Vegetation analysis of Shorea robusta forests in the Royal Bardia NationalPark, Nepal

Vegetation in three tropical Shorea robusta forests viz., Terai pure Shorea robusta forest (TPSRF), Terai mixed S. robusta forest (TMSRF) and Hill S. robusta forest (HSRF) in the Royal Bardia National Park, Nepal has been com pared. A total of 45 permanent research plots (25 m x 25 m) were laid to as sess the vegetation characteristics. The upper canopy of all the three fore st types was mainly dominated by Shorea robusta and Terminalia alata. Howev er, in each forest type, the extent of dominance varied considerably. Total density ranged between 332 stem ha-lin the TMSRF and 432 stem ha(-1) in HS RF and the total basal area ranged between 29 m(2)ha(-1) in TMSRF and 36 m( 2)h(-1) in TPSRF. In TPSRF forest and HSRF both density and basal area were greatest for Shorea robusta. Whereas in TMSRF, density and basal area were higher for Terminalia alata. The distribution of trees (greater than or eq ual to 10 cm dbh) among diameter class showed a higher density of stem with 10-20 cm diameter at breast height. The highest above ground biomass of 34 8.02 ton ha(-1) was found in TMSRF followed by 330.87 ton ha(-1) in TPSRF f orest and 267.3 ton ha(-1) in HSRF. The lower basal area, biomass and highe r density showed that the forests were younger and were in a state of regen eration.