graphics and maps. there is an unquantified potential for double counting with lands in both domestic and international certification schemes. Five countries had reported the use of only a domestic certification scheme: China, Israel, Cuba, Tajikistan and Guadalupe (France). References
Anonymous. Circa 500–200 B.C. Yi Zhou Shu. 4. Conclusions Beckley, T. et al., 1995. Forest Stakeholders’ Attitudes and Values: A review of Social Science Contributions. Manitoba Model Forest Inc., Pine Falls, Canada, 73 p. Determining progress toward SFM at the global scale is chal- Brown, J.C., 1883. French Forest Ordinance of 1669. English translation of Colbert (1669). Oliver and Boyd. Edinburgh. 196 pp. lenging. This is in part because the definition of what makes forest Canadian Council of Forest Ministers 2008. Measuring our progress: Putting management sustainable is not universally agreed (CBD, 2009). sustainable forest management into practice across Canada and beyond. FRA 2015 presents data that allows users to evaluate different
Kimmons, J.P., 1997. Forest Ecology: A Foundation for Sustainable Management. Rametsteiner, E., Simula, M., 2003. Forest certification—an instrument to promote Prentice-Hall, New Jersey, USA, 596 pp. sustainable forest management? J. Environ. Manage. 67 (2003), 87–98. Lovrc, M., Martinic, I., Lovric, N., Landekic, M., Sporcic, M., 2010. Assessment of Schmithüsen, F., 2013. Three hundred years of applied sustainability in forestry. progress of forests in Croatia towards sustainable forest management SEEFOR Unasylva 240, vol. 64, 2013/1. (South-east European forestry), vol. 1 No. 2 December 2010. UNFF, 2007. Highlights from Enabling Sustainable Forest Management: Strategies for MacDicken, K.G., 2015. Global Forest Resources Assessment 2015: What, why and equitable development, for forests, for people United Nations New York
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Forest Ecology and Management
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Changes in planted forests and future global implications q ⇑ Tim Payn a, , Jean-Michel Carnus b, Peter Freer-Smith c, Mark Kimberley a, Walter Kollert d, Shirong Liu e, Christophe Orazio f, Luiz Rodriguez g, Luis Neves Silva h, Michael J. Wingfield i a Scion, New Zealand b INRA, France c Forest Research, UK d FAO, Rome, Italy e Chinese Academy of Forestry, China f European Forest Institute, Atlantic Region, France g University of Sao Paulo, Brazil h WWF, Switzerland i FABI, South Africa article info abstract
Article history: This paper focuses on an analysis of planted forests data from the 2015 Forests Resources Assessment of Received 13 March 2015 the U.N. Food and Agriculture Organisation (FRA 2015). It forms one of a series of papers in the FRA 2015 Received in revised form 15 June 2015 special issue of this journal. Accepted 17 June 2015 While total forest area decreased from 4.28 billion hectares to 3.99 billion hectares from 1990 to 2015, Available online 7 September 2015 with percent global forest cover dropping from 31.85% to 30.85%, the area of planted forests increased from 167.5 to 277.9 million hectares or 4.06% to 6.95% of total forest area. Increase was most rapid in Keywords: the temperate zone, and regionally in East Asia, followed by Europe, North America, and Southern and Planted forests Southeast Asia. Global trends Climate However the annualised rate of increase in area of planted forests slowed in the 2010–2015 period to Population 1.2%, below the 2.4% rate suggested is needed to supply all of the world’s timber and fibre needs. The majority of planted forests comprised native species with only 18–19% of the total area being of introduced species. Introduced species were dominant in the southern hemisphere countries of South America, Oceania and Eastern and Southern Africa where industrial forestry is dominant. Twenty countries accounted for 85% of planted forest area and a different 20 countries for 87% of planted forest roundwood supply. As with forest area, roundwood supply from planted forests also showed an increasing trend although this was based on minimal data. There was a mismatch in compo- sition and rankings of the top 20 countries with top forest area and roundwood production suggesting that there are substantial opportunities to increase roundwood production in the future, especially in China which has the largest area but is currently ranked 3rd in roundwood production. Outlook statements were developed for the FAO sub regions based on past changes in planted forest area, population growth, and climate and forest health risks to identify key issues for the future. The over- all view from this study suggests that climate impacts, especially from extreme climatic events will affect planted forests in the future and that forest health impacts can also be expected to increase. Outlooks vary regionally. Europe and North America are likely to be most concerned with climate and health risks; Asia will experience population pressure that will impact on land availability for new forests and risks from extreme weather events, and will need to make the most of its existing forests; Africa will need to increase planted forest area to offset continuing deforestation and rapid population growth; and Oceania, the Caribbean, Central and South America are likely to be most concerned with climate impacts. To ensure the continued contribution of planted forests, a number of responses will be required to both maintain existing and also to develop new forests. Intensification of production in existing forests will lessen the need for greater forest areas and offset any land use conflicts related to food security; climate adaptation strategies will need to be developed as a matter of urgency, and forest health focus must remain a priority for research. Establishment of new forests will be eased through greater community
q This article is part of a special issue entitled ‘‘Changes in Global Forest Resources from 1990 to 2015’’. ⇑ Corresponding author at: Scion, Private Bag 3020, Rotorua, New Zealand. E-mail address: [email protected] (T. Payn). http://dx.doi.org/10.1016/j.foreco.2015.06.021 0378-1127/Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 58 T. Payn et al. / Forest Ecology and Management 352 (2015) 57–67
and stakeholder engagement. Application of models such as WWF’s New Generation Plantations, which recognises the importance of society and the need to consider the full range of forest products and ser- vices within the wider landscape and spectrum of land uses, will be important. We recommend that to enable deeper analysis related to planted forests future FRA Assessments con- sider ways to better gather data specific to planted forests such as productivity so that this important component of global forests can be better understood. Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction forest, comprising natural and planted regeneration (SNPF); (4) plantations comprising productive and protective plantations; The 3rd International Congress on Planted Forests was held in and (5) trees outside forests. Productive and protective plantations, 2013 to discuss the current state of knowledge on planted forests together with SNPFs, constituted the subgroup ‘planted forests’ globally and regionally (ICPF, 2013). Amongst a number of findings (FAO, 2010). The FRA 2015 definition (FAO, 2012) refined this to: (Payn et al., 2014) the congress noted that planted forest areas con- forest predominantly composed of trees established through plant- tinued to increase and that the goods and services provided by ing and/or deliberate seeding, where the planted/seeded trees are these forests were becoming increasingly diverse. The interaction expected to constitute more than 50 percent of the growing stock of planted forests with other land uses within landscapes and their at maturity. They include coppice from trees that were originally contribution to poverty alleviation and food security was identified planted or seeded and rubberwood, cork oak and Christmas tree as deserving attention. Risks to planted forests from climate plantations. change, socio-economic pressures and responses to these risks were seen as important. A global analysis indicated the importance 2.2. FRA dataset and analysis of planted forests for economic, environmental and social values. Regional perspectives indicated that expansion of planted forests The FRA 2015 dataset contains a number of variables (FAO, varies regionally as do issues affecting them. Africa for example 2012) directly related to planted forests that allowed us to explore has challenges regarding governance, and the opportunity to various aspects of trends in planted forests over the period 1990 to expand farm forests and woodlots. In contrast, Asia is constrained 2015. Other variables were derived from the core variables. From in its ability to further expand its commercial planted forest area these data we analysed trends globally, sub-regionally and by cli- and will need to increase production from existing forests. mate domain in: 1. Planted forest area; 2. Proportion of total forest The availability of a new comprehensive dataset from FAO’s area made up of planted forests; 3. Proportion of exotic and natural Forest Resources Assessment 2015 project provided the opportu- species within the planted forest resource; and 4. The relationship nity to explore some of the issues emerging from the 3rd between population trends and planted forest area. International Congress on Planted Forests in more detail both at A second stage of the analysis focussed on planted forest area at the global and regional scale. The FRA 2015 dataset covers all for- the country level. This focussed on the top 20 countries and evalu- ests and the period 1990 to 2015 (www.fao.org/forestry/ ated areas, species mix, and population relationships. FRA2015/database). For this study, one of a series commissioned Overall the planted forest data formed a small subset of the full by FAO, we concentrate on planted forests and interrogate the lat- FRA database, and in a number of instances it was not possible to est available data on planted forests in the context of current and view planted forest attributes of a specific variable. These included future climate and population pressures. We further present an issues such as the proportion of forest used for production or pro- outlook for the forests globally and regionally. tection purposes, or roundwood supply specific to planted forests. There have been significant studies on planted forests previ- In other instances, such as forest productivity or forest health, the ously. These, for example, include data trends and projections available data were very limited. To add value to the analyses we (Carle and Holmgren, 2008), plantations, biodiversity and climate therefore sought data sources supplementary to the FRA dataset. change (Pawson et al., 2013); the impact of planted forests on the global forest economy (Buongiorno and Zhu, 2014); timber 2.3. Additional data sources investment (Cubbage et al., 2014); and multi-purpose plantations (Paquette and Messier, 2009). Although extending beyond only 2.3.1. Jürgensen et al. (2014) roundwood study planted forests, the recently released Global Forest Expert Panel To investigate timber production from planted forests we uti- report on forests and food security also treats important related lised data gathered as part of an FAO study (Jürgensen et al., issues (Vira et al., 2015). 2014). This allowed us to investigate levels and trends of produc- tion in planted forests. The FAO analysis focussed on industrial 2. Methods roundwood production from forest plantations in 78 countries and information on roundwood production from the semi natural 2.1. Planted forests and planted forest (SNPF) category from only 17 countries as many countries could not provide information on roundwood production 2.1.1. Definition of planted forests for this category. We present 2012 data for the proportion of Since 1980, the Food and Agriculture Organisation of the United roundwood sources from natural and planted forests (SNPF and Nations (FAO) through its Forest Resources Assessments (FRA), has plantations combined); regional production levels in planted for- been collecting data on forest areas for two main categories of for- ests; and production levels from the top 20 country producers of ests: natural forests and forest plantations. In 2005, the FRA intro- planted forest roundwood. The Jürgensen et al. (2014) study covers duced two additional forest categories: modified natural forests most of the important planted forest countries. However, they and semi-natural forests (Evans, 2009), which resulted in five missed some countries and we have filled in these gaps using the major forest categories based on the degree of human intervention FRA database for 2010 industrial roundwood production for total and the silvicultural methods of forest regeneration. These include forest. We assumed in these cases that the wood comes from nat- (1) primary forest; (2) modified natural forest; (3) semi-natural ural forest. So the overall roundwood estimates for planted forests T. Payn et al. / Forest Ecology and Management 352 (2015) 57–67 59 will therefore be somewhat conservative. We also calculated 2012 Greener Future’’ (http://www.iufro.org/science/task-forces/- roundwood per unit of planted area in 1990 as a crude estimate of planted-forests/). productivity across the climate domains and sub regions.
3. Results 2.3.2. FAO planted forests thematic study The FRA dataset apportions forests depending on their proposed 3.1. Total forest trends (1990–2015) use; production, multi-use, and protection categories. These statis- tics are for all forests combined. The intended use of planted for- Total forest area decreased between 1990 and 2015 from 4.12 ests is important to know when looking at future timber supply to 3.99 billion hectares. The Tropics and Subtropics both decreased so we sourced data from the thematic study of planted forests in area while Boreal and Temperate increased (Table 1). (Del Lungo et al., 2006) where 61 countries were surveyed in detail Changes in total forest cover varied regionally (Table 2). Central as to their planted forests. We used this dataset to analyse the pro- America, East Africa, North Africa, Oceania, South America, portion of planted forests intended for production vs protection Southern and Southeast Asia, and West and Central Africa use on the 2015 top 20 planted forest countries (see Section 2.1) decreased while the Caribbean, East Asia, Europe, North America, identified. and West and Central Asia increased. Overall percentage of land covered by forest decreased from 31.85% to 30.85%. 2.4. Outlook analysis: climate, population pressure, and forest health While total forest area declined, forest productivity increased over the period from an average 4.10 m3 haÀ1 yrÀ1 to 5.26 m3 - An aim of this paper was to present an outlook for planted for- haÀ1 yrÀ1 with the changes varying by climate domain and region. ests that relates to the two key global drivers – climate and popu- Temperate zone productivity increased the most (1.91 m3 haÀ1 - lation change. Another aspect that is hard to extract from the FRA yrÀ1) with the boreal zone also increasing slightly. These data dataset is forest health status but one that is very important to should be taken as indicative as only 45% of countries surveyed consider. provided data for this variable. Population data are well covered in the FRA dataset and we analysed various planted forests variables in relation to population trends. However climate trends are not covered in the FRA dataset. 3.2. Planted forest trends To evaluate the impact of climate on the planted forest outlook we utilised two sources on information: 1. The IPCC 5th Assessment 3.2.1. Planted forest area report (IPCC, 2014); and 2. The Germanwatch climate risk index Global planted forest area increased from 1990 to 2015 from (Kreft and Eckstein, 2013). 167.5 million ha to 277.9 million ha with the increase varying by The IPCC 5th Assessment report outlines climate related drivers region and climate domain. Annualised rates of increase in area e.g. warming trends, drying trends, extreme precipitation; and were highest in the 1990–2000 period (2.0%) and the 2000–2005 associated key risks e.g. drought, storm and flood damage, period (2.7%) but dropped in 2005–2010 (1.9%) and further in decreased crop production. We mapped these drivers and risks to 2010–2015 to 1.2%. This drop may be of concern given that a study the FAO subregions. by WWF and IIASA have suggested that a rate of increase of 2.4% is The Germanwatch risk index is developed from historic data needed to meet future demands and supply all of the world’s tim- analyses regarding the extent to which countries have been ber and fibre and thus offset deforestation impacts on wood supply affected by the impacts of weather-related loss events (storms, (WWF and IIASA, 2012). floods, heat waves, etc.). The 2014 index is based on data from Of the 277.9 million ha of planted forests in 2015 56% are in the 1993 to 2012. It provides a country level index which we compiled temperate zone, 15% boreal, 20% tropical, and 9% subtropical to give a population weighted average for each of the FAO subre- (Fig. 1). All zones showed an increase in area, with the largest gions. It serves to provide an indication of past impacts that may increase in area in the temperate zone (93.4–154.4 million ha) fol- be extrapolated to the future where these climate impacts will lowed by tropical, boreal, and subtropical (Fig. 2). remain the same or worsen under climate change. The subregional Overall East Asia and Europe had the largest areas of planted range was from 40 (highest risk) to 111 (lowest risk). forests, followed by North America and Southern and Southeast Forest health data in the FRA dataset shows area affected by the Asia (Fig. 3). All regions, except Central America, showed an 10 most important extensive pest and disease impacts/outbreaks increase in planted forest area over the period with the greatest for each country. We summed the total area affected and calcu- absolute increases in these top four regions followed by South lated percentage of total forest area affected and averaged this by America. Central America showed a very slight decrease between region. Only 76 countries reported this variable so values must 1990 and 2015, probably within the margin of error. The trend of be taken as only indicative. Additionally, and as for other variables, a slowing of expansion rate (annualised% change in area) noted this does not relate to planted forests per se but could provide a globally was also apparent at the subregional level (Table 3). perspective on current forest health impacts by country and Most regions showed a peak in annualised percent change in either region. To augment these data we considered published studies 2000–2005 or 2005–2010 followed by a decrease in expansion rate to develop the regional outlook for health risk. in 2010–2015. The only exception was East Africa where the Utilising the forest area, population, climate and health infor- mation we developed a subregional outlook from a three class (low, medium and high) ranking of current forest areas (planted Table 1 Change in total forest area by climate domain from 1990 to 2015. and natural), population and population density; and changes in population and natural and planted forest area between 1990 Year Forest area by climate domain (Million ha) and 2015. This information was then considered in relation to Boreal Temperate Subtropics Tropics Total the climate drivers and risks, and forest health state, and an out- 1990 1219.3 618.0 325.4 1965.5 4128.3 look statement developed. This outlook was developed in terms 2000 1219.8 640.9 324.8 1870.1 4055.6 of level of future challenge facing planted forests. These outlook 2005 1218.9 659.2 323.9 1830.8 4032.7 statements were subject to review by planted forest experts in 2010 1224.9 673.4 319.6 1797.8 4015.7 2015 1224.5 684.5 320.1 1770.2 3999.1 the new IUFRO task force ‘‘Sustainable Planted Forests for a 60 T. Payn et al. / Forest Ecology and Management 352 (2015) 57–67
Table 2 Change in total forest area by FAO sub region from 1990 to 2015.
Year Forest area by subregion (Million ha) Central Caribbean East East Europe North North Oceania South South and West and West and America Asia Africa Africa America America Southeast Asia Central Africa Central Asia 1990 27.0 5.0 209.2 319.8 994.3 39.4 720.5 176.8 930.8 319.6 346.6 39.3 2000 23.4 5.9 226.8 300.3 1002.3 37.7 719.2 177.6 890.8 298.6 332.4 40.5 2005 22.2 6.3 241.8 291.7 1004.1 37.2 719.4 176.5 868.6 296.6 325.7 42.4 2010 21.0 6.7 250.5 282.5 1013.6 37.1 722.5 172.0 852.1 296.0 318.7 42.9 2015 20.3 7.2 257.0 274.9 1015.5 36.2 723.2 173.5 842.0 292.8 313.0 43.5
100 15% 91.8 20% 90 80 1990 70.4 2000 70 2005 60 Tropics 2010 50 42.1 2015 Subtropics 40 29.9 9% 30 Temperate 20 15.0 Boreal forest area (Mha) Planted 8.4 6.8 10 4.6 4.4 3.3 0.7 0.4 0
56%
Fig. 1. Percentage of total planted forest area in 2015 by climate domain. Subregion
Fig. 3. Changes in Planted Forest Area by FAO subregion 1990–2015. 180 1990 2000 160 154.5 2005 composition of the planted forests, with only between 18% and 140 2010 19% of the planted forests comprising exotic or introduced species. 2015 The high proportion of native species in planted forests is not well 120 appreciated by those opponents of planted forests who cite as a
100 major concern the use of introduced species. When considering the distribution regionally we can see that 80 South America, Oceania, and East and Southern Africa are the
60 56.8 regions dominated by plantings of introduced species with 88%, 41.9 75% and 65% of plantings with introduced species respectively
Planted forest area (Mha) 40 (Fig. 5). North America, West and Central Asia, and Europe are at 24.7 the other end of the spectrum with 1%, 3% and 8% of the area 20 planted in introduced species. 0 Tropics Subtropics Temperate Boreal 3.2.3. Country level trends Climate zone For country-level data, planted forest area for the top 20 coun- Fig. 2. Trends in planted forest area 1990–2015 by climate domain. tries is shown in Fig. 6. These top 20 countries accounted for 85% of planted forest area and were distributed across most regions bar Central America, the Caribbean, and West, Central, East and percentage change increased in each five year period peaking at Southern Africa. In 2015, China had by far the largest planted forest 2.65% in the 2010–2015 period. area at 91.8 million ha followed by the USA (26.4), the Russian Federation (19.8) and Canada (15.8). 3.2.2. Planted forest contribution to global forest area None of the 20 countries showed a decrease in planted forest Deforestation is a major concern globally, and total forest area area though Japan and Germany were static over the period. has decreased over the 1990–2015 period (Table 1). Planted forests China showed by far the largest absolute increase in area (37.0 mil- play a role in offsetting the pressure and negative impacts on nat- lion ha) followed by Canada (11.2), the USA (8.4) and Russia (7.2). ural forests. Analysis of total global area and the relationship The next tier were India and Sweden (6.3), Brazil (2.8) and Finland between natural and planted forest area shows that the decrease (2.4). Data for Indonesia were missing for 1990 but this country in natural forest area is offset by the increase in planted forest area also appears to be of this second tier order of increase. to an increasing degree with time. Planted forests increased from These countries also exhibited the slowdown in expansion rate 4.1% to 7.0% of the total forest area over the period, or 1.29% to noted at the global and regional level (Table 3). Generally, the per- 1 2.14% of total land area (Fig. 4). Also of interest was the species iod 2000–05 had the most rapid increase in planted forest area with the rate slowing in 2005–10 and slowing again in 2010–15, 1 Based on land area from UN Statistics Division. although for some countries the peak was between 2005 and T. Payn et al. / Forest Ecology and Management 352 (2015) 57–67 61
Table 3 Annualised rate of change in planted forest area (%) (shaded cells are peak values).
2010. The decline in planting rate was common across most coun- Planted forest Planted forest tries with only 3 of the 20 countries (Chile, Sudan, and Ukraine) (introduced (native species) planting at a greater rate in the last 5 years (2010–2015) than in species) Natural forest 33% the 5 previous years.
