Doc: Vegetation - Geography Notes | EduRev

Geography for UPSC (Civil Services) Prelims

UPSC : Doc: Vegetation - Geography Notes | EduRev

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TROPICAL EVERGREEN OR RAINFORESTS
Trees in these forests do not have a distinct season of shedding leaves and hence they are evergreen. They occur where the average annual temperature is about 250C to 270C and rainfall exceeds 200 cm. They grow on rainy slopes facing the monsoon currents. These areas are in the western parts of the Western Ghats (parts of Maharashtra, Karnataka and Kerala); the eastern Himalayas (Terai region); northeast India (comprising Lushai, Garo, Khasi, Jaintia and other hills); and most of Andaman Islands.

Doc: Vegetation - Geography Notes | EduRevRainforestTropical evergreen forests have a dense growth of trees with climbers and epiphytes, bamboo and ferns. The trees are 45 m high. They produce valuable hardwood such as rosewood, ebony and ironwood used for furniture, railway sleepers and house building.


TROPICAL DECIDUOUS FORESTS
Also called the monsoon forests, they form the natural cover almost all over India. They occur in areas of rainfall between 150cm and 200cm. Most trees are deciduous i.e. they shed their leaves for some 6 to 8 weeks in the hot weather. Depending on the species, the period of shedding generally from early March to end of April and therefore at no particular time the forests are absolutely bare. 

These forests are of two types:
(i) Moist deciduous 
(ii) Dry deciduous
It has been observed that most deciduous forests are getting gradually replaced by dry deciduous forests. The moist deciduous forests occur in the eastern slopes of the Western Ghats, (teak in an important species of this region) and are common in the northeastern part of the peninsula, i. e. around Chhotanagpur plateau covering east Madhya Pradesh, South Bihar and West Orissa. They are also common along the Shivaliks in the north including the bhabhar and the terai. The remaining area with 100-150cm rainfall within the parameters explained before has dry deciduous forests. The dry deciduous forests have more open and dwarfish composition, the trees being more stunted and widely spaced, though the species are mostly the same as in moist deciduous.

Doc: Vegetation - Geography Notes | EduRevDeciduous forestThe deciduous forests are economically most important forests as they possess a large number of commercially important timber tree species which, due to high degree of gregariousness, are also easy to exploit.
The important trees of these forests are:
(i) Sal, whose wood is very hard and heavy and immune to termite attacks. It is mostly found in North, Central and Northeast India (Bihar, U.P., Orissa, M.P., Tripura, Assam). It occurs in large pure 'strands'. Its timber is useful for railway sleepers and house construction.
(ii) Teak (Tectona grandis) gives very hard and durable timber, suitable for ship building, house construction and furniture. Seasoned Teakwood can resist termites. Also, it does not corrode iron nails. It is found in the forests of M.P., Assam, Orissa, Bihar, Maharashtra and Tamilnadu.
(iii) Sandal tree provides sandalwood for handicraft and sandalwood oil, which is used in perfumery. It is mainly found in Karnataka.
(iv) Semul is found in Assam, Bihar and  Tamilnadu. Its timber is soft and white and is used for packing cases, match boxes and making toys.
(v) Myrobalan provides material for tanning leather and dyeing cotton, wood and silk.
(vi) Mahua flowers are eaten and used for distilling alcohol and khair provides material for chewing along with betel leaves.

MONTANE FORESTS
In mountainous regions a succession of natural vegetation belts from tropical to tundra region, all compressed into an altitude of 6 km or so, is found. However, even at the same altitude vegetation of sunny areas differs from those that are not so sunny.
The Montane forests can be studied under two heads:
(i) Montane (Southern): The Nilgiri and Palni hills in the South have a wet hill forests at 1,070-1,525 m height; below it occurs stunted type of rainforest and above it, the temperate forests begin to replace it. Higher slopes of Sahyadris, Satpura and Aikal hills also have this type of forests. Above 1,500 m on the slopes of Nilgiris, Anamalais and Palnis occur the west temperate forest, locally termed as sholas. At lower levels are found a rich rolling savanna with occasional peat bogs. Shola forests are dense but low with much undergrowth and many epiphytes, mosses and ferns. Common species are magnolia, laurel, rhododendron, elm and prunus. Eucalyptus, cinchona and wattle have been introduced from outside.

