Potential vegetation can be thought of as the vegetation that would exist at a given location had human forms of land use never existed. In other words, if farms and cities weren't around, this dataset would be an accurate description of the planet's land cover.
To determine what would be covering the surface of the Earth, scientists use giant computer models of the Earth system. This dataset was generated using a model known as IBIS, developed at the University of Wisconsin, which breaks down the land cover categories into 15 biomes.
Ramankutty, N., and J.A. Foley (1999). Estimating historical changes in land cover: North American croplands from 1850 to 1992. Global Ecology and Biogeography 8, 381-396.
(All images are provided at a resolution of 1600x1200 pixels)
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