THE WORLD'S LAST INTACT FOREST LANDSCAPES
(A direct Extract from Green Peace, Taken with permission purely for blog display)
The world's remaining ancient forests are vital to the future of the planet. Forests are home to two thirds of all known species of land plants and animals. They are also home to thousands of indigenous cultures that rely on forests for food, water and the necessities of life. Forests also play a key role in regulating local and global climate. They are vital to the future of life on Earth.
This Greenpeace map is the first global assessment of remaining tracts of intact forest landscapes larger than 500 sq. km that are not fragmented by infrastructure, such as roads, settlements, waterways, pipelines, power lines etc. These tracts are located within the forest vegetation zone and are mostly forested but also contain swamps and other non-forested ecosystems which are without significant visible signs of human impact such as logging, burning or other forms of forest clearing.
There are three reasons to focus on large tracts. First, only sufficiently large areas can conserve populations of large animals in their natural state and survive natural disturbance dynamics such as fires and storms. Second, large intact areas can serve as references to better understand and manage already degraded or fragmented areas (which make up the vast majority of forest landscapes). Third, large intact areas are often comparatively cheap to conserve, as they tend to rely on remoteness as their main guarantee of protection.
The map identifies forest landscapes which include non-forested areas. The reason for mapping landscapes instead of individual ecosystems is that the forest is a natural mosaic of integrated ecosystems, including forests, wetlands, rivers, lakes, and other treeless areas. Separating these ecosystems would not only be difficult but also artificial.
This assessment is based on the most up-to-date high-resolution satellite imagery and a consistent set of global criteria which allows for the first time direct comparison of the state of forests throughout the world. The finest-scale infrastructure maps and the latest available satellite imagery (2000-2004) were used. The goal of this project was to find and record forest landscapes with a minimum of human disturbance. Two things must be stressed: the boundary of human influence is often diffuse and areas without any human disturbance no longer remain. In this study, an area was considered to be in an intact, natural state if it showed no signs of infrastructure, industrial forest harvesting during the last 30-50 years, mining, land clearing or other essential human impacts. Traces of low-intensity human disturbance (such as hunting, pollution, forest grazing) did not lead to exclusion from the intact forest landscapes.
This map of large intact natural forest landscapes is an important component of a general conservation strategy, but it is not in itself sufficient. Many ecosystems have already been disturbed to the point where only small fragments remain. Mapping of these remnants was outside the scope of this study but this in no way precludes their potential assessment as having high conservation values and is therefore an important task for future examinations.
This map was prepared by Greenpeace with the participation of the Biodiversity Conservation Center (Russia), International Socio-Ecological Union, Forest Watch Indonesia and Luonto-Liitto (Finnish Nature League). Additionally, the following publications were used as references: "The Last Intact Forest Landscapes of Northern European Russia" (Greenpeace and GFW, 2001); "Remaining Wildlands of the Northern Forests" (GFW, 2002, unreviewed draft); and "Atlas of Russia's Intact Forest Landscapes"(GFW,2002). This website (www.intactforests.org) provides detailed maps, statistics and other related information. For more general information see www.greenpeace.org/forestmaps
The Natural Value of Large Intact Forest Landscapes
Researchers recognize the special value of large natural areas for preserving all strata of biological diversity (McCloskey, Spalding, 1989, Bryant et al., 1997, Noss, 1990 etc.). Forest biodiversity largely depends on intact forest landscapes. Large animal populations (such as forest elephants, great apes, bears, wolfs, tigers, jaguars, eagles, deer etc.) especially require these intact forest landscapes for preservation. The fragmentation and loss of natural habitats is a main factor threatening plant and animal species with extinction. Also regionally or globally important ecological processes and services (such as water and air purification, nutrient cycling, carbon sequestration, erosion and flood control, etc.) are supported by intact forest landscapes and other intact ecosystems. All of this makes the conservation value of intact forest landscapes relatively high overall while it may differ from area to area.
