The riverine flood plain of the
reserve comprises hill wash and alluvial deposits.
More than 33 percent of the reserve is covered
by Sal (Shorea robusta) and other mixed forest.
There are extensive grassland called phanta
in Nepal. The biggest grassland is called Sukla
Phanta. Several other extensive grasslands are
separated bt the patches of the forest. A small
lake called Rani Talk (Lake) lies on the eastern
side of the reserve and it is the most fascinating
area for the water birds and migratory birds.
There are also several water-logged
area known as dhap or swampy ground covered
by reed and tall grasses.
