As per Champion and Seth classification there are seven forest types found in VTR which makes VTR a special destination for nature lovers. Due to diverse topographical and edaphic factors the Reserve harbors varied vegetation types:-
The important tree species found in valley areas of VTR are Sal (Shorea robusta), Karam (Adina cardifolia), Asan (Terminalia tomentosa), Bahera (Terminalia balerica), Asidh (Lagestromia parviflora), Simal (Salmelia malaberica), Satsal (Dalbergia latifolia), etc.
In hilly regions apart from Sal, Piyar (Buchanania lanzon), Mandar (Dillenia aurea), Banjan (Anogeissus latifolia), Bhelwa (Semicarpus anacadium), Harra (Terminalia chebula), Bodera (Eugenia operculata), etc tree species are found.
Cane breaks are mainly found in Madanpur Forest block and it is a good habitat for Tiger. Cane occurs in damp areas along almost all the nalas of Madanpur Range. In hindi cane is known as BETTH and the name Bettiah (District Headquarter of West Champaran District) is derived from this BETTH.
There is a small isolated patch of Chirpine forest, locally known as DHUP found in Raghia Forest block. Generally Chirpine forest occurs at an altitude of 4000 ft. to 5000 ft. but here it is found between the altitudes of 1000 ft. to 1700 ft. which is unique.
Grasses found in VTR are Munj (Saccharum munja), Kans (Saccharum spontanum), Elephant grass (Typha elephantina), Narkat (Phragmites karka), Vitiveria zizanioides, Imperata cylindrica, Choranth (Heteropogon contortus), Sabai(Eulaliopsis binata), etc. Climbers are also very common in VTR, common species being Mahulan (Bauhinia vahlii) Mahai (Butea parviflora), Panilat (Vitis repanda), Ramdatwan (Smilax parviflora), and Arar (Acacia pinnata).
There are several medicinal plants found in VTR. Some of them are Satawar (Asparagus racemosus), Safed Musli, Dudhkoraiya (Holarrahena antidysenterica), Amla (Emblica officinalis), Piper (Piper longum), etc.