Plants that grow naturally in nature, without any human help, are called natural vegetation. This natural vegetation can form forests or jungles.
Natural vegetation of India is mostly dependent on the quantity of rainfall in the region. However, temperate and altitude plays a dominant role in Himalayan and other mountain forests.
Classification of Natural Vegetation in India: The Natural Vegetation of India can be classified into seven types on the basis of rainfall, temperature, relief, soil etc. The natural vegetation types are:
Evergreen forest: They are found in areas receiving very heavy rainfall, so the soil is always wet. Trees never face shortage of moisture so green leaves permanently form a canopy of the trees in the forest. Thus being permanently green, the forest is called Evergreen forest. The most important varieties of trees are gurjar, chaplasha, toon, dhup, white cedar, jamun, rose wood, Indian chestnut, bamboos etc. these trees are mainly used as railway sleepers, furniture etc. as the wood is strong fire-grained, durable and hard. These forests are distributed in regions receiving rainfall above 200 cm annually. E.g. – Terai region of Eastern Himalayas, western slopes of Western Ghats, islands of Andaman and Nicobar etc.
Desert Vegetation: In the deserts of Rajasthan hardly any plants are seen. The average annual rainfall is less than 25 cm, and temperatures are very high. For plants to germinate, grow or even survive in such conditions is very difficult. So few clumps of grass grow on the sand, some thorny plants, cactii etc. are also seen.
Himalayan Vegetation: It is commonly said that most plants growing on the earth are found in the Himalayas. The reasons are – the earth’s surface has a great variety of temperature and rainfall condition which gives rise to a variety of plants. In the Himalayas due to change in elevation and also due to its location in a sub-tropical region, a variety of temperature and rainfall conditions prevail. The Eastern and Western Himalayas vary in temperature and rainfall conditions compared to each other. Therefore a great variety of natural vegetation is seen in this geomorphic unit.
Humid deciduous Forests: Region receiving a rainfall in summer and rainy seasons, with winters remaining dry, and where average rainfall varies between 100 and 200 cm annually, have deciduous trees. Top avoid loss of moisture in the dry season by transpiration from leaves, the trees shed their leaves. Thus these trees are called deciduous trees. Trees of this variety are sal, teak or shegun, shimul, jarul, mahua, shirish, mango, banyan, neem etc. They are mainly used for furniture, frames for doors and windows, construction etc. In villages they are used as firewood too. For the production of lac the lac insect is reared on palash, mahua trees etc. The distribution of these forests are seen in the plains of Assam, plateau of Jharkhand, Chhattisgarh, eastern Ganga plain, plateau and plains of West Bengal and Orissa, eastern slopes of Western Ghats etc. These forests are also called Monsoon forest.
Dry Deciduous Forest: Generally the regions of India receiving 50-100 cm of rainfall annually, with high temperature have this type of forest. Thus grasses, scrubs and some deciduous trees are found intermittently in these forests. Near rivers density of trees increase and are of deciduous variety. The natural vegetation consists of sabai grass, elephant grass, coarse grass, palash, berries, shirish etc. The main uses of these trees are as firewood or fuel wood, furniture etc. Sabai grass is an important raw material in the paper industry. Distribution of this natural vegetation is seen in eastern Rajasthan, western Bihar, eastern U.P., Maharashtra, Karnataka, Tamil Nadu and Telengana plateau region of Andhra Pradesh.
Thorny Scrubs: Where rainfall is low the soil is dry. Plants growing in such dry soil absorb water from the soil after a lot of search and great difficulty. To conserve this water, plants in dry areas adapt themselves by not growing large leaves, as transpiration or loss of water occurs through them mainly; or the leavers are small in size or thorns occur. These thorns act as leaves and at times protect it from herbivorous animals. In arid areas the natural vegetation is mainly of cacti, babla, date, palm, khair, babul, acacias, etc. In India the distribution of thorny bushes and scrubs are found in areas where rainfall is low, average annual rainfall varying between 25-50 cm and temperatures are high. E.g. – the semiarid regions – near desert areas of Rajasthan, Kachchh – Kathiawad areas of Gujarat, rain-shadow area of the Deccan, i.e. interior of the Peninsula.