Doc: Vegetation - Geography Notes | EduRevMontane forest(ii) Montane (Northern): The foothills of the Himalayas, the Shivaliks, are covered with tropical moist deciduous flora. The most dominant and economically important species of this belt is Sal. Bamboo trees are also common.
Wet hill forests occur at 1,000-2,000 m height in the Himalayas. Evergreen oak and chestnut species predominate with some ash and beech. Climbers and epiphytes are common in these forests. At the same altitude in northeastern hills, where it rains heavily, sub-tropical pine forests are found in which chir trees dominate. Chir is useful for extraction of resin and turpentine and is also exploited for timber purpose used for furniture, building and railway sleepers.
Further up, between 1600 m - 3300 m above sea level occurs the coniferous forests of the temperate region, also called moist temperate forests. Pine, cedar, silver fir and spruce are the important trees forming these forests with undergrowth of oak, rhododendron, laurel and some bamboo. In the inner himalayan ranges and in drier climates where rainfall is below 100 cm these trees along with deodar and chilgozah occur predominantly.
The Himalayas from 2,881-3,640 m height are covered largely with a dense shrubby forest called Alpine forests. They consist of silver fir, juniper, pine, birch and rhododendrons. Alpine forests give way to Alpine grasslands through shrub and scrub and are found on the southern slopes and northern slopes of the Himalayas.

SCRUB AND THORN FORESTS
These occur where rainfall is scanty, less than 100cm, which is insufficient for tree growth. These forests extend over north-western part of India from Saurashtra in South to Punjab plains in north. 

Doc: Vegetation - Geography Notes | EduRev

Scrub and Thorn forest

In east it stretches to northern Madhya Pradesh (mainly Malva plateau) and south-west Uttar Pradesh covering Bundelkhand plateau. Khair, kikar, babul, date palms (Khajur) are common trees of these forests. The trees are stunted and widely scattered. These forests gradually fade away into scrubs and thorny bushes leading to typical desert vegetation.

Desert and Semi Desert Vegetation
It is found in regions where rainfall is below 25 cm and where average annual temperature is 25-270C. The vegetation mostly consists of thorny bushes, acacia, wild berries, babul and kikar. These trees are barely six to 10 meters in height but have long roots. They are armed with hard thorns or sharp spines to protect themselves from animals. These are found in Rajasthan, Kutch and Saurashtra in Gujarat, south western Punjab and part of the Deccan.

MANGROVE FORESTS (Tridal or Littoral)
These are found in tidal areas along the coasts and rivers. These can survive in both fresh and saltwater the major characteristic of tidal areas. Some of these forests are supported by a number of still like roots, which are underwater at high tide; at low tide, these can be seen. This tangled mass of root system is a wonderful adaptation for survival in the soft and shifting mud. 

Doc: Vegetation - Geography Notes | EduRevMangrove forest

Tidal forests are found in great abundance and in almost continuous stretch along the edges of deltas on the east coast, namely, the deltas of the Ganga, Mahanadi, Godavari, Krishna and Cauvery and along the coast of Andaman and Nicobar islands. These are also found along the west coast in a few places. In Bengal they are called Sunderbans (meaning forests of the sundari tree). The other principal trees are Nagarajan and hintal. These forests are a valuable source of fuel.
 

Geographical distribution of different types of forests in India:

(1) West Tropical Evergreen Forests. These forests are found in areas receiving more than 250 cms. of annual rainfall. These forests occur in western ghats and Assam. These include rubber, Mahagony & Ironwood etc.
(2) Monsoon Forests. These typical monsoon deciduous forests are found in areas with a rainfall of 150-250 cm. These forests occur in Chota Nagpur Plateau, Assam and Southern slopes of Himalayas. Tea and the Sal are the main trees.
(3) Dry Forests. These forests are found in a broad belt having less than 100 cms of rainfall. Khair, Sheesham, are useful for timber. These occur in Punjab, Haryana, UP. and Deccan Plateau.
(4) Coniferous Forests. These occupy about 6% forests of India. These are found in the Himalayas varying according to the height and amount of rainfall. Deodar, Pine, Fir, and Spruce are valuable softwood trees.
(5) Tidal Forests. These forests are found in the deltas of Ganges, Mahanadi, Godavari, Krishna, Cauveri. The Mangrove forests in the under Bans (Ganges Delta) are the most important.

Why does the exotic flora become a problem for us? 
Nearly 40% of plant species found in India have come from outside and are called exotic plants. These plants have been brought from Sino-Tibetan, African and Indo-Malaysian areas. These plants were brought as decorative garden plants in India. These plants grow rapidly as weeds under hot-wet tropical conditions. These rapidly multiply so that it is difficult to eradicate these. These reduce the useful land cover. These prevent the growth of economic plants. These spread diseases and are a hazard to public health.

  •  Lantana and water Hyachinth are two such species. Water Hyacinth is known as “Terror of Bengal”. It has chocked up all the watercourses like rivers, streams, tanks, canals, etc.