For many factors, reserve size is vital to the success of conservation efforts. Such factors include stable populations of large animals that are especially sensitive to human impact or habitat changes, lakes and wetlands as objects of reference, and the natural dynamics of forest ecosystems associated with large-scale disturbances such as fire or wind damage. Also, the central parts of large reserves are better protected from "edge effects," which include invasion of alien species, increased human access with subsequent increase of poaching and fires, drying-out of the forest, etc. Relatively small forest fragments can exhibit increased vulnerability to threats beyond their borders.
It's impossible to pinpoint the minimum area required for indefinite preservation of all natural components of a forest landscape. Habitats of different sizes are needed to support a diversity of bio-components. These areas also depend on a vast variety of local conditions with best estimates utilized to approximate the needed space for intact habitat viability.
Certainly, the greater the area, the greater the number of organisms and natural properties that can be preserved and ultimately the greater the overall viability of the intact forest landscape. Also of note is the knowledge gap regarding spatial relationships among the components of forest ecosystems. The same is true for the mechanisms that govern the survival of particularly sensitive plant and animal species. Protecting large intact forest landscapes is therefore a matter of reasonable precaution, as it promotes the conservation of all species, both those well-studied and those yet unknown.
In this study, large intact areas were defined as landscapes greater than or equal to 500 km2, internally undivided by infrastructure, and with a minimum linear dimension no smaller than 10 kilometers. Such spaces are capable of maintaining most natural values and functions of a self-sustaining boreal landscape, including the following:
Small-scale (the falling down or death of individual trees) and large-scale (fire, insect infestations, extreme weather conditions) random disturbances
Self-maintaining populations of plant and animal species especially sensitive to human disturbance
Intact catchment basins around rivers, bogs and streams
Spatial patterns of ecosystems and habitats
Rare or extremely sensitive ecosystems, that disappear in fragmented landscapes as a result of permanent human influence
These dimensions sufficiently buffer most edge effects, including the collapse of the forest edge of logging sites, outbreaks of pest insects in logging debris, changes in water regime due to clearing of neighboring areas, and the effects of intensive hunting and fishing.
Criteria & Definitions
Intact Forest Landscape
An intact forest landscape is a territory within the forest zone which contains forest and non-forest ecosystems minimally disturbed by human economic activity, with an area of at least 500 km2 and with a minimal width (diameter of the inscribed circle) of 10 km.
The following objects are excluded from the intact forest landscapes:
Settlements (with 1 km buffer zone)
1 km buffer zones around infrastructure used for communication between settlements and industrial sites; or for industrial exploitation of natural resources (including motor roads, railways, navigable waterways, pipelines, trunk power transmission lines and other linear objects)
Agricultural lands, except small scale which are used by local communities for their needs and are not connected with the rest of the world by infrastructure
Territories disturbed by economic activities during the last 30-70 years (logging, mining operation sites, abandoned agricultural lands, etc.)
Artificially restored forests, tree plantations
Burnt lands and young tree sites adjacent to infrastructure objects (buffer zones of km)
The ratio of forest and non-forest ecosystems within intact forest landscapes has no restriction; the key criteria are absence of disturbed territories and infrastructure objects. Thus, intact forest landscapes can consist primarily of non-forest nature ecosystems that are minimally disturbed by human economic activity (for example, treeless swamps or mountains fully surrounded by forest).
It should be noted that some human impact is invisible from space (for example, small forest roads and paths or, specifically in Central African forests, the decline of populations of large mammals as a result of over-hunting). Also, smaller-scale impacts (including some selective logging) that occurred more than 30-70 years ago - depending on the region - often become invisible on satellite imagery, undistinguishable from the natural dynamics of the forest.
The map was based primarily on 2000-2002 Landsat images. The most recent human impacts are also not shown on it as the satellite imagery used is on average 4-5 years old. All this leads to some - albeit globally insignificant - overestimations of intact forest landscape areas despite the 1 km buffer exclusion zones. Only on local ground verifications can provide a more accurate picture in these situations.
Forest Zone
Borders of the forest zone were defined according to the "Global Percent Tree Cover at a Spatial Resolution of 500 meters" map (Hansen et al., 2003). The forest zone includes all parts of the forests with a tree cover density of 20 percent or more, if the distance between them is less than two kilometers, and all non-forest plots which are fully surrounded by forests. All forest plots generated in this way were considered to be part of the forest zone if their area was 500 km2 and more.
