Deforestation: is a large-scale removal of forest prior to its replacement by other land uses. Forests are removed for a variety of reasons, including agriculture, timber harvesting, and mining, and to make way for roads, dams, and human settlements. Deforestation poses a severe worldwide environmental problem. Forests take enormous amounts of carbon dioxide from the atmosphere in the process of photosynthesis. The destruction of forests exacerbates the accumulation of carbon dioxide in the atmosphere, which then contributes to global warming. In addition, deforestation causes soil erosion and destabilizes watersheds, resulting in flooding or drought. Deforestation also reduces biodiversity, particularly significant in tropical forests that are home to a substantial portion of the world’s plant and animal species. Deforestation processes are, in general, more destructive in the tropics. Most forest soils in the tropics are far less fertile than temperate soils, and more vulnerable to erosion. This is due to high rainfall, which leaches nutrients from the soil and speeds erosion.