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Environmental issues

Biology Index


It is removal, decreases or deterioration of forest cover of an area.


  1. Jhuming In India about 5 lakh hectares of land is cleared every year through lopping, burning the remainder, mixing the ash with soil and sowing the cleared land with crop seeds. The land is used for 2-3 years without manuring. This results in nutrient depletion reduced moisture retention and increased soil erosion
  2. Hydroelectric projects Dams, reservoirs and hydroelectric projects submerge forest killing all plants and animals.
  3. Forest fires Huge forest fires engulfing areas of 40,000 km2 have occurred in Indonesia in 1983 and 1997.
  4. Human establishmen
  5. Mountain and Forest Road Construction of roads and railways in hilly forested areas bring about a lot of deforestation, landslides and soil erosion large sections are dynamited. This weakens the already fragile mountain system. The fragments pass into valleys. They increase soil erosion.
  6. Overgrazing India with 2.4% geographical area has some 500 million livestock population. Grazing area is only 13 million hectors where one hectare of land supports only 6 livestock heads. The remaining livestock naturally grazes in forests trampling seedlings and compaction of soil. Compaction of soil reduces water storing capacity.
  7. Requirement of wood It is rising, some 300 million m3 for fuel and 40 million m3 for the industry, mostly timber and paper industry.
  8. Quarrying and mining.

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Effects of deforestation

  1. Shrinking fuelwood In India, availability of fuelwood in 58 million m3 / year against the requirement of 300 million m3/year.
  2. Reduced timber
  3. Change in climate Deforestation results in reduced rainfall, increased drought, hotter summers and cold winters.
  4. Soil erosion The soil is exposed in insolation, dries up and get eroded by wind and water.
  5. Flash floods They occur during rainy season due to non-retention of water in the soil, increased runoff water flowing into streams and rivers during rains.
  6. Siltation Rainy season rivulets bring eroded soil and bring the deposits on a bed of reservoirs reducing storage capacity.
  7. Drought loss of biodiversity, rainfall
  8. Global warming Deforestation increases atmospheric CO2 content by releasing carbon stored in organic matter and reduced primary productivity.

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