Intact Forest Landscapes. Russia © Greenpeace/Kantor
Intact Forest Landscapes in Amazon. Brazil © Greenpeace/Cannalonga
This map follows the WRI map from 1997 assessing intact forest landscapes, but for the first time uses the latest satellite imagery for the global assessment. It is based on strict rules of interpretation in order to make the results globally as comparable as possible.
The mapping method: The method of mapping is based on a subtractive approach to identifying intact forest landscapes. All sources of information were analyzed to detect disturbed areas or infrastructure lines dividing natural landscape into separate isolated parts. All areas remaining after the identification of disturbed areas and infrastructure were classified as intact forest landscapes, so long as they met the size criteria (see definitions). This method follows the precautionary approach: unless an area is clearly identified as disturbed, according to the available sources of information, it is considered to be an intact forest area.
The second important aspect of the mapping method is the stepwise use of materials of different precision and accuracy.
Mapping algorithm: 1) the forest zone was defined and identified according to the "Global Percent Tree Cover at a Spatial Resolution of 500 meters" map (Hansen et al., 2003). As this map shows a gradual transition from the forest zone to non-forest territories, the following algorithm was used to establish the linear borders of the forest zone. All parts of the forests with a treecanopy cover density of 20 percent or more were considered solid forest tracts if the distance between them is less than two kilometers. All forest plots combined in this way were considered to be the parts of the forest zone if their area was 50 thousand hectares or more. All non-forest plots within the forest zone (i.e. fully surrounded by forests) were regarded as a part of the forest zone. The borders of the forest zone were slightly changed in some areas of the world, but only in cases when they obviously did not fit with the existing vegetation maps or higher resolution imagery (this happened only in areas of open forests with tree cover of 20 to 39%).2) The best and most up-to-date topographic maps available in every region were used. According to these maps, the global forests were divided by infrastructure (with 1 km buffer zones along it) into a great number of separate sections. Each of these was regarded as a potential intact forest landscape. Questionable objects of infrastructure in these maps (for example, temporary or seasonal roads and trails) were not considered. After that, the first sorting of potential intact forest landscapes was held according to their size. This considerably decreased both the area for further analysis of satellite images and the amount of work. So, before the beginning of work with satellite images, significant territories within the most densely populated and developed parts of the forest biomes were excluded from further analysis.
3) LANDSAT TM (global coverage of about 1990) and LANDSAT ETM+ (global coverage of about 2000) space images were used to identify disturbed landscapes and objects of infrastructure, which were not shown in reliable topographic maps. Both sets of images were used together: LANDSAT ETM+ images made it possible to detect the most recent disturbances, while LANDSAT TM - were used for older ones, whose traces have become less evident now. This is especially important in tropical forests, where the traces of disturbances disappear much faster than in temperate and boreal forests. 1 km buffer zones around human infrastructure (roads, waterways, settlements etc) and fire scars in the vicinity of human infrastructure where excluded from intact forest landscapes, because most natural fire cycles have been significantly altered in the vicinity of human infrastructure (eg increased fire frequency).
Disturbances: logging roads. Congo
Disturbances: logging roads. Gabon
Disturbed areas: agriculture clearings and pastures with fire dynamics. Democratic Republic of the Congo
Deforested landscape with human-induced pyrogenic dynamic. Congo
Using satellite images in the final stage allowed for the smoothing out of differences between regions that occurred at the stage of using topographical maps (as the quality, scale and age of the maps was significantly different for different areas). If any infrastructure was not shown in topographical maps or if it was of an "unreliable" type (like a temporary road), the decision regarding its exclusion from potentially intact forest landscapes depended on how it looked in the LANDSAT image.
Disturbances: different types of anthropogenic disturbances in boreal forests
4) Borders of intact forest landscapes were refined: long (where length was greater than width) ledges with a width of 2 meters or more were eliminated. Then the final sorting of the remaining intact forest landscapes was carried out according to their size, and those of less than 50 thousand hectares were excluded.
