Dibang Wildlife Sanctuary is a mountainous, consisting steep to very steep and rugged terrain. The altitude varies from 1800 MSL to 5000 MSL. The variety of flora and fauna is perhaps unequal here.
Flora: The vegetation of Dibang Wildlife Sanctuary is of temperate and alpine type. The vegetation in the sanctuary is Tsuga, Abies, Pinus walli chinana Rhododendra arboratum, Taxus baccata and gregarious occurance of bamboo forests.
Alpine Forests-The Alpine type of vegetation occurs on the peaks of higher reaches above an altitude 4000 m to 5500 m. Major part of the year remains covered with snow and the physiological activities of plants are restricted only for a few months during the period snow melts. The trees are stunted and dwarf in bushes. The plants are mostly herbs with deep root. The ground is mostly cushioned with leaves and branches. The area becomes very attractive during flowering season with bright colored gregarious flowering for brief period. Plants like Rhododendra nivals, Rthomaonii, Sedum spp., Saxifraga spp. etc.
Fauna: The Sanctuary is very rich in animal population. The herbivores found are Goral, Takin, Serow and Musk Deer. Migration of population takes place due to food crises during seasonal variation. Among this, carnivores are snow leopards in high altitudes and clouded leopard in the lower latitudinal zone found here.
There is a beautiful lake called as Kahai white means lake in the middle of the flower valley. The flowering season of this valley is during the month of May and June.