Land-cover definitions define forests based upon the type and density of vegetation growing on the land. Under such a land-use definition, cleared roads or infrastructure within an area used for forestry-or areas that have been cleared by harvesting, disease, or fire-are still considered forests, even if they contain no trees. For example, a forest may be defined as any land that is used primarily for production of timber. Land-use definitions are based on the primary purpose that the land serves. Administrative definitions are based primarily upon the legal designations of land, and commonly bear little relationship to its vegetation: land that is legally designated as a forest is defined as such even if no trees are growing on it. There are three broad categories of definitions of forest in use: administrative, land use, and land cover. Although a forest is usually defined by the presence of trees, under many definitions an area completely lacking trees may still be considered a forest if it grew trees in the past, will grow trees in the future, or was legally designated as a forest regardless of vegetation type. Īlthough the word forest is commonly used, there is no universally recognised precise definition, with more than 800 definitions of forest used around the world. Human activities, including unsustainable use of forest resources, can negatively affect forest ecosystems. Forests provide ecosystem services to humans and serve as tourist attractions. Human society and forests influence each other in both positive and negative ways. The remaining 20 percent is located in more than 34 million patches around the world – the vast majority less than 1,000 hectares (2,500 acres) in size. Roughly 80 percent of the world's forest area is found in patches larger than 1 million hectares (2.5 million acres). Tropical rainforests and boreal coniferous forests are the least fragmented, whereas subtropical dry forests and temperate oceanic forests are among the most fragmented.
Areas at higher elevations tend to support forests similar to those at higher latitudes, and the amount of precipitation also affects forest composition.Īlmost half the forest area (49 percent) is relatively intact, while 9 percent is found in fragments with little or no connectivity. įorests at different latitudes and elevations, and with different precipitation and evapotranspiration form distinctly different biomes: boreal forests around the North Pole, tropical moist forests and tropical dry forests around the Equator, and temperate forests at the middle latitudes. Net primary production is estimated at 21.9 gigatonnes of biomass per year for tropical forests, 8.1 for temperate forests, and 2.6 for boreal forests. įorests account for 75% of the gross primary production of the Earth's biosphere, and contain 80% of the Earth's plant biomass. The largest share of forests (45 percent) are in the tropical latitudes, followed by those in the boreal, temperate, and subtropic domains. More than half of the world's forests are found in only five countries (Brazil, Canada, China, the Russian Federation, and the United States of America). įorests are the predominant terrestrial ecosystem of Earth, and are distributed around the globe. It does not include land that is predominantly under agricultural or urban use." Using this definition, Global Forest Resources Assessment 2020 (FRA 2020) found that forests covered 4.06 billion hectares (10.0 billion acres 40.6 million square kilometres 15.7 million square miles), or approximately 31 percent of the world's land area in 2020. The United Nations' Food and Agriculture Organization (FAO) 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. 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. A forest is an area of land dominated by trees.