About GFR Indicators

Tracking vital forest trends at a global scale.

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About the Indicators

The Global Forest Review (GFR) indicators aim to provide data-driven and global-scale monitoring of vital forest trends. They are intended to support the tracking of targets and commitments under the Sustainable Development Goals, the New York Declaration on Forests, the Convention on Biological Diversity, and other international commitments. 

The GFR indicators take a different approach from other monitoring initiatives such as the Global Forest Resources Assessment (FRA), which is published every five years by the Food and Agriculture Organization of the United Nations. Whereas the FRA compiles national statistical data produced by governments, the GFR relies on globally consistent geospatial data (i.e., data that can be depicted in high resolution on a map) produced by independent researchers. This allows the GFR indicators to go beyond global- and national-scale statistics and reveal the local dynamics driving these larger trends. It also allows for more comparability between places and more frequent data updates. The GFR intends to complement resources such as the FRA by providing novel insights and an independent perspective that can be viewed in parallel with official government-reported data.  
 

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Topics Covered

The GFR currently includes 17 indicators tracking forest trends across five topic areas, which can be used to monitor the improving or declining state of the world’s forests over time:

  • Forest Extent indicators monitor changes in forest extent, including forest gain and forest loss related to deforestation and other causes.
  • Forest Condition indicators monitor changes in the condition or quality of remaining forests, including forest degradation and recovery.
  • Forest Designation indicators monitor how forests are designated to be managed and used for different purposes, from conservation to timber production.
  • Biodiversity and Ecological Services indicators monitor the capacity of forests to sustain biodiversity and provide critical ecological services, including carbon sequestration and water and soil regulation. 
  • Social and Governance Issues indicators monitor the link between forests and people who most depend on them, including indigenous communities.

The GFR indicators are not exhaustive of all potential topics important to forests. The FRA tracks more than 60 forest-related variables, including important social and economic indicators that are not captured here. The GFR indicators reflect the topics for which analysis of high-resolution geospatial data—as opposed to national statistical data—can bring new insights. As the availability of geospatial data on forests continues to expand, so will the scope of these indicators. 

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Data Limitations

Please refer to Data and Methods for more detail on this topic.  

The indicator titles in the GFR are aspirational: they define what we aim to monitor in an “ideal” world of data. Due to limitations in the availability, scope, and accuracy of existing data, some indicators can only be assessed partially or by proxy at this time. Each indicator is therefore discussed in terms of its current limitations and prospects for improvement. A key goal of the GFR is to help prioritize and support continued improvements in geospatial data for global forest monitoring. We strive to update the indicators annually; however, some indicators may be updated less frequently as feasible based on the underlying data sources. 

Remote sensing has become an incredibly important tool in global forest monitoring over the past decade but, like all tools, it has limitations. Users of these indicators should keep in mind the following important considerations:

