Depending upon the climate, soil, relief and structure, Indian forest can be divided into following categories.
(I) Tropical Evergreen Rainforests:
Trees in these forests do not have a distinct season of shedding leaves as the region is warm and wet throughout the year. The average annual rainfall in these areas is above 200 cms and the average temperature is near about 24°C. And average annual humidity exceeds 77 per cent.
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These forests are dense, have luxuriant growth of vegetation and appear evergreen because their trees do not shed their leaves annually at least not altogether. Such areas are confined to rainy slopes of the Western Ghats, plains of West Bengal and Odisha and North-eastern India.
This area-are characterised by tall trees whose height varies from 15 to 60 metres and dense forests due to high heat and high humidity. The number of species is too large and ton mixed to exploit each one of them commercially.
Example: (i) Ranni, Kerala, 1000m.
Important Trees:
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Ebony, mahogany and rosewood, coconut palms, iron-wood and bamboos etc. Due to thick growth the sun’s rays do not reach the surface of the earth and there is darkness below the trees therefore trees rise high competing with one another for sunlight.
Important Species:
Mesua, White Cedar, Calophylum, Toon, dhup, Palanquin, Jamun, Lanes, etc.
(ii) Cachar, Assam:
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Important Species: Gurjan, Chaplasha, Jamun, Mesua, Agar, Muli, Bamboo etc.
(II) Tropical Deciduous Forest:
These are also called the monsoon forests par excellence. This is so because they form the natural cover almost all over India particularly between region of 200 and 75 centimetres of rainfall. Monsoon forest grows over the Sahyadris, the northeastern parts of the peninsular, middle and lower Ganga valley and along the foothills of the Himalayas in the Shivalik and terai region. Subdivided into two they are (i) moist deciduous and (ii) dry deciduous.
Example: (i) Palghat, Kerala: Important Species:
Semul, Gutel, Mundani, Benteak, Kadam, Rosewood, Mesua, Irul, Laurel.
(ii) Kalimpong, West Bengal: Important Species:
Bonsum, White Cedar, Indian Chestnut, Hollock, Champ, Mango etc.
(a) Moist Deciduous Forests:
The moist deciduous forest is found in the eastern slopes of the Western Ghat. Teak is an important species of plant of this region. They are also found in Chhotanagpur plateaucovering Chhatisgarh, Jharkhand and west Odisha. They are also common along the Shivaliks in the north. They are 30 to 45 metrs tall and cover about 20 per cent of the forest area.
Example: (i) Andamans: Important Species:
Padauk, White Chuglam, Badam, Dhup, Kokko
(ii) Allapalli, Maharashtra: Important Species:
Teak, Laurel, Rosewood, Mahua, Amla, Garari, Semul.
(b) Dry Deciduous Forest:
Sal is the most important tree of the dry deciduous type. Besides this other trees are Shisham, Sandalwood, and Khair etc. These trees provide useful wood and are economically very important. Recently it has been observed that moist deciduous forests are getting replaced by dry deciduous forest. These trees are called deciduous because they shed leaves for about six to eight weeks in summer.
Example: (i) Betul, Madhya Pradesh: Important Species:
Red Sanders, Axlewood, Anjan, Harra, Satinwood,
(ii) Ramnagar, Uttrakhand: Important Species:
Sal, Laurel, Axlewood, Bhilama, Achar, Khair, Ghont, Bel etc.
(III) Tropical Dry Forests:
These forest are found in areas receiving 50 to 100 centimetres of annual rainfall. A large parts of Maharasthra, Karnataka, Punjab, Andhra Pradesh, northern and western Paris of Madhya Pradesh and Southern parts of Uttar Pradesh cover this delta.
They are less dense and small in size than the trees of monsoon forests and these trees shed their leaves with the advance of summer season. Trees like babul, neem, pipal, mango etc. are found in these forests.
Their roots are thick and long so that they can use the underground water in the best possible manner and most of these forest have been cleared for cultivation.