Intact Forest Landscape borders, Tropical forests. Papua-New Guinea
Intact Forest Landscape borders, Boreal forest region. Russia
The result of the project is a map of the borders of intact forest landscapes within the forest zone. The information about the limits of the forest zone itself, as well as limits of closed and open forests and non-forested areas within the forest zone and within intact forest landscapes is taken from the "Global Percent Tree Cover at a Spatial Resolution of 500 meters" map.
Important remarks
The World Intact Forest Landscapes map is the first global assessment of intact forest landscapes based on high-resolution satellite imagery analysis. The world map of intact forest landscapes is based on a global set of criteria and approaches, the same for all countries and continents. This can lead to the neglection of some regional differences in understanding the human role in certain types of forest landscape disturbances (like fires or hunting). Also, the world map may contain inaccuracies caused by lack of available information about local land-use practices and the state of forests in some regions of the Earth. The authors plan for the map to be periodically updated as soon as new data and more sophisticated sources of information and technologies are available. Ideally it should become a "living map", which will periodically be improved and updated to reflect the results of intact forest landscape monitoring.
The world map is based on the best available non-commercial space images for each region. Most of them are GLCF images of Landsat 7 1999-2002. This has two important implications: first, the map does not reflect changes of intact forest landscapes that occurred during last 3-5 years, and second, the map does not reflect some types of disturbances or fragmentation of the natural landscape which cannot be detected using Landsat images (for example, local forest roads, small temporary agricultural clearings or seismic lines that are not used as roads). These disadvantages of the world map can be corrected in the process of making more detailed regional or national maps, which could be based on more recent and detailed information.
The world map may contain some inaccuracies caused by a lack of available information for mapping experts about local land use practices and the state of forests in each country or region of the Earth. This is an inevitable challenge for any group of experts struggling to secure the global compatibility of the mapping work. Inaccuracies can be corrected during the composition of regional and national maps, which can better take into account local knowledge and experience.
Key Findings:
Intact Forest Landscapes identification and mapping was carried out for the whole forest zone in the area of approx. 56,000,000 km2, which occupies 37.6% of the Earth's land surface.
The area of identified Intact Forest Landscapes of the world is 13,134,731 km2. Less than one fourth of the forest zone (23.4%) of the Earth forest zone (regions with average tree canopy coverage above 20%) remain as Intact Forest Landscapes. That is only 8.8% of the Earth's land surface.
The remainder of forest zone has been degraded, converted to plantations or fragmented to areas smaller than 500 km2 in size by roads, settlements etc. Many of these smaller areas have a high conservation value too, due to their rarity or their unique diversity of plant and animal species.
The vast majority of the remaining Intact Forest Landscapes of the world are made up of the boreal (taiga) forests of Russia, Canada and Alaska (43.9 %) and dense lowland tropical forests of the Amazon, Congo and South East Asia Pacific (45.7%). Some forest types like temperate broadleaf forests have less than 4% of Intact Forest Landscapes left.
69.3% of the world's Intact Forest Landscapes are occupied by closed forests (forest areas with more then 40% tree canopy coverage), 16.4% - open forests (tree canopy coverage 20-40%) and 14.3% - non forest ecosystems (swamps, mountain ecosystems, lakes etc.). 29.4% of the world's dense forests remain in Intact Forest Landscapes.
Of all countries full or partly within the forest zone, 82 have lost all of their Intact Forest Landscapes and whilst 66 countries still have Intact Forest Landscapes, for half of these it's less than 10% of their forest zone area.
Only fourteen countries, including Canada, Brazil, Russia, Papua New Guinea, Democratic Republic of the Congo, and Indonesia control 92% of the world's remaining Intact Forest Landscapes.
Overall, only 7.9% of all Intact Forest Landscapes lie in strictly protected areas (IUCN categories I - III) according to UNEP/IUCN World Database on Protected Areas.
Conservation of large Intact Forest Landscapes is a robust and cost-effective way to conserve biological diversity. The remoteness and large size of these areas provide the best guarantee of continued intactness.
