The lowland tropical forests of Namdapha are perhaps the last remaining Dipterocarpus forests in India. This type of forest is found in the Diyun Valley and in the hills up to a certain elevation. These forests are typically three- storeyed with Hollong and Mekai forming a definite dominant layer. The variety of saprophytic fungi is also staggering. On alluvial flats, along rivers and stream banks and on the hill slopes, moist deciduous forests with most of the species in the top storey shedding their leaves, are found.
Climbers are also plentiful.
1.5.3 Miscellaneous forests There are scattered patches of Khokan, Borpat, Hilika etc. of various sizes. Undergrowth is very dense and contains canes besides other species. Wherever the natural vegetation has been disturbed Mikenia cordata has invaded the area and prevented any other vegetation from coming up. No details of the temperate and alpine forests is currently available, because these areas are inaccessible. The subtropical humid climate and the virgin untouched forests of the area sustain the richest and most varied mamallian fauna, compared to any other area in India.