3.3. Forest timber production [Roundwood supply] 32%
3.3.1. Area trends 31% Statistics and trends in forest area as presented previously are important, however the production from these forests is the ulti- mate measure of their use. Roundwood (industrial roundwood) 30% supply is the major production variable to be considered here. Table 4 summarises the results from this analysis. Globally in 29% 2012 46.3% of industrial roundwood comes from planted forests. One interesting result was that in the tropics and subtropics, 65% of production is from planted forest, but this reduces to 45% for
Land area occupied by Land area occupied by (%) forest 28% temperate and only 14% for the boreal zone. The lower values for boreal and temperate zones could reflect that planted forests in 27% these cooler areas may be too young to produce much wood. 1990 1995 2000 2005 2010 2015 However, given the large areas of planted forest especially in the Year temperate zone (15% of total forest area) there appears to be Fig. 4. Proportion of total forest cover made up of natural and planted forests and potential for much greater production in the future from these for- changes with time. ests. Also, the rate of increase in planted area across all regions 62 T. Payn et al. / Forest Ecology and Management 352 (2015) 57–67
100% Other regions probably contain a higher proportion of less inten- sively managed planted forests. 90% 88% In 2012, 20 countries (Fig. 7) together produced 87 percent of the global industrial roundwood production from planted forests, 80% 3 75% totalling about 675 million m . The country mix and rankings of these top 20 countries differs from the top 20 area rankings 70% 65% (Fig. 6) reflecting opportunities for large increases in production in countries such as China where area is high and production cur- 60% rently relatively low.
50% 3.3.2. Temporal trends in roundwood supply 1990–2015 42% The FRA 2015 dataset showed an overall increase in roundwood 40% production from 1990 to 2015 though data was sparse. The time-series data on the industrial roundwood production from 17 30% 25% countries reported in the Jürgensen et al. (2014) study showed that 21% for many countries in Latin America and Asia (Chile, Brazil, China, 20% 18% Indonesia, Malaysia, Myanmar, Thailand, Uruguay and Vietnam), 12% 10% the production had increased considerably since 2000; while in Area of planted forest withintroduced species (%) 10% 8% 3% Argentina, Australia, New Zealand and the United States of 1% America, production had been increasing at a considerably slower 0% pace. In European countries (Portugal, Spain, and Turkey) and in South Africa, the trend in industrial roundwood production had basically been stagnant since 2000, with some noticeable ups and downs during this period.
Subregion 3.4. Population, climate and forest health trends Fig. 5. Proportion of planted forests with introduced species by FAO subregion. 3.4.1. Population Over the period 1990 to 2015 global population increased from
79.0 just over 5bn to just over 7bn an annualised rate of increase of 80 1.46%. Highest 2015 population densities were in Southern and 70 1990 Southeast Asia, Caribbean and East Asia (Table 5). All regions show 2000 2005 increasing population but rate of population increase varies 60 2010 regionally. Southern and Southeast Asia, Western and Central 2015 50 Africa, and East Asia showed the largest rate of increase with 44.1 Europe the lowest rate. Comparing annualised population growth 40 rate with annualised change in planted forest area showed that 30 26.4 globally the rates are similar, but regionally these vary. Europe 19.8 for example, had minimal population growth, but a 37% increase 20 15.8
Planted forest area (Mha) 13.7 12.0 10.3 in planted forest area while Central America has shown a 45% 7.7 6.8 10 6.1 5.3 4.9 4.9 4.0 3.7 increase in population with only a 17% increase in planted forest 3.4 3.0 2.9 2.1 2.0 area. Southern and Southeast Asia by contrast shows large 0 increases in both population and planted forest area. We used these relationships to infer pressure on future supply of timber Country regionally – high pressure where annualised population growth rate was greater than annualised forest area increase and vice Fig. 6. Planted forest area and trends (1990–2015) for the top 20 countries by versa for low pressure. planted forest area. 3.4.2. Climate The regional analysis of the Germanwatch climate risk index must be reflected by a corresponding increase in wood production showed a range of risk indices across regions and also across cli- in future decades. This all points to a greater proportion of wood mate zones (Table 5). Highest risk regions (lowest scores) were being supplied from planted forests in the future. Already in Central America, the Caribbean, East Asia, and Southern and 2012, almost as much (46.3%) industrial wood comes from planted Southeast Asia; and lowest risk regions Western and Central than natural forest when fuel wood is excluded from the analysis. Africa, Western and Central Asia, North Africa, and Eastern and An analysis of the data by region indicated that the production Southern Africa. In terms of planted forest regions this suggests of industrial roundwood in planted forests in 2012 was close to that Eastern Asia and Southern and Southeast Asia with large and 200 million m3 in South America (193 million m3), followed by increasing areas of planted forests are most at risk. This analysis Asia (151 million m3) and North and Central America (104 mil- gives a retrospective view and future risk distributions may lion m3). Oceania, Europe and Africa produced considerably less, change. ranging from 26 million to 47 million m3. Productivity and per- The IPCCC AR5 findings suggest that all regions will be affected centage roundwood sourced from planted forests was highest in by climate change and that there may well be effects on planted South America (24.0 m3 haÀ1 yrÀ1; 92.4%) and Oceania followed forests. IPCC AR5 projections (IPCC, 2014) for climate change sug- by East and Southern Africa and Southern, Southeast, and East gest increased risks and impacts globally, both from direct climatic Asia. These regions host countries with highly developed inten- events such as storms, but also indirectly from increased risks from sively managed tree plantations and fast growing exotic species. fire, pests and diseases, or spread of invasive species. As most T. Payn et al. / Forest Ecology and Management 352 (2015) 57–67 63
Table 4 Planted forest roundwood production in 2012 by region and climate domain adapted from Jürgensen et al., 2014.
Total forest Planted forest Annualised% change in Planted forest Planted forest % of 2012 Planted forest area 2015 area 2015 planted forest industrial roundwood total industrial roundwood productivity (Million ha) (Million ha) area 1990–2015 2012 (1000 m3) roundwood index based on 1990 area (m3 haÀ1 yrÀ1) World 3999.1 277.9 2.0 770,200 46.3 4.6 Tropical 1770.1 56.8 2.5 255,300 63.7 8.4 Subtropical 320.0 24.7 1.2 69,600 64.7 3.8 Temperate 1031.5 154.4 2.0 410,100 45.2 4.4 Boreal 877.3 41.9 2.0 35,200 13.9 1.4 South America 842.0 15.0 2.5 193,000 89.8 24.0 Oceania 173.5 4.3 1.9 47,500 84.0 17.2 East and Southern Africa 274.8 4.6 1.2 20,700 64.7 6.0 Caribbean 7.1 0.7 2.4 300 24.7 0.7 East Asia 257.0 91.8 2.2 78,700 46.9 1.5 Central America 86.2 0.4 0.6 1600 18.0 4.3 West and Central Africa 313.0 3.2 3.2 5100 14.1 3.5 Southern and SE Asia 292.8 29.9 3.4 82,700 52.0 6.4 North Africa 36.2 8.4 0.9 400 15.7 0.1 Europe 1015.4 70.4 1.3 166,200 33.4 3.2 West and Central Asia 43.5 6.7 2.1 3900 19.1 1.0 North America 657.1 42.1 2.5 170,100 36.0 7.6
Africa. Extreme drought conditions will also decrease yields in 160 areas not water limited. Under all future climate projections, a 141.5 140 131.9 range of climate change-related factors (extreme events and dis- ) 3 120 turbances, changes in precipitation, increased temperatures and CO2) will continue to exacerbate the establishment and spread of 100 pests, vectors and pathogens, and negatively impact production 80 systems such as planted forests (Robinet and Roques, 2010). 64.2 Globally, biomass and soil carbon stocks in forest ecosystems are 60 43.1 currently increasing but are vulnerable to loss to the atmosphere 38.4 40 28.6 28.5 planted forest (Mm 27.5 as a result of rising temperatures, droughts, and fires projected in 20.4 19.2 18.9 15.9 Industrial roundwood from 14.6 13.7 13.5 20 12.5 11.6 11.6 10.0 9.6 the 21st century. Measurements of increased tree growth over the last several decades, a large sink for carbon, are consistent with 0 this (Settele et al., 2014), but confounding factors such as N depo- sition, increasing area of productive planted forests, and forest management practices make attribution of these trends to climate Country change difficult.
Fig. 7. The world’s top 20 producers of industrial roundwood from planted forests in 2012. 3.4.3. Forest health Only 76 countries supplied data for this variable covering a total forest area of 2.8 billion hectares or 30% of global forests. Averaged terrestrial ecosystems, planted forests are vulnerable to climate across the 76 countries, 8.5% of forest area was affected by pest and change projected even under low to medium-range warming sce- disease outbreaks. The percentage area affected was highly vari- narios (RCP22.6 to RCP6.0) as defined in IPCC AR5; in the second half able and ranged from very close to zero to 82%. Average percent of the 21st century, climate change is projected to be a powerful area affected varied regionally (Table 5) from a minimum of stressor specially under high-warming scenarios such as RCP6.0 0.37% in Western and Central Africa to 12.04% in Europe. Trend and RCP8.5 (Settele et al., 2014). Increases in the frequency or inten- data were not available, but it seems that the total area affected sity of disturbances such as droughts, wind storms, fires and pest has increased from previous FRA surveys – total area affected in outbreaks have been detected in many parts of the world where 2015 was 141 million ha, as compared to 68 million ha in 2005 planted forests are located and in some cases are attributed to cli- (FRA 2005/thematic study/chapter4). mate change (medium confidence in IPCC AR5). Also, the establish- ment, spread and survival of populations of invasive species have increased (IPCCAR5), mainly due to increased dispersal opportunities 4. Discussion or to increased disturbances rather than climate change. The consequences for the provision of timber and other wood 4.1. Outlook products are projected to be highly variable between regions and products, but might induce an increased demand on wood supply The FRA 2015 data analysed in this study suggest that in from planted forests. Decreased production from planted forests is planted forests, a new timber resource is continuing to be created expected in already dry forest regions where increasing water def- and that it will contribute significantly not only to future wood and icit is projected such as the south-western part of Europe, USA or energy supplies but can also meet a range of wider social and envi- ronmental benefits (ecosystem services). Planted forests are likely to continue to supply an increasing proportion of the world’s wood 2 RCPs (Representative Concentration Pathways) are identified with the radiative forcing by 2100; four main RCPs scenarios have been used in AR5 (8.5, 6.0, 4.5, and requirements; the trend is supported by this new dataset. The abil- 2.6 W mÀ2). ity of planted forests to increase supply will depend on global and Table 5 64 Summary of forest, population trends, and climate impacts and risks by FAO sub-region.
Subregion Population % Change % Change % Change IPCC key risks IPCC climate related Climate % Forest area Outlook density since since since 1990 drivers Risk affected by 2015 1990 1990 Population Index 2 outbreaks (n/km ) Natural Planted Forest Forest
South and 276 À14 132 49 Drought, decreased crop Warming trend, drying 40 1.2 High population density, rapid population increase, large natural Southeast Asia productivity, storm and trend, extreme forest loss, but large planted forest expansion though rate flood damage, drought temperatures, extreme slowing, climate impacts high. Population pressure and climate precipitation, cyclones impacts likely to put pressure on further planted forest area. Focus on increasing productivity from existing resource, adaptation to extreme climate impacts Europe 33 0 37 2 Storm and flood damage, Warming trend, drying 59 12 Medium density but stable population, stable natural forest, low decreased crop trend, extreme planted forest expansion, medium climate impacts and high production, wildfires temperatures, extreme disease impacts. Focus on climate adaptation and forest health precipitation management to maintain status
Caribbean 188 40 79 25 Storm and flood damage, Warming trend, drying 44 2.1 High population density, increased area of natural forest, 57–67 (2015) 352 Management and Ecology Forest / al. et Payn T. decreased crop trend, extreme medium increase in planted forest area, low population growth, production temperatures, extreme high climate impacts and medium disease. Focus on adaptation precipitation to extreme climate impacts Eastern Asia 137 6 72 16 Drought, decreased crop Warming trend, drying 49 8.7 High population density, low population growth, low increase in productivity, storm and trend, extreme natural forest area and medium increase in planted forest area, flood damage, drought temperatures, extreme climate impacts high and medium level of health impacts. Focus precipitation, cyclones on adaptation to extreme climate impacts Western and 40 4 70 63 Drought, decreased crop Warming trend, drying 98 11.4 Medium population density, high population growth, low Central Asia productivity, storm and trend, extreme increase in natural forest, medium growth in planted forest area, flood damage, drought temperatures, extreme low climate impacts, high health impacts. Focus on increasing precipitation, cyclones production from existing planted forests and adaptation to extreme climate impacts East and Southern 43 À15 35 35 Drought, decreased crop Warming trend, drying 84 1.7 Medium population density, medium population growth, high Africa productivity, flood trend, extreme loss of natural forest, low increase in planted forest, medium damage, increased pest temperatures, extreme climate and health impacts. Focus on expanding planted forest and disease impacts precipitation area and adaptation to drought and health risks Oceania 5 À3 58 46 Storm and flood damage Warming trend, 59 2.0 Low population density and growth, low loss in natural forests, cyclones, extreme medium increase in planted forests, medium levels of climate precipitation and health impacts. Focus on adaptation to extreme climate impacts Central America 68 À11 17 45 Storm and flood damage, Warming trend, drying 50 0.4 High population density and growth, high loss of natural forest, decreased crop trend, extreme low planted forest increase, high climate impacts, low health production temperatures, extreme impacts. Focus on increasing planted forest area, adaptation to precipitation extreme climate impacts Western and 47 À10 122 94 Drought, decreased crop Warming trend, drying 111 0.4 Mediumimpacts. population Focus density, on increasing high population planted forest growth, area medium and Central Africa productivity, flood trend, extreme adaptationnatural forest to droughtloss, high planted forest increase, low climate and Northern Africa 25 À15 24 63 Drought,damage, decreased increased croppest Warmingtemperatures, trend, extreme drying 105 12.1 Lowhealth population density, high population growth, high loss of productivity,and disease impacts flood trend,precipitation extreme natural forest, low increase in planted forest area, low climate damage, increased pest temperatures, extreme impacts, high health impacts, dependence on fuel wood. Focus and disease impacts precipitation on increasing planted forest area, adaptation to drought, forest health management South America 24 À10 87 39 Storm and flood damage, Warming trend, drying 78 1.2 Low population density, medium population growth, medium decreased crop trend, extreme loss of natural forest, high increase in planted forest area, low production temperatures, extreme climate and health impacts. Focus on increasing planted forest precipitation area, adaptation to extreme climate impacts North America 18 À2 87 27 Wildfires, storm and Warming trend, drying 50 11.2 Low population density, low population growth, stable natural flood damage trend, extreme forest, high increase in planted forests, medium climate impacts, temperatures, extreme high health impacts. Focus on health management and precipitation, cyclones adaptation to extreme climate impacts T. Payn et al. / Forest Ecology and Management 352 (2015) 57–67 65 country policies, the sustainable forest management and trade competition for forest land, both natural and planted, and requires requirements, and the development of supply chains and markets forestry and farming practices that produce more with less land (Freer-Smith and Carnus, 2008). The FRA dataset has allowed us to and water. Regions with the highest population pressure (mainly develop a global and regional picture of the extent and trends in a Asia) will have the highest level of competition and future expan- number of planted forests variables over the period 1990 to 2015. sion may not be an option or may be very difficult. Overall planted forests are playing a very significant role in 2015. The focus may then move to intensification of management and While deforestation has continued to occur, the area of planted for- increasing productivity in existing forests. Well managed planted ests has increased to 277 million hectares (now making up 6.95% of forests usually have higher yields of wood than natural, unman- forest area) and this has slowed deforestation. While expansion aged forests, with commercial plantations in the tropics having has continued over the period, the rate of that expansion has annual growth rates of 10–30 m3 haÀ1 compared to 1–5 m3 haÀ1 dropped in the decade from 2005 to 2015. So while general signals for natural forests (Evans and Turnbull, 2004). Annual growth rates concerning the state of planted forests are good – increase in area, could not be assessed for planted forests within the FRA 2015 data roundwood supply approaching that from natural forests – there set, but the planted forests thematic study (Del Lungo et al., 2006) are some potential concerns regarding the ability to meet future gives a more comprehensive picture that complements Evans and demands, but also some opportunities. Outlook statements devel- Turnbull. There are a number of examples of improvements in oped for the FAO sub regions based on past changes in planted for- planted forest productivity in the literature, often related to est area, population growth, and climate and forest health risks to genetic improvement, e.g., Bouffier et al. (2008). Brazil has shown identify key issues for the future are summarised in Table 5. a steady increase in productivity; in the 1970s, the average yield Overall, we suggest that climate impacts, especially from extreme was 13 m3 haÀ1 yrÀ1, and it currently exceeds 40 m3 haÀ1 yrÀ1 climatic events will affect planted forests in the future and that for- (Gonçalves et al., 2013; IBA, 2015). New Zealand can demonstrate est health impacts can be expected to increase. Expansion of a 25% improvement in productivity through use of improved geno- planted forest area will be at a slower rate than previously and this types in its radiata pine forests (Kimberley et al., 2015). may put pressure on roundwood supply; however there will be a Intensification is a feature of many national research programmes, lag between increase in area and supply so this may not be a real e.g., www.gcff.nz. concern over time. It is clear from this study and from the associated literature that Regionally there are variations in the outlook for planted for- pest (including insects and pathogens) problems are giving rise to ests. The two most stable regions are Europe and North America. increasing levels of loss in planted forests. This includes both those Both these regions have well established and relatively stable, or that are established based on native and non-native species. Native increasing, areas of planted forests. They also have stable natural species in planted forests are often very seriously damaged by forest areas, and populations are either stable or only growing native pests but they are also subject to increasing problems due slowly. The main issues for these two regions will be climate to accidental introductions of non-native organisms. Plantations change, adaptation to extreme events and managing forest health of non-native, or introduced, species such as Eucalyptus, Pinus impacts. By contrast Asia – South and Southeastern, Western and and Acacia have typically been relatively free of pest problems dur- Central, and to a lesser degree Eastern – has a high and increasing ing the early years of establishment due to a separation from their population pressure, recent rapid expansion of planted forest area natural enemies (Wingfield et al., 2008, 2010). In all areas studied, and relatively low roundwood production from these new forests this situation has changed dramatically as pests are accidentally and high climate impacts and risk index. These regions will proba- introduced, but also where native organisms have adapted the bly face a number of challenges both from population pressure ability to infect/infest trees (Wingfield, 2003; Wingfield et al., slowing any future increase in planted forest area and from some 2010). Given the dramatic increases in the movement of pests very significant impacts from extreme climate events. To respond globally, largely driven by anthropogenic factors (Liebhold et al., to these pressures, focus on enhancing productivity from existing 2012; Santini et al., 2013), forest health will be an increasingly forests and developing robust climate adaptation strategies is important constraint to forest productivity although the applica- likely to be a high priority. The dominant risk to South America, tion of modern breeding and other technologies can offset losses including the planted forest powerhouses of Brazil and Chile, (Wingfield et al., 2012). The impacts of future climate related appears to be climate impacts. Africa has a major issue with con- events remain poorly understood although there is good evidence tinuing loss of natural forest area, population growth and only for increased pest problems in some situations (Sturrock et al., low to moderate increase in planted forest areas. This suggests that 2011). These will require increased emphasis on forest health man- focus will need to be on expanding planted forest areas, but that agement and also adaptation strategies to deal with a changing cli- this will have to take into account the high risk of future droughts mate. Investment in forest health research is globally significant and also pests and diseases on the success of these new forests. and organisations such as IUFRO (www.iufro.org) are coordinating Other smaller regions – Oceania, the Caribbean, Central America major global initiatives on forest health including for example – will face their main challenges around the impacts of extreme newly established task forces on these topics. climate events. One of the most important challenges to the further expansion of planted forests and indeed the on-going management of existing 4.2. Challenges and opportunities facing planted forests forests is that of societal expectations. In the past there was serious concern about conversion of natural forest systems to plantations The challenges facing planted forests will come from population and thus a strong negative perception of planted forests. growth and climate impacts, but also other issues such as However, with the development of independent third party audit Governance (Cubbage et al., 2014) which can affect forest invest- certification schemes such as FSC (www.fsc.org) and PEFC (www. ment and management. The noted decrease in expansion rate of pefc.org) in the 2000s this perception is changing. These schemes planted forest area, while unexplained here, is of concern. disallow conversion of natural forests to plantations, and together Competition for land is likely to be a major factor affecting future with the development of WWF’s New Generation Plantations plat- expansion. The UN is projecting that an increase in food production form and its concept of well-managed and designed, inclusive and of 60% will be required by 2050 (UN 2013). A more recent study profitable plantations (NGP, 2014), the negative views of planted (Ray et al., 2013) suggests it will not be possible to meet this target forests will most likely change. Acceptability does appear to be by boosting crop yields on existing land. This will lead to increasing with a more positive view from bodies such as FSC 66 T. Payn et al. / Forest Ecology and Management 352 (2015) 57–67 where plantations are now fully integrated into global standards strategies to mitigate climate change impacts. Additionally the (Maunder 2014 pers comm). This will make it easier to develop increasing involvement of communities with planted forest issues new forests in the future. Community involvement and dialogue and the development of socially based programmes such as forest between forestry companies and stakeholders is becoming increas- certification and New Generation Plantations will aid in future ingly important. Initiatives such as The Forests Dialogue (The management of existing forests and development of new ones. Forests Dialogue, 2015), convenes exchanges between forestry companies and civil society organisations, provides an ongoing, Acknowledgements multi-stakeholder dialogue focused on developing mutual trust, a shared understanding, and collaborative solutions to sustainable The authors acknowledge the support of their organisations for forest management across a range of topics such as ‘‘Intensively the development of this paper; the support and encouragement of Managed Planted Forests (IMPF)’’, and ‘‘Food, Fuel, Fibre and the FAO, and especially Ken MacDicken, in making available the Forests (4F’s)’’. 2015 Global Forest Resources Assessment dataset for the analysis Increasingly, planted forests will need to be recognised within undertaken here; and the comments of three anonymous review- the wider community for the range of values provided, not just ers on an earlier draft. the timber. While this analysis has shown that the predominant use of planted forests by the top 20 countries was for ‘production’, References planted forests are established and managed for a wide range of objectives not solely for intensive wood production. Historically Bateman, I.J., Harwood, A.R., Mace, G.M., Watson, R.T., Abson, D.J., Andrews, B., trees and woodlands have been planted for landscape, protection Binner, A., Crowe, A., Day, B.H., Dugdale, S., Fezzi, C., Foden, J., Hadley, D., Haines-Young, R., Hulme, M., Kontoleon, A., Lovett, A.A., Munday, P., Pascual, U., (against snow avalanche, landslip and soil erosion), hunting and Paterson, J., Perino, G., Sen, A., Siriwardena, G., Van Soest, D., Termansen, M., other socio economic objectives. In the East Asian region for exam- 2013. Bringing ecosystem services into economic decision-making: land use in ple the protection which planted forests provide against soil ero- the United Kingdom. Science 341 (6141), 45–50. Bouffier, L., Rozenberg, P., Raffin, A., Kremer, A., 2008. Wood density variability in sion and flooding have been important drivers of woodland successive breeding populations of maritime pine. Canadian J. Forest Res. 38 (8), creation. In China alone, the Natural Forest Protection Program 2148–2158. (NFPP) and the Conversion of Cropland to Forest Program (CCPF), Boyd, I.L., Freer-Smith, P.H., Gilligan, C.A., Godfray, H.C.J., 2013. The consequence of triggered mainly by the flooding disaster of 1998, have generated tree pests and diseases for ecosystem services. Science 342 (6160). Buongiorno, J., Zhu, S., 2014. Assessing the impact of planted forests on the global afforestation area of more than 32.5 million hectares. forest economy. NZ J. Forest Sci. 44 (Suppl 1), S2. In Europe and North America the increasing areas of planted Carle, J., Holmgren, P., 2008. Wood from planted forests: a global outlook 2005– forests are likely to have even broader explanations. The 2030. Forest Prod. J. 58, 6–18. Cubbage, F., Mac Donagh, P., Balmelli, G., Morales Olmos, V., Bussoni, A., Rubilar, R., Millennium Ecosystem Assessment and subsequent research and De La Torre, R., Lord, R., Huang, J., Afonso Hoeflich, V., Murara, M., Kanieski, B., policy initiatives have been informed by the ecosystem services Hall, P., Yao, R., Adams, P., Kotze, H., Monges, E., Hernandez Perez, C., Wikle, J., concept. This categorises the benefits/services of ecosystems as: Abt, R., Gonzalez, R., Carrero, O., 2014. Global timber investments and trends, 2005–2011. NZ J. Forest. Sci. 44 (Suppl 1), S7. Supporting Services such as primary production, soil formation, Del Lungo, Ball, J., Carle, J., 2006. Global planted forests thematic study: results and nutrient and water cycling which provide the basic infrastructure analysis FAO. Planted Forests and Trees Working Paper 35b , p. 38. of life; Provisioning Services which are the goods such as food, fuel Evans, J., 2009. Planted forests: uses, impacts and sustainability. Rome: CAB International and Food and Agriculture Organization of the United Nations and fibre; Regulating Services such as climate and hazard regula- (FAO). tion (prevention of erosion, carbon storage, water regulation, ava- Evans, J., Turnbull, J.W., 2004. Plantation forestry in the tropics: the role, silviculture lanche protection, etc.); and Cultural Services such as recreational and use of planted forests for industrial, social, environmental and agroforestry purposes, OUP Oxford. use, benefits to health and spiritual well-being. The important pol- Food and Agriculture Organization of the United Nations (FAO), 2010. Global Forest icy development has been the recognition that as populations Resources Assessment 2010.
