India is a land of great variety of natural vegetation. Himalayan heights are marked with temperate vegetation; the Western Ghats and the Andaman Nicobar Islands have tropical rain forests.
- Tropical evergreen forests are found in warm and humid areas with an annual precipitation of over 200 cm and mean annual temperature above 22°C. In these forests, trees reach at great heights up to 60 m or above. The semi¬evergreen forests are found in the less rainy parts of these regions.
- Tropical deciduous forests are spread over regions which receive rainfall between 70-200 cm.
- The moist deciduous forests are more pronounced in the regions which record rainfall between 100-200 cm. Dry deciduous forest covers vast areas of the country, where rainfall ranges between 70-100 cm.
- Tropical thorn forests occur in the areas which receive rainfall less than 50 cm. In mountainous areas, the decrease in temperature with increasing altitude leads to a corresponding change in natural vegetation.
- The Himalayan ranges show a succession of vegetation from the tropical to the tundra, with change in the altitude. Deciduous forests are found in the foothills of the Himalayas. It is succeeded by the wet temperate type of forests between an altitude of 1,000-2,000 m. In the higher hill ranges of north-eastern India, hilly areas of West Bengal and Uttarakhand, evergreen broad leaf trees such as oak and chestnut are predominant. Between 1,500-1,750 m, pine forests are also well-developed in this zone, with Chir Pine as a very useful commercial tree.
