Tree species composition and population structure of a secondary tropical evergreen forest in Cachar district, Assam

Abstract

Aim: Species composition, structure and dynamics are becoming an important tool to estimate the level of adaptation to the environment and providing useful information to their ecological significance. The present study was carreid out to determine the tree species composition, diversity and population structure of a secondary tropical evergreen forest in Cachar district, Assam. Methodology: Assessment of tree was carried out in a permanent plot (1 ha) subdivided into one hundred (10 m x 10 m) quadrats for enumeration of all trees (≥ 10 cm) girth at breast height. Girth was measured at (1.37 m) above ground level and trees of girth size (≥ 10 cm) (gbh) were taken. The tree species were collected and herbarium was prepared and identified from collection of herbaria at the Botanical Survey of India, Eastern Regional Centre, Shillong. Results: A total of 2152 stems ha-1 belonging to 52 species, 43 genera and 28 families with a total basal area of 23.80 m2 ha-1 were recorded. The most dominant families were Sapotaceae, Myrtaceae, Fagaceae, Euphorbiaceae and Clusiaceae according to the Family Importance Value (FIV) index. Palaquium polyanthum, Memecylon celastrinum, Castanopsis purpurