Forest cover is one category of terrestrial land cover. Land cover is the observed physical features, both natural and manmade, that occupy the earth's immediate surface ... forest cover is defined as 25% or greater canopy closure at the Landsat pixel scale (30-m × 30-m spatial resolution) for trees >5 m in height-- 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 everywhere, as a direct consequence of agriculture, logging, and mining. Forest cover can be increased by reforestation and afforestation efforts, but loss of old-growth forests is irreversible in terms of its ecological services.
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 30% or 40 million square kilometres (4.3×1014 sq ft) in 2006 with 12-yearly losses (2000-2012) amounting to 2.3 million square kilometres (2.5×1013 sq ft) and reforestation gains about 0.8 million square kilometres (8.6×1012 sq ft).
In particular, forest cover may refer to