Paquette, A., Messier, C., 2009. The role of plantations in managing the world’s Group II to the Fifth Assessment Report of the Intergovernmental Panel of forests in the Anthropocene. Front. Ecol. Environ. 8 (1), 27–34. Climate Change. Cambridge University Press, Cambridge, United Kingdom and Pawson, S.M., Brin, A., Brockerhoff, E.G., Lamb, D., Payn, T.W., Paquette, A., Parrotta, New York, NY, USA, pp. 271–359. J.A., 2013. Plantation forests, climate change and biodiversity. Biodivers. Sturrock, R.N., Frankel, S.J., Brown, A.V., Hennon, P.E., Kliejunas, J.T., Lewis, K.J., Conserv. 22 (5), 1203–1227. Worrall, J.J., Woods, A.J., 2011. Climate change and forest diseases. Plant. Pathol. Payn, T., Carnus, J., Freer-Smith, P., Orazio, C., Nabuurs, G.-J., 2014. Third 60, 133–149. international congress on planted forests: planted forests on the globe – The Forests Dialogue, 2015. The Forests Dialogue: Overview.
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Forest Ecology and Management
journal homepage: www.elsevier.com/locate/foreco
Status and trends in global primary forest, protected areas, and areas designated for conservation of biodiversity from the Global Forest Resources Assessment 2015 q ⇑ David Morales-Hidalgo a, Sonja N. Oswalt b, E. Somanathan c, a Food and Agriculture Organization of the United Nations, Forestry Department, Viale delle Terme di Caracalla, 00153 Roma, Italy b USDA Forest Service Southern Research Station, Forest Inventory and Analysis, 4700 Old Kingston Pike, Knoxville, TN 37922, USA c Indian Statistical Institute, Economics and Planning Unit, 7 Shaheed Jeet Singh Marg, New Delhi 110016, India article info abstract
Article history: The global community has recognized the importance of forests for biodiversity, and has prioritized the Received 18 December 2014 preservation of forest biodiversity and ecosystem functions through multiple multilateral agreements Received in revised form 5 June 2015 and processes such as the Convention on Biodiversity’s Aichi Targets and the Millennium Development Accepted 8 June 2015 Goals. The Global Forest Resources Assessment (FRA) provides one mechanism for tracking progress Available online 7 September 2015 toward such goals in three particular areas: primary forest area, protected forest areas, and areas desig- nated for the conservation of biodiversity. In this paper, we quantify current area and trends in forest Keywords: areas designated for the conservation of biodiversity, protected forest areas, and primary forests by coun- FRA 2015 try and biome; and examine the association between total forest area and measures of protection, Biodiversity conservation Global Forest Resource Assessment per-capita income, and population. The overall findings suggest that countries are increasingly protecting Primary forest forests of ecological significance at the global scale (7.7% of forests were protected in 1990 rising to 16.3% Protected areas in 2015), with a strong upward trend in protected areas in the tropical domain (from 12% in 1990 to 26.3% in 2015). However, primary forest area has declined by 2.5% globally and by 10% in the tropics over the period 1990–2015 (using data for countries that reported in all years). Given that many species in the tropics are endemic to primary forests, losses in that climatic domain continue to be of concern, although the rate of decline appears to be slowing. Using multiple regression analysis, we find that a 1% increase in protected area or area designated for biodiversity conservation within a country is associated with an increase in total forest area in that coun- try of about 0.03% (p < 0.05). A 1% within-country increase in population density and per capita GDP are associated with a decrease in forest area of about 0.2% (p < 0.01) and an increase in forest area of about 0.08% (p < 0.05) respectively. Our findings also indicate that, since FRA is used as one mechanism for tracking progress toward goals like the AICHI Biodiversity Targets, country correspondents may require additional assistance toward reporting on primary forest, protected forest, and biodiversity conservation statistics. Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction biomass and providing habitat for over half of the world’s known terrestrial plant and animal species (Shvidenko et al., 2005; Aerts Forests provide critical ecosystem goods and services such as and Honnay, 2011). food, water, shelter, and nutrient cycling among others, and play The global community has recognized the importance of forests a fundamental role in conservation of biodiversity. According with for biodiversity, and has prioritized the preservation of forest bio- recent studies, forests cover nearly 30 percent of the Earth’s land diversity and ecosystem functions through multiple multilateral area (Keenan et al., 2015), containing 80 percent of terrestrial agreements and processes. For example, the Aichi Biodiversity Targets established by the Convention on Biological Diversity (CBD) in its strategic plan include halving the rate of loss of natural habitats including forests (target 5) and conserving 17% of terres- q This article is part of a special issue entitled ‘‘Changes in Global Forest Resources from 1990 to 2015’’. trial areas through effectively and equitably managed, ecologically ⇑ Corresponding author. representative and well connected systems of protected areas (tar- E-mail address: [email protected] (E. Somanathan). get 11) (SCBD, 2006). Despite global acknowledgement of the http://dx.doi.org/10.1016/j.foreco.2015.06.011 0378-1127/Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). D. Morales-Hidalgo et al. / Forest Ecology and Management 352 (2015) 68–77 69 importance of forests, recent data show that forest area has contin- adjust their estimates as needed to bring them in line with the FAO ued to shrink (Keenan et al., 2015) as agricultural land continues to definitions [see more details about the definitions and reporting expand in 70% of countries (FAO, 2003). Deforestation is declining, process in MacDicken (2015)]. globally from 16 million ha annually in the 1990s to 13 million ha The global FRA offers one of the few, if not only, opportunities to annually between 2000 and 2010 (FAO, 2010), but the current collate and analyze data on the above metrics across a long time 0.08% rate of loss reported by Keenan et al. (2015) for the years period at a global scale. When analyzed in relation to other metrics 2010–2015 is still a matter of concern because the loss is occurring (e.g., socioeconomic data), trends in these measures of forest area in areas with particularly high ecological value. may provide insights into the factors that influence conservation Given that a majority of known terrestrial species live in forests, of forests at a broad scale and offer possibilities for improvement and 9 percent of tree species alone are currently threatened with both in forest conservation and in tracking the status of forests extinction, it is clear that achieving success in meeting the Aichi believed to be particularly important for conservation. This explo- Biodiversity Targets and Millennium Development Goals is linked ration of FRA data should reveal strengths and weaknesses in the to slowing or reversing deforestation (JLG, 2008). While the global metrics currently reported in the global assessment. community appears to agree on the importance of biological diver- sity and forest cover, quantifying progress toward meeting biodi- 2. Methods versity and forest degradation targets proves challenging. Currently, designating protected areas is one of the primary 2.1. Sources strategies for conserving biodiversity. Watson et al. (2014) discuss the increase in protected areas over the past century; however, FAO has been monitoring the world’s forests since 1946, ini- they find that many key biodiversity areas are not adequately cov- tially at 10-year intervals, and every 5 years since 2000. Since its ered by protected area status. Joppa and Pfaff (2009) reached sim- inception, FAO has produced eleven Global Forest Assessments. ilar conclusions. This paper is intended to serve as one component of the 12th glo- Beyond forests that are specifically protected, countries may bal FRA, dated 2015. recognize certain forest areas as important for the conservation The FRA provides a consistent approach to describing the of biodiversity. The Global Forest Resource Assessment (FRA) asks world’s forests and how they are changing. The assessment is countries to report on forests that are designated for conservation based on two primary sources of data: (a) Country and territory of biodiversity with the understanding that these forests may reports prepared by national correspondents and (in some cases) include those in protected areas, but may also encompass other desk studies by the FRA team and (b) remote sensing analysis con- areas. That additional forest area may contribute to meeting ducted by FAO together with national focal points and regional Aichi Biodiversity Target 11, which calls for including 17% of ter- partners. This paper excludes the remote-sensing analyses and is restrial area in protected areas and other effective area-based con- based only on the data collected for the country and territory servation measures (SCBD, 2006). reports and contained within the FRA database (available online). While forests are recognized as important for biodiversity and The FRA report compiles information from 234 countries and protected areas are doubtless important for biodiversity conserva- territories around the world. Since 2000, each participating coun- tion, not all forests are equal in terms of the diversity they support try has designated an official national correspondent who is and the quality of the ecological functions they provide. Primary charged with providing the official national statistics for their forests are globally irreplaceable with unique qualities that make country. For FRA 2015, in addition to the national reports, ancillary significant contributions to biodiversity conservation, climate data such as gross domestic product (GDP), per capita income level, change mitigation, and sustainable livelihoods (Foley et al., 2007; and population were incorporated using information from World Gibson et al., 2011), and with particular importance in tropical Bank (World Bank, 2013). For more detail regarding the methods, areas. Barlow et al. (2007) found that 25% of species in classifications and definitions used in FRA 2015 please refer to Amazonian Brazil were unique to primary forests, and almost 60 MacDicken (2015). percent of tree and liana genera were recorded only in primary for- In this paper, whenever trends and changes in areas are ests. In North America, primary forest (sometimes referred to as described, the figures include only countries and territories that ‘‘old growth’’ or ‘‘mature forest’’) is characterized by high struc- reported in all years, so as not to bias trends by including a chang- tural heterogeneity as well as biodiversity. Biodiversity in North ing set of countries. The numbers thus presented may, therefore, American primary forests often includes a wide range of lichens, not match the corresponding area reported in a given year. fungi, insects, bats, spiders, and other organisms found only in For data analysis, descriptive statistics per country, sub-region structurally complex mature forests (Spies, 2003). or climatic domain were used. In addition, multiple regression Given the global recognition of the importance of biodiversity, analysis was used to investigate the relationship between socioe- the link between biodiversity and forests, the need for protected conomic variables such as population density, per-capita GDP, areas to preserve biodiversity, and the contribution of primary for- and the impacts of conservation efforts on forest cover. ests (or structurally complex mature forests) to biodiversity within A descriptive analysis of data reliability was performance using countries, tracking those resources through time is integral to the tier system introduced by MacDicken (2015), in order to have a maintaining target goals. To this end, the Food and Agriculture better understanding of the information provided. Organization of the United Nations (FAO) includes in the FRA instrument questions requesting countries to report forest area within formally established protected areas independent of the 2.2. Examining the effects of protected area and biodiversity purpose for which the protected areas were established; forest conservation area on forest area area designated primarily for conservation of biological diversity, including but not limited to areas within protected forests; and While primary forest area is assumed to relate to biodiversity at ‘primary forest’ – naturally regenerated forests of native species, the global scale, protected area and biodiversity conservation area where there are no clearly visible indications of human activities can be thought of as measures of conservation effort. Below we and the ecological processes are not significantly disturbed. report the results of multiple regression analysis directed at exam- Countries are asked to review their national definitions for the rel- ining the impacts of these two measures of conservation effort as evant metrics in light of the definitions specified in the FRA, and to well as other variables (population density and per capita GDP) 70 D. Morales-Hidalgo et al. / Forest Ecology and Management 352 (2015) 68–77 on total forest area. The main question of interest is whether an 3. Results increase in protected and biodiversity conservation area are asso- ciated with an increase in forest area, all else remaining the same. 3.1. Global forest area We do not attempt to explain most variation in forest area, an undertaking that is beyond the scope of this article. The total global forest area reported by country in year 2015 We wish to avoid estimating spurious correlations that are was 4000 million ha, a decrease of 3% from 4128 million ha likely to arise in such cross-country data. For example, there may reported in 1990. This decrease was due to a decline of 200 mil- be a negative correlation between protected area and forest area lion ha in the tropical domain, partly offset by an increase of across countries because countries with small remaining forest 65 million ha in the temperate domain, with smaller changes in areas may expand protected areas. To deal with this, we specify boreal and sub-tropical domains. The tropical domain reported our first regression model as the highest percentage of forest area in 2015 (44% of the total), fol- lowed by the Temperate domain (26%). In terms of regions, Europe y ¼ a þ b p þ b g þ b a þ u it i 1 it 2 it 3 it it (including the Russian Federation), has the highest reported forest where i 2f1; ...; Ng denotes a country and area at 25% of the total, followed by South America (21%) and North t 2f1990; 2000; 2005; 2010; 2015g denotes a year. y; p and g America (16%). For more information regarding forest area statis- are the natural logs of forest area, population density, and GDP tics and trends, see Keenan et al. (2015). per capita at purchasing power parity in constant dollars respec- tively, a is the natural log of either Protected Area or Biodiversity 3.2. Forest designated as protected areas or for conservation of Conservation Area, and u is a random error term. ai is a ‘‘country biodiversity fixed effect’’, an unknown quantity that represents all country-specific effects on forest area that do not change over time. Protected areas in FRA 2015 were defined in accordance with We now eliminate the country fixed effects as follows. For each the IUCN definition (excluding categories V and VI) as ‘‘areas espe- country, i sum this equation over t and divide by the number of cially dedicated to the protection and maintenance of biological years to get diversity, and of natural and associated cultural resources, and managed through legal or other effective means’’. All figures y i ¼ ai þ b p i þ b g i þ b a i þ u i 1 2 3 reported in this paper include only forests in protected areas. where xi denotes the average or mean of x in country i over all years. Areas designated for conservation of biodiversity were defined as Subtracting the second equation from the first, we get ‘‘forest area designated primarily for conservation of biological diversity that includes but is not limited to areas designated for ^ ^ ^ ^ ^ yit ¼ b1pit þ b2git þ b3ait þ uit biodiversity conservation within the protected areas’’. Data on both forest included in protected areas and forest in where x^it denotes the deviation of x in year t from its mean in coun- try i. Differentiating this equation with respect to, p^ we find that areas designated for biodiversity conservation was incomplete (Fig. 1), though increasing; data on these variables are not available @y^ for all countries in all years, with a maximum of 86% reporting on ¼ b @p^ 1 forest designated for biodiversity conservation in 2010 and fewer reporting on formally protected forest (Fig. 1, left panel). so that the slope coefficient b1 is the effect of a unit change in the However, the percentage of global forest area in countries report- log of population density within a country on the log of forest area ing biodiversity conservation area was 99.6% in 2010 (right panel). in that country. This formulation makes it transparent that only Even in 1990, the year with the least reporting, more than 80% of within-country variations over time in the logs of forest area, pop- the global forest area was in countries that reported forest area ulation density, per capita income, and Protected Area or protected, and more than 88% of the global forest area was in coun- Biodiversity Conservation Area are used to estimate the slope coef- tries that reported biodiversity conservation area. Countries with ficients, b1; b2 and b3. Possible spurious correlations arising from large forest areas that did not report on forest in protected areas between-country comparisons have been removed along with the in all years, included the Democratic Republic of Congo, country-fixed effects. The estimated coefficients are reported in Australia, Peru, Mexico, Bolivia, and Venezuela. the columns labeled ‘Model 1’ in Tables 6 and 7. Variable and incomplete reporting made it difficult to compare Model 2 accounts for the possibility that a coincidence in trends between years, so we examined trends by including only data for over time in forest area and an explanatory variable may give rise countries that reported in all periods (Fig. 2; these account for to a spurious correlation even in the de-meaned variables. For 507 million ha of the total 651 million ha of protected forest example, if forest area is decreasing and protected area increasing reported for 2015). The area of forest included in protected areas over time, Model 1 will tend to produce a negative estimate of the increased considerably in all climatic domains over the 25-year per- effect of protected area on forest area. Model 2 adds a term ct to iod with most of the increase taking place prior to 2010.1 Forest in the first equation above so that the passage of time can have a (lin- protected areas, as a percentage of total forest area in the consistently ear) effect on (the log of) forest area. This allows us to de-trend the reporting countries, rose from 16% to 29% in the tropics and from 10% variables in addition to the de-meaning procedure carried out to 16% globally over the period. The largest reported percentage of for- above, and eliminates the possibility of a spurious correlation aris- est area in protected status was in the Tropics domain (Table 1). ing from coincidental global trends in forest area and the explana- There was considerable variability between sub-regions in tory variables. The coefficients from this model are reported in the reported forest area protected in relation to total forest area columns headed ‘Model 2’ in Tables 6 and 7. (Fig. 3). While forest in protected areas increased over time in all Finally, Model 3 eliminates the possibility that different trends sub-regions, Central and South America showed the greatest in each domain – tropical, subtropical, temperate and boreal – increases in protection since 1990, and South America had the rather than simply a common global trend, could bias the slope coefficients. The results are in Tables 6 and 7 in the column headed 1 In fact, protected areas increased in every FRA subregion as well. Only 15 ‘Model 3’. countries reported a decrease in protected area between 1990 and 2015, mostly of The de-meaned data were checked for outliers using the BACON small magnitude. The decline exceeded a million hectares in only one country, algorithm (Billor et al., 2000) and none were found. Botswana, although it was just under a million hectares in Mongolia and Mali. D. Morales-Hidalgo et al. / Forest Ecology and Management 352 (2015) 68–77 71
Fig. 1. Extent of country reporting to the FRA by year on total forest area, forest area in protected areas or designated for biodiversity conservation and primary forest area. Left panel: Percent of 234 countries or territories with data on the relevant variables. Right Panel: Percent of global forest area in countries or territories with data.
