Dehing Patkai, is the only rainforest in Assam. It is a sanctuary with an area of 111.19 square kilometers located in the Dibrugarh and Tinsukia Districts of Assam. It falls under the category of Assam valley tropical wet evergreen forest. This sanctuary consists of three parts: Joypur, Upper Dihing River and Dirok Rainforest. It was declared as sanctuary on 13 June 2004. This sanctuary is also a part of Dehing-Patkai Elephant Reserve. The area also has some historic attractions, including several World War II cemeteries, the Stillwell Road and the Digboi refinery, the oldest in Asia.
The rainforest stretches for more than 575 square kilometers in the districts of Dibrugarh, Tinsukia and Sivasagar. A part of the forest was declared as a Wildlife Sanctuary by the Government of Assam, while another part falls under the Dibru-Deomali Elephants Reserve. The forest further spreads over in the Tirap and Changlang districts of Arunachal Pradesh. The Dehing Patkai forms the largest stretch of tropical low-land rainforests in India. The forest is often referred as “The Amazon of the east” owing to its large area and thick forests.
Being a completely virgin rainforest, this sanctuary is very rich in biodiversity. It is an ideal habitat for non-human primates. Till date, 47 species of mammals, 47 species of reptiles and 30 species of butterflies have been listed from here. The most common mammal species of this sanctuary are – Hoolock Gibbon, Slow Loris, Pig-Tailed Macaque, Stump-Tailed Macaque, Capped Langur, Asian Elephant, Tiger, Black Panther, Leopard, Gaur, Chinese Pangolin, Himalayan Black Bear, Himalayan Squirrel, Leopard Cat, Clouded Leopard, Porcupine, Crab Eating Mongoose, Sambar, Sun Bear, Binturong, Barking Deer, Golden Cat and Marbled Cat.
Dehing Patkai Rain forest in Upper Assam is known to harbour about 293 bird species, belonging to 174 genera and 51 families. The majority are residents (63.7%), some are winter visitors (23.1% ), and very few are summer visitors (2.5%). About 10.7% are altitudinal migrants, coming mainly from the higher reaches of the western, central and eastern Himalayas. There are 13 globally threatened species here viz. the Slender-Billed Vulture, White-Winged Duck, Greater Adjutant, Greater Spotted Eagle, Lesser Adjutant, Beautiful Nuthatch, Marsh Babbler, Tawny-Breasted Wren Babbler, White-Cheeked Hill Partridge, Great Hornbill, Brown Hornbill, Oriental Darter and Painted Stork.
At least 10 of the bird species are listed in Schedule-1 of Wildlife Protection Act 1972 (1994) including the White-Winged Duck, Kalij Pheasant, Grey Peacock Pheasant, Besra, Black Baza, Slender-Billed Vulture, Osprey, Great Hornbill, Wreathed Hornbill and Common Hill Myna.
Dehing Patkai Rain forest is home to five endemic bird species, which is 26% of the endemics reported from the north eastern region and all belong to the family Sylviidae. These are the Yellow-Vented Warbler, Broad-Billed Warbler, Marsh Babbler, Tawny-Breasted Wren Babbler and White-Naped Yuhina.
The Dehing Patkai Forest region not only boast rich biodiversity but also has a rich culture and heritage. There are more than a dozen different tribes and communities living in the area including Tai Phake, Khamyang, Khampti, Singpho, Nocte, Ahom, Nepali, Burmese, Tea-tribes etc.