Positioned on the low hills in the northeastern Indian state of Orissa, the Orissa semi-evergreen forests are vulnerable to the full force of the southwestern monsoon winds that sweep in from the Bay of Bengal. Due to the rainfall from this monsoon and the ameliorating year-round oceanic influences, moister climatic conditions are created here. As a result, the Orissa semi-evergreen forests in India have the original extent of distinctly moister semi-evergreen forests that once existed to the east of the Eastern Ghats Mountains. The ecoregion has an ancient geological lineage of Gondwanaland origins and for this reason; it still harbours relicts of an ancient biota.
The Orissa semi-evergreen forests in India have patches of several habitat types like the canebrakes, wet bamboo brakes, moist bamboo brakes, lateritic semi-evergreen forests, and secondary moist bamboo brakes. However, most of these habitat types are sometimes not identifiable in the field because of excessive deforestation and changes in land-use practices. The natural vegetation in the forests mainly includes five series like the Shorea-Buchanania-Cleistanthus, Shorea-Cleistanthus-Croton, Shorea-Terminalia-Adina, Shorea-Syzygium operculatum-Toona, and the Shorea-Dillenia-Pterospermum.
The Orissa semi-evergreen forests in India are also quite rich in its biotic community. The most common flora species in the upper story of these forests include the Artocarpus lakoocha, Michelia champaca, Celtis tetrandra, Bridelia tomentosa, B. verrucosa, Dillenia pentagyna, Saraca indica, Ficus spp., Mangifera indica, and Firmiana colorata, etc. The second story of the forests is characterized by the species like Aphanamixis polystachya, Mesua ferrea, Phoebe lanceolata, Polyalthia spp., Macaranga peltata, Glochidion spp., and Litsea nitida, etc. There is also an understory of evergreen shrubs, canes, and herbs present in these forests. The forests situated in the hilly areas, which have lateritic soils (the residual product of rock decay), house the species like Xylia xylocarpa, Pterocarpus marsupium, Anogeissus latifolia, Grewia tiliaefolia, Terminalia tomentosa, and Terminalia bellirica, etc.
The total number of mammal species found in the Orissa semi-evergreen forests in India is fifty-nine and none of them is considered as endemic. However, there are a number of threatened species found in the forests that need urgent conservation attention. These species include the Tiger, Asian Elephant, Gaur, Wild Dog, Sloth Bear, and Chousingha. The forests located along the higher elevations may also provide dispersal habitat for Tigers and Leopards from Simlipal in the north to Andhra Pradesh to the south of Orissa. Apart from the vegetation and mammal species, the Orissa semi-evergreen forests are quite rich in bird species, as well. The forests are home to a large number of more than 215 bird species and none of them are considered as endemic. However, there are a few globally threatened bird species inhabit in these forests and the species include the Lesser Florican. Some of the other birds that warrant conservation attention include the Oriental Darter, Greater Flamingo, and White-Bellied Sea Eagle.