The increasing trends for forests in protected areas also held true for forest in areas designated for biodiversity conservation (Fig. 4). The consistently reporting countries included in Fig. 4 accounted for 427 million ha of the total 524 million ha forest area reported as designated for biodiversity conservation area for all countries in 2015. The countries reporting the greatest area desig- nated for biodiversity conservation in 2015 (Table 3) were largely the same as those reporting the greatest protected area (Table 2), with the exceptions of Mexico and Colombia.
3.3. Primary forest area
While 234 countries reported (including countries and territo- ries reports and desk studies) total forest area for all report years, the number of countries reporting primary forest area increased Fig. 2. Trends in forest area included in protected areas for each climatic domain. from 187 in 1990 to 202 in 2015 (Fig. 1). The total primary forest Countries that did not report in all years were excluded from the domain totals. The area reported by these 202 countries in 2015 was 1,277 million ha, consistently reporting countries included in the domain totals accounted for about 32% of the total forest area of all 234 reporting countries.2 The 80–81% of the global forest area in each year. Russian Federation, Canada, Brazil, the Democratic Republic of the Congo, United States, Peru and Indonesia together accounted for greatest proportion of formally protected forests of all the 75% of the global reported primary forest area in 2015 (Table 4). sub-regions (34%). Oceania reported a large increase in forest pro- Tropical countries that reported on their primary forest area in tection during the past 10 years, as well, from almost zero protec- all reporting periods from1990 to 2015, showed an overall decline tion in 1990 to 15% of forest area included in protected areas in of 62 million ha (10%; Fig. 5) between 1990 and 2015, and subtrop- 2015. Other sub-regions such as North America, Caribbean, East ical countries reported a similar proportional reduction in primary and Southern Africa, showed a more modest growth in forest pro- forest area of 5 million ha and at global scale, primary forest area, tection. The sub-regions with proportionally least protected forests experienced a net decrease of 31 million hectares (2.5%) over the in 2015 (Fig. 3) were Europe (including the Russian Federation) period 1990–2015 – about 1% per decade. These declines were with 4.6% protected forest, followed by West and Central Asia roughly in line with the rates of overall forest area loss for these (5.6%) and North America (8.6%). The countries that reported the domains (Keenan et al., 2015). The reported increases of 6 and largest designated protected forest area in 2015 (Table 2) included 30 million ha in temperate and boreal countries, respectively, are several countries excluded from the temporal trend analysis accounted for almost entirely by Russia (boreal) and the United because they did not report in all years. States (temperate) (Table 4), with the annual percent rates of increase in these countries 0.4% and 0.3%, respectively. A few coun- tries reported large percentage increases in primary forest, the lar- Table 1 Percentage of forest included in protected areas in each domain, as reported to FRA gest being Bulgaria with an annual average growth rate of over 7%, 2015 by countries. however most of this increment is related to a change in the meth- ods to assess primary forest area and change in the definitions. Climatic Protected area as percent of forest area Some countries with large areas of primary forest that did not Domain 1990 (%) 2005 (%) 2015 (%) report in all years include Venezuela and Indonesia, which Tropical 12.0 19.6 26.6 reported over 45 million ha of primary forest each in some years Sub-tropical 1.3 11.0 13.5 (Table 4), as well as Australia, the Republic of Korea, and New Temperate 6.5 10.1 11.0 Boreal 1.6 2.6 2.8 2 Total 7.7 12.8 16.3 And 32% of the total forest area of the 202 reporting countries since these countries accounted for more than 97% of the global forest area (Fig. 1, right panel). 72 D. Morales-Hidalgo et al. / Forest Ecology and Management 352 (2015) 68–77
40% 1990 2005 2015 35% 30% 25% 20% 15% 10% 5% 0% Percentage of protected forest area TOTAL Oceania East Asia Caribbean North Africa South America North America Central America West and Central Asia West and Central Africa Europe (inc Russia Fed.) East and Southern Africa South and Southeast Asia Sub-regions
Fig. 3. Change in forest area in protected areas by sub-region and over time according country data reported to FRA 2015.
Table 2 Top 15 countries reporting the largest amounts of forest included in protected areas (ordered by area in year 2015).
Country 1990 2000 2015 Area (‘000 ha) % of forest area Area (‘000 ha) % of forest area Area (‘000 ha) % of forest area Brazil 95,263 17.4 185,564 36.6 206,227 41.8 United States 19,826 6.6 28,189 9.2 32,863 10.6 Indonesia 29,862 25.2 29,855 30.5 32,211 35.4 China 4640 3.0 23,831 12.3 28,097 13.5 Congo, the Democratic Republic – 0.0 – 0.0 24,297 15.9 Venezuela, Bolivarian Republic of – 0.0 – 0.0 24,046 51.5 Canada 23,924 6.9 23,924 6.9 23,924 6.9 Australia – 0.0 17,012 13.3 21,422 17.2 Peru – 0.0 – 0.0 18,844 25.5 Russian Federation 11,815 1.5 16,488 2.0 17,667 2.2 India 12,740 19.9 15,600 23.0 16,122 22.8 Botswana 13,718 100.0 11,943 100.0 10,840 100.0 Bolivia, Plurinational State of – 20.2 10,680 21.2 10,680 22.0 Zambia 10,680 0.0 10,680 18.2 10,680 19.5 Thailand 7134 50.9 9,394 58.3 10,624 64.8
Table 3 Top 15 countries reporting area for conservation of biodiversity to the FRA report 2015 by year (ordered by year 2015).
Country FRA reporting years (area ‘000 ha) 1990 2000 2005 2010 2015 United States 60,561 60,715 60,846 65,050 64,763 Brazil 18,952 21,491 33,536 46,841 46,969 Mexico 3998 16,520 22,887 25,468 28,049 Russian Federation 21,170 25,281 25,840 26,603 26,511 Australia 16,430 18,902 21,909 26,397 Congo, the Democratic 19,600 19,600 26,314 26,314 Republic of the Venezuela, Bolivarian 15,755 15,755 15,755 24,742 Fig. 4. Trends in forest area designated for biodiversity conservation by climatic Republic of domain (countries that did not report in all years are excluded from the domain Canada 23,924 23,924 23,924 23,924 23,924 totals in this figure). The consistently reporting countries included in the domain Indonesia 19,672 19,649 19,696 21,233 21,233 totals accounted for about 88% of the global forest area in each year. Peru 4777 13,321 18,505 16,977 19,674 India 12,740 13,029 15,600 16,122 16,122 Zealand, which collectively accounted for over 10 million ha of pri- Bolivia, Plurinational State of 0 10,680 10,680 10,680 10,680 mary forest in 2010. Fig. 5 therefore, understates the total primary Zambia 10,680 10,680 10,680 10,680 forest area in each domain (in fact, by more than 90 million ha in Colombia 7199 7270 8426 9910 10,523 the tropical domain in 2010). Thailand 6726 8707 8853 8853 10,500 D. Morales-Hidalgo et al. / Forest Ecology and Management 352 (2015) 68–77 73
Table 4 The 15 countries reporting largest primary forest area (in 1000 ha) to FRA 2015 (representing 90% of the global primary forest area reported in FRA 2015).
Country Primary forest area (area ‘000 ha) 1990 2000 2005 2010 2015 % of total (2015) Cumulative,% Russian Federation 241,726 258,131 255,470 273,343 272,718 21.4 21.4 Canada 206,638 206,359 206,225 206,062 205,924 16.1 37.5 Brazil 218,240 210,466 206,578 202,691 202,691 15.9 53.4 Congo, the Democratic Republic of the 105,189 104,455 104,088 103,387 102,686 8.0 61.4 United States 70,012 72,305 75,709 75,294 75,300 5.9 67.3 Peru 69,632 67,684 67,148 66,524 65,790 5.2 72.5 Indonesia 49,453 48,310 47,167 46,024 3.6 76.1 Venezuela, Bolivarian Republic of 46,568 45,746 3.6 79.7 Bolivia, Plurinational State of 40,804 39,046 38,164 37,164 36,164 2.8 82.5 Mexico 39,443 35,303 33,826 33,168 33,056 2.6 85.1 Papua New Guinea 31,329 25,837 23,091 20,345 17,599 1.4 86.5 India 15,701 15,701 15,701 15,701 15,701 1.2 87.7 Suriname 14,986 14,742 14,590 14,422 14,019 1.1 88.8 Gabon 20,934 17,634 15,984 14,334 12,804 1.0 89.8 Mongolia 12,534 11,714 11,305 13,038 12,552 1.0 90.8
36% 1,800,000 Primary forest area
1,600,000 Total forest area
1,400,000
1,200,000 31% 1,000,000 31%
800,000
600,000 Area in 1000 ha 15% 400,000
200,000
0 Sub Tropical Boreal Template Tropical Fig. 5. Trends in primary forest area by climatic domain (Countries that did not Climatic domain report in all years are excluded from the domain totals in this figure). The consistently reporting countries included in the domain totals accounted for about 88–89% of the global forest area in each year. Fig. 6. Total and primary forest area and percentage of primary forest by climatic domain reported for all countries in year 2015 to FRA.
Fig. 6 shows the total and the primary forest area per climatic Table 5 domain in the year 2015. The tropical domain had the highest total The 15 countries reporting to FRA 2015 with the greatest loss of primary forest area between 1990 and 2015 (area ‘000 ha). area and with the highest percentage of primary forest area, fol- lowed by the template domain. The subtropic domain had the low- Country Primary % of the change % of Global est percentage of primary forest area (15%). forest area at country level primary forest Change (1990 baseline area (1990 Table 5 shows the countries that reported the largest losses of 1990–2015 year) baseline year) primary forest area over the 25-year reporting period. This table Brazil 15,549 7.1 1.3 excludes Indonesia because 1990 data were not reported for that Papua New Guinea 13,730 43.8 1.1 country. Indonesia reported a loss of primary forest of about Gabon 8130 38.8 0.7 3.4 million hectares in the period 2000–2015, the fourth-largest Mexico 6387 16.2 0.5 after Papua New Guinea, Brazil and Gabon. There was considerable Bolivia, Plurinational 4640 11.4 0.4 State of variability in the rate of loss of primary forest reported across Peru 3842 5.5 0.3 countries, with Nigeria reporting that nearly all its primary forest Guyana 3000 31.7 0.2 was lost. Congo, the Democratic 2503 2.4 0.2 Eighty-two countries also reported zero primary forest area in Republic of the all reporting years. Most of these countries and territories have Ecuador 2119 14.5 0.2 Central African 1912 49.0 0.2 only small forest areas, but some have substantial forest areas. Republic The latter include several European countries – for example Guatemala 1617 54.8 0.1 Spain (16 million ha), Germany (11 million ha), Greece, and the Nigeria 1536 98.7 0.1 UK. There were also several African countries with forest area in Suriname 967 6.5 0.1 the millions of hectares that reported zero primary forest in all Malawi 882 51.1 0.1 Canada 444 58.0 0.0 years. These included Angola with 59 million ha of forest (averaged over all years), Mozambique (40 million ha), Tanzania (50 mil- lion ha), Zambia (50 million ha), and several others. In most of least reliable level according with the Tier definitions for FRA these countries primary forest data were reported as Tier 1, the 2015 (MacDicken, 2015). 74 D. Morales-Hidalgo et al. / Forest Ecology and Management 352 (2015) 68–77
3.4. Impacts of protection, demographics, and income on forest area Table 6 Effects of protected area on forest area.
We now examine to what extent an increase in protected and Model 1 Model 2 Model 3 biodiversity conservation area are associated with an increase in Dependent variable: Log(forest area) forest area, all else remaining the same. Log(Population density) 0.180*** 0.203** 0.118 The first column of Tables 6 and 7 show the estimated slope (0.0557) (0.0939) (0.0920) ** * * coefficients for Model 1 (described in Section 2.2 above) using Log(real GDP per capita) 0.0792 0.0669 0.0666 (0.0312) (0.0377) (0.0368) Protected Area in Table 6 and Biodiversity Conservation Area in Log(Protected Area) 0.0372** 0.0338* 0.0240* 3 Table 7. Since the variables are in logs, a slope coefficient is an elas- (0.0173) (0.0175) (0.0136) ticity – the percentage change in forest area induced by a 1% change Boreal domain trend (5-year unit) 0.0333 in an explanatory variable. We see from Table 6, Model 1, that if pop- (0.0354) * ulation density were to increase by 1% in a country and the other Subtropical trend (5-year unit) 0.0219 (0.0113) variables (GDP and Protected Area) were held constant, then the Temperate trend (5-year unit) 0.00401 model implies a 0.18% decrease in forest area in that country. The (0.00732) effect of an increase in GDP on forest area is positive – a 1% increase Tropical trend (5-year unit) 0.0111 in GDP is associated with a 0.08% increase in forest area. The effect of (0.0109) Global trend (Unit = 5 years) 0.00427 an increase in Protected Area is also positive, but quite small, a 1% (0.00973) increase in Protected Area is associated with a 0.037% increase in for- Constant 6.562*** 6.751*** 6.875*** est area. In Table 7, Model 1, in which Protected Area is replaced by (0.482) (0.561) (0.570) Biodiversity Conservation Area, the results are quite similar. Observations 586 586 586 The results reported in the columns headed ‘Model 2’ in Tables R-squared 0.114 0.116 0.174 Number of countries 137 137 137 6 and 7 pertain to de-trended as well as de-meaned data. The coef- ficients on population density, GDP per capita, and Protected Area Note: All models include country fixed effects. Reported coefficients are the per- and Biodiversity Conservation Area are not very different from centage change in forest area associated with a 1% change in population density, per capita GDP, and protected area, and with a five-year change in the others. Robust those in Model 1. standard errors, clustered by country, in parentheses. As noted earlier, Model 3 eliminates the possibility that differ- *** p < 0.01. ent trends in each domain – tropical, subtropical, temperate and ** p < 0.05. * boreal – rather than simply a common global trend, could bias p < 0.1. the slope coefficients. Once again, the elasticity of forest area with respect to the different variables are quite similar to those in the Table 7 previous two models. Only in Model 3 of Table 6 does the coeffi- Effects of biodiversity conservation area on forest area. cient of population density become distinctly smaller and not sta- tistically significant at even the 10% level. However, the estimated Model 1 Model 2 Model 3 effect of population density on forest area remains quite similar Dependent Variable: Log(Forest Area) *** ** * and statistically significant even in Model 3 in Table 7 where Log(Population density) 0.242 0.256 0.223 (0.0593) (0.0996) (0.122) Biodiversity Conservation Area is used instead of Protected Area. Log(real GDP per capita) 0.0817** 0.0751** 0.0740** When these models are run after excluding boreal and temper- (0.0329) (0.0339) (0.0336) ate countries, very similar coefficients are obtained (not reported Log(Biodiversity Conservation area) 0.0292** 0.0269* 0.0232* to save space), although the smaller sample results in their being (0.0119) (0.0144) (0.0126) less statistically significant for the most part. Boreal domain trend (5-year unit) 0.00317 (0.00547) This evidence is suggestive of a positive effect of an increase in Subtropical trend (5-year unit) 0.0182 protection on total forest area, although the effect is not very large (0.0154) – a slope coefficient of 0.03 implies that a doubling of protected Temperate trend (5-year unit) 0.00472 area leads to an increase in forest area of about 2%. (0.00650) Tropical trend (5-year unit) 0.00442 A similar regression analysis was attempted to examine the (0.0138) effects of these variables on primary forest area using 99 countries Global trend (Unit = 5 years) 0.00252 for which data on all variables are available. However, variation in (0.00944) primary forest area over time is very limited – 82 countries Constant 6.490*** 6.592*** 6.656*** reported consistently zero primary forest area. Many countries also (0.528) (0.528) (0.532) Observations 664 664 664 reported no or small changes in primary forest area. R-squared 0.171 0.172 0.192 Unsurprisingly, then, the results of the econometric analysis were Number of countries 146 146 146 inconclusive. The estimated effects of the independent variables Note: All models include country fixed effects. Reported coefficients are the per- on primary forest area are not statistically different from zero. centage change in forest area associated with a 1% change in population density, per Therefore, the tables of results were not included. capita GDP, and biodiversity conservation area, and with a five-year change in the others. Robust standard errors, clustered by country, in parentheses. *** 3.5. Data reliability p < 0.01. ** p < 0.05. * p < 0.1. The FRA uses a tier rating system for countries to self-report data quality, ranging from tier 3 (data collected less than 10 years ago using National Forest Inventory or remote sensing with ground tier 1, which is designated only as ‘‘other’’ and could represent a truthing (highest quality data) to tier 2 (full cover mapping/remote respected professional opinion (MacDicken, 2015). Tiers are sensing or National Forest Inventory >10 years old) and finally to reported for both current status and for trends. Fig. 7 shows the percentage of area by tiers and categories. While 45% of countries reported using the lowest tier for forest 3 Some countries are missing in Tables 6 and 7 because they showed no variation in Protected Area or Biodiversity Conservation Area between FRA years, so they cannot area, those countries represent only 11% of total forest area. Only be used in the estimation that uses only within-country variation. 28% reported using tier 3 data, but those countries represent 59% D. Morales-Hidalgo et al. / Forest Ecology and Management 352 (2015) 68–77 75
Conservation of biodiversity
Protected forest
Primary forest
Forest
0% 10% 20% 30% 40% 50% 60% 70%
Conservation of Forest Primary forest Protected forest biodiversity Tier 3 59% 33% 34% 53% Tier 2 30% 11% 53% 24% Tier 1 11% 57% 13% 23%
% Area in each category by tier
Fig. 7. Percentage of countries reporting by tier and category and percentage of area in each category by tier. of forest area. Fifty-five percent of countries representing 57% of definition as it applied to their specific forests, and/or how coun- forest area reported using tier 1 data for primary forest, while only tries arrived at their estimates. For example, some increases in pri- 33% of area was represented by tier 3 data, suggesting that primary mary forest area over the years analyzed in this paper appeared to forest may be a less accurate variable. The largest percent of pro- result from new definitions of forest area or primary forest; other tected forest area was represented by tier 2 and 3 data, at almost increases appeared to be due to the use of new technologies 87% of reported area in those two tiers. Finally, 51% of countries (e.g.: high resolution and multispectral imagery, UAV, others) reported using tier 2 and 3 data for conservation of biodiversity, and approaches for analysis. which accounted for 77% of area in that category. Continuing loss of primary forests in both the tropics (62 M ha) and the subtropics (5 M ha) mirrors patterns of total forest area loss in those biomes. Global primary forest loss of 1 percent per 4. Discussion decade (and 4 times that in the tropics) is potential cause for con- cern. While ecologists debate the conservation value of ‘‘sec- The designation of areas specifically meant to protect forests ondary’’ versus ‘‘primary’’ forest, and differing ideas about what and for the conservation of biodiversity is one of the primary constitutes a primary forest make it difficult to assess the true mechanisms currently used to help meet biodiversity targets out- impact of these changes, some authors have attempted to assess lined in such strategic programs as the Aichi Biodiversity Targets. impacts of primary forest loss. Gibson et al. (2011) reviewed 138 Similarly, tracking primary forest area is one method of capturing studies of primary forests to determine impacts of primary forest change in forests that are assumed to be particularly important loss and/or disturbance on overall biodiversity in the tropics and ecologically. The global FRA serves as a unique instrument for found that secondary forests have demonstrably lower overall bio- tracking changes in areas that countries self-report as primary for- diversity and that disturbance effects were ‘‘essentially universal,’’ est, protected forest, or forests set aside for the conservation of leading the authors to conclude that primary forests are irreplace- biodiversity. able reserves of tropical biodiversity. In many cases, the persis- Our study showed a loss of 128 M ha of total global forest area tence of threatened and endangered species appears to be from 1990 to 2015, with the majority of that occurring in the trop- dependent upon the availability of intact primary forest. For exam- ics. Both FRA and Hansen et al. (2013) show that global forest loss ple, Gregory et al. (2012) found that orangutan population size was is highest in the tropical domain, an area with high biological bio- heavily influenced by the degradation of primary forests, and esti- diversity and increasing concern over forest protection. Global for- mated a reduction in orangutan populations of 40–80 percent est area change and further comparisons with other datasets is without measures toward protection of these forests. There is some further explored in this special issue by Keenan et al. (2015). hope, as tropical primary forest loss appears to be slowing over In FRA 2015, primary forest area was defined as: ‘‘naturally time. Additionally, the lack of complete country reporting may regenerated forest of native species where there are no clearly vis- underestimate the total amount of global primary forest, and ible indications of human activities and the ecological processes may impact overall global trends. are not significantly disturbed. Key characteristics include: they Our results were similar to those reported by Mackey et al. show natural forest dynamics, such as natural tree species compo- (2014) in that almost 98% of primary forest was found within 25 sition, occurrence of dead wood, natural age structure, and natural countries, where half of this percentage belong to developed coun- regeneration processes; the area is large enough to maintain its tries (Russian Federation, Canada, USA, Australia, Japan, Republic of natural characteristics; there has been no known significant Korea). We also found that a large proportion of primary forest human intervention or the last significant human intervention (75%) reported by countries was contained within 7 countries, was long enough ago to have allowed the natural species composi- including Indonesia. Indonesia alone reported a 3.4 M ha loss of tion and processes to have become re-established’’. However, there primary forest from 2000 to 2015, which is half the 6 M ha appeared to be some variability in how countries interpreted the Landsat-derived primary forest loss estimate for Indonesia 76 D. Morales-Hidalgo et al. / Forest Ecology and Management 352 (2015) 68–77 reported by Margono et al. (2014). In this particular case, Indonesia showed that protected areas experienced deforestation due to agri- reports that their primary forest variable for FRA 2015 was derived cultural expansion, human population growth, and infrastructure using the highest FRA tier rating, implying that the variable was development, along with economic activities outside of forests, determined from a national forest inventory sample or remotely and that reforestation was more common in community forests sensed data coupled with ground truthing. While some of the dis- (Porter-Bolland et al., 2012). Other studies similarly report that crepancy between the 3.4 M ha reported to FRA and the 6 M ha protected areas may not be successful at preventing deforestation derived from landsat is certainly methodological or definitional (Andam et al., 2008; Nagendra, 2008; DeFries et al., 2005). and hinders direct correlation between the two, it’s clear from both Tittensor et al. (2014) project based on current trends that pro- that Indonesia is losing primary forest at an alarming rate. Kessler tected areas will increase significantly by 2020, meeting terrestrial et al. (2005) reported distinct declines in species richness of both Aichi Targets (which includes forests). However, they also note vegetation and wildlife when Indonesian forests were converted that declared protection does not always mean adequate from primary states to other forested states, suggesting that bio- protection. logically, even if the loss of primary forest is not a loss of forest Human population pressure has long been understood as one of cover in general, in Indonesia it represents a distinct loss of many drivers in the conversion of natural habitats to other land biodiversity. uses. We found that increases in population density within coun- Protected area establishment and setting forest area aside for tries are negatively associated with increases in forest area while biological diversity conservation are two ways in which both glo- per capita income shows a positive association. This is the case bal forest area losses and loss of primary forest can be slowed or globally and also in the subsample of tropical and sub-tropical reversed and/or important functions and resources