In their altitudinal range, Himalayas represent a succession of vegetation regions from the tropical to the Alpine.
Different types of vegetation regions are found in the Himalayas from its southern foothills to high altitudes. The natural vegetation ranges from the equatorial to Tundra Type. A series of vegetation regions exist according to the changes of temperatures and rainfall with altitude. A gradual changes in vegetation results according to attitude and climate.
(i) Tropical West Deciduous Forests. These forests are found along the Southern foot-fills of Himalayas, upto a height of 1000 metres. Due to high rainfall, dense forests of Sal are found.
(ii) Temperate Forests The dense wet temperate forests occur upto a height of 2000 metres. These include evergreen oaks, Chestnut and pine trees which are commercially useful.
(iii) Broad-leaved evergreen Forests. These occur between the height of 200- metres and 3000 metres. These include Oak, Laurels and Chestnut trees.
(iv) Coniferous Forests. These occur upto a height of 3500 metres. These include the trees of Pine, Cedars, Silver fir and Spruce. Deodar is commercially important for timber and railway sleepers. At higher altitudes, near the Snow line, Birch, Juniper and Silver fir trees are found
(v) Alpine Pastures. These occur beyond a height of 3500 metres. These include short grasses, these are used for trans-human grazing by Nomadic tribes like the Gujjars.
 

Each vegetation has its characteristics life cycle which represents its delicate balance with its environment. 

  • Vegetation has a close relationship with its environment. Each plant species maintains a delicate balance with its environment. It grows as a community under particular conditions of soil, climate and temperature. The vegetation adopts its appearance and form to the ecological frame
  • Their full development follows different stages of growth. Thus each vegetation passes through a life-cycle. It passes through different stages of growth as young, mature and old. The time and period of each stage varies from plant to plant. The life cycle of plant is controlled by the elements of natural environment such as supply of water, rainfall, sunlight, soils and slope of the land.

For example, Indian Teak is known for its collective growth. Other species do not grow with teak due to its particular environment. This is the climax of the growth of the plant where it develops as a community. Thus each vegetation passes through a definite life cycle, their form, adaptation, stages of growth and collective growth depend upon its environment or ecological balance.


BOREAL
Most of the of Himalayan and Peninsular areas are covered with indigenous vegetation. But the Indo-Gangetic plain and Thar desert contain plant species that have come from outside. These are known as exotic plants. The plant species receive from Sino-Tibetan areas are known as ‘boreal’.

Depletion of Forest in India
A country should have at least one-third of its total area under forests to have a healthy ecological balance. India has only 23% of its land under forests. Really good forests have been depleted in extent due to the following reasons:—
(i) The clearing of extensive forest areas.
(ii) The practice of Shifting Cultivation.
(iii) Heavy soil erosion.
(iv) Overgrazing of pastures.
(v) Cutting of trees for timber and fuel.
(iv) Human occupance of Land.

There is a heavy pressure of population on forest resources of the country. The increasing population needs more land for agriculture. The livestock farming needs land for pastures. Forests are being rapidly exploited to supply many forest products for industrial uses. Therefore, it is essential to adopt different methods for the conservation of forests.  Afforestation and reforestation are being developed in many areas. Grasslands are being regenerated. Improved methods of Silviculture are being used. Fast-growing plant species are being planted. Areas under forests is being increased.


Forests are beneficial for us

Indirect benefits from forest are ecological improvements, influence on climate and moderation of temperature, conservation of soil and regulation of moisture and stream flow. Forests cause perennial flow in hill streams and rivers. The intensity of flood in the plains is reduced.


Direct benefits

The major forest-based industries are pulp paper, newsprint, rayon, saw-milling, wood- panel products, matches, resins, medicinal herbs, wild lift and tourism. Fir and spruce are best for rayon and newsprint. Forests provide a verity of minor products like tanning material, honey, lac, dyes, essential oils, grass, fodder etc.
Earn foreign exchange from export of teak, rosewood, paper and paper board, natural gums, seeds etc. Forests can help in import substitution. Royalty on forest leases generate revenue for the states. Besides it provides employment to many.


FOREST POLICY OF INDIA
India is among the world’s first few countries to have adopted a forest policy. The policy was revised first in 1952 and again in 1988.
The main objectives of the revised forest policy of 1988 were:
(i) Preservation of ecological balance and conservation of natural heritage
(ii) To control erosion of soil, denudation in catchment areas and extension of sand dunes in the north-west desert region and along the coasts
(iii) To provide rural and tribal people their requirement of forest products
(iv) Utilising products of forestry in the best manner possible
(v) Increasing the productivity of forests as well as the forest cover by afforestation programmes among others
(vi) Involving the people to meet the objective.
Also in 1988, the forest (conservation) Act of 1980 to prevent deforestation and use of forest land for non-forestry purposes was amended. Punishments in case of violations were included. To prevent destruction of forest area by fires, a Modern Forests Fire Control Project was started in 1984 with the assistance of the UNDP.


