Plant diversity, population structure, and regeneration status in disturbed tropical forests in Assam, northeast India

We investigated the plant population structure and the phytosociological and regeneration status in two disturbed tropical forests in Assam Province, the Hojai Reserve Forest and Kumorakata Reserve Forest. A total of 166 species (80 trees, 20 shrubs and 66 herbs) of 136 genera and 63 families were recorded in both study sites. The disturbance index at the two sites, Kumorakata Reserve Forest and Hojai Reserve Forest, were recorded at 11.4% and 3.70% respectively. Reverse J-shaped population curve and exploitation of tree species in higher girth classes were recorded at both study sites. In the girth classes (10-30 cm, 30-60 cm, 60-90 cm and 90-120 cm in size) the percentage of cut stump density was higher than the percentage of individual living trees. The 18% (Kumorakata Reserve Forest) and 7% (Hojai Reserve Forest) species were recorded as not regenerating. Illegal felling and over-exploitation of forest resources may lead to species-specific changes in the population structure and can alter the future structure and composition of the forests.