  • Tree cover does not always make a forest. The GFR frequently refers to tree cover when talking about forest extent, loss, and gain. Tree cover is a convenient metric because it can be measured frequently, at low cost, and over large geographic scales using freely available satellite imagery. The tree cover data used in this report are based on Hansen et al. (2013),  who define tree cover as woody vegetation with a height of at least 5 meters (m) and a canopy density of at least 30 percent at 30 m resolution. As such, it includes industrial tree plantations and commercial tree crops (such as oil palm or apple orchards), which would not typically be defined as a forest.
  • Tree cover loss does not always imply forest loss or deforestation. Tree cover loss is defined as the complete removal of tree cover for any reason. It includes temporary losses of tree cover related to wood harvesting, fire, and other human activities and natural disturbances that are likely to be followed by forest regrowth. It also includes deforestation, which typically refers to human-caused, permanent removal of natural forest cover. To the extent possible, the GFR draws on additional data sources to help distinguish these different forms of tree cover loss.
  • The monitoring of tree cover gain currently lags behind tree cover loss. Tree cover gain is defined as an increase in tree cover from 0 percent to at least 50 percent canopy cover at 30 m resolution. Tree cover gain is more difficult to detect from satellite imagery over short intervals because tree growth is a gradual process compared to tree removal. As such, the tree cover gain data used in this report are only available as a cumulative estimate from 2001 to 2012. Based on ongoing research, we anticipate that tree cover gain data will soon be updated to the most recent year and made available as annual updates. 
  • Global data can have local inaccuracies. Global data products allow for consistent measurement of key variables across countries and through time. The researchers that produced the tree cover loss data used in this report found a 13 percent false positive rate (identifying an area of loss incorrectly) and a 12 percent false negative rate (failing to identify an area of loss) at a global scale. However, accuracy rates vary locally, and we are most likely to see higher levels of inaccuracy in areas where tree cover canopy density is low and where forest change takes the form of many small-scale clearings. A detailed discussion of the accuracy of the tree cover change data, summarized from the original publication by Hansen et al. (2013), can be found here
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{"Glossary":{"141":{"name":"agroforestry","description":"A diversified set of agricultural or agropastoral production systems that integrate trees in the agricultural landscape.\r\n"},"101":{"name":"albedo","description":"The ability of surfaces to reflect sunlight.\u0026nbsp;Light-colored surfaces return a large part of the sunrays back to the atmosphere (high albedo). Dark surfaces absorb the rays from the sun (low albedo).\r\n"},"94":{"name":"biodiversity intactness","description":"The proportion and abundance of a location\u0027s original forest community (number of species and individuals) that remain.\u0026nbsp;\r\n"},"95":{"name":"biodiversity significance","description":"The importance of an area for the persistence of forest-dependent species based on range rarity.\r\n"},"142":{"name":"boundary plantings","description":"Trees planted along boundaries or property lines to mark them well.\r\n"},"98":{"name":"carbon dioxide equivalent (CO2e)","description":"Carbon dioxide equivalent (CO2e) is a measure used to aggregate emissions from various greenhouse gases (GHGs) on the basis of their 100-year global warming potentials by equating non-CO2 GHGs to the equivalent amount of CO2.\r\n"},"153":{"name":"climate domain","description":"Major ecosystem regions, summarized as boreal, temperate, tropical and subtropical.\u0026nbsp;"},"99":{"name":"CO2e","description":"Carbon dioxide equivalent (CO2e) is a measure used to aggregate emissions from various greenhouse gases (GHGs) on the basis of their 100-year global warming potentials by equating non-CO2 GHGs to the equivalent amount of CO2.\r\n"},"1":{"name":"deforestation","description":"The change from forest to another land cover or land use, such as forest to plantation or forest to urban area.\r\n"},"77":{"name":"deforested","description":"The change from forest to another land cover or land use, such as forest to plantation or forest to urban area.\r\n"},"76":{"name":"degradation","description":"The reduction in a forest\u2019s ability to perform ecosystem services, such as carbon storage and water regulation, due to natural and anthropogenic changes.\r\n"},"75":{"name":"degraded","description":"The reduction in a forest\u2019s ability to perform ecosystem services, such as carbon storage and water regulation, due to natural and anthropogenic changes.\r\n"},"79":{"name":"disturbances","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"68":{"name":"disturbed","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"65":{"name":"driver of tree cover loss","description":"The cause of tree cover loss, such as agriculture or urban development. There are direct drivers, which are the immediate cause of the loss, and indirect drivers, which are the secondary cause of loss (i.e., land speculation)."