The physiography and the warm humid climate of the state are conducive to luxuriant vegetation growth. Assam is home to 51 forest and sub-forest types, and the confluence of diverse patterns of vegetation, lying in the eastern Himalayas the state is bestowed with fertile soil and a moist tropical climate enabling it to have a treasure trove of biodiversity. This region‘s lowland and montane moist to wet tropical evergreen forests are considered to be the northernmost limit of true tropical rainforests in the world. The state has total forest cover of 35.48% of its total geographic area with 5 National Parks, 13 Wildlife Sanctuaries and 2 Bird Sanctuaries.

The Eastern Himalaya sand the Assam plains have been identified as an Endemic Bird Area by the Royal Society for Protection of Birds. Assam is also famous for its mega-fauna the Rhinoceros unicornis (Rhino), Trachypithecus geei (Golden Langur), Hoolock hoolock (Hoolock Gibbon) and other highly endangered species like the Porcula salvania (Pygmy Hog), Caprolagus hispidus (Hispid Hare) and Cairina scutulata (White winged wood duck).

Assam‘s faunal wealth is matched by the diversity of its plant resources. The North East region of India has been identified by the Indian Council of Agriculture and Research (ICAR) as the centre of rice germplasm and center of origin of commercially important plants such as banana, citrus, zizyphus and tea, The National Bureau of Plant Genetic Resources (NBPGR) has highlighted NE India as rich in wild relatives of crop plant.

The State is also very rich in medicinal plants as many as 952 plant species of medicinal value are found here. Assam‘s richness of flowering plants is estimated at about 3010 . About 293 species of orchids have been reported from Assam representing 44.39% of North East species and 24.42% of species occurring in India. Assam also has much bamboo (41 species) and cane species diversity (14 species). Broadly speaking the forest resources are divided into the following types Tropical Wet Evergreen forests, Tropical Semi Evergreen forests, Tropical Moist Deciduous forests, Sub-Tropical Broadleaf Hill forests, Sub-Tropical Pine forests, Littoral and Swamp forests and grasslands and savannahs.