Definitions/Explanation
Deforestation : 

Explanation

Deforestation is the conversion of forested land areas to non-forested ones.
According to an estimate, almost 40 per cent forests have been lost in the tropics compared to only 1 per cent in the temperate region.
The present scenario of deforestation is particularly grim in India.
At the beginning of the twentieth century, forests covered about `30%` of the land of India.
By the end of the century, it shrunk to `19.4%`.
National Forest Policy (1988) of India has recommended `33%` forest cover for the plains and `67%` for the hills.
 Main reason is the conversion of forest to agricultural land so as to feed increased human population.
Human activities like slash and burn agriculture also called Jhum cultivation where farmers cut down trees and burn the plant remains.
Ash is used as a fertiliser and the land is then used for farming or cattle grazing use of fertilizers and cutting of trees for industries and residential use.
Main consequence of deforestation includes : (a) Enhanced carbon dioxide concentration (b) Loss of biodiversity (c) Disturbed hydrologic cycles (d) Soil erosion (e) Desertification etc.