Tree species composition and diversity along an altitudinal gradient in moist tropical montane valley slopes of the Garhwal Himalaya, India

Abstract

The study was conducted along an altitudinal gradient (1500 to 2850 m above sea level) in moist tropical montane valley slopes of the Mandal-Chopta area in the Garhwal region of India. Twelve forest types according to the altitude, slope aspect, and species compositions were selected for the study. The aims of the study were to describe and examine the structure and composition of the tree vegetation along an altitudinal gradient, and to compare the results of the present study with the other forests of Uttarakhand Himalaya growing at similar altitudinal range. High values of stem density and species diversity were recorded in mixed broad-leaved forest types growing between 1600 and 2400 m a.s.l., whereas forest types growing at higher altitudes (>2400 m a.s.l.) had low species richness and stem density. Tree density (tree ha−1) showed positive relationship with species richness and Shannon–Wiener diversity index. Forest types growing at higher altitude (>2400 m a.s.l.) showed geometric dominance-diversity curves. The values of stem density and total basal area in most of the forest types were higher than the earlier reported values from other parts of the Uttarakhand Himalaya.