Deforestation is the conversion of forest to another land use, such as cropland, pasture, settlements, or transport facilities. It differs from temporary tree removal because the land ceases to function or be classified as forest. Its consequences extend beyond the cleared area: forest conversion changes biodiversity, carbon storage, water movement, and the resources available to forest-dependent communities. Agricultural expansion is its principal global driver. (fao.org)
Definitions and distinctions
International forest statistics distinguish land use from the presence of trees. The Food and Agriculture Organization of the United Nations (FAO) generally defines forest as land exceeding 0.5 hectares, with trees taller than 5 metres and canopy cover above 10 percent, or trees capable of reaching those thresholds. Predominantly agricultural or urban land is excluded. Temporarily unstocked areas expected to regenerate can remain classified as forest. Thus, clear-cutting followed by forest regeneration is not necessarily deforestation. (fra-data.fao.org)
Forest degradation refers to deterioration within land that remains forest, rather than conversion to a different land use. Selective logging, excessive fuelwood extraction, and repeated disturbance can degrade forests without immediately eliminating them. “Tree-cover loss,” a common satellite-derived measure, is broader than deforestation: it includes losses caused by harvesting, fire, and other disturbances, whether temporary or permanent. These distinctions are essential when comparing statistics. (ipcc.ch)
Extent and measurement
FAO’s Global Forest Resources Assessment 2025 estimated that 489 million hectares had undergone deforestation since 1990. Average annual deforestation declined from 17.6 million hectares in 1990–2000 to 13.6 million in 2000–2015 and 10.9 million in 2015–2025. These are period averages, not measurements of individual years. (fao.org)
Gross deforestation differs from net forest-area change. Net change combines forest losses with gains through planting and natural expansion. For 2015–2025, FAO estimated annual forest expansion of 6.78 million hectares and net forest loss of 4.12 million hectares. A smaller net loss therefore does not imply that an equally small area was cleared. Nor does new forest elsewhere necessarily replace the ecological characteristics of the forest lost. (fao.org)
Monitoring combines national inventories, land-use records, and remote sensing. Satellite observations reveal where tree cover disappears, but determining whether that disappearance constitutes deforestation requires information about subsequent land use and regeneration. Differences in definitions, observation periods, and treatment of temporary disturbance can produce different estimates without making the datasets directly contradictory. (fao.org)
Drivers
FAO’s remote-sensing survey, announced in 2021, attributed almost 90 percent of global deforestation to agricultural expansion. Conversion to cropland accounted for more than half, while livestock grazing accounted for almost 40 percent. The relative importance of these activities varies geographically; the survey identified grazing as particularly important in South America. (fao.org)
Other direct drivers include mining, urbanization, and infrastructure development. Roads can also facilitate further conversion by opening forest areas to settlement and commercial activity. Logging may be a degradation process rather than deforestation itself, although it can form part of a sequence ending in agricultural conversion. Demand transmitted through international trade connects forest clearance in producing regions with consumption elsewhere. Commodity supply chains therefore feature prominently in analyses of agricultural deforestation. (ipcc.ch)
Ecological and climatic effects
Deforestation removes habitat and can divide remaining forest into isolated patches through habitat fragmentation. The resulting changes affect species composition, movement, and persistence. Losses involve not only trees but also the animals, fungi, and other organisms associated with forest environments. Conversion consequently changes the structure and functioning of the wider ecosystem. (ipcc.ch)
Forests hold carbon in vegetation and soils. Burning, decomposition, and soil disturbance following clearance release part of this stock, including as carbon dioxide. Deforestation also removes vegetation that would otherwise continue absorbing carbon, altering the carbon cycle and contributing to climate change. The climatic consequences depend on the original forest, the replacement land use, and changes in soil carbon and vegetation growth. (ipcc.ch)
Forest conversion also modifies the water cycle. Changes in canopy interception, evapotranspiration, and rooting alter exchanges of water between land and atmosphere. Reduced protective vegetation can increase erosion and sediment delivery to waterways. Hydrological effects are context-dependent: rainfall, soils, terrain, and subsequent land management influence whether and how water availability changes. (ipcc.ch)
Social consequences and responses
Forests supply food, fuel, materials, and income, alongside cultural and regulating ecosystem services. Conversion can create agricultural or commercial opportunities while reducing resources available to other users. Its effects therefore depend partly on who controls land and receives benefits, making forest governance and property rights important to both research and policy. (ipcc.ch)
Responses include protected areas, enforcement of land-use rules, community forest management, and commodity-sourcing controls. Ecological restoration can recover some forest functions, but preventing conversion preserves existing carbon stocks and ecological relationships that planting alone may not readily replace. (ipcc.ch)
REDD+ is a United Nations climate-policy framework covering reduced emissions from deforestation and degradation, forest conservation, sustainable management, and enhancement of forest carbon stocks in developing countries. Access to results-based payments requires monitoring, reference levels, and measured, reported, and verified results. Its safeguards address natural-forest conservation, Indigenous peoples’ and local communities’ rights and participation, reversal risks, and displacement of emissions to other areas. (redd.unfccc.int)