DOMINANCE AND DIVERSITY RELATIONS OF WOODY VEGETATION STRUCTURE ALONG AN ALTITUDINAL GRADIENT IN A MONTANE FOREST OF GARHWAL HIMALAYA

Abstract

Woody vegetation composition, dominance and diversity were studied along a southwest facing altitudinal gradient in a montane forest of Garhwal Himalaya. Quercus leucotrichophora (1800-2000m) and Quercus-Rhododendron (2000-2200 m) were the dominating species. Soils were acidic. Percentage organic carbon ranged from 2.1 ±0.23 (upper) to 2 ±0.25 (lower). C:N ratio assessed the steady state of litter decomposition in the soil. On lower slope Quercus leucotrichophora was the dominant species, and on upper slope, Quercus leucotrichophora and Rhododendron arboreum were the competing species. Invasion of Pinus roxburghii (chir-pine) is an indication of Quercus leucotrichophora (oak) replacement in the near future. Marked degree of dissimilarity between upper and lower slopes was due to variation in altitude. Decreasing diversity indices from seedling to tree strata reflected the poor regeneration potential of these forests. Across the strata, shrub layers had a specific niche approach owing to higher betadiversity.