A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing and ecological function. The Food and Agriculture Organization defines a forest as land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent, or trees able to reach these thresholds in situ. It does not include land that is predominantly under agricultural or urban land use. Using this definition FRA 2020 found that forests covered 4.06 billion hectares or approximately 31 percent of the global land area in 2020.
Forests are the predominant terrestrial ecosystem of Earth, and are distributed around the globe. More than half of the world’s forests are found in only five countries. The largest part of the forest is found in the tropical domain, followed by the boreal, temperate and subtropical domains.
Forests account for 75% of the gross primary production of the Earth's biosphere, and contain 80% of the Earth's plant biomass.