desertification

The degradation of land in arid, semi-arid and dry sub-humid climates resulting from climatic variation, damaging agricultural practices and climate change. While naturally-occurring drought alone can contribute to desertification, the immediate cause is often the removal of vegetation through deforestation (eg. for fuelwood), overgrazing, excessive cultivation and the use of fire for land clearance. About a third of the earth’s land area is sufficiently dry to be more or less prone to desertification, and up to half of this area has already been degraded.

This definition is abridged from A – Z of tree terms: A companion to British arboriculture.
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