Forest cover is the amount of land area that is covered by forest. It may be measured as relative (in percent) or absolute (in square kilometres/square miles). Around a third of the world's surface is covered with forest, with closed-canopy forest accounting for 4 - 5 billion hectares of land.
According to the UN Food and Agriculture Organization (FAO), a forest is defined as land spanning more than 0.5 hectares (1.2 acres) with trees higher than 5 metres (16 ft) and a canopy cover of more than 10%, or trees able to reach these thresholds in situ. It does not include land that is predominantly under agricultural or urban land use.
— Hansen et al., 2010
Global forest cover, however crucial for soil health, the water cycle, climate and air quality it is, is severely threatened by deforestation, as a direct consequence of agriculture, grazing, and mining. Forest cover can be increased by reforestation and afforestation efforts, but it is virtually impossible to restore the full range of ecological services once natural forests are converted to other land uses.
Since the onset of agriculture (about 12,000 years ago), the number of trees worldwide has dropped by 46%, according to one research published in 2018.
Global forest cover now has been estimated to be just 31% or 40 million km2 (15 million sq mi) in 2006 with 12-yearly losses (2000-2012) amounting to 2.3 million km2 (0.89 million sq mi) and reforestation gains about 0.8 million km2 (0.31 million sq mi). According to the FAO's Global Forest Resources Assessment 2020, the world has a total forest area of 4.06 billion hectares (10.0 billion acres), which is 31% of the total land area.
The largest part of the forest (45%) is found in the tropical domain, followed by the boreal, temperate and subtropical domains. These domains are further divided into terrestrial global ecological zones, 20 of which contain some forest cover. Almost half the forest area (49%) is relatively intact, while 9% is found in fragments with little or no connectivity. Tropical rainforests and boreal coniferous forests are the least fragmented, whereas subtropical dry forest and temperate oceanic forests are among the most fragmented. Roughly 80% of the world’s forest area is found in patches larger than 1 million hectares (2.5 million acres). The remaining 20% is located in more than 34 million patches across the world – the vast majority less than 1,000 hectares (2,500 acres) in size.
The world’s total growing stock of trees decreased slightly, from 560 billion m3 (20 trillion cu ft) in 1990 to 557 billion m3 (19.7 trillion cu ft) in 2020, due to a net decrease in forest area. On the other hand, growing stock is increasing per unit area globally and in all regions; it rose from 132 m3 per ha in 1990 to 137 m3 per ha in 2020. Growing stock per unit area is highest in the tropical forests of South and Central America and West and Central Africa.
This article incorporates text from a free content work. Licensed under CC BY-SA 3.0 License statement/permission. Text taken from Global Forest Resources Assessment 2020 Key findings, FAO, FAO.
This article incorporates text from a free content work. Licensed under CC BY-SA 3.0 License statement/permission. Text taken from The State of the World’s Forests 2020. In brief – Forests, biodiversity and people, FAO & UNEP, FAO & UNEP.