Indian forests perform an important role to make a healthy environment and it reduce air pollutions. Near about 19.26% of total indian areas are covered with forest. these forests can be classified in six major groups namely, 1. moist tropical, 2. dry tropical, 3. Montane sub tropical, 4. Montane temperate, 5. sub alpine and 6. alpine forest.
Where the amount of annual rainfall ranges between 200 and 250 cm, the mean annual temperature lies between 24 and 27 and humidity percentage is 80, the evergreen forests degenerate into semi evergreen forests; such forests are found along the Western Coast, in Upper Assam, lower slopes of the eastern Himalaya, Orissa coast and neighboring hills.
Important plant varieties include bamboos, epiphytes, Aini, Semul, Gutel, mundane, Hopea, Benteak, Kadam Irul, rosewood, Haldu, Kanju, Bijasal, Kusum, Bomsum, Indian chestnut, Litsea, Holloch, Champa and Mesua etc.
This types of forests mainly found in Indian Northern Hilly regions and some states of Southern India. Basically, these forests are generated where average annual rainfall ranges varies from 51 cm to 151. Trees of these forests drop its leaves in winter (when the weather remains driest) and new leaves are generated after winter. During rainy season these types of forest completely decorate lush green leaves. Some significant trees of Dry Tropical Forest are Sal, Acacia, Mangoes and Bamboo.
These types of forests are mainly generated in Northern middle Himalayas ranges (1801 to 3001 Meters) and Southern Niligiri higher Mountain ranges. It takes about 201 cm average annual rainfalls to produce these types of forests. Some significant trees of Montane temperate Forest are Rhododendrons, Ferns, Oak, Maple, Juniper, Deodar, Chilgoza, etc.
These types of forests mainly generated in the state of Assam, Nagaland, Mizoram, Meghalaya, Manipur, Arunachal Pradesh, etc. mountain ranges of Western Ghats are also the abode of these types' forests. Some significant trees of Montane sub tropical Forest are Poonspar, cinnamon, rhododendron, Sal, Sandan, Laburnum, pomegranate, olive, oleander, etc.
These grasslands start at an elevation of above 3000m grow up to the region just below the snowline. They are common in both the main Himalayan regions as well as the barren cold deserts of the Tran Himalaya. Low alpine grasslands are common with the vegetation not growing higher than 1.5m.
Climatic conditions vary from the sub-arctic to arctic, with snow covering the ground for over 5 months a year. The growing season for the plants is thus stunted. Pastures are grazed by migratory cattle in summer. The vegetation consists mainly of the black juniper, the drooping juniper; honeysuckle and willow are the common trees.
These forests are found between 2901 and 3501 meters, near the snow line all over the Himalayas and the dry cold deserts. Average temperatures in summers range from 20°C to 22°C. Winter temperatures are usually below the freezing point accompanied by lots of snow. Major common trees of this type forest are Juniper, Rhododendron, Willow and Black Currant. In the eastern parts, Red Fir, Black Juniper, Birch and Larch are the common trees.