AIPMT Biology Aspirants, read out the next AIPMT Biology Study material/ Notes of Deforestation, Causes of deforestation, Effects of deforestation, Jhum Cultivation, important for AIPMT Biology.Free online notes for AIPMT
Deforestation is the conversion of forested areas to non-forested ones. 40 % forests have been lost in the tropics, and 1% in the temperate region.
- According to National Forest Policy (1988) of India, 33 % forest must cover the plains and 67 % for hills, but only 19.4 % forest cover is present by the end of this century. While at the beginning of the twentieth century, forests covered about 30 % of the land of India.
Causes of Deforestation: 1. Human activities that lead to conversion of forest to agricultural land so as to feed the growing human population.
2. Trees are cut down for timber, firewood, cattle ranching and for several other purposes.
3. Slash and burn agriculture (Jhum cultivation): In slash and burn agriculture, farmers cut down the trees of the forest and burn the plant remains. Ash is used as fertiliser and the land is then used for farming or cattle grazing. After cultivation, the area is left for several years so as to allow its recovery. The farmers then move on to other areas and repeat this process. More common in north-eastern states of India.
Previously in Jhum cultivation enough time-gap was given to land to recover from the effects of cultivation, but with increasing population, and repeated cultivation, this recovery phase is cut short resulting in deforestation.
Effects of Deforestation: 1. Increase in CO2 concentration in the atmosphere as trees that use carbon in their biomass are lost with deforestation.
- Leads to loss of biodiversity due to habitat destruction of plants, animals and birds.
- Disturbance of hydrologic cycle.
- Loss of forest trees causes soil erosion, and may lead to desertification in extreme cases.
Reforestation: Process of restoring a forest that once existed at some point of time in the past. Reforestation can occur naturally in a deforested area but can be speeded up by planting trees that earlier existed in that area.
Case Study of Conservation of Forests
- Amrita Devi Bishnoi Wildlife Protection Award: Given on the name of woman Amrita Devi Bishnoi, who sacrificed her life along with her three daughters and hundreds of other Bishnoi community people, to save the trees in 1731 in Jodhpur, Rajasthan. She hugged the tree to save it from cutting. Award is given to individuals or communities from rural areas that have shown extraordinary courage and dedication in protecting wildlife.
- Chipko Movement: In 1974 in Garhwal, Himalayas, local women showed enormous bravery in protecting trees from the axe of contractors by hugging them. People all over the world have acclaimed the Chipko movement.
- Joint Forest Management (JFM): In 1980s, Government of India introduced the concept of JFM by keeping in mind the importance of participation by local communities in protecting forests. According to JFM, government works closely with the local communities for protecting and managing forests. In return for their services to the forest, the communities get benefit of various forest products (e.g., fruits, gum, rubber, medicine, etc.), and thus the forest can be conserved in a sustainable manner.