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 18 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),Hansen et al. 2013, https://doi.org/10.1126/science.1244693 .  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":{"51":{"name":"agricultural tree crops","description":"Trees cultivated for their food, cultural, or economic values. These include oil palm, rubber, cocoa, cashew, mango, oranges (citrus), plantain, banana, and coconut.\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"},"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 direct cause of forest disturbance.\r\n"},"70":{"name":"drivers of loss","description":"The direct cause of forest disturbance.\r\n"},"81":{"name":"drivers of tree cover loss","description":"The direct cause of forest disturbance.\r\n"},"2":{"name":"forest","description":"Forests include tree cover greater than 30 percent tree canopy density and greater than 5 meters in height as mapped at a 30-meter Landsat pixel scale.\r\n"},"3":{"name":"forest concession","description":"A legal agreement allowing an entity the right to manage a public forest for production purposes.\r\n"},"90":{"name":"forest concessions","description":"A legal agreement allowing an entity the right to manage a public forest for production purposes.\r\n"},"53":{"name":"forest 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"},"54":{"name":"forest disturbance","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"},"6":{"name":"forest management plan","description":"A plan that documents the stewardship and use of forests and other wooded land to meet environmental, economic, social, and cultural objectives. Such plans are typically implemented by companies in forest concessions.\r\n"},"62":{"name":"forests","description":"Forests include tree cover greater than 30 percent tree canopy density and greater than 5 meters in height as mapped at a 30-meter Landsat pixel scale.\r\n"},"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"},"7":{"name":"hectare","description":"One hectare equals 100 square meters, 2.47 acres, or 0.01 square kilometers and is about the size of a rugby field. A football pitch is slightly smaller than a hectare (pitches are between 0.62 and 0.82 hectares).\r\n"},"66":{"name":"hectares","description":"One hectare equals 100 square meters, 2.47 acres, or 0.01 square kilometers and is about the size of a rugby field. A football pitch is slightly smaller than a hectare (pitches are between 0.62 and 0.82 hectares).\r\n"},"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"},"9":{"name":"loss driver","description":"The direct cause of forest disturbance.\r\n"},"10":{"name":"low tree canopy density","description":"Less than 30 percent tree canopy density.\r\n"},"84":{"name":"managed forest concession","description":"Areas where governments have given rights to private companies to harvest timber and other wood products from natural forests on public lands.\r\n"},"83":{"name":"managed forest concession maps for nine countries","description":"Cameroon, Canada, Central African Republic, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Indonesia, Liberia, and the Republic of the Congo\r\n"},"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."},"56":{"name":"mosaic restoration","description":"Restoration that integrates trees into mixed-use landscapes, such as agricultural lands and settlements, where trees can support people through improved water quality, increased soil fertility, and other ecosystem services. This type of restoration is more likely in deforested or degraded forest landscapes with moderate population density (10\u2013100 people per square kilometer). "},"86":{"name":"natural","description":"A forest that is grown without human intervention.\r\n"},"12":{"name":"natural forest","description":"A forest that is grown without human intervention.\r\n"},"63":{"name":"natural forests","description":"A forest that is grown without human intervention.\r\n"},"82":{"name":"persistent gain","description":"Forests that have experienced one gain event from 2001 to 2016.\r\n"},"13":{"name":"persistent loss and gain","description":"Forests that have experienced one loss or one gain event from 2001 to 2016."},"97":{"name":"plantation","description":"An area in which trees have been planted, generally for commercial purposes.\u0026nbsp;\r\n"},"93":{"name":"plantations","description":"An area in which trees have been planted, generally for commercial purposes.\u0026nbsp;\r\n"},"88":{"name":"planted","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"14":{"name":"planted forest","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"73":{"name":"planted forests","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"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"},"87":{"name":"seminatural","description":"A managed forest modified by humans, which can have a different species composition from surrounding natural forests.\r\n"},"59":{"name":"seminatural forests","description":"A managed forest modified by humans, which can have a different species composition from surrounding natural forests. "},"96":{"name":"shifting agriculture","description":"Temporary loss or permanent deforestation due to small- and medium-scale agriculture.\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":"Less than 30 percent tree canopy density.\r\n"},"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."},"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. "},"19":{"name":"tree plantation","description":"An agricultural plantation of fast-growing tree species on short rotations for the production of timber, pulp, or fruit.\r\n"},"72":{"name":"tree plantations","description":"An agricultural plantation of fast-growing tree species on short rotations for the production of timber, pulp, or fruit.\r\n"},"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"}}}