Natural vegetation refers to a plant community that has been left undisturbed over a long time, so as to allow its individual species to adjust themselves to climate and soil conditions as fully as possible.
- Himalayan heights are marked with temperate vegetation;
- Western Ghats and the Andaman Nicobar Islands have tropical rain forests
- Deltaic regions have tropical forests and mangroves;
- Desert and semi desert areas of Rajasthan are known for cactii, a wide variety of bushes and thorny vegetation
On the basis of certain common features such as predominant vegetation type and climatic regions, Indian forests can be divided into the following groups
TYPES OF FORESTS
- Tropical Evergreen and Semi-Evergreen forests
- Tropical Deciduous forests
- Tropical Thorn forests
- Montane forests
- Littoral and Swamp forests
Tropical Evergreen and Semi Evergreen Forests
- Western slope of the Western Ghats, hills of the northeastern region and the Andaman and Nicobar Islands.
- Warm and humid areas
- Annual precipitation of over 200 cm
- mean annual temperature above 22oC
- Tropical evergreen forests are well stratified, with layers closer to the ground and are covered with shrubs and creepers, with short structured trees followed by tall variety of trees.
- In these forests, trees reach great heights up to 60 m or above.
- There is no definite time for trees to shed their leaves, flowering e.g. rosewood, mahogony, aini, ebony,fruition.
Semi evergreen forests
- Found in the less rainy parts of these regions. Such forests have a mixture of evergreen and moist deciduous trees.
- The under growing climbers provide an evergreen character to these forests.
- Main species are white cedar, hollock and kail
- British were aware of the economic value of the forests in India, hence, large scale exploitation of these forests was started. The structure of forests was also changed.
- The oak forests in Garhwal and Kumaon were replaced by pine (chirs) which was needed to lay railway lines.
- Forests were also cleared for introducing plantations of tea, rubber and coffee.
- The British also used timber for construction activities as it acts as an insulator of heat.
Tropical Deciduous Forests
- Most widespread forests in India (monsoon forests) – Rainfall- 70-200 cm.
- Further divided into moist (200-100)and dry (70-100) deciduous.
- Moist northeastern states along the foothills of Himalayas, eastern slopes of the Western Ghats and Orissa.
- Teak, sal, shisham, hurra, mahua,amla, semul, kusum, and sandalwood
- Dry Rainier areas of the Peninsula and the plains of Uttar Pradesh and Bihar.
- In the higher rainfall regions of the Peninsular plateau and the northern Indian plain, these forests have a parkland landscape with open stretches in which teak and other trees interspersed with patches of grass are common.
- As the dry season begins, the trees shed their leaves completely and the forest appears like a vast grassland with naked trees all around.
- Tendu, palas, amaltas, bel, khair, axlewood, etc.
- In the western and southern part of Rajasthan, vegetation cover is very scanty due to low rainfall and overgrazing.
Tropical Thorn Forests
- Rainfall less than 50 cm
- Grasses and shrubs
- Semi-arid areas of south west Punjab, Haryana, Rajasthan, Gujarat, Madhya Pradesh and Uttar Pradesh.
- Plants remain leafless for most part of the year and give an expression of scrub vegetation.
- babool, ber, and wild date palm, khair, neem, khejri, palas, etc.
- Tussocky grass grows upto a height of 2 m as the under growth.
Montane Forests –
- Decrease in temperature with increasing altitude leads to a corresponding change in natural vegetation
- Types- northern mountain forests and the southern mountain forests.
- Himalayan ranges show a succession of vegetation from the tropical to the tundra, which change in with the altitude.
Deciduous forests are found in the foothills of the Himalayas.
- 1,000-2,000 m – wet temperate type of forests
- 1,500-1,750 m- pine forests, Chir Pine ,Deodar – construction activity. chinar and walnut –Kashmir handicrafts
- 2,225-3,048 m – Blue pine and spruce
- 3,000-4,000 m – Silver firs, junipers, pines, birch and rhododendrons
Littoral and Swamp Forests
- About 70 per cent of this comprises areas under paddy cultivation.
- Total area of wet land is 3.9 million hectares.
- Two sites — Chilika Lake (Orissa) and Keoladeo National Park (Bharatpur) are protected as water-fowl habitats under the Convention of Wetlands of International Importance (Ramsar Convention).
The country’s wetlands have been grouped into eight categories-
- The reservoirs of the Deccan Plateau in the south together with the lagoons and other wetlands of the southern west coast;
- The vast saline expanses of Rajasthan, Gujarat and the Gulf of Kachchh;
- Freshwater lakes and reservoirs from Gujarat eastwards through Rajasthan (Keoladeo National Park) and Madhya Pradesh;
- The delta wetlands and lagoons of India’s east coast (Chilika Lake);
- The freshwater marshes of the Gangetic Plain; (vi) the floodplains of the Brahmaputra;
- The marshes and swamps in the hills of northeast India and the Himalayan foothills;
- The lakes and rivers of the montane region of Kashmir and Ladakh;
- The mangrove forest and other wetlands of the island arcs of the Andaman and Nicobar Islands.
- Mangroves grow along the coasts in the salt marshes, tidal creeks, mud flats and estuaries.
- Crisscrossed by creeks of stagnant water and tidal flows, these forests give shelter to a wide variety of birds.
- In India, the mangrove forests spread over 6,740 sq. km which is 7 per cent of the world’s mangrove forests.
- Andaman and Nicobar Islands and the Sunderbans of West Bengal, Mahanadi, the Godavari and the Krishna deltas
- Transhumance tribes – Gujjars, the Bakarwals, the Bhotiyas and the Gaddis.
- At higher altitudes, mosses and lichens form part of the tundra vegetation.
- Southern slopes of the Himalayas carry a thicker vegetation cover because of relatively higher precipitation than the drier north-facing slopes.
- The southern mountain forests include the forests found in three distinct areas of Peninsular India viz; the Western Ghats, the Vindhyas and the Nilgiris.
- Temperate forests are called Sholas in the Nilgiris, Anaimalai and Palani hills.
Forest– magnolia, laurel, cinchona and wattle.