within forests countries. This is broadly consistent with DeFries et al. (2010)’s can be maintained. Interestingly, though primary forest area is finding that urban population density and agricultural exports declining we found that, in countries that report regularly, forests were correlated with deforestation measured using satellite data in protected areas have increased. The increase in protected areas between 2000 and 2005 in a sample of tropical countries (although was highest in the tropics, where – as noted above – primary forest this study uses between, rather than within-country comparisons). area loss is highest. Inconsistent reporting rates across years Mills Busa (2013) notes that high-income countries import more severely limit the ability to report on and draw meaningful conclu- wood than do countries with lower GDP, suggesting that ‘‘rich sions from trends in protected forests and forest set aside for bio- countries practice preservation within borders but appropriate logical conservation. For example, only 77 percent of the forest resources from poorer countries to sustain consumption’’ leading area reported as protected in FRA 2015 could be examined in this her to the conclusion that consumption reduction is as important paper in terms of trends. a strategy as forest protection. Meyfroidt et al. (2010) also note Forest area set aside to conserve biodiversity also grew in all that countries that experience increased forest cover have often domains with the highest increases in the tropics. This begs the redistributed their resource use to other countries; i.e., exploita- question of whether high-productivity primary forests are being tion of resources elsewhere is facilitating reforestation locally. protected at the same rate as secondary forests. Indeed, Indonesia – the country with the largest primary forest loss Our analysis found that increases in protected area and in bio- as mentioned earlier – is among the countries absorbing the dis- diversity conservation area within countries are associated with placed agricultural demand from countries experiencing reforesta- increases in forest area but the effect is not large. These relations tion (Meyfroidt et al., 2010). persist in the smaller sample of tropical and sub-tropical countries, Among studies that used only within-country variation, Scrieciu more strongly in the case of biodiversity conservation area which is (2007) and Culas (2007) failed to find statistically significant reported by more countries. It is possible that the beneficial effect effects of income and population density on deforestation, but of protection could to some extent be masked in the data by spurts were limited by having data on fewer countries over a shorter time of deforestation leading to an increase in protected area. It could span in the late 20th century. In the Democratic Republic of the also be true that countries that increased protection simultane- Congo, forest loss intensity was associated with areas of high pop- ously adopted other policies to reduce deforestation, so that the ulation density (Potapov et al., 2012). estimated effect of protection could also be overstated. Andam Drawing meaningful conclusions from the FRA data requires an et al. (2008) found that from the 1960s to the 1990s, deforestation assessment of the quality and credibility of data at such a large in Costa Rica was decreased as a result of protected areas, but that scale. While many countries used tier 1 data in reporting, most the impact of protected areas on deforestation had previously been of the area represented in each category was covered by tier 2 overestimated (by as much as 65 percent). Wendland et al. (2015) and 3 data, suggesting that data quality comes from fairly reliable found that protected areas in European Russia had little impact on sources, overall. The exception seems to be primary forest, which rates of forest disturbance. This may be somewhat unsurprising, may be a reflection of the difficulty in applying the definition of given that the Millennium Ecosystem Assessment (2005) reported primary forests in each country. Assessment of the impact of tier that many protected forest areas are specifically situated because 1 data on the overall quality of the results of our study is infeasible they are unsuitable for other use by humans. Despite the afore- given that there is little or nothing with which to compare the data mentioned limitations in their effectiveness, the increase in pro- reported for countries using tier 1 information. tected forest area and forests designated for biodiversity Additional challenges exist in analyzing trends in primary for- conservation is encouraging, particularly given that the largest est, protected area, and area set aside for conservation of biodiver- increase in protected areas was in the tropical domain where total sity. First, country response rates are variable, both among years global forest loss is highest. and among countries, limiting the types of analyses that we were In the Democratic Republic of the Congo, forest cover loss able to conduct as well as the sensitivity of our analyses. Second, within protected areas was more than two times lower than the we noted that challenges exist in the harmonization of country national average, but forest cover loss still increased by 64% data to FRA definitions, suggesting that additional conversations between 2000–2005 and 2005–2010 in protected areas (Potapov may be necessary amongst national correspondents to FRA as et al., 2012). In a meta-analysis of published case studies assessing regards some variables, particularly primary forest. The overall tropical forest cover change, Porter-Bolland et al. (2012) found that findings of our study suggest that, while some progress has been community managed forests resulted in lower deforestation rates made in the protection of forests at the global scale in that last in the tropics than the declaration of protected forests. Their study 25 years, and while tropical countries are increasingly protecting D. Morales-Hidalgo et al. / Forest Ecology and Management 352 (2015) 68–77 77 forests, primary forests of ecological significance in the tropical Chini, Justice, C.O., Townshend, J.R.G., 2013. High-resolution global maps of domain are still declining. The decline is decreasing, however, 21st-century forest cover change. Science 342 (6160), 850–853. http:// dx.doi.org/10.1126/science.1244693. which allows for some optimism as global conversations and Joint Liaison Group of the Rio Conventions (JLG), 2008. Forests: CLIMATE CHANGE, awareness continue. Our findings also indicate that, if FRA is to BIODIVERSITY and Land Degradation.
Contents lists available at ScienceDirect
Forest Ecology and Management
journal homepage: www.elsevier.com/locate/foreco
Global forest area disturbance from fire, insect pests, diseases and severe weather events q ⇑ Pieter van Lierop a, , Erik Lindquist a, Shiroma Sathyapala a, Gianluca Franceschini b a Forestry Department, Food and Agriculture Organization, Rome, Italy b Natural Resources Department, Food and Agriculture Organization, Rome, Italy article info abstract
Article history: Reliable global data on forest degradation and disturbances due to fire, insect pests, diseases and severe Received 10 March 2015 weather are important to understand ecosystem health and condition, safeguard production of goods and Received in revised form 5 June 2015 services and avoid negative impacts on human livelihoods. This paper presents a global analysis of forest Accepted 8 June 2015 area affected by fire, significant insect pest outbreaks, diseases and severe weather reported by countries Available online 7 September 2015 as part of the Global Forest Resources Assessment 2015. Between 2003 and 2012, approximately 67 mil- lion hectares (1.7%) of forest land burned annually, mostly in tropical South America and Africa. In a sim- Keywords: ilar reporting period, in total 142 million hectares of forest land were affected by other disturbances than Forest disturbances fire. Insect pests affected more than 85 million hectares of forest, of which a major part was in temperate Fire Insect pests North America. Severe weather disturbed over 38 million hectares, mostly in Asia. About 12.5 million Weather events hectares were reported to be disturbed by diseases, mostly in Asia and Europe. There were strong corre- Partial canopy cover reduction lations between burned forest area and the area of partial canopy cover reduction, as well as between burned forest area and net forest loss. Partial canopy cover reduction is used as a proxy for forest degra- dation, although it also includes land under management that is not degraded. A decreasing trend in burned forest area was found, largely accounted for by decreased area burned within the last ten years in tropical South America. However, an increasing trend in burned forest area was found in the boreal climatic domain. The data on other disturbances was not suitable for determining any year on year cor- relations and should be improved in future data collection exercises. Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction destroyed nearly 80% of staple crops within a province. Chambers et al. (2007), using data from moderate spatial resolu- Forest disturbances are the environmental fluctuations and tion satellites, estimated that damage caused to forest land in the destructive events that disturb forest health and/or structure United States from hurricane Katrina in 2006 resulted in carbon and/or change the resources or the physical environment at any emissions to the atmosphere of between 50% and 140% the annual spatial or temporal scale (FAO, 2005). Disturbances caused by net carbon sink of all forests in the country. agents such as fire, insect pests, diseases and severe weather are Forest disturbance, deforestation due to land use change and important influences on forest ecosystems. climate change are interrelated and compound one another (Dale Under normal circumstances, in healthy forests, disturbances et al., 2001). Cochrane and Laurence (2008) describe how new by insect pests and diseases are an integral part of the forest deforestation due to land use change in the Amazon can lead to ecosystem (Dajoz, 2000). However, catastrophic disturbances can cascading effects including increased flammability of forests, have undesired impacts on forest ecosystems and can affect envi- increased burned area and more destructive fires. Climate change ronmental functions, with consequences for biodiversity and liveli- could have wide-ranging detrimental effects on the distribution hoods (Schowalter, 2012) and climate change impacts. Cochrane and severity of forest insect and disease outbreaks; Ayres and and Barber (2009), for example, describe incidence of catastrophic Lombardero (2000) estimate that in the United States these could wildfire in Brazil during the El Niño years of 1997–1998 that result in economic losses of over USD 1 billion annually. Accurate assessment of the size and scope of forest disturbances other than complete overstorey removal is therefore critical for monitoring q This article is part of a special issue entitled ‘‘Changes in Global Forest Resources from 1990 to 2015’’. the Earth’s natural systems, especially in the face of a changing glo- ⇑ Corresponding author. bal climate (van der Werf et al., 2009). E-mail address: [email protected] (P. van Lierop). http://dx.doi.org/10.1016/j.foreco.2015.06.010 0378-1127/Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). P. van Lierop et al. / Forest Ecology and Management 352 (2015) 78–88 79
To assess the state and trend of forest disturbance globally, the requested specifically for these years because they are by nature Food and Agriculture Organization of the United Nations (FAO) has episodic. Countries were asked to report annual figures for number sought to aggregate information on forest disturbances in its peri- of fires and area burned from 2003 to 2012. The area of forest odic Global Forest Resources Assessment (FRA). FRA 2000 (FAO, affected by insects, diseases and severe weather was reported 2001) revealed a lack of national data sources capable of generat- non-systematically according to the year the disturbance was ing global estimates of land and forest area burned. FRA 2005 detected. The area of forest with reduced canopy cover was calcu- (FAO, 2007) provided data on global and regional areas burned lated on an annual basis, but annual figures were summed to pro- based on 12 regional working papers prepared within the Global duce a single statistic representing the total area affected between Wildland Fire Network of the United Nations International 2000 and 2010. Strategy for Disaster Reduction (UNISDR). In FRA 2010, FAO National reporting of burned area and PCCR was supplemented attempted to quantify the impacts of many factors that affect the through the use of remote-sensing data (see Section 2.2). health and vitality of forests by collecting data on the impact of fire Remote-sensing based values for total burned area, burned forest together with insect pests and diseases and other biotic and abiotic area and PCCR were provided to the countries as pre-filled vari- factors. ables, and country experts were asked to accept, reject or modify Early attempts to assemble global-level information on forest the supplied area estimates with better quality, nationally derived insect pests and diseases included several international meetings data where available (MacDicken, 2015). This was done in an held in the 1960s and 1970s (e.g. FAO, 1965, 1976), but since then attempt to make global estimates of burned area more consistent. most of the information available at the global level has been pest PCCR was summed for all the years between 2000 and 2012. Thus specific. As part of FRA 2005, FAO asked countries to report on area there is no time series of estimates to determine changes in rates affected by insect pests, diseases and other disturbances. This or locations of PCCR. information was supplemented by a thematic study reviewing for- est pests in 25 countries (FAO, 2009). In FRA 2010, countries were 2.2. Derivation of pre-filled data for burned area again asked to report on the impact of insect pests and diseases. However, most countries were unable to provide reliable quantita- Burned area estimates for FRA 2015 were derived from the tive information because they did not systematically monitor these Moderate Resolution Imaging Spectroradiometer (MODIS) disturbances or had limited access to data (FAO, 2011). FRA 2015 Collection 5 Burned Area product (MCD45A1) (Roy et al., 2008) dis- responded by modifying the data request to indicate significant tributed as part of the MODIS fire products suite (Justice et al., outbreaks only. This resulted in more precise reporting of impor- 2002). The MODIS sensor is aboard the AQUA and TERRA satellite tant disturbance than in previous years. platforms and is capable of imaging nearly the entire Earth’s sur- This paper updates the state of knowledge on global forest dis- face daily with a pixel size of up to 250 m. The algorithm for map- turbances from fire, insects, diseases and severe weather. It analy- ping burned areas is based on the spectral, temporal and structural ses the status and trend of these various disturbance agents and changes that characterize the land surface after a fire occurs (Roy events as reported by countries for FRA 2015. Total land area et al., 2005). It detects the approximate date of burning at 500 m burned annually is included, but the analysis and discussion by locating the occurrence of rapid changes over a long time series focuses, as much as possible, specifically on disturbed forest area. of daily land-surface reflectance observations. First presented are the aggregated results of the areal extent of for- Estimates of burned forest area were obtained by spatially est disturbances globally, by broad climatic domain and by region. intersecting the burned area with forest area. Forest areas were The article describes the trend in burned forest area over time and determined using Collection 4, Version 3 (Hansen et al., 2006)of compares the amount of forest area burned with net deforestation. the MODIS Vegetation Continuous Fields (VCF) product Further, a new disturbance-related variable in FRA 2015, called (MOD44B) (Hansen et al., 2003). The VCF product is a globally con- partial canopy cover reduction (PCCR), is introduced and analyzed sistent depiction of per-pixel percent cover for three types of veg- as a proxy indicator of forest degradation. PCCR is summarized by etative cover – woody vegetation, herbaceous vegetation and bare climatic domain and region and related with burned forest area ground – with a pixel size (spatial resolution) of 250 Â 250 m. VCF and net forest loss for each. data have been produced annually since 2000. Forest was distin- guished from non-forest by applying a 30% threshold to the contin- uous VCF values for woody vegetation. Values of less than 30% 2. Data and methods were considered non-forest, and those of 30% or greater were con- sidered forest. It should be noted that this threshold is different 2.1. The Global Forest Resources Assessment than the 10% used for FRA 2015 and that the MODIS definition of woody vegetation includes areas that are not forest using the The results presented in this paper are based on data from FRA FRA forest definition. 2015. FRA relies on responses to a standardized questionnaire sub- mitted by countries through a network of official national corre- 2.3. Derivation of pre-filled data for partial canopy cover reduction spondents. For the history and details of the FRA reporting process see MacDicken (2015). National correspondents were Partial canopy cover reduction (PCCR) was defined as a detect- asked to respond to questions in the following six categories relat- able modification of canopy cover, at the 250 Â 250 m MODIS pixel ing to the type, number and areal extent of forest disturbances in size, that resulted in a partial loss of tree cover relative to a prede- their countries: number of fires per year; total land and forest area termined reference time period, in this case the year 2000. Partial burned per year; area affected by insect outbreaks; area affected by loss was determined on the basis of a change in per-pixel percent disease outbreaks; area affected by severe weather events; and tree canopy cover as estimated from the annual VCF time series. area of forest with reduced canopy cover. Where possible, coun- Pixels with PCCR between 2000 and 2012 were identified using tries were asked to report on specific types of pests, diseases and three main criteria: an initial VCF value greater than 30%; an over- weather disturbances as well as on the species or forest type all decrease in percent canopy cover greater than 20% between affected. 2000 and 2012; and a negative slope (>À1) of the line formed by The target reporting years for FRA 2015 were 1990, 2000, 2005, the linear regression of the VCF percent tree cover over the period 2010 and 2015. Disturbance variables, however, were not from 2000 to 2012. Pixels where VCF values dropped and stayed 80 P. van Lierop et al. / Forest Ecology and Management 352 (2015) 78–88
Table 1 Absolute area calculations with MODIS pixels are prone to sys- Land and forest areas burned globally, 2003–2012. tematic over- or underestimation, because the MODIS pixel size of Year Burned %of Burned Burned Total %of 6.25 ha is a limitation to detecting truly fine-scale change. Much land land forest forest as % forest total change due to PCCR will take place at a scale not detectable by (000 ha) burned (000 ha) of burned (000 ha) forest the MODIS pixel unless the change is of a large, diffuse nature. A land burned single MODIS pixel flagged as PCCR can contain either large, diffuse 2003 355300 2.8 68592 19.3 4042531 1.7 partial canopy cover loss or areas of complete tree cover removal 2004 384798 3.0 75636 19.7 4038801 1.9 within a matrix of dense tree cover (e.g. smallholder clearing for 2005 369817 2.9 78497 21.2 4035072 1.9 2006 337990 2.6 64250 19.0 4031342 1.6 agriculture in an otherwise forested pixel). These clearings, at a 2007 381897 3.0 84965 22.2 4027613 2.1 finer scale of analysis, may meet the definition of deforestation. 2008 322705 2.5 56820 17.6 4023883 1.4 Researchers are currently exploring the potential of high spatial 2009 308935 2.4 53728 17.4 4020154 1.3 resolution satellite data for measuring and monitoring forest 2010 325229 2.5 65225 20.1 4016424 1.6 2011 322228 2.5 55479 17.2 4012695 1.4 degradation, but this effort is largely in its early phases (Gascon 2012 297137 2.3 63141 21.2 4008965 1.6 and Eva, 2014; GFOI, 2013). Average 340604 66633
Note: Total land area for all years: 12 908 461 (000 ha). It should be noted that in 2.4. Analysis of variables the case of repeated fires on the same area, it has been accounted for each time. The areal extent of forest disturbances was summarized glob- ally and by smaller geographic region including climatic domain, below the threshold that defines forest (e.g. 10%) were considered geographic region and income category. Climatic domains were deforestation and removed from the analysis. Pixels within the delineated into four global ecological zones: boreal, temperate, bounds of an intact forest landscape (Potapov et al., 2008)or subtropical and tropical (FAO, 2012; MacDicken, 2015). If a coun- wetland (Carroll et al., 2009) were also eliminated from the try’s national boundaries, as defined by the Global Administrative analysis. Unit Layers (GAUL) (FAO, 2008), encompassed more than one cli- matic domain, the country was assigned to the domain occupied by the largest part of the country’s forest area. Countries were also 2.3.1. Limitations to the method for calculating PCCR divided into five regions defined in the FRA process and into low, Forest degradation is a term that suffers from many disparate medium–low, medium–high and high-income categories accord- definitions that are often stakeholder dependent (FAO, 2011). ing to the World Bank income-group classification. Income cate- Finding a single indicator that serves each of these definitions gories are defined by gross national income per capita per year: requires a generic approach. FRA 2015 chose a proxy variable of low (USD 1045 or less), lower middle (USD 1046–4125), upper partial canopy cover reduction (PCCR) to estimate such a proxy. middle (USD 4126–12 745) and high (USD 12 746 or more) Detecting PCCR from remotely sensed data, especially with the (MacDicken, 2015). most commonly used forms of medium spatial resolution data, is difficult because forest canopy change almost always takes place at sub-pixel resolution scale when MODIS-sized pixels are used 2.5. Missing data in the analysis. That is to say that the nature of canopy cover change affects areas smaller than the detection capability of the A few very large forested countries (Australia, Brazil and India) remotely sensed pixel. The methods described here can best be did not provide annual estimates of burned area for all years. considered a ‘‘hot-spot’’ approach to the detection of partial Without these countries included, the burned area analysis would canopy cover removal. be incomplete for the purposes of this paper. Accordingly, data for the missing years were imputed from the available values in the annual records of these countries. The area of burned forest for Burned Land and Forest, 2003 - 2012 missing years was calculated using the average percentage forest 450 000 burned obtained from the data reported by the country. 400 000 Brazil reported burned area directly for 2005–2010. The burned area reported by Brazil was between 3 and 16 times greater than 350 000 the MODIS burned area product. The reason for this discrepancy is not known; it may be attributable to a large burned area under 300 000 y = -8,065.18x + 16,531,443.93 R² = 0.63 dense tree canopy which may go undetected by the MODIS burned 250 000 area algorithm (Giglio et al., 2006). The reported burned area, how- ever, exhibited a high correlation (R2 = 0.71) with the number of Area 200 000 fires detected by the MODIS sensor and published by the 150 000 y = -1,916.54x + 3,914,086.13 Instituto Nacional de Pesquisas Espaciais (INPE, 2015). The burned R² = 0.31 area for the years that were not reported directly were imputed by 100 000 using the equation formed by the linear regression of number of 50 000 fires and burned area for the years directly reported. Australia reported burned area annually for 2006–2011. The 00 000 2 2003 2005 2007 2009 2011 reported burned area exhibited a very high correlation (R = 0.99) Year with the MODIS-derived pre-filled values for those years. Thus, Total Burned Land (000 ha) the FRA pre-filled values were used for the years not directly reported by Australia. Burned Forest (000 ha) India supplied no burned area values for any years in its report to FRA 2015. Values for India’s annual burned land and forest area Fig. 1. Total area of burned land and burned forest from 2003 to 2012. The linear trend over time is shown as a solid black line. The equation describing the line and were taken directly from the FRA pre-filled values as these were the goodness of fit (R2) are shown. the best available information. P. van Lierop et al. / Forest Ecology and Management 352 (2015) 78–88 81
Table 2 Forest area, burned forest and proportion burned forest by climatic domain, 2003–2012.