(A direct Extract from Green Peace, Taken with permission purely for blog display)
The world's remaining ancient forests are vital to the future of the planet. Forests are home to two thirds of all known species of land plants and animals. They are also home to thousands of indigenous cultures that rely on forests for food, water and the necessities of life. Forests also play a key role in regulating local and global climate. They are vital to the future of life on Earth.
This Greenpeace map is the first global assessment of remaining tracts of intact forest landscapes larger than 500 sq. km that are not fragmented by infrastructure, such as roads, settlements, waterways, pipelines, power lines etc. These tracts are located within the forest vegetation zone and are mostly forested but also contain swamps and other non-forested ecosystems which are without significant visible signs of human impact such as logging, burning or other forms of forest clearing.
There are three reasons to focus on large tracts. First, only sufficiently large areas can conserve populations of large animals in their natural state and survive natural disturbance dynamics such as fires and storms. Second, large intact areas can serve as references to better understand and manage already degraded or fragmented areas (which make up the vast majority of forest landscapes). Third, large intact areas are often comparatively cheap to conserve, as they tend to rely on remoteness as their main guarantee of protection.
The map identifies forest landscapes which include non-forested areas. The reason for mapping landscapes instead of individual ecosystems is that the forest is a natural mosaic of integrated ecosystems, including forests, wetlands, rivers, lakes, and other treeless areas. Separating these ecosystems would not only be difficult but also artificial.
This assessment is based on the most up-to-date high-resolution satellite imagery and a consistent set of global criteria which allows for the first time direct comparison of the state of forests throughout the world. The finest-scale infrastructure maps and the latest available satellite imagery (2000-2004) were used. The goal of this project was to find and record forest landscapes with a minimum of human disturbance. Two things must be stressed: the boundary of human influence is often diffuse and areas without any human disturbance no longer remain. In this study, an area was considered to be in an intact, natural state if it showed no signs of infrastructure, industrial forest harvesting during the last 30-50 years, mining, land clearing or other essential human impacts. Traces of low-intensity human disturbance (such as hunting, pollution, forest grazing) did not lead to exclusion from the intact forest landscapes.
This map of large intact natural forest landscapes is an important component of a general conservation strategy, but it is not in itself sufficient. Many ecosystems have already been disturbed to the point where only small fragments remain. Mapping of these remnants was outside the scope of this study but this in no way precludes their potential assessment as having high conservation values and is therefore an important task for future examinations.
This map was prepared by Greenpeace with the participation of the Biodiversity Conservation Center (Russia), International Socio-Ecological Union, Forest Watch Indonesia and Luonto-Liitto (Finnish Nature League). Additionally, the following publications were used as references: "The Last Intact Forest Landscapes of Northern European Russia" (Greenpeace and GFW, 2001); "Remaining Wildlands of the Northern Forests" (GFW, 2002, unreviewed draft); and "Atlas of Russia's Intact Forest Landscapes"(GFW,2002). This website (www.intactforests.org) provides detailed maps, statistics and other related information. For more general information see www.greenpeace.org/forestmaps
The Natural Value of Large Intact Forest Landscapes
Researchers recognize the special value of large natural areas for preserving all strata of biological diversity (McCloskey, Spalding, 1989, Bryant et al., 1997, Noss, 1990 etc.). Forest biodiversity largely depends on intact forest landscapes. Large animal populations (such as forest elephants, great apes, bears, wolfs, tigers, jaguars, eagles, deer etc.) especially require these intact forest landscapes for preservation. The fragmentation and loss of natural habitats is a main factor threatening plant and animal species with extinction. Also regionally or globally important ecological processes and services (such as water and air purification, nutrient cycling, carbon sequestration, erosion and flood control, etc.) are supported by intact forest landscapes and other intact ecosystems. All of this makes the conservation value of intact forest landscapes relatively high overall while it may differ from area to area.