},"70":{"name":"drivers of loss","description":"The cause of tree cover loss, such as agriculture or urban development. There are direct drivers, which are the immediate cause of the loss, and indirect drivers, which are the secondary cause of loss (i.e., land speculation)."},"81":{"name":"drivers of tree cover loss","description":"The cause of tree cover loss, such as agriculture or urban development. There are direct drivers, which are the immediate cause of the loss, and indirect drivers, which are the secondary cause of loss (i.e., land speculation)."},"102":{"name":"evapotranspiration","description":"When solar energy hitting a forest converts liquid water into water vapor (carrying energy as latent heat) through evaporation and transpiration.\r\n"},"154":{"name":"fastwood monoculture","description":"Stands of single species planted trees that grow quickly.\u0026nbsp;"},"53":{"name":"forest degradation","description":"The reduction in a forest\u2019s quality and ability to perform ecosystem services, such as carbon storage and water regulation, due to natural and anthropogenic changes."},"54":{"name":"forest disturbance","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"100":{"name":"forest disturbances","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"5":{"name":"forest fragmentation","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"155":{"name":"Forest Landscape Restoration","description":"The ongoing process of restoring landscapes to regain ecological functionality and enhance human well-being across deforested or degraded forest landscapes."},"156":{"name":"forest moratorium","description":"A temporary restriction on activities that cause forest loss or degradation."},"69":{"name":"fragmentation","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"80":{"name":"fragmented","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"74":{"name":"gain","description":"The establishment of tree canopy in an area that previously had no tree cover. Tree cover gain may indicate a number of potential activities, including natural forest growth or the crop rotation cycle of tree plantations.\r\n"},"143":{"name":"global land squeeze","description":"Pressure on finite land resources to produce food, feed and fuel for a growing human population while also sustaining biodiversity and providing ecosystem services.\r\n"},"7":{"name":"hectare","description":"One hectare equals 100 square meters, 2.47 acres, or 0.01 square kilometers.\r\n"},"66":{"name":"hectares","description":"One hectare equals 100 square meters, 2.47 acres, or 0.01 square kilometers."},"67":{"name":"intact","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"78":{"name":"intact forest","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"8":{"name":"intact forests","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"55":{"name":"land and environmental defenders","description":"People who peacefully promote and protect rights related to land and\/or the environment.\r\n"},"161":{"name":"logging concession","description":"A legal agreement allowing an entity the right to manage a public forest for production purposes, including for timber and other wood products."},"157":{"name":"logging concessions","description":"A legal agreement allowing an entity the right to manage a public forest for production purposes, including for timber and other wood products."},"160":{"name":"Logging concessions","description":"A legal agreement allowing an entity the right to manage a public forest for production purposes, including for timber and other wood products."},"9":{"name":"loss driver","description":"The cause of tree cover loss, such as agriculture or urban development. There are direct drivers, which are the immediate cause of the loss, and indirect drivers, which are the secondary cause of loss (i.e., land speculation).\r\n"},"10":{"name":"low tree canopy density","description":"Less than 30 percent tree canopy density.\r\n"},"104":{"name":"managed natural forests","description":"Naturally regenerated forests with signs of management, including logging and clear cuts.Lesiv et al. 2022, https:\/\/doi.org\/10.1038\/s41597-022-01332-3"},"91":{"name":"megacities","description":"A city with more than 10 million people.\r\n"},"57":{"name":"megacity","description":"A city with more than 10 million people."},"86":{"name":"natural","description":"A forest that that grows with limited or no human intervention. Natural forests can be managed or unmanaged (see separate definitions).\u0026nbsp;"},"12":{"name":"natural forest","description":"A forest that that grows with limited or no human intervention. Natural forests can be managed or unmanaged (see separate definitions). \r\n"},"63":{"name":"natural forests","description":"A forest that that grows with limited or no human intervention. Natural forests can be managed or unmanaged (see separate definitions).\u0026nbsp;"},"144":{"name":"open canopy systems","description":"Individual tree crowns that do not overlap to form a continuous canopy layer.\r\n"},"88":{"name":"planted","description":"Stands of trees established through planting, including both planted forest and tree crops."