Important Species: Teak, Laurel, Rosewood, Mahua, Amla, Garari, Semul, Lendi
(IV) Tropical Thorn and Scrub Forests:
These forests are confined to areas with rainfall under 50-75 centimetres. These forests are found in Kutch, Saurashtra, south-western Punjab, western Haryana, western and northern Rajasthan, upper Ganga plains, the Deccan Plateau and the lower Peninsular India.
Kikar, babul, khair, and date palms are some of the useful trees. Scattered trees with long roots spread in a radial pattern are common features. These forests gradually fade away into scrubs and thorny bushes. They constitute the typical desert vegetation.
Example: (i) Sholapur (Maharashtra: Important Species:
Khair, Reunjha, Axlewood, Neem, Sandalwood, and Dharnan
(ii) Jaipur (Rajasthan): Important Species:
Neem, Palas, Kherja, etc.
(V) Tidal Forests:
The tidal area along the coasts and rivers is covered by mangrove trees that can survive in both fresh and salt water-the major characteristic of the tidal areas. On tide-washed coast where mud and silt have accumulated, dense mangrove forests flourish. They are found along the deltas of the Ganga, Mahanadi, Godavari, Krishna and Cauvery.
The great Sunderbans delta is covered with Sundari (Heritiera Minor) trees. It is after this tree that the name Sunderban has been given to the forested parts of the Ganga- Brahmaputra delta.
Example: Sunderbans: Importants Species:
Sundri, Bruguiera, Agar, Bhendi, Keora, Nipa
(VI) Riparian Forests:
These flourish along banks of rivers and other wet lands where rainfall is less than 50 cms. Short tree vegetation and grasses like Kans and munj predominate here. Deciduous vegetation like neem, shisham, pipal, mango, jamun, mahua, tamarind, babul etc. are also found.
(VII) Sub-Tropical Broad Leaves Hill Forests:
They are mainly found between 915 m to 1830 m above sea level, where mean annual temperature is about 18″C to 21 °C, mean annual rainfall about 75 cms to 125 cms and humidity 80 per cent.
They occur in the highlands of Bastar, Pachmarhi, Mahabaleshwar, Nilgiris, Palni and Khasi hills; and on the lower slopes of the Himalayas, in West Bengal and Assam. These luxuriant forests in which evergreen species predominate are called Shola’ forests in South India.
Example: Trivendrum, Kerala; Important Species:
Jamun, Machilus, Celtis, Meliosma, Elaceocarpus, etc.
(VIII) Montane Wet Temperate Forests:
They flourish at a height of 1,800-3,000 m above sea level, in areas where the mean annual temperature is about 11°C to 14°C; mean annual rainfall is 150 cms. To 300 cms. And humidity is 83 per cent. Deodar, Indian chestnut, magnolia, plum, michilus, blue pine, oaks and hemlocks are important trees.
Example: Kalimpong, West Bengal: Important Species:
Machilus, Cinnamomum, Litsea, Mangolia
(i) Montane Moist Temperate Forests:
They occur at a height of 1600 m to 3500 m in the temperate eastern and western Himalayas, i.e. along the entire length of the Himalayas between the pine and the subalpine forests in Jammu and Kashmir, Himachal Pradesh, Punjab, Uttarakhand, Darjeeling and Sikkim.
They mainly consist of coniferous species, 0 m to 50 m high with mosses and ferns growing on trees. The important trees are pine, deodar, spruce, silver fir, oak, beech, birch, rhododendrons, chestnut, maple etc.
Example: (i) Chakrata (Uttarakhand): Important Species:
Oak, fir, spruce, Deodar, Celtis Chestnut, Maple
(ii) Sutlaj Valley (H.P.): Important Species:
Spruce, Deodar, Ffir, Kail, Dak, Maple, Birch.
(ii) Alpine Forests:
They occur in the Alpine areas of the Himalayas at a height between 2,900 to 3,500 m and consist of dwarf shrubs of juniper, fir, honeysuckle, betula, rhododendrons and birch. At still higher altitude alpine shrub of low herbs is the only type of vegetation found.
Example: Kumaun (Uttarakhand): Important Species:
Birch, Rhododendron, Berberis, Honeysuckle.