BLUE PINE (<em>PINUS</em> <em>WALLICHIANA</em>) FOREST STANDS OF GARHWAL HIMALAYA: COMPOSITION, POPULATION STRUCTURE AND DIVERSITY
Keywords:Altitude, aspect, structure, dominance, diversity, similarity, Garhwal Himalaya
The study reports the composition, population structure and diversity of blue pine (Pinus wallichiana) forest stands of Garhwal Himalaya with special reference to altitude and aspect. A total of four sites were studied, of which two were on the southeast and the other two on the northwest facing slopes. Pinus wallichiana was the dominant tree species; however, competition was observed on the northwest upper slope. Higher species richness was noticed in the sapling and seedling layers. Berberis aristata, Cotoneaster affinis, Pyracrantha
crenulata and Pyrus pashia were the dominant shrub species. Tree layers had a similarity of 43.30 to 82.92%. The higher degree of dissimilarity between the lower gradients of opposite aspects indicated a significant change jn the community structure due to variation in aspect conditions. Species diversity (H) ranged from 0.73 to 1.60,1.71 to 2.53,1.83 to 2.47 and 1.87 to 2.33 for tree, sapling, seedling and shrub layers respectively. Among the different strata, within the present study area, the tree stratum showed comparatively greater habitat specialization owing to the higher value of beta-diversity than the saplings, seedlings and/or shrubs.