},"14":{"name":"planted forest","description":"Planted trees \u2014 other than tree crops \u2014 grown for wood and wood fiber production or for ecosystem protection against wind and\/or soil erosion.\r\n"},"73":{"name":"planted forests","description":"Planted trees \u2014 other than tree crops \u2014 grown for wood and wood fiber production or for ecosystem protection against wind and\/or soil erosion."},"148":{"name":"planted trees","description":"Stands of trees established through planting, including both planted forest and tree crops."},"149":{"name":"Planted trees","description":"Stands of trees established through planting, including both planted forest and tree crops."},"15":{"name":"primary forest","description":"Old-growth forests that are typically high in carbon stock and rich in biodiversity. The GFR uses a humid tropical primary rainforest data set, representing forests in the humid tropics that have not been cleared in recent years.\r\n"},"64":{"name":"primary forests","description":"Old-growth forests that are typically high in carbon stock and rich in biodiversity. The GFR uses a humid tropical primary rainforest data set, representing forests in the humid tropics that have not been cleared in recent years.\r\n"},"58":{"name":"production forest","description":"A forest where the primary management objective is to produce timber, pulp, fuelwood, and\/or nonwood forest products."},"89":{"name":"production forests","description":"A forest where the primary management objective is to produce timber, pulp, fuelwood, and\/or nonwood forest products.\r\n"},"159":{"name":"restoration","description":"Interventions that aim to improve ecological functionality and enhance human well-being in degraded landscapes. Landscapes may be forested or non-forested."},"87":{"name":"seminatural","description":"Forest with predominantly native trees that have not been planted. Trees are established through silvicultural practices, including natural regeneration or selective thinning.FAO"},"59":{"name":"seminatural forests","description":"Forest with predominantly native trees that have not been planted. Trees are established through silvicultural practices, including natural regeneration or selective thinning.FAO"},"96":{"name":"shifting agriculture","description":"Agricultural practices where forests are cleared, used for agricultural production for a few years, and then temporarily abandoned to allow trees to regrow and soil to recover.\u0026nbsp;"},"103":{"name":"surface roughness","description":"Surface roughness of forests creates\u0026nbsp;turbulence that slows near-surface winds and cools the land as it lifts heat from low-albedo leaves and moisture from evapotranspiration high into the atmosphere and slows otherwise-drying winds. \r\n"},"17":{"name":"tree cover","description":"All vegetation greater than five meters in height and may take the form of natural forests or plantations across a range of canopy densities. Unless otherwise specified, the GFR uses greater than 30 percent tree canopy density for calculations.\r\n"},"71":{"name":"tree cover canopy density is low","description":"The percent of ground area covered by the leafy tops of trees. tree cover: All vegetation greater than five meters in height and may take the form of natural forests or plantations across a range of canopy densities. Unless otherwise specified, the GFR uses greater than 30 percent tree canopy density for calculations.\u0026nbsp;\u0026nbsp;"},"60":{"name":"tree cover gain","description":"The establishment of tree canopy in an area that previously had no tree cover. Tree cover gain may indicate a number of potential activities, including natural forest growth or the crop rotation cycle of tree plantations.\u0026nbsp;As such, tree cover gain does not equate to restoration.\r\n"},"18":{"name":"tree cover loss","description":"The removal or mortality of tree cover, which can be due to a variety of factors, including mechanical harvesting, fire, disease, or storm damage. As such, loss does not equate to deforestation.\r\n"},"163":{"name":"tree cover loss due to fire","description":"The mortality of tree cover where forest fires were the direct cause of loss.\u0026nbsp;"},"164":{"name":"tree cover loss due to fires","description":"The mortality of tree cover where forest fires were the direct cause of loss.\u0026nbsp;"},"162":{"name":"tree cover loss from fires","description":"The mortality of tree cover where forest fires were the direct cause of loss.\u0026nbsp;"},"150":{"name":"tree crops","description":"Stand of perennial trees that produce agricultural products, such as rubber, oil palm, coffee, coconut, cocoa and orchards."},"85":{"name":"trees outside forests","description":"Trees found in urban areas, alongside roads, or within agricultural land\u0026nbsp;are often referred to as Trees Outside Forests (TOF).\u202f\r\n"},"151":{"name":"unmanaged","description":"A forest that grows without human intervention and has no signs of management, including primary forest.Lesiv et al. 2022, https:\/\/doi.org\/10.1038\/s41597-022-01332-3"},"105":{"name":"unmanaged natural forests","description":"A forest that grows without human intervention and has no signs of management, including primary forest.Lesiv et al. 2022, https:\/\/doi.org\/10.1038\/s41597-022-01332-3"},"158":{"name":"tree cover loss from fire","description":"The mortality of tree cover where forest fires were the direct cause of loss.\u0026nbsp;"}}}