For many factors, reserve size is vital to the success of conservation efforts. Such factors include stable populations of large animals that are especially sensitive to human impact or habitat changes, lakes and wetlands as objects of reference, and the natural dynamics of forest ecosystems associated with large-scale disturbances such as fire or wind damage. Also, the central parts of large reserves are better protected from "edge effects," which include invasion of alien species, increased human access with subsequent increase of poaching and fires, drying-out of the forest, etc. Relatively small forest fragments can exhibit increased vulnerability to threats beyond their borders.
It's impossible to pinpoint the minimum area required for indefinite preservation of all natural components of a forest landscape. Habitats of different sizes are needed to support a diversity of bio-components. These areas also depend on a vast variety of local conditions with best estimates utilized to approximate the needed space for intact habitat viability.
Certainly, the greater the area, the greater the number of organisms and natural properties that can be preserved and ultimately the greater the overall viability of the intact forest landscape. Also of note is the knowledge gap regarding spatial relationships among the components of forest ecosystems. The same is true for the mechanisms that govern the survival of particularly sensitive plant and animal species. Protecting large intact forest landscapes is therefore a matter of reasonable precaution, as it promotes the conservation of all species, both those well-studied and those yet unknown.
In this study, large intact areas were defined as landscapes greater than or equal to 500 km2, internally undivided by infrastructure, and with a minimum linear dimension no smaller than 10 kilometers. Such spaces are capable of maintaining most natural values and functions of a self-sustaining boreal landscape, including the following:
Small-scale (the falling down or death of individual trees) and large-scale (fire, insect infestations, extreme weather conditions) random disturbances
Self-maintaining populations of plant and animal species especially sensitive to human disturbance
Intact catchment basins around rivers, bogs and streams
Spatial patterns of ecosystems and habitats
Rare or extremely sensitive ecosystems, that disappear in fragmented landscapes as a result of permanent human influence
These dimensions sufficiently buffer most edge effects, including the collapse of the forest edge of logging sites, outbreaks of pest insects in logging debris, changes in water regime due to clearing of neighboring areas, and the effects of intensive hunting and fishing.
Criteria & Definitions
Intact Forest Landscape
An intact forest landscape is a territory within the forest zone which contains forest and non-forest ecosystems minimally disturbed by human economic activity, with an area of at least 500 km2 and with a minimal width (diameter of the inscribed circle) of 10 km.
The following objects are excluded from the intact forest landscapes:
Settlements (with 1 km buffer zone)
1 km buffer zones around infrastructure used for communication between settlements and industrial sites; or for industrial exploitation of natural resources (including motor roads, railways, navigable waterways, pipelines, trunk power transmission lines and other linear objects)
Agricultural lands, except small scale which are used by local communities for their needs and are not connected with the rest of the world by infrastructure
Territories disturbed by economic activities during the last 30-70 years (logging, mining operation sites, abandoned agricultural lands, etc.)
Artificially restored forests, tree plantations
Burnt lands and young tree sites adjacent to infrastructure objects (buffer zones of km)
The ratio of forest and non-forest ecosystems within intact forest landscapes has no restriction; the key criteria are absence of disturbed territories and infrastructure objects. Thus, intact forest landscapes can consist primarily of non-forest nature ecosystems that are minimally disturbed by human economic activity (for example, treeless swamps or mountains fully surrounded by forest).
It should be noted that some human impact is invisible from space (for example, small forest roads and paths or, specifically in Central African forests, the decline of populations of large mammals as a result of over-hunting). Also, smaller-scale impacts (including some selective logging) that occurred more than 30-70 years ago - depending on the region - often become invisible on satellite imagery, undistinguishable from the natural dynamics of the forest.
The map was based primarily on 2000-2002 Landsat images. The most recent human impacts are also not shown on it as the satellite imagery used is on average 4-5 years old. All this leads to some - albeit globally insignificant - overestimations of intact forest landscape areas despite the 1 km buffer exclusion zones. Only on local ground verifications can provide a more accurate picture in these situations.
Forest Zone
Borders of the forest zone were defined according to the "Global Percent Tree Cover at a Spatial Resolution of 500 meters" map (Hansen et al., 2003). The forest zone includes all parts of the forests with a tree cover density of 20 percent or more, if the distance between them is less than two kilometers, and all non-forest plots which are fully surrounded by forests. All forest plots generated in this way were considered to be part of the forest zone if their area was 500 km2 and more.