Year Tropical Subtropical Temperate Boreal
Forest Burned %of Forest Burned %of Forest Burned %of Forest Burned %of area forest forest area forest forest area forest forest area forest forest (000 ha) (000 ha) burned (000 ha) (000 ha) burned (000 ha) (000 ha) burned (000 ha) (000 ha) burned 2003 1854869 57577 3 324237 4949 2 648037 2235 0.3 1219710 4056 0.3 2004 1847336 59509 3 323807 8556 3 651328 3874 0.6 1220168 3729 0.3 2005 1830799 67753 4 323912 4248 1 659176 4140 0.6 1218855 2519 0.2 2006 1832271 44877 2 322949 8854 3 657910 6682 1.0 1221084 3760 0.3 2007 1824739 71138 4 322519 6913 2 661200 4303 0.7 1221542 2582 0.2 2008 1817206 44729 2 322090 6041 2 664491 2204 0.3 1222000 3800 0.3 2009 1809674 36278 2 321660 10545 3 667782 3966 0.6 1222458 2895 0.2 2010 1797758 56045 3 319613 2751 1 673429 1361 0.2 1224873 5084 0.4 2011 1794609 42547 2 320802 8752 3 674364 2060 0.3 1223374 3844 0.3 2012 1787077 50655 3 320372 8045 3 677655 2115 0.3 1223832 4106 0.3
Burned Forest Area by Climatic Domain, 2003-2012 countries, representing >90% of the total land area and >99% of 80 000 the world’s total forest area, reported burned area. Only 75 countries reported on the areal extent of disturbances 70 000 from insect pests, diseases or severe weather. In total, these 75 60 000 countries represented 70% of the total global forest area. PCCR val- 50 000 ues of >0 were found in 133 countries and territories, of which 29% were desk studies and were not subject to review by national 40 000 authorities. 30 000 y = -1,768.33x + 3,603,037.18 20 000 R² = 0.22 3.2. Land area and forest area burned Area ('000 hectares) 10 000 3.2.1. Land area and forest area burned globally 00 000 The results over the ten-year period from 2003 to 2012 indicate 2003 2005 2007 2009 2011 2013 that an average of 341 million hectares, or 2.6% of all land area, was Year burned annually (Table 1). This is in line with the estimate by Boreal Temperate Chatenoux and Peduzzi (2013) of 327 million to 391 million hec- Sub Tropical Tropical tares per year from 2000 to 2011 based on SPOT (Satellite Pour l’Observation de la Terre) Vegetation satellite sensors and Fig. 2. Annual burned forest area by climatic domain, 2003–2012. The linear trend MODIS; the 350 million hectares estimated for the year 2000 by over time is shown for the tropical domain as a solid black line. The equation describing the line and the goodness of fit (R2) are shown. the Joint Research Centre of the European Commission, based on MODIS products (JRC, 2005); and the estimate by Roy et al. Annual forest area figures used in burned area analyses were (2008) of 280 million to 290 million hectares for the first consecu- taken from Keenan et al. (2015) for the nominal FRA reporting tive 12 months (2001–2002) of the MODIS global burned area years. Forest area for years not reported in FRA was imputed lin- product. early and separately at the global, regional and climatic domain In the same time period, an average of about 67 million hectares levels. These are the best estimates available for the missing years; or 1.7% of forest land burned each year (Table 1). About 20% of all however, they will not sum correctly and are subject to rounding. area burned annually was in forests as compared with 80% outside Significance of the trend in burned forest area over time was forests. assessed using the Mann–Kendall test for monotonic trend in Total land area burned over the 10 years analyzed in this paper time-series data. Significance was tested at each level of aggrega- exhibits a variable but decreasing trend (Fig. 1). This result is sim- tion twice, once with raw data and a second time with values ilar to findings reported by Giglio et al. (2010), who used a combi- smoothed by applying a moving average. Statistical tests were per- nation of moderate and coarse resolution satellite imagery sources formed using the statistical software R (R Core Team, 2014) and the to analyze trends and variability in burned area globally from 1996 ‘rkt’ package (Marchetto, 2015). to 2009. The amount of forest area burned is also decreasing annu- The availability of quantitative data for insect pests, diseases ally, but at a lesser rate than total land area. and severe weather events was limited – although this can indicate either a lack of data or a lack of significant disturbance. The aggre- 3.2.2. Land area and forest area burned by climatic domain gated data on insect pests, diseases and severe weather events are By climatic domain, the largest area of land and forest burned based on latest occurrence so they refer to different reporting years was in the tropics, where more than 290 million hectares of land and sometimes to multiple years (e.g. intervals). Thus it was only burned annually (between 79% and 91% of total global burned possible to summarize all incidences, for any year and for any kind area). Of the total area burned in the tropics, over 53 million hec- of insect pest, diseases or severe weather event. tares were in forest land (Table 2). In the subtropical domain, nearly 33 million hectares of land burned each year, of which 3. Results approximately 7 million hectares were forest land. The temperate and boreal domains accounted for nearly 15 million hectares of 3.1. Countries reporting land burned, of which approximately 7 million hectares were for- est land. In total, 155 country reports were examined for disturbance The highest proportion of forest area burned was also in the from fire, pests, disease and severe weather. Of these, over 140 tropics, where almost 3% of forest burned annually during the 82 .vnLeo ta./Frs clg n aaeet32(05 78–88 (2015) 352 Management and Ecology Forest / al. et Lierop van P.
Table 3 Forest area, burned forest and proportion burned forest by region, 2003–2012.
Year Africa Asia Europe North and Central America Oceania South America Forest Burned %of Forest Burned %of Forest Burned %of Forest Burned %of Forest Burned %of Forest Burned area forest forest area forest %of forest area forest forest area forest forest area (000 ha) (000 ha) forest forest area forest forest burned (000 ha) (000 ha) burned (000 ha) (000 ha) burned (000 ha) (000 ha) burned (000 ha) (000 ha) burned (000 ha) (000 ha) burned 2003 660827 18658 3 574207 1093 0.2 1004469 3039 0.6 748586 3660 0.5 186428 4177 2 878054 38190 4 2004 657723 16321 2 576025 1342 0.2 1005448 1251 0.1 748758 6365 0.9 186091 8270 4 874796 42120 5 2005 654679 15449 2 580868 2813 0.5 1004147 1727 0.2 747953 5450 0.7 176485 3436 2 868611 49785 6 2006 651515 18383 3 579660 1279 0.2 1007407 4207 0.4 749102 6038 0.8 185418 8472 5 868280 25794 3 2007 648411 21205 3 581478 2216 0.4 1008386 2080 0.2 749274 5013 0.7 185081 6663 4 865022 47758 6 2008 645307 17186 3 583296 2270 0.4 1009365 2595 0.3 749446 3415 0.5 184745 5826 3 861764 25484 3 2009 642203 14503 2 585114 1078 0.2 1010345 3975 0.4 749618 2970 0.4 184408 10236 6 858506 20921 2 2010 638282 18986 3 589406 1377 0.2 1013572 2614 0.3 750278 3892 0.5 172002 2557 1 852133 35815 4 2011 635995 14929 2 588749 0502 0.1 1012303 1710 0.2 749963 4324 0.6 183735 8494 5 851990 27243 3 2012 632891 14290 2 590567 0612 0.1 1013283 2659 0.3 750135 3833 0.5 183398 7679 4 848732 35848 4 P. van Lierop et al. / Forest Ecology and Management 352 (2015) 78–88 83
Burned Forest Area by Region, 2003-2012 3.2.4. Land and forest area burned by income category 60 000 The largest area of land and forest burned annually was in coun- tries in the upper-middle income category, 123 million hectares y = -1,405.80x + 2,857,045.25 and 40 million hectares, respectively (Table 4). The low-income 50 000 R² = 0.19 countries had the next largest area of land burned annually, or 101 million hectares, but a smaller proportion was forest land, 40 000 approximately 11 million hectares. High-income countries reported 38 million hectares of land burned annually, of which 30 000 approximately 13 million hectares were forest land. High-income and low-income countries on average had similar 20 000 amounts of forest area burned. However, the low-income countries
Area ('000 hectares) have far less forest area (Keenan et al., 2015), so they have a much 10 000 higher proportion of their forest area burned, and non-forest land constitutes a far greater proportion of area burned in low-income 00 000 countries than in high-income countries (90% versus 61%). 2003 2005 2007 2009 2011 Year Decreasing trends in forest area burned are observed in nearly all income categories, with the strongest seen in the upper Africa North and Central America middle-income category (Fig. 4). Low and lower middle-income Asia Oceania categories showed slight decreasing trends in forest area burned Europe South America as well. The high-income category did not exhibit a strong trend.
Fig. 3. Annual burned forest area by region, 2003–2012. The linear trend over time is shown for South America as a solid black line. The equation describing the line 3.2.5. Significance of trends in burned area and burned forest area 2 and the goodness of fit (R ) are shown. To assess the significance of the trend in burned area and burned forest area over time, the Mann–Kendall test for monotonic trend in time-series data was applied at each aggregation level. period (Table 2). At the same time 2% of subtropical forests burned When all observations were considered independently, the tropical annually and less than 1% of temperate and boreal forests. The domain exhibited a significantly negative trend in total burned tropical domain shows a decreasing trend in forest area burned. land area. The African region also exhibited a significantly negative The subtropical, temperate and boreal domains, however, do not trend in total burned land area. No climatic domain or region show any definite trend (Fig. 2). exhibited a significant trend in burned forest area. By income group, lower-middle and lower income groups showed signifi- 3.2.3. Land and forest burned by region cantly decreasing trends in total land area burned. No income The largest area of land burned was in Africa: over 213 million group had significant trends, positive or negative, in burned forest hectares annually. Of this amount, nearly 17 million hectares of area (Table 5). forest land burned each year (Table 3). In South America, an aver- Trends in burned land and burned forest area were examined a age of 72 million hectares of land area burned each year, of which second time, but with moving averages applied at 3 or 4-year 35 million hectares were forest land. Oceania reported 31 million intervals to smooth the trend over time. When the Mann– hectares of land burned annually, of which approximately 7 mil- Kendall test was applied to these data, significant declines in total lion hectares were forest land. Asia had approximately 17 million area burned were again found in the tropical domain but also in hectares of burned land per year, of which less than 2 million hec- the temperate domain. Regional total area burned significantly tares were forest land. Nearly all of the land burned in North and decreased in Africa, Asia and South America. Burned forest area Central America (total 5 million hectares) and Europe (total 3 mil- exhibited significant declines in the tropical and temperate lion hectares) was forest land. domains and a significant increase in the boreal domain. Only At the regional level, annual burned forest area was variable. South America exhibited a significant trend, declining, in forest However, a few regions show signs of a noticeable trend. A definite area burned at the regional level. By income group, the decreasing trend in forest area burned is noticeable in South upper-middle, lower-middle and lower groups exhibited a signifi- America (Fig. 3). A slight decreasing trend in forest area burned cant decreasing trend in total land area burned. Only the is detectable in Africa. Other regions show no clear trend in burned upper-middle income group showed a significant trend, decreas- forest area. ing, in forest area burned (Table 5).
Table 4 Forest area, burned forest and proportion of forest burned by income category, 2003–2012.
Year High Upper middle Lower middle Low Forest Burned %of Forest Burned %of Forest Burned %of Forest Burned %of area forest forest area forest forest area forest forest area forest forest (000 ha) (000 ha) burned (000 ha) (000 ha) burned (000 ha) (000 ha) burned (000 ha) (000 ha) burned 2003 1818541 10642 0.6 1233967 43510 4 553186 3462 0.6 427711 11203 3 2004 1819480 15355 0.8 1233363 45382 4 551598 4209 0.8 425240 10722 3 2005 1817957 10174 0.6 1231708 53862 4 550997 5365 1.0 422921 9260 2 2006 1821357 16112 0.9 1232153 31726 3 548423 4745 0.9 420297 11591 3 2007 1822295 12826 0.7 1231548 52774 4 546836 5001 0.9 417825 14334 3 2008 1823233 11340 0.6 1230943 29982 2 545248 5977 1.1 415354 9476 2 2009 1824172 15432 0.8 1230338 26929 2 543661 2533 0.5 412882 8789 2 2010 1825524 8608 0.5 1228041 40174 3 542767 4088 0.8 410211 12368 3 2011 1826049 12534 0.7 1229128 31526 3 540486 2395 0.4 407939 8987 2 2012 1826987 12122 0.7 1228523 39808 3 538898 2640 0.5 405468 8585 2 84 P. van Lierop et al. / Forest Ecology and Management 352 (2015) 78–88
Burned forest area by income category, 2003 - 2012 3.3.2. Total forest area affected by other disturbances by region 60 000 Insect pests were the leading cause of forest disturbance other y = -1,429.83x + 2,909,942.44 than fire in nearly all geographic regions. In North America, they 50 000 R² = 0.21 are the leading cause of forest disturbance. North America reported the largest area of forest disturbed by insect pests, 57 million hec- 40 000 tares (Table 7), again demonstrating the continuing significance of damage by bark beetles (Walton, 2013). African countries reported 30 000 over 9 million hectares of forest damaged by insect pests. Severe weather events were the leading cause of reported forest 20 000 disturbance other than fire in Asia. Nearly 18 million hectares of
Area ('000 hectares) forest were damaged by severe weather in this region. North and 10 000 Central America reported over 13 million hectares of forest dam- 00 000 aged by severe weather. 2003 2005 2007 2009 2011 Diseases affected a relatively small extent of forests in all geo- Year graphic regions. Asia reported over 5 million hectares of forest High Lower Middle affected by diseases, and Europe reported just under 5 million hec- Upper Middle Low tares affected.
Fig. 4. Annual burned forest area by income category, 2003–2012. The linear trend over time is shown for upper-middle income category as a solid black line. The 3.4. Partial canopy cover reduction equation describing the line and the goodness of fit (R2) are shown. 3.4.1. Total forest area exhibiting PCCR by climatic domain The tropical domain was the climatic domain with the most 3.3. Forest area affected by other disturbances PCCR detected, over 156 million hectares or 9% of the domain’s for- est area as reported in 2010 (Table 8), as compared with 1–2% in In the 75 countries that reported on insect pests, diseases and the other domains. severe weather events, the total forest area affected by these dis- The study found a strong linear correlation between PCCR and turbances, over all years reported, was 141.6 million hectares. net deforestation by climatic zone (r2 = 0.92). This represents 5% of the total forest area in these countries (2807 million hectares). Insect pests accounted for the greatest part of the area damaged, followed by severe weather events 3.4.2. PCCR by region (Table 6). However, many factors limit the ability to report on for- Asia was the region with the highest amount of indicated PCCR, est damaged by disease, including the nature of disease cycles, spa- almost 54 million hectares. Africa was next, followed by South tial distribution of pathogens and complexities in assessment of America (Table 9). disease in standing trees (Burdon, 1987; Sturrock et al., 2011). As The study found a strong linear correlation between PCCR and a result, reported disease damage may be underestimated. net deforestation by region (excluding Asia) (r2 = 0.83).
3.3.1. Forest area affected by other disturbances by climatic domain 4. Discussion Temperate forests accounted for the largest area of forest reported damaged by insect pests, 69.6 million hectares Forest disturbance covers phenomena that, in most cases, do (Table 6). Recent outbreaks of bark beetles in North America not necessarily cause conversion of forest land to other land uses. (Hicke et al., 2012; Walton, 2013) appear to have been the biggest It is important to measure and monitor these disturbances as they contributor to temperate forest damage. are important indicators of ecosystem health, have a large impact
Table 5 Significance of trend (columns 1–4) and smoothed trend (columns 5–10) in total land area and forest area burned between 2003 and 2012 by climatic domain, region and income group. The sign (+/À) indicates the direction of the slope of the line formed by burned area over time. Significance (p < 0.05) of the trend as determined from the Mann–Kendall test is indicated as (n.s.) if no significance and (⁄) if significant. Column ‘Avg’ indicates the number of years included in the moving average to smooth the trend.
