Dharan forests stretch from east to west in Sunsari and Morang districts, and constitute a significant portion of the forest remaining in Sunsari. Tropical evergreen tree species mixed with Sal Shorea robusta form the main vegetation type. Apart from the lower Mai valley forests, which are more degraded and fragmented, Dharan forests form the only significant area of this forest type that remains in Nepal. The forest is bisected by the major Itahari to Dharan road and lies nearly one hour’s drive from Koshi Tappu Wildlife Reserve. In addition five gravelled roads run parallel to the Dharan to Itahari road in the east linking the people of the Siwalik region with the terai.
It is estimated that the large number of 300 bird species occurs in this forest, although a complete inventory is still to be made. The globally threatened Lesser Adjutant, White-rumped and Slender-billed Vultures are some of the globally threatened bird species found in the area. The near-threatened Wedge-billed Wren Babbler was recently recorded in Nepal for the first time from Dharan forests; it was probably overlooked previously. There are large areas of tropical forests that are likely to support significant populations of species characteristic of the Indo-Chinese Tropical Moist Forest and Indo-Malayan Tropical Dry Zone biomes.
Non-bird biodiversity: Bengal Fox Vulpes bengalensis, Hanuman Langur Semnopithecus entellus, Wild Boar Sus scrofa, Chital Axis axis, Black Giant Squirrel Ratufa bicolor and Indian Hare Lepus nigricollis are a few of the mammal species found here. The forest is also the main corridor route of the Asian Elephant Elephas maximus which visits east Nepal from India.
Conservation responses/actions for key biodiversity
Although most of the forest areas have been handed back to local people to manage as community forests, forest clearance and degradation of forests through livestock grazing, and cutting of the understorey and tree branches are rampant. Tree felling and collection of several plant species are ongoing. Several trees are cut every day. Livestock grazing is allowed and there is uncontrolled collection of timber, firewood and other NTFP. If such activities are not stopped immediately, Nepal may lose several valuable timber species. Recently, the invasive Mikania micrantha has attacked several parts of the forest destroying the natural vegetation cover.
This is also the only place in Nepal where a healthy population of the Black Giant Squirrel Ratufa bicolor survives. However hunting, disturbance and habitat loss are causing enormous pressure on this mammal.
None of the protected areas in Nepal include a significant area of tropical moist forests and therefore there is an urgent need for HMG/N to declare the Dharan forests protected. The current security situation has led to an increase in timber smuggling in Morang district (Anon 2003a). The ornithological value of forest types found here are discussed in Inskipp (1989a). ). A brief biological survey was carried out by Himalayan Nature in 1999 but the deteriorating security situation in the country stopped further work. Some baseline information on the birds of Dharan forest IBA has been collected (Khanal and Yonzon 2000, Basnet 2003, Himlayan Nature unpublished).