Intact Forest Landscapes. Russia © Greenpeace/Kantor
Intact Forest Landscapes in Amazon. Brazil © Greenpeace/Cannalonga
This map follows the WRI map from 1997 assessing intact forest landscapes, but for the first time uses the latest satellite imagery for the global assessment. It is based on strict rules of interpretation in order to make the results globally as comparable as possible.
The mapping method: The method of mapping is based on a subtractive approach to identifying intact forest landscapes. All sources of information were analyzed to detect disturbed areas or infrastructure lines dividing natural landscape into separate isolated parts. All areas remaining after the identification of disturbed areas and infrastructure were classified as intact forest landscapes, so long as they met the size criteria (see definitions). This method follows the precautionary approach: unless an area is clearly identified as disturbed, according to the available sources of information, it is considered to be an intact forest area.
The second important aspect of the mapping method is the stepwise use of materials of different precision and accuracy.
Mapping algorithm: 1) the forest zone was defined and identified according to the "Global Percent Tree Cover at a Spatial Resolution of 500 meters" map (Hansen et al., 2003). As this map shows a gradual transition from the forest zone to non-forest territories, the following algorithm was used to establish the linear borders of the forest zone. All parts of the forests with a treecanopy cover density of 20 percent or more were considered solid forest tracts if the distance between them is less than two kilometers. All forest plots combined in this way were considered to be the parts of the forest zone if their area was 50 thousand hectares or more. All non-forest plots within the forest zone (i.e. fully surrounded by forests) were regarded as a part of the forest zone. The borders of the forest zone were slightly changed in some areas of the world, but only in cases when they obviously did not fit with the existing vegetation maps or higher resolution imagery (this happened only in areas of open forests with tree cover of 20 to 39%).2) The best and most up-to-date topographic maps available in every region were used. According to these maps, the global forests were divided by infrastructure (with 1 km buffer zones along it) into a great number of separate sections. Each of these was regarded as a potential intact forest landscape. Questionable objects of infrastructure in these maps (for example, temporary or seasonal roads and trails) were not considered. After that, the first sorting of potential intact forest landscapes was held according to their size. This considerably decreased both the area for further analysis of satellite images and the amount of work. So, before the beginning of work with satellite images, significant territories within the most densely populated and developed parts of the forest biomes were excluded from further analysis.
3) LANDSAT TM (global coverage of about 1990) and LANDSAT ETM+ (global coverage of about 2000) space images were used to identify disturbed landscapes and objects of infrastructure, which were not shown in reliable topographic maps. Both sets of images were used together: LANDSAT ETM+ images made it possible to detect the most recent disturbances, while LANDSAT TM - were used for older ones, whose traces have become less evident now. This is especially important in tropical forests, where the traces of disturbances disappear much faster than in temperate and boreal forests. 1 km buffer zones around human infrastructure (roads, waterways, settlements etc) and fire scars in the vicinity of human infrastructure where excluded from intact forest landscapes, because most natural fire cycles have been significantly altered in the vicinity of human infrastructure (eg increased fire frequency).
Disturbances: logging roads. Congo
Disturbances: logging roads. Gabon
Disturbed areas: agriculture clearings and pastures with fire dynamics. Democratic Republic of the Congo
Deforested landscape with human-induced pyrogenic dynamic. Congo
Using satellite images in the final stage allowed for the smoothing out of differences between regions that occurred at the stage of using topographical maps (as the quality, scale and age of the maps was significantly different for different areas). If any infrastructure was not shown in topographical maps or if it was of an "unreliable" type (like a temporary road), the decision regarding its exclusion from potentially intact forest landscapes depended on how it looked in the LANDSAT image.
Disturbances: different types of anthropogenic disturbances in boreal forests
4) Borders of intact forest landscapes were refined: long (where length was greater than width) ledges with a width of 2 meters or more were eliminated. Then the final sorting of the remaining intact forest landscapes was carried out according to their size, and those of less than 50 thousand hectares were excluded.
