General info The Himalayas stretches over a distance of about 2500 kms from west to east. It average width along the entire longitudinal extension ranges from 100 - 400 km. The vast area covered by the mountain range along with some fantastic altitude gradients result in the tremendous biodiversity of the Himalayan region. Vegetation and wildlife, both change according to the varying altitude and the resulting differences in climatic conditions.

The magic of the Bhyundar Valley or the Valley of Flowers (Download Realplayer)

The rare Himalayan Blue Poppy Credit: Raj Shirole

Flora
Himalayan vegetation varies according to both altitude and climatic conditions. They range from the tropical deciduous forests in the foothills, to temperate forests in the middle altitudes. Higher up, coniferous, sub-alpine, and alpine forests spring up. These finally give way to alpine grasslands and high altitude meadows. They are followed by scrublands which lead up to the permanent snowline.

The vegetation also varies from the unexplored tropical rainforests of the Eastern Himalayas, to the dense subtropical and alpine forests of the Central and Western Himalayas to the sparse desert vegetation of the cold desert areas of the Transhimalaya.

However, the floral wealth of the Himalayas have also been affected by man. Over the centuries, man has always been dependent on his forests for a number of his needs. But earlier, these needs were few, the forests were able to replenish the resources, and the delicate natural balance was maintained. But over the years, the human population increased dramatically, and with it the number of industries that depended on forests. Extraordinary demands were made on the forests. Forests were cut down for firewood and to feed the growing number of forest-based industries. They were also cleared to accommodate the growing population. As a result, many species of trees that were very common even 50 years ago, are now rare or have completely disappeared from certain areas.

Rain forests in Arunachal Credit: Karamjeet Singh

Tropical forests
There are mainly two types of tropical forests that are found in the Himalayas - the tropical rainforests, and the tropical deciduous forests. The tropical rainforests are dense, evergreen, gloomy and similar to the forests of the Amazon basin and other equatorial areas. They occur mainly in the eastern Himalayas which receives very heavy rainfall.

Tropical deciduous forests are found in regions of slightly lower rainfall. They are common in the lower slopes of the Himalayas. These forests shed their leaves in certain seasons. Also the forests tend to be less dense than the rainforests. Forests of teak and sal are common in areas of deciduous vegetation.