means destruction of forests.
forests area of the world in 1900 was estimated to be 7,000 million hectares
which was reduced to 2890 million ha in 1975 fell down to just 2,300 million ha
rate is relatively less in temperature countries, but it is very alarming in
is a continuous process in India where about 3.3 hectares of forest land has
been lost. The per capita availability of forest in India is 0.08 hectares per
person which is much lower than the world average of 0.8 hectares.
presence of waste land is a sign of deforestation in India.
1 Causes of Deforestation
causes of deforestation are listed below:
requirements cutting and burning
1.1 Consequences of deforestation
the effects of deforestation are listed below:
a) Effect on climate
warming Less rainfall Hot climate.
b) Effect on biodiversity
medicinal plants. Loss of timber, fuel wood.
land resource Loss of soil fertility Soil erosion
changes in biogeochemical cycles
d) Effect on economy
in medicinal values Demand of industrial products. e) Effect on food
fruit production Loss of root based foods.
in hilly regions of the Himalayas:
in Himalayas, involving clearance of natural forests and plantation of
monocultures like Pinus roxburghi, Eucalyptus camadulensis etc., have upset the
ecosystem by changing various soil and biological properties.
is invaded by exotic weeds. These areas are not able to recover and are losing
the destruction of forest rain fall declined in Chhota Nagpur to such an extent
that tea-gardens also disappeared from the region.
Waning rain fall in Udhagamandalam
rainfall pattern was found to fluctuate with wooded land area in the hills.
When the Nilgiri mountains had luxuriant forest cover annual rainfall used to
be much higher.
for valuable timber such as teak and mahogany not only involves a few large
trees per hectare but about a dozen more trees since they are strongly
interlocked with each other by vines etc.
construction for making approach to the trees causes further damage to the
firewood demand would continue to rise in future mostly consumed in rural
areas, where alternative sources of energy, are yet to reach.
the process of removing deposits of ores from substantially very well below the
carried out to remove several minerals including coal.
mineral deposits invariably found in the forest region, and any operation of
mining will naturally affect the forests.
from shallow deposits is done by surface mining while that from deep deposits
is done by sub-surface mining.
80,000 ha of land of the country are presently under the stress of mining
1 Effects of mining resources
operation require removal of vegetation along with underlying soil mantle and
overlying rock masses. This results in destruction of landscape in the area.
scale of deforestation has been reported in Mussorie and Dehradun valley due to
mining of various areas.
mining in Goa since 1961 has destroyed more than 50,000 ha of forest land.
Mining of radioactive mineral in Kerala, Tamilnadu and Karnataka are posing
similar threats of deforestation.
DAMS AND THEIR EFFECTS ON FORESTS AND TRIBAL PEOPLE
and river valley projects have multi-purpose uses and have been referred to as
"Temples of modern India”.
more than 1550 large dams, the maximum being in the state of Maharashtra (more
than 600) followed by Gujarat (more than 250) and Madhya Pradesh (130).
highest one is Tehri dam, on river Bhagirathi in Uttaranchal and the largest in
terms of capacity is Bhakra dam on river Sutlej.
Fig 3.6 Dams
1 Effects on Tribal people
greatest social cost of big dam is the widespread displacement of local people.
estimated that the number of people affected directly or indirectly by all big
irrigation projects in India over the past 50 years can be as high as 20
Hirakud dam, one of the largest dams executed in fifties, has displaced more
than 20,000 people residing in 250 villages.
2 Effects on forests
of hectares of forests have been cleared for executing river valley projects
which breaks the natural ecological balance of the region. Floods, landslides
become more prevalent in such areas.
Narmada sagar project alone has submerged 3.5 lakh hectares of best forest
comprising of rich teak and bamboo forests.
dam submerged 1000 hectares of forest affecting about 430 species of plants
according to the survey carried out by the botanical survey of India.