Intact Forest Landscape borders, Tropical forests. Papua-New Guinea
Intact Forest Landscape borders, Boreal forest region. Russia
The result of the project is a map of the borders of intact forest landscapes within the forest zone. The information about the limits of the forest zone itself, as well as limits of closed and open forests and non-forested areas within the forest zone and within intact forest landscapes is taken from the "Global Percent Tree Cover at a Spatial Resolution of 500 meters" map.
Important remarks
The World Intact Forest Landscapes map is the first global assessment of intact forest landscapes based on high-resolution satellite imagery analysis. The world map of intact forest landscapes is based on a global set of criteria and approaches, the same for all countries and continents. This can lead to the neglection of some regional differences in understanding the human role in certain types of forest landscape disturbances (like fires or hunting). Also, the world map may contain inaccuracies caused by lack of available information about local land-use practices and the state of forests in some regions of the Earth. The authors plan for the map to be periodically updated as soon as new data and more sophisticated sources of information and technologies are available. Ideally it should become a "living map", which will periodically be improved and updated to reflect the results of intact forest landscape monitoring.
The world map is based on the best available non-commercial space images for each region. Most of them are GLCF images of Landsat 7 1999-2002. This has two important implications: first, the map does not reflect changes of intact forest landscapes that occurred during last 3-5 years, and second, the map does not reflect some types of disturbances or fragmentation of the natural landscape which cannot be detected using Landsat images (for example, local forest roads, small temporary agricultural clearings or seismic lines that are not used as roads). These disadvantages of the world map can be corrected in the process of making more detailed regional or national maps, which could be based on more recent and detailed information.
The world map may contain some inaccuracies caused by a lack of available information for mapping experts about local land use practices and the state of forests in each country or region of the Earth. This is an inevitable challenge for any group of experts struggling to secure the global compatibility of the mapping work. Inaccuracies can be corrected during the composition of regional and national maps, which can better take into account local knowledge and experience.
Key Findings:
Intact Forest Landscapes identification and mapping was carried out for the whole forest zone in the area of approx. 56,000,000 km2, which occupies 37.6% of the Earth's land surface.
The area of identified Intact Forest Landscapes of the world is 13,134,731 km2. Less than one fourth of the forest zone (23.4%) of the Earth forest zone (regions with average tree canopy coverage above 20%) remain as Intact Forest Landscapes. That is only 8.8% of the Earth's land surface.
The remainder of forest zone has been degraded, converted to plantations or fragmented to areas smaller than 500 km2 in size by roads, settlements etc. Many of these smaller areas have a high conservation value too, due to their rarity or their unique diversity of plant and animal species.
The vast majority of the remaining Intact Forest Landscapes of the world are made up of the boreal (taiga) forests of Russia, Canada and Alaska (43.9 %) and dense lowland tropical forests of the Amazon, Congo and South East Asia Pacific (45.7%). Some forest types like temperate broadleaf forests have less than 4% of Intact Forest Landscapes left.
69.3% of the world's Intact Forest Landscapes are occupied by closed forests (forest areas with more then 40% tree canopy coverage), 16.4% - open forests (tree canopy coverage 20-40%) and 14.3% - non forest ecosystems (swamps, mountain ecosystems, lakes etc.). 29.4% of the world's dense forests remain in Intact Forest Landscapes.
Of all countries full or partly within the forest zone, 82 have lost all of their Intact Forest Landscapes and whilst 66 countries still have Intact Forest Landscapes, for half of these it's less than 10% of their forest zone area.
Only fourteen countries, including Canada, Brazil, Russia, Papua New Guinea, Democratic Republic of the Congo, and Indonesia control 92% of the world's remaining Intact Forest Landscapes.
Overall, only 7.9% of all Intact Forest Landscapes lie in strictly protected areas (IUCN categories I - III) according to UNEP/IUCN World Database on Protected Areas.
Conservation of large Intact Forest Landscapes is a robust and cost-effective way to conserve biological diversity. The remoteness and large size of these areas provide the best guarantee of continued intactness.
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