Afforestation Programmes

  • Different schemes have been undertaken to increase, preserve and maintain forest cover. Conservation efforts have been devised for the fragile ecosystems on hill slopes, catchment areas, canal banks, etc.
  • Social forestry programmes were initiated in the Sixth Plain and included schemes for producing fuelwood without destroying forest. 
  • Priority was given in the Seventh Plan to block plantations, strip plantations and farm forestry. A National Wasteland Development Board was set up for reclaiming wastelands through afforestation with people’s participation. Decentralised people’s nurseries were set up in 1986-87 to encourage production of seedlings for local plantations. Research is also being encouraged to improve planting material and efficiency of trees. In order to meet the rural and tribal population’s need of fuelwood and fodder, area-specific programmes for developing these are being pursued.

Objectives of social forestry programme

Social forestry programmes were initiated in the sixth plan including schemes for producing fuelwood, fodder fruit, fibre and fertilizers (5F) without destroying forest.
India’s National Commission on Agriculture spelt out the objective of Social Forestry programme in 1976 as:

(i) To provide fuel and thus to release cowdung for use as manure.
(ii) To increase production of fruits and thus add to the potential food resources for the country.
(iii) To help conservation of soil and stop further deterioration of soil fertility.
(iv) To help create shelter belts around agricultural fields to increase their productivity.
(v) To provide leaf fodder for cattle and thus to relieve intensity of grazing over reserved forests.
(vi) To provide shade and ornamental trees for the landscape.
(vii) To provide small plots and timber for agricultural implements, house construction and fencing.
(viii) To include tree consciousness and love of trees amongst the people.
(ix) To popularise the planting and tending of trees in farms, villages, municipal and public lands for their aesthetic, economic and protective value.


Relation between social forestry & environment

Social forestry is closely linked with environmental amelioration and social-economic upliftment, the latter resolution in considerable improvement of the quality of life in rural and urban centres of human habitation.
The relationship between ecosystem, social forestry and environment are so intimately interlinked as to preclude a simplistic understanding. Further, the major objectives of social forestry being both economic and environmental, the complexity are doubly compounded.

To take the environment alone, the social forestry when extensively and successfully implemented can generate several positive environmental impacts like improvement in hydrological balance and production of water from watersheds, improvement of physical properties of soil favourable to improved infiltration, retention capacity and in depth percolation, lamentation of ground water table, reduction of surface run-off water and sedimentation of reservoirs, rivers, streams, etc., recycling of carbon, creation of favourable microclimate conditions conductive to higher food production, increased rainfall through transpiration, maintaining balance in oxygen, carbon dioxide, atmospheric temperature and relative humidity and Ozone layer.

  •  The different components of the social forestry programme related to environmental regeneration are
    (i) Protection and afforestation of degraded forests in the vicinity of habitations.
    (ii) Creation of village woodlands on community lands and government waterlands.
    (iii) Block plantations in tank beds and foreshore lands.
    (iv) Agro- forestry on marginal and sub-marginal farmlands.
    (v) Tree planting along home steads, field boundaries, diffused planting within the fields, particularly in the arid and semi-arid zones.
    (vi) Pasture and silvipasture development.
    (vii) Tree planting in urban and industrial areas for aesthetic purposes, purification of polluted air and control of noise pollution.
    (viii) Control of water and wind erosion by tree and shrub planting, planting of shelter belts, green belts and noise protection belts, etc.
    (ix) Strip plantations along roadsides, canal banks and rail lines. 
  •  These programme if carried out effectively with active involvement of people could ensure that basic needs of the rural people could be met in respect of fuel, fodder, fibre, small timber and raw materials for cottage industry, etc., on one hand and ensure ecological security like protection against wind and water erosion polluted water and air, and availability of clean air on the other.

Problem areas of social forestry
The social forestry programme comprises many areas which open new avenues for people’s participation in forestry management. The following problems are the main areas where participation of the people many be the critical factor.
(i) Stop illicit felling
(ii) Control of grazing
(iii) Managing Productive forests
(iv) Protection of wildlife.
(vii) Rehabilitation of degraded forests
(viii) Soil and water conservation.
(ix) Afforestation Programmes of the government.

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