Forest stand structure and regeneration status on trekking route of Barsey Rhododendron Sanctuary, Sikkim Himalaya, India

Abstract

This study estimates the stand structure and regeneration pattern of woody species on the trekking route extended from Hilley to Guras kunj of Barsey Rhododendron Sanctuary (BRS) in Soreng District, Sikkim, India. A total of 11 tree species belonging to four different families were recorded from 27 plots and nested plots laid on sanctuary’s 4.5 km transect line in the trekker’s pathway. For each species, number of individuals and their seedlings and saplings were counted. The Girth at Breast Height (GBH) and tree height were measured. Basal area, frequency, density, abundance, Importance value index (IVI) and four indices of diversity were considered for stand structure analysis. Rhododendron hodgsonii Hook. f. had the highest IVI (73.03). The correlation coefficient of order 2 polynomial is 0.91 for density and IVI. Shannon Weiner Index is 1.94 and Simpson’s diversity index is 0.18. Margalef’s species richness index is 2.13 and Pielou’s evenness index is 0.76. A standard equation estimated biomass for all the species. Lithocarpus pachyphylla had the highest biomass value (306.86 Mg ha− 1). Regeneration status was determined by estimating relative proportion of seedlings saplings, and trees within sample plots. 7 out of 11 tree species were not regenerating at all. These findings highlight the need for informed policy formation to address the declining regeneration of tree species along the trekking route.