Aggregation Trend burned p < 0.05 Trend burned p < 0.05 Trend burned area, Avg p < 0.05 Trend burned forest area, Avg p < 0.05 area forest area smoothed smoothed Climatic domain Tropical À ⁄ À n.s. À 3 ⁄ À 3 ⁄ Subtropical + n.s. + n.s. + 3 n.s. + 3 n.s. Temperate À n.s. À n.s. À 3 ⁄ À 4 ⁄ Boreal + n.s. + n.s. + 3 n.s. + 4 ⁄ Region Africa À ⁄ À n.s. À 3 ⁄ À 3 n.s. Asia À n.s. À n.s. À 3 ⁄ À 3 n.s. Europe + n.s. + n.s. + 3 n.s. + 3 n.s. North and Central À n.s. À n.s. À 3 n.s. À 3 n.s. America Oceania + n.s. + n.s. + 3 n.s. + 3 n.s. South America À n.s. À n.s. À 3 ⁄ À 3 ⁄ Income group High + n.s. À n.s. + 3 n.s. À 3 n.s. Upper middle À n.s. À n.s. À 3 ⁄ À 3 ⁄ Lower middle À ⁄ À n.s. À 3 ⁄ À 3 n.s. Low À ⁄ À n.s. À 3 ⁄ À 3 n.s. P. van Lierop et al. / Forest Ecology and Management 352 (2015) 78–88 85
Table 6 sub-Saharan Africa from 1975 to 2000, largely in previously Forest area affected by other disturbances by climatic domain as reported to FRA forested landscapes. 2015. The results presented in this paper indicate a decreasing trend Climatic Forest area affected (000 ha) in burned area and burned forest area globally. This was most domain Insect Disease Severe Unknown Total notable in the tropical domain and in the South American region. pests weather The decrease in burned area in the tropics is corroborated by other Boreal 3702 3165 3397 4657 14920 recent studies (Yang et al., 2014; Giglio et al., 2010). Yang et al. Temperate 69582 3034 32251 117 104983 (2014) noted that decreasing forest conversion to pasture and Subtropical 2619 5195 37 343 8194 increasing forest conversion to cropland and mechanized agricul- Tropical 9616 1060 2749 42 13467 ture – as observed by Morton et al. (2006) in the Brazilian Total 85518 12454 38433 5158 141564 Amazon – may contribute to the decrease in burned forest area in tropical South America because pastureland is prone to larger and more frequent fires than cropland. Not only is less burning on the delivery of forest ecosystem services and may not be readily required for conversion, but repeat burning is also reduced. reported in deforestation statistics. Gregoire et al. (2012) found, similarly, that conversion of land to Forest disturbances also interact. Veblen et al. (1994) found that cropland in Africa has the effect of decreasing the amount of in a subalpine forest severe snow avalanches influenced the spread burned area detected in that region. of wildfires and young Picea sp. populations did not support a The decreasing trend in forest area burned is also visible in the spruce beetle attack following devastating fire or avalanche. Also upper middle-income category. Brazil is a large forested country for a subalpine forest, Buma and Wessman (2011) investigated a within this income category, which suggests again that activities gradient of disturbance interaction severities and found that wind- in Brazil may be affecting the total status and trend in forest distur- storms in 1997 followed by wildfire in 2002 created novel condi- bance for the tropical domain. tions that exceeded the resilience of the ecosystem, leading to There was a significantly increasing trend in burned forest area the absence of regeneration eight year post fire in areas were fire in the boreal climatic domain, when considering the smoothed came after medium to high severity blowdown. For this paper trend line. Kasischke and Turetsky (2006) found an increasing however, the interaction of disturbances could not be analyzed. trend in burned area, larger fire years and increased lightning igni- tions in the boreal zone of North America from the 1960’s to 1999. 4.1. Burned area Oris et al. (2013) suggest that increased burning in the boreal zone was predicted as a result of a warming global climate and could The results of this study indicate that annual burned forest area have positive feedbacks on boreal area burned. is highest in the tropics. Burning of forests in the tropics is of great concern, as tropical forests are home to over one-half the biological 4.2. Insect pests, diseases and severe weather diversity on Earth (Lewis, 2006), support the livelihoods and well-being of hundreds of millions of people (Dawson et al., Fire is clearly one of the most dominant forces affecting the 2014), are extremely important for maintaining local, regional Earth’s land surface. However, on forest land insect pests, diseases and even global weather and climate (Avissar and Werth, 2005; and severe weather are also significant disturbance agents. For Spracklen et al., 2012) and are large carbon sinks (Pan et al., 2011). example, Dale et al. (2001) found that in the temperate forests of A very strong exponential relationship was found between the North America insect pests and diseases affected almost 50 times total forest area burned and total net forest loss at the regional as much forest as burning annually. Logan et al. (2003) corrobo- and climatic domain levels (R2 = 0.96 and 0.95, respectively). rated the large-scale impacts of insect pests and diseases on forest Though there are few data points, it is likely that burning of forests land in North America and indicated that most global climate is the precursor to forest conversion, especially in the tropics change scenarios favor the increased incidence of outbreaks in where slash-and-burn agricultural practices are common (Lambin temperate forests in the future. et al., 2003; Carmenta et al., 2011). Alencar et al. (2011) deter- The data available from FRA 2015 do not allow for year on year mined that nearly 23% of burned area in a portion of the Amazon comparison of the relative amounts of forest affected by burning forest was ultimately converted to a different land use. Gibbs and other disturbances. Complexities associated with assessing et al. (2010) showed that tropical forest land, both primary and the areas affected by these disturbances limit countries’ ability to secondary, comprised 83% of all global agricultural expansion report in this category and in many cases there are no severe dis- between 1980 and 2000 and predicted that this proportion would turbance events to report. Forest disturbances and diebacks are remain high with rising demand for meat and grains. Brink and Eva often associated with a broad range of interrelated biotic and abi- (2009), through analysis of a 25-year time-series of satellite ima- otic causative agents, and multi-scale monitoring approaches are gery, determined that agriculture increased by 57% in required to quantify their impacts (Michaelian et al., 2011). Such
Table 7 Forest area affected by other disturbances by region as reported to FRA 2015.
Region Forest areaa (000 ha) Forest area disturbed (000 ha) % of forest area disturbed Insect pests Diseases Weather Unknown Total Africa 104392 9518 1042 2563 5 13128 12.6 Asia 399796 7406 5251 17814 307 30778 7.7 Europe 941992 10449 4681 4963 4774 24867 2.6 North and Central America 738287 57024 1260 13087 61 71432 9.7 Oceania 10158 2 196 6 0 204 2 South America 612358 1120 24 0 12 1156 0.2 Total 2806983 85519 12454 38433 5159 141564 5.0
a Aggregated 2010 forest area of the countries that reported on these disturbances to FRA 2015. 86 P. van Lierop et al. / Forest Ecology and Management 352 (2015) 78–88
Table 8 new deforestation on the island of Sumatra occurred in previously Partial canopy cover reduction (PCCR) area by climatic domain, sum for 2000–2010. disturbed or degraded forests. Proportion of total 2010 forest area. The results of this study also indicate a moderate linear correla- Climatic Total forest area, 2010 PCCR PCCR as % of total forest tion between total burned forest area and PCCR (R2 = 0.67) at the domain (000 ha) (000 ha) area 2010 regional level (excluding Asia). Thus, fire is a likely contributor to Tropical 1797758 156549 8.7 forest degradation in most subregions. Sub- 319613 6751 2.1 Satellite imagery analysis of PCCR does not indicate the cause of tropical canopy cover reduction, which could include anthropogenic Temperate 673429 6010 0.9 Boreal 1224873 15819 1.3 actions which may be considered harmful to the functioning of intact forests as well as human management activity and natural Total 4015673 185129 4.6 causes that are part of properly functioning forest ecosystems or could be considered enhancements to forest systems. It is certain that some areas where canopy cover is reduced are actually man- complete surveys are rare, so the quantifiable impact on forest aged sustainably. Unfortunately, no suitable data were available to cover by insect pests and diseases is often underestimated. test this relationship. Assessment methods were not reported to FRA, but are likely to Finally, this paper does not consider the type of forest area – vary among countries, domain and region and are affected by veg- primary, natural or planted, as reported in FRA 2015 – affected etation assemblages and climate. by disturbance. It is likely that most of the results and discussion The analysis by climatic domain and region must be interpreted presented here refer largely to natural forest and not planted forest with caution, as these figures are influenced by the number of areas. reporting countries. The global area damaged by insect pests, dis- eases and severe weather events overall is expected to be higher 5. Conclusion than reported.
This paper analyzed data reported by countries for FRA 2015 on 4.3. Forest degradation forest disturbance from fire, insect pests, diseases and severe weather globally, by climatic domain and by region. Over the Forest degradation is an important, yet difficult parameter to ten-year period from 2003 to 2012, an average of over 50 million measure. It is important because it affects forest productivity, bio- hectares of forest land burned each year, representing 1.4% of all diversity and atmospheric carbon flux can be a precursor to forest forest area and 16% of all land area burned. Burned area was well loss. Over the period 1991–2015 deforestation is estimated a net correlated with net forest loss and forest degradation at the cli- À1 matic zone and regional levels. A variable but decreasing trend in emission source (4.04 Gt CO2 yr ) and forest degradation is esti- À1 burned forest area was detected, especially in the tropics and par- mated at about one fourth (0.8 Gt CO2 yr ) of this (Federici et al., 2015). Locally, degradation rates can be equal to, or in some ticularly in South America. South America was the region that cases as much as double, the rates of true deforestation accounted for the largest proportion of forests burned, nearly (Zhuravleva et al., 2013). 40%. Forest area burned annually was similar for high and low Measuring forest degradation is problematic in part because it income categories, but since low income countries have far less is difficult to define and often difficult to separate from any form forest land, a higher proportion of their forest was affected by fires. of forest management, whether sustainable or not. Lund (2014) Over a similar time period countries reported nearly 142 mil- lists more than 50 different definitions of forest degradation, with lion hectares of forest affected by other disturbances, including determinant characteristics ranging from biophysical alteration to 85 million hectares affected by insect pests and over 38 million biodiversity reduction and reduced ability to provide ecosystem hectares by severe weather events. Of the total, more than 104 mil- services. Degradation per se was not measured in FRA 2015, rather lion hectares were affected in temperate countries; the bark beetle PCCR was used as a proxy. outbreak in North America was a major contributor. This study found a strong linear correlation between PCCR and It is important to provide information that may assist in the net forest loss by region (excluding Asia) and climatic zone quantification of forest disturbance and degradation where it is (R2 = 0.83 and 0.92, respectively). This indicates that, generally occurring, despite difficulties in defining, detecting, measuring speaking, where forest loss rates are highest so too is the rate of and monitoring. This is especially critical with changing climatic partial canopy cover loss, or degradation. Because forest conver- conditions, under which many biotic and abiotic disturbances are sion usually occurs in areas proximal to existing cleared areas, it expected to alter in intensity, quantity and frequency, with conse- is likely that much of the detected PCCR will ultimately convert quences for forests in many parts of the world. to forest loss. Margono et al. (2012) found that almost 97% of The availability of country-level information on disturbances is still relatively poor. More complete information on fire, insect pests, diseases and severe weather events could make it possible Table 9 to answer important questions, e.g. how does forest canopy cover Partial canopy cover reduction (PCCR) by region, sum for 2000–2010. loss vary with the rates of natural phenomena such as fires, insect Region Total forest area, PCCR PCCR as % of total pests and diseases? How does the incidence of severe weather con- 2010 (000 ha) (000 ha) forest area 2010 ditions such as drought affect the incidence of insect pests and dis- Africa 638282 50337 7.9 eases? How does the management of one type of disturbance Asia 589406 53859 9.1 ameliorate or exacerbate the impact of associated disturbances? Europe 1013572 17911 1.8 North and 750278 10379 1.4 Central Acknowledgements America Oceania 172002 5443 3.2 Special thanks to Canada, the European Commission, Finland, South America 852133 47198 5.5 Food and Agriculture Organization of the United Nations, Japan Total 4015673 185127 4.6 and the United States for funding provided to the Global Forest P. van Lierop et al. / Forest Ecology and Management 352 (2015) 78–88 87
Resources Assessment. The authors would also like to thank Gascon, L., Eva, H., 2014. Field Guide for Forest Mapping with High Resolution Data: Andrea Perlis for providing proofreading and editorial suggestions, Monitoring Deforestation and Forest Degradation in the Context of the UN- REDD Programme Tanzania REDD+ Initiative. JRC Technical Report. Publications Orjan Jonsson for his continues support with data analysis and Office of the European Union, Luxembourg. Leticia Piña for her valuable suggestions. The authors also wish GFOI, 2013. Integrating Remote-sensing and Ground-based Observations for to thank the very valuable suggestions of two reviewers whose Estimation of Emissions and Removals of Greenhouse Gases in Forests: Methods and Guidance from the Global Forest Observation Initiative. Group comments greatly improved the manuscript. In addition, authors on Earth Observations, Geneva, Switzerland. are also very grateful to Kenneth MacDicken for his constant guid- Gibbs, H.K., Ruesch, A.S., Achard, F., Clayton, M.K., Holmgren, P., Ramankutty, N., ance and useful inputs to improve and finalize this paper. Foley, J.A., 2010. Tropical forests were the primary sources of new agricultural land in the 1980s and 1990s. Proc. Natl. Acad. Sci. U.S.A., 1–6 Giglio, L., van der Werf, G.R., Randerson, J.T., Collatz, G.J., Kasibhatla, P., 2006. Global References estimation of burned area using MODIS active fire observations. Atmos. Chem. Phys. 1, 957–974. Giglio, L., Randerson, J.T., van der Werf, G.R., Kasibhatla, P.S., Collatz, G.J., Morton, Alencar, A., Asner, G.P., Knapp, D., Zarin, D., 2011. Temporal variability of forest fires D.C., Defries, R.S., 2010. Assessing variability and long-term trends in burned in eastern Amazonia. Ecol. Appl. 21, 2397–2412. area by merging multiple satellite fire products. Biogeosciences 7, 1171–1186. Avissar, R., Werth, D., 2005. Global hydroclimatological teleconnections resulting Gregoire, J.M., Eva, H.D., Belward, A.S., Palumbo, I., Simonetti, D., Brink, A., 2012. from tropical deforestation. J. Hydrometeorol. 6 (2), 134–145. Effect of land-cover change in Africa’s burnt areas. Int. J. Wildland Fire 22, 107– Ayres, M.P., Lombardero, M.J., 2000. Assessing the consequences of global change 120. for forest disturbance from herbivores and pathogens. Sci. Total Environ. 262, Hansen, M.C., DeFries, R.S., Townshend, J.R.G., Carroll, M., Dimiceli, C., Sohlberg, R.A., 263–286. 2003. Global percent tree cover at a spatial resolution of 500 meters: first Brink, A.B., Eva, H.D., 2009. Monitoring 25 years of land cover change dynamics in results of the MODIS Vegetation Continuous Fields algorithm. Earth Interact. 7 Africa: a sample based remote sensing approach. Appl. Geogr. 29 (4), 501–512. (10). Buma, B., Wessman, C.A., 2011. Disturbance interactions can impact resilience Hansen, M., DeFries, R., Townshend, J.R., Carroll, M., Dimiceli, C., Sohlberg, R., 2006. mechanism of forests. Ecosphere. http://dx.doi.org/10.1890/ES11-00038.1 Vegetation Continuous Fields MOD44B, 2001 Percent Tree Cover, Collection 4. (2:art64). University of Maryland, College Park, Maryland, USA. Burdon, J.J., 1987. Diseases and Plant Population Biology. Cambridge University Hicke, J.A., Johnson, M.C., Hayes, J.L., Preisler, H.K., 2012. Effects of bark beetle- Press, Cambridge, UK. caused tree mortality on wildfire. For. Ecol. Manage. 271, 81–90. Carmenta, R., Parry, L., Blackburn, A., Vermeylen, S., Barlow, J., 2011. Understanding INPE, 2015. Monitoramento de queimadas e incindios.
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Contents lists available at ScienceDirect
Forest Ecology and Management
journal homepage: www.elsevier.com/locate/foreco
q New estimates of CO2 forest emissions and removals: 1990–2015 ⇑ Sandro Federici a, Francesco N. Tubiello a,b, , Mirella Salvatore a, Heather Jacobs a, Josef Schmidhuber b a Climate, Energy and Tenure Division, Food and Agriculture Organization of the United Nations, Via Terme di Caracalla, Rome 00153, Italy b Statistics Division, Food and Agriculture Organization of the United Nations, Via Terme di Caracalla, Rome 00153, Italy article info abstract
Article history: Using newly available data from the 2015 Forest Resources Assessment (FRA), we refined the informa- Received 2 January 2015 tion, currently available through the IPCC AR5 and FAOSTAT, on recent trends in global and regional Received in revised form 16 April 2015 net CO2 emissions and removals from forest land, including from net forest conversion (used as a proxy Accepted 22 April 2015 for deforestation) and forest remaining forest. The new analysis is based on the simplified forest carbon Available online 7 September 2015 stock method of the FAOSTAT Emissions database, equivalent to a Tier 1, Approach 1 IPCC methodology,
limited to biomass carbon stocks. Our results indicated that CO2 emissions from net forest conversion Keywords: 1 1 decreased significantly, from an average of 4.0 Gt CO2 yr during 2001–2010 to 2.9 Gt CO2 yr during Forest 1 2011–2015. More than half of the estimated reductions over the last five years, some 0.6 Gt CO2 yr , took CO2 emissions place in Brazil. Detailed analyses further indicated that remaining forests continued to function as a net CO2 removals 1 Deforestation carbon sink globally, with an average net removal of 2.2 Gt CO2 yr during 2001–2010, and 1 Forest degradation 2.1 Gt CO2 yr during 2011–2015. Annex I Parties represented the bulk of this sink, contributing 60% REDD+ of the total in 2011–2015, down from 65% in 2001–2010. Compared to previous FAOSTAT assessments Carbon for the period 2001–2010, based on the 2010 FRA and published in the IPCC AR5, the use of FRA 2015 Stock change data led to estimates of net forest conversion that were consistent with previous ones (4.0 vs. FAOSTAT 1 1 3.8 Gt CO2 yr ), while the estimated forest sinks were 22% larger ( 2.2 vs. 1.8 Gt CO2 yr ). The net FRA contribution of forests to anthropogenic forcing based on FRA2015 data was thus smaller than previously estimated by the IPCC AR5. Finally, we separated for the first time net emissions and removals from forest
land into a sink component and a degradation component. Results indicated that, contrary to CO2 emis-
sions from deforestation, CO2 emissions from forest degradation increased significantly, from 1 1 1 0.4 Gt CO2 yr in the 1990s, to 1.1 Gt CO2 yr in 2001–2010 and 1.0 Gt CO2 yr in 2011–2015. Emissions from forest degradation were thus one-fourth of those from deforestation in 2001–2010, increasing to one-third in 2011–2015. Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction GHG Inventories (IPCC, 2006). Since 2012, FAO has used FRA data
to estimate net CO2 emissions and removals associated with C The Food and Agriculture Organization of the United Nations stock changes of the biomass C pools, related to forest land and (FAO) makes available online data on forests, originally submitted net forest conversion, the latter used as a proxy for net deforesta- by its Member States and analyzed through the Global Forest tion (FAOSTAT, 2015; FAO, 2014). The FAO data, considered equiv- Resource Assessment (FRA) (MacDicken, 2015). FRA data, available alent to a Tier 1, approach 1 estimate using the carbon stock over the period 1990–2015, include, among others, estimates of difference method of the IPCC guidelines, were published in the forest area and of carbon stocks in aboveground and belowground IPCC AR5 (Smith et al., 2014). biomass carbon pools. The latter data categories are needed in The FRA is the only global database that provides the value and standard carbon cycle computations of forest dynamics, in line historical trend of C stock changes in forest for each country, using with methods provided in the 2006 IPCC Guidelines for National official data provided by countries to FAO. An additional repository of data on forest carbon dynamic is the database of the UN Framework Convention on Climate Change (UNFCCC), which con- q This article is part of a special issue entitled ‘‘Changes in Global Forest Resources tains data submitted by its Parties (http://unfccc.int/national_re- from 1990 to 2015’’. ports/items/1408.php). ⇑ Corresponding author at: Food and Agriculture Organization of the United There are important differences between the FRA and UNFCCC. Nations, Via Terme di Caracalla, Rome 00153, Italy. E-mail address: [email protected] (F.N. Tubiello). First, the UNFCCC database currently does not cover all UN http://dx.doi.org/10.1016/j.foreco.2015.04.022 0378-1127/Ó 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 90 S. Federici et al. / Forest Ecology and Management 352 (2015) 89–98
Member States. In coming years, new country submissions of 2010, and 2015, including total national forest area, A, and its three Biennial Update Reports1 to UNFCCC by non-Annex I Parties2 will subcategories: primary forest, other naturally regenerated forest, and increase coverage, while adding valuable information on manage- planted forest; as well as total woody biomass carbon stock, B (defined ment practices, area, carbon stocks and their changes. as above and below-ground biomass)7. FRA data also included some Second, even though UNFCCC requires its Parties to provide information on carbon stocks in litter, deadwood and soils. Coverage data on forest land that are consistent with those they submit to by country was rather incomplete however, so that this information FAO3, often the data provided to FAO are numerically different from was not used herein. those submitted to UNFCCC, stemming from discrepancies in forest FRA 2015 data presented country data gaps on forest area by definitions applied4, and from the fact that different national focal subcategory, especially for the first two mentioned above, and on points are responsible for FAO and UNFCCC submissions. woody biomass. These data gaps were filled as follows. For forest The FAOSTAT Emissions database is one of three independent area, missing total forest area data were linearly extrapolated or sources used in the recent IPCC Fifth Assessment Report (AR5) to interpolated using existing FRA data, as needed. When the propor- estimate anthropogenic GHG emissions and removals from tion of forest area among sub-categories was missing we used Agriculture, Forestry and Other Land Uses (AFOLU) (Tubiello information on shares by forest subcategory from neighboring et al., 2015). In particular, for CO2 emissions and removals from countries with similar forest conditions, and applied these shares forest, FAOSTAT provided estimates of net forest carbon stock to total forest area. For total woody biomass, we used the relevant change at national, regional and global levels to the IPCC AR5. sub-regional weighted average value8, and multiplied it by the total Using data from the FRA 2010 (FAO, 2010), and with reference to country forest area. the period 2001–2010, FAO estimated average decadal CO2 emis- All data were linearly interpolated to obtain a yearly time series 1 sions from deforestation of 3.8 Gt CO2eq yr and a net carbon sink over the period 1990–2015. As described below in more detail, 1 in forest land of 1.8 Gt CO2eq yr . Additional GHG emissions annual data were used as input to compute net CO2 emissions from terrestrial C pools estimated by FAO to the IPCC AR5, but and removals on forest, including forest land area (hereafter not discussed herein, included emissions from drained peatlands referred to as forest land) and forest area converted to other land 1 1 (0.9 Gt CO2eq yr ) and from biomass fires (0.3 Gt CO2eq yr ). uses (hereafter referred to as net forest conversion or deforestation). This paper provides FAOSTAT updates of CO2 emissions and The terminology used herein is in line with the relevant database removals from forests, based on FRA 2015 data. Furthermore, this categories of the FAOSTAT Emissions database—Land use paper introduces an improved methodology to assess separately, (http://faostat3.fao.org/browse/G2/⁄/E). It may be considered con- within the forest domain, net CO2 emissions from forest degrada- sistent with REDD+, albeit representing an over-simplification of 9 tion and net CO2 removals from forest re-growth, thus providing current GHG national reporting practice . for the first time in the literature, an assessment of both of these 2.1. Derived input data important terrestrial carbon fluxes.
