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What is tree cover loss?
The tree cover loss data captures disturbances to tree cover, defined here as woody vegetation with a height of at least 5 meters — learn more about tree cover in Key Terms and Definitions.
Tree cover loss includes disturbances that clear at least half of tree cover within a 30-meter pixel, and are detected on an annual basis for each calendar year. Only the first year of loss that occurs after the year 2000 is recorded, meaning that if multiple disturbances occur over time within the same pixel, only the first disturbance event is included.
Disturbances include mortality or removal of trees in natural forests as well as in wood fiber or tree crop plantations, agroforestry, urban parks or other areas with tree cover. Loss of tree cover can be due to human causes such as clearing of trees for agriculture, logging or wood harvest — all of which can be legal or illegal — or due to natural events such as storms, wildfire, landslides, flooding or insect outbreaks. These losses can also be permanent or temporary, meaning that forests may regrow or recover following disturbances.
The tree cover loss data can be filtered by a baseline data set to focus on the most concerning losses, such as primary forest areas (see below).
How is tree cover loss different from deforestation?
Tree cover loss is not always deforestation, which typically refers to a human-caused, permanent change from forest to another land use. Some forms of human-caused tree cover loss, such as conversion of a natural forest to agricultural land, are widely considered to be deforestation, while other forms, such as timber harvesting in plantation forests or natural disturbances, are frequently not — read more about the differences in Key Terms and Definitions.
In some cases, such as in the Deforestation and Restoration Targets Tracker , we use a proxy for deforestation. That proxy uses data on the drivers of tree cover loss and includes all tree cover loss globally from permanent agriculture, hard commodities (mining or energy infrastructure) and expansion of settlements and infrastructure, as well as loss in humid tropical primary forests from shifting cultivation. Temporary losses, such as from fires or logging activities, are not included.
What baselines do we use to measure tree cover loss?
Tree cover loss statistics throughout the GFR (unless otherwise noted), and by default on Global Forest Watch, use a baseline of tree cover with greater than 30 percent canopy density in the year 2000. This means that loss within this 30% tree canopy density area is included, but loss in lower tree canopy densities or in areas that regrew since the year 2000 are not included.
In the Forest Pulse, we largely focus on tropical primary forest loss because tropical forests experience the vast majority (94%) of the world’s deforestation, and loss in those areas has huge impacts on biodiversity and carbon storage. Even if these losses are eventually reversed, it will take decades for these habitats and carbon stocks to recover, and permanent biodiversity loss may occur.
For these analyses, we use data on humid tropical primary forest extent in 2001 as a baseline. In this data set, primary forests are defined as mature humid tropical forests that have not been completely cleared and regrown in recent history, and tree cover loss within this baseline excludes loss in young secondary forest, plantations or tree crops.
What does tree cover loss from fires include?
We report specifically on tree cover loss due to fires because fires are often one of the single biggest drivers of loss globally. The tree cover loss from fire data distinguishes fire-driven loss from all other drivers of loss for each 30-meter tree cover loss pixel by using a machine learning model to detect burned trees.
The data captures natural wildfires and intentionally set fires that result in the direct loss of tree cover, including escaped fires started by humans for purposes related to agriculture, hunting, recreation or arson. However, instances where trees are first felled and the residue vegetation is later burned are not included since the initial driver of loss is mechanical removal.
How has the tree cover loss data improved over time, and how does this affect comparability between years?
Algorithm adjustments and better satellite data have improved the tree cover loss data set over time. The original algorithm was developed for the years 2001-2012 and assigned loss to a single year in that block of time. Subsequent improvements were developed for the following time periods:
- 2013-2014: Short-interval model, adding the years 2013 and 2014 by assessing changes within a 4-year interval.
- 2015-2017: Landsat 8 data incorporated; annual change detection algorithm applied using regionally and locally calibrated models.
- 2018-2022: Collection 2 Landsat Analysis Ready Data incorporated, as well as improved change detection algorithm using locally calibrated models.
- 2023-2024: DIST-ALERT land disturbance data set incorporated to assist with late season changes.
Together, these improvements have resulted in increased sensitivity in detecting changes such as selective logging, small-scale shifting cultivation and fires. The addition of DIST-ALERT has also improved the detection of late season loss that would otherwise be missed until the following year due to limited satellite data or cloud cover. In addition to methodological changes, variations in satellite image availability (which has generally increased over time) also mean there are inconsistencies with the quality and number of images available to capture data each year.
To address these inconsistencies, we assess the three-year moving average to interpret long-term trends, and also disregard the increase in loss post-2012 in places likely to be impacted by these changes, like Central Africa and tropical Asia.
How does tree cover loss compare to other types of monitoring systems?
There are important definitional and methodological differences between the tree cover loss data presented in the GFR and national monitoring systems — such as PRODES in Brazil and SIMONTANA in Indonesia. These data sets have different strengths and purposes. They can present complementary information that can help us better understand different types of changes within forests, but it is important to understand the differences before comparing them. While not a complete overview, some common differences include:
- Definitions of loss and forest monitoring baseline: While the tree cover loss data includes the loss of any type of tree cover from any cause, national monitoring systems are often more restrictive in the types of disturbances that are included in their statistics and in their baseline used for forest monitoring because they aim to measure deforestation according to official definitions. For example, Brazil’s PRODES measures clearcut deforestation of natural forests for agriculture, pasture and mining, but does not include selective logging or fire.
- Minimum area measured: While tree cover loss uses 30-meter pixels, national monitoring systems may use a minimum mapping unit that is larger; for example, both PRODES and SIMONTANA use a minimum mapping unit of 6.25 hectares.
- Reporting period: While the reporting period of the tree cover loss data covers the calendar year, both PRODES and SIMONTANA use a different reporting period — PRODES covers August to July, while SIMONTANA covers July to June.
- Methods: While various monitoring systems may use satellite imagery as input data, the methods used to detect loss may vary. The tree cover loss data is produced using an automated algorithm to detect loss based on Landsat satellite imagery. However, both PRODES and SIMONTANA use manual visual interpretation of satellite imagery to delineate loss.
These differences are important to consider when interpreting statistics between monitoring systems and often result in differences in the area of loss reported annually from the various systems.
Read our blog on Global Forest Watch to learn more about details and differences specific to the latest data.
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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;"}}}
