Forest dynamics along altitudinal gradient covering treeline ecotone of Indian Western Himalaya

The present study is an attempt to analyze the pattern of trees distribution, population structure and regeneration status along altitudinal gradients by sampling vegetation within each 100 m altitudinal belts from 2100 m a.s.l. upto treeline ecotone (3300 m a.s.l.) in Kedarnath Wildlife Sanctuary in western Himalaya. The study documented 39 species of trees belonging to 32 genera and 21 families; among these 13 (61.90%) families and 27 (84.38%) genera were monotypic indicating poor genetic base and recent speciation of the species in the region. The results of vegetation assessment reveal that tree density, species diversity (H´) and species richness decreased with increasing altitude. The average total tree basal area (TBA) was found 60–70 m2/ha upto 2800 m altitude, which considerably declined (24 m2/ha) upto 2800 m onward upto treeline ecotone. The forest population structure showed a classic inverse J-shape curve pattern in the lower altitude zone, suggesting a healthy proportional conversion rate of individuals (seedlings > saplings > adults) of tree species into higher size classes. The absence of tree saplings in many forest stands, suggests that seedlings had failed to reach sapling stage in recent years. At higher altitudes, the population structure was hill shaped, indicates poor regeneration of tree species. These findings have significant implications for appropriate forest management and conservation planning in the Himalayan region.