Natural Regeneration Dynamics of Tree Species along the Altitudinal Gradient in a Subtropical Moist Deciduous Forest of Northern India

The present study was conducted to examine the regeneration pattern in 72 random plots of six tropical forest sites of Rajaji Tiger Reserve, Uttarakhand, India. The population structure of the forest was determined through density of seedlings, saplings and trees from the sampling quadrat. Based on individual density of seedling, sapling and adult, the regeneration potential of the species was determined. A total of 58 tree species under 50 genera belonging to 30 families were recorded in the forest. The overall density ranged from 1525 to 6600 ind/ha and the total basal area ranged from 0.577 to 46.81 m²/ha in case of trees and saplings, whereas for seedlings, the value ranged from 511.96 to 1221 cm²/ha. The good regeneration pattern of tree species varied from 12.12% to 31.575%, fair regeneration pattern from 12.12% to 31.57%, new regeneration from 5.26% to 39.13%, poor regeneration from 0% to 10.52%, and no regeneration of trees from 15.78% to 42.42%. Inadequate regeneration status and population structure of tree species like Shorea robusta, Careya arborea, Ficus auriculata were observed which could be due to looping, scraping, grazing and trampling. Anthropogenic disturbances have resulted in the population decline of tree species which may lead to many species becoming endangered, rare and threatened. Therefore, proper management and conservation initiatives with active involvement of the locals must be taken to protect the tropical forest sites of the Reserve.