Dehing Patkai National Park harbours the largest stretch of lowland rainforests in India.

Avifauna includes white-cheeked partridge, kalij pheasant, grey peacock pheasant, Oriental darter, lesser adjutant, white-winged wood duck, pied falconet, slender-billed vulture, white-backed vulture, greater spotted eagle, besra, black baza, osprey, pale-capped pigeon, green imperial pigeon, mountain imperial pigeon, red-breasted parakeet, Oriental bay owl, tawny fish owl, great pied hornbill, brown hornbill, wreathed hornbill, yellow-vented warbler, hill myna and scaly thrush.

There is an abundance of ferns, epiphytes, wild banana, orchids, arums, climbers and lianas in this humid forest habitat.

The important species of over wood are Dipterocarpus macrocarpus, Mesua ferrea, Castanopsis indica, Shorea assamica, Vatica lanceaefolia, Amoora wallichii, Dysoxylum binectiferum etc.

The other species found in understorey are Garcinia lanceifolia, Michelia muni, Baccaurea sapida, Bischofia javanica, Myristica limifolia etc.

The shrub and herb layer has Glochidion spp., Alpinia spp., Mallotus philippinensis, wild banana, tree fern, pepper etc.

There are more than a dozen different ethnic groups living in the area including the indigenous Assamese communities, particularly Tai Phake, Khamyang, Khampti, Singpho, Nocte, Chutia, Ahom, Kaibarta, Moran, Burmese, and Nepali people.