What is deforestation? State its causes and consequences.

(N/A) Deforestation is the conversion of forested areas to non-forested areas.
Approximately $40$ percent of forests have been lost in the tropics,compared to only $1$ percent in the temperate region.
In India,the situation is more serious. At the beginning of the $20^{th}$ century,forests covered about $30$ percent of the land of India. By the end of the century,it shrank to $21.54$ percent. The National Forest Policy $(1988)$ of India has recommended $33$ percent forest cover for the plains and $67$ percent for the hills.
Causes of deforestation: $(i)$ Conversion of forest land to agricultural land to feed the growing human population. $(ii)$ Trees are felled for timber,firewood,cattle ranching,and for several other purposes.
Slash and burn agriculture,commonly called Jhum cultivation in the north-eastern states of India,is a major cause.
In slash and burn agriculture,farmers cut down the trees of the forest and burn the plant remains. The ash is used as a fertilizer and the land is then used for farming or cattle grazing.
After cultivation,the area is left uncultivated for several years so that it can recover.
Consequences of deforestation: It increases the concentration of $CO_2$ in the atmosphere because trees that could hold a lot of carbon in their biomass are being destroyed.
It causes an imbalance in the hydrological cycle,leads to soil erosion,and may eventually lead to desertification. Reforestation can be achieved by planting trees,keeping in mind the biodiversity that existed in that area previously.