PLANT DIVERSITY ........................

Abstract

Plant community structure in particular area determines the forest stage and its importance. Different topographical, climatic, edaphic and population factor affects the community composition and its life span. Thus, the present study has aimed to find out the role of different topographical features in species diversity, tree regeneration and total biological carbon stock in the Kaleshwar area of Lalitpur district, Central Nepal. A quantitative study was carried out along the altitudinal gradients at both Northern and Southern aspect of Lahuribina community forest and Gimdi community forest respectively at Kaleshwar area. The study was carried out by using stratified random sampling method. Study area was divided into 5 different altitudinal strata in both the aspects (i.e.1500m-1600m, 1700m-1800m, 1900m-2000m, 2100m-2200m and above 2300m). 10 circular plots of sizes 10m radius for trees, within it, subplots of 5m radius for shrubs including sapling and 1m radius for herbs and seedling were laid in each strata. Regeneration of tree species were calculated by counting the seedlings (height < 20 cm) with in 1 m radius and saplings (height > 20 cm) with in 5m in circular plot. Carbon stock of tree species were calculated with the help of tree DBH and height. Total of 155 plant species were enumerated from north facing aspect, with 42 species of tree, 37 species of shrubs and 76 herbs species. But in southern aspect 134 species were recorded; 32 trees, 37 shrubs and 65 herbs species. Numbers of species were slightly higher in northern aspect than in the southern aspect however, the difference was not significant. There was slight variation in species richness and evenness between two aspects. There was very low number of seedlings than that of sapling and adults along all the altitudinal strata in both the aspects. Carbon stock was higher at 1500m followed by 2100m and 2300m altitudinal strata along northern aspect and at 1700m and 1900m altitude along southern aspect. Study concluded that the altitude and aspect play significant role in plant species diversity, regeneration and carbon stock.