Annual data needed as input into the FAOSTAT stock difference 2. Materials and methods methodology were derived from FRA2015, by country and over the period 1990–2015, including: FAOSTAT estimates of CO2 emissions and removals from forest were computed following the carbon stock difference equation of Forest area, AiðtÞ. Total forest area A, disaggregated into two for- the 2006 IPCC Guidelines, using FRA country information on forest est strata i as follows: 5 area and carbon stock density as input. This was considered equiv- – Natural forest area, defined as the sum of FRA area data for alent to an IPCC Tier 1, approach 1 method (FAO, 2014). In fact, the sub-categories primary forest and other naturally regenerating 6 stock difference method is not the IPCC default , because its applica- forest; and tion requires the use of statistically consistent time-series of – Planted forest area, taken directly from the FRA. national forest inventory data, which are not typically available in all countries. The FRA however provides exactly this type of informa- The above aggregation of natural forest was made to ensure that tion, including forest area activity data and carbon stock-change fac- net area losses of primary to secondary forest, a typical outcome of tors by country, making the application of stock difference equations forest resources exploitation, would not be counted as forest area within FAOSTAT much simpler than the gain-loss method. More change. Thus the associated carbon losses were counted as forest specifically, we used FRA data for the years 1990, 2000, 2005, degradation rather than deforestation. At the same time, separat- ing this stratum from planted forest was necessary in order to iden- 1 Biennial Update Reports contain, among other information, a GHG Inventory for tify areas and associated CO2 emissions from deforestation of forest land, and an annex on the implementation of REDD+ activities: forest natural forest, separately from those associated to afforestation conservation, sustainable forest management, enhancement of carbon stocks, reduc- with plantations. ing emissions from deforestation and forest degradation. 2 Annex I Parties include the 24 original OECD members, the European Union, and 14 countries with economies in transition. While non-Annex I Parties have currently Woody biomass carbon stock density, b. Computed as B/A, where no legal commitment to reducing their greenhouse-gas (GHG) emissions, Annex I B was the FRA national total woody biomass carbon stock and A Parties committed to returning their GHG emissions to 1990 levels by the year 2000, the total national forest area. FRA biomass data were provided under UNFCCC Article 4.2 (a) and (b), and accepted emissions targets for the period 2008–12 under Article 3 and Annex B of the Kyoto Protocol. 3 UNFCCC decision 16/CMP1, para16; 2/CMP8 Annex I para1f; 12/CP7 Annex, 7 FRA data by country are available at http://www.fao.org/forestry/fra/67090/en/. para n. 8 FAO sub-regions and number of countries (in parenthesis) with no national value 4 FAO member countries must report to FRA using the FAO forest definition (i.e., in FRA: Eastern Africa (1), Western Africa (2), North America (2), Central America (1), minimum area 0.5 ha, minimum cover 10%, minimum height 5 m), while they can Caribbean (13), South America (3), South-Eastern Asia (3), Western Asia (6), Northern report to UNFCCC using their national forest definitions, which may differ from FAO’s. Europe (3), Southern Europe (1), Australia and New Zealand (1), Melanesia (2), Furthermore, reported FRA data cover the entire national forest area, as they must Micronesia (1), Polynesia (5). include unmanaged forest land. By contrast, UNFCCC submissions may be limited to 9 In GHG national inventories, net emissions associated with deforestation are managed forest land. reported in the new land category to which forest was converted. By contrast, 5 Defined as carbon stock per hectare of total biomass (above-and below-ground). assessing net emissions and removals from deforestation and from forest land 6 The IPCC default method is the ‘‘gain-loss’’ method, requiring information on net separately, as well as reporting their sum as net emissions and removals from forest, forest growth rates, harvest data and estimated losses from disturbances. is relevant to REDD+. S. Federici et al. / Forest Ecology and Management 352 (2015) 89–98 91
only for total forest, hence no further stratification between the Table 1 two above forest strata was made. Rather, each was assigned Subdivisions of Forest land categories and forest strata used in the FAOSTAT methodology. with the same value b, with limitations discussed below. Forest Forest land Natural Stable forest area in the inventory 2.2. Stock difference equations forest year (SFA1) New net forest area in the inventory
year (FAC1) We estimated annual C stock change, limited to changes in car- Planted Stable forest area in the inventory bon in woody biomass, and thus net CO2 emissions and removals, forest year (SFA2) over the period 1990–2015, associated with the following process New net forest area in the inventory types: (i) net forest area loss with associated net C stock loss year (FAC2) (reported under net forest conversion or deforestation); and (ii) net Net forest Natural Net deforestation in the inventory forest area gain with associated net C stock gain; and (iii) net conversion forest year (FAC3) Planted Net deforestation in the inventory changes in C stock density over the forest land area. The last two forest year (FAC4) process types were reported together under forest land)10. The stratification of the forest area and equations applied followed the IPCC (2006) guidelines and are summarized for convenience in Table 1 and 2. Forest land area : AiðtÞ¼SFAiðtÞþMax½FACiðtÞ; 0 ; ð3Þ In general, net C stock change was computed by applying: Deforestation area : Min½FACiðtÞ; 0 ð4Þ Approach 1 (IPCC, 2006, Ch. 3, Vol. 4) for land representation. For each of the process type j defined above, the carbon stock Only net forest area changes were considered, since FRA data change factor CSCFjðtÞ was computed as follows: did not allow for quantification of gross area changes. 8 > IPCC stock-difference equation (IPCC, 2006; equation 2.5, Vol. 4) < bðtÞ bðt 1Þ; for j ¼ SFA; for the calculation of average C stock density change. CSCF ðtÞ¼ bðt 1Þ; for j ¼ FAC < 0 ð5Þ j :> bðtÞ; for j ¼ FAC > 0 11 More specifically, net CO2 emissions and removals were com- puted for each of the two forest strata i (natural forest and planted Note that under Eq. (5), the carbon stock density of deforested land, forest) each of the three process types j and for each year t, as follows as well as the previous woody biomass carbon stock density of land (see also Table 2): that was converted to forest, are both assumed to be zero. Similarly, the woody biomass carbon stock density of new forested land is 44 3 assumed to be that of the remaining forest. This is a consequence netCO2emissioni;jðtÞ¼ai;jðtÞ CSCFjðtÞ 10 ð1Þ 12 of the methodology applied herein, leading to either under and over where: estimates of carbon stock changes reported for natural forest and
netCO2emission is expressed in Gg CO2 (or equivalently, kt CO2); planted forest under net forest conversion and under forest land, ai,j (t) is the area underpinning the process type j in strata i,at depending on national forest circumstances. Errors however cancel year t, expressed in ha (see below); out once estimates are summed up for the category forest, since the
CSCFjðtÞ, or carbon stock change factor, is the woody biomass net C stock change calculated for forest corresponds exactly to the carbon stock density change relative to process type j, estimated difference in the woody biomass C stocks reported by countries at time t, expressed in metric tonnes C ha 1. The factor 44/12 con- under FRA, and thus are not a source of bias at the level of total for- 3 verts C to CO2;10 converts metric tonnes to Gg. The minus sign est area. allows to assign emissions (positive sign) to carbon stocks losses, and removals (negative sign) to carbon stocks gains. 2.3. Definition of net emissions from forest degradation
For each of the forest strata i defined above, the area ai;jðtÞ was defined as follows: Using Eqs. (1)-(3) and (5), net CO2 emissions and removals esti- mated over forest land area at country level, netCO2emission ðtÞ cor- SFAiðtÞ ai;jðtÞ¼ ð2Þ responded to net annual decreases or increases in forest woody FACiðtÞ biomass C stock density. Irrespective of the underlying processes, which could not be further analyzed using FRA data, whenever where SFAiðtÞ is the stable forest area of strata i at time t, defined as the forest area remaining forest between two successive years (t 1) netCO2emission ðtÞ > 0, we counted net forest emissions as forest and t: degradation. Similarly, whenever netCO2emission ðtÞ <0, we counted them as net forest removals. This allowed us to separate SFAiðtÞ¼Min ½AiðtÞ; Aiðt 1Þ ð2aÞ estimates of net forest sinks at global and regional level into a degradation component and into a net removal component. And FACiðtÞ is forest area change of strata i at time t: FAC ðtÞ¼½A ðtÞ A ðt 1Þ ð2bÞ i i i 3. Uncertainties and limitations The latter was recorded as net forest area increase, when
FACiðtÞ > 0, and as net forest conversion, used herein as a proxy for Uncertainties in the estimates of CO2 emissions and removals deforestation, when FACiðtÞ <0. discussed herein stemmed from the methodology applied, and Therefore the following area identity holds for each of the forest depended on the availability and quality of FRA data submitted strata and each time t: by countries to FAO.
3.1. Methodological uncertainties
10 Including in principle C stock changes in both primary and other naturally regenerating forests, since FRA C stock values are averaged over the total forest. Our estimates were limited to only two carbon pools, above- 11 The term removal herein refers to removal of carbon from the atmosphere and its and below-ground biomass, out of six pools identified by the storage into forest woody biomass. IPCC guidelines: above- and below-ground biomass, dead wood, 92 S. Federici et al. / Forest Ecology and Management 352 (2015) 89–98
Table 2 Equations applied for estimating the components A and CSCF of Eq. (1).
Subdivision A CSCF
Forest land Natural forest Stable forest area in the inventory year (SFA1) Min[A(t),A(t 1)] CSCF = b(t) – b(t 1)
New net forest area in the inventory year (FAC1) Max[A(t)–A(t 1),0] CSCF = b(t)
Planted forest Stable forest area in the inventory year (SFA2) Min[A(t),A(t 1)] CSCF = b(t) – b(t 1)
New net forest area in the inventory year (FAC2) Max[A(t)-A(t 1),0] CSCF = b(t)
Net forest conversion Natural forest Net deforestation in the inventory year (FAC3) |Min[A(t)-A(t 1),0]| CSCF = b(t 1)
Planted forest Net deforestation in the inventory year (FAC4) |Min[A(t)-A(t 1),0]| CSCF = b(t 1)
litter, soil organic carbon, and harvested wood products. This likely C stock change (+13.4%), including for Annex I (+10.2%) and impacted the magnitude of estimated net C stock change, as the non-Annex I Parties (+20.4%). inclusion of other C pools would probably have increased the mag- Regarding the quality of country data, FRA 2005 estimated nitude of estimated changes, but not their direction of change, i.e., uncertainties of growing stock at ±8% for industrialized countries the identification of a net sink or a net source, since the dynamics (Annex I) and ±30% for non-industrialized countries (non-Annex of C pools are strictly linked. Soil carbon pools in forest over I). The uncertainty of biomass density for estimating C stock losses drained organic soils represent a notable exception, since they from net deforestation was larger, and was set by expert judge- may be characterized by long-term C losses even as carbon bio- ment at ±80%. Uncertainties for wood density data were estimated mass and litter pools increase. in the range 10–40%. Additionally, FAOSTAT estimates uncertain- By excluding dead wood, litter and soil organic carbon, ties of area data at ±10% in general, and possibly as low as ±3% in
FAOSTAT estimates of net CO2 emissions and removals were likely industrialized countries. Additional uncertainties were linked to under-estimates of actual net CO2 emissions. By analysing UNFCCC the use of conversion factors needed to estimate total living bio- country submissions, we assessed the magnitude of this underesti- mass stocks from nationally reported wood volumes. These factors mate to be as large as one-third of the potential C stock change include a biomass conversion and expansion factor (BCEF = 1.3), a from all pools. CO2 Emissions from deforestation are possibly fur- root-to-shoot ratio (R:S = 0.2), and a biomass-to-carbon conversion ther underestimated, since they were based on net, rather than factor (CF = 0.5). The IPCC associates uncertainties of ±30% to these gross, deforested area. factors. The resulting overall uncertainty12 at global level, com- Additional methodological uncertainties were linked to the use puted by applying relevant 2006 IPCC equations for error propaga- of average C stock densities, i.e., not differentiated by forest strata. tion, was about ±30% for CO2 emissions from deforestation and This would lead to an over or under-estimation of net emissions ±15% net CO2 emissions and removals from forest land. It should be and removals for forest strata with C density significantly above noted that FRA applies the conversion factors described above or below the average values. Because the information on C density equally across all countries. This simplification introduced additional is however correct when considered over the sum of forest and uncertainties, which we did not know how to quantify. deforested areas, these errors cancel out at the level of total net C stock change of forest. 4. Results and discussion Finally, our estimates included CO2 gas only. Including CH4 and N O emissions would have increased our emission estimates, espe- 2 Updated annual net CO2 emissions and removals from forest and cially in countries where forest fires play a significant role in defor- from its two sub-components forest land and net forest conversion estation and forest degradation. Analyses we performed with the (deforestation), were computed and made available via the FAOSTAT Emissions database, however, showed that such addi- FAOSTAT database (http://faostat3.fao.org/faostat-gateway/go/ tional non-CO2 emissions were typically one order of magnitude to/download/G2/GF/E)13. Results were summarized globally and lower than the CO2 estimated values. disaggregated by Annex I and non-Annex I Parties as averages for the periods 1991–2000, 2001–2010, 2011–2015, and 1991–2015 (Table 3). Only mean values were reported. 3.2. Uncertainties associated with FRA data 4.1. Global trends Additional uncertainties stemmed from: (i) Heterogeneity in country data quality; and (ii) FRA data projections within given Results indicated that over the period of study, 1991–2015, for- FRA cycles. est land was a net source of CO emissions globally, averaging The latter type of uncertainty was related to the fact that, for 2 1.52 Gt CO yr 1. These corresponded to emissions from any FRA cycle, the last years of data are in fact projections rather 2 than actual measurements. The impact of this on estimated emis- 12 sions and removals was evaluated herein by comparing results for From IPCC 2006: Lack of knowledge of the true value of a variable that can be described as a probability density function (PDF) characterising the range and years 2009–2010, which were projections in FRA 2010 data, likelihood of possible values. The uncertainty in the mean (e.g. the uncertainty revised using actual measurements in FRA 2015. This was a simpli- associated with the calculation of the average biomass C density across the country) is fied exercise, recognizing that periods longer than two years may estimated as plus or minus k (or approximately 2) multiples of the standard error in fact represent projections in any given FRA cycle, and acknowl- divided by the sample mean times 100, where the standard error is the sample edging that uncertainties may grow by comparing periods further standard deviation divided by the square root of the sample size. The uncertainty in the individual (e.g. the uncertainty associated with the use of the average biomass C apart in time. Our analyses comparing net CO2 emissions and density for estimating C stock losses of a single unit of land) is estimated as plus or removals for 2009–2010 made with FRA2015 to FRA2010, indi- minus k (or approximately 2) multiples of the sample standard deviation divided by cated small relative effects on global deforestation estimates the sample mean times 100. Both calculations are based on an assumption of a ( 0.6%), including for non-Annex I Parties ( 5.8%), and large rela- normal distribution, and k is obtained from the student’s t-distribution. 13 The Forest sub-domain in FAOSTAT contains data by country, with a range of tive effects in Annex I Parties (+43.8%), although it should be con- regional aggregations, including Annex I and non-Annex I groups. Data for download sidered that in the latter case absolute values were very small. are net CO2 emissions/removals in GgCO2; C stock change in GgC; implied emission Similarly, we found small effects on estimates of global forest net factors; and area. S. Federici et al. / Forest Ecology and Management 352 (2015) 89–98 93
Table 3
Estimates of annual net CO2 emissions and removals from forest (woody biomass C stock changes only). Mean values only are reported.
Subdivision 1991–2000 2001–2010 2011–2015 1991–2015 t C (thousand)
Total Forest Total Annex I 981,451.76 1,096,888.72 1,158,287.58 1,063,025.76 non-Annex I 2,675,855.92 2,809,900.98 1,949,565.06 2,583,693.79 Global 1,694,404.17 1,713,012.26 791,277.48 1,520,668.03 Natural forest Annex I 494,133.03 527,360.69 773,006.17 563,227.53 non-Annex I 3,093,295.83 3,477,942.01 2,479,090.54 3,123,887.64 Global 2,599,162.81 2,950,581.32 1,706,084.38 2,560,660.11 Planted forest Annex I 487,318.73 569,528.03 385,281.41 499,798.23 non-Annex I 417,439.91 668,041.03 529,525.48 540,193.84 Global 904,758.64 1,237,569.06 914,806.90 1,039,992.08 Forest land Total Annex I 1,206,517.43 1,459,683.16 1,285,657.13 1,323,611.66 non-Annex I 1,781,025.72 777,879.76 862,408.08 1,196,043.81 Global 2,987,543.15 2,237,562.92 2,148,065.21 2,519,655.47 Natural forest Annex I 713,692.06 872,441.74 888,801.61 812,213.84 non-Annex I 1,335,910.28 85,900.98 285,925.07 625,909.52 Global 2,049,602.34 958,342.72 1,174,726.68 1,438,123.36 Planted forest Annex I 492,825.37 587,241.42 396,855.51 511,397.82 non-Annex I 445,115.44 691,978.78 576,483.01 570,134.29 Global 937,940.81 1,279,220.20 973,338.53 1,081,532.11 Net forest conversion Total Annex I 225,065.67 362,794.45 127,369.54 260,585.90 non-Annex I 4,456,881.65 3,587,780.74 2,811,973.14 3,779,737.60 Global 4,681,947.32 3,950,575.18 2,939,342.69 4,040,323.51 Natural forest Annex I 219,559.03 345,081.05 115,795.44 248,986.32 non-Annex I 4,429,206.12 3,563,842.99 2,765,015.61 3,749,797.16 Global 4,648,765.15 3,908,924.04 2,880,811.06 3,998,783.47 Planted forest Annex I 5,506.64 17,713.39 11,574.10 11,599.59 non-Annex I 27,675.53 23,937.75 46,957.53 29,940.45 Global 33,182.17 41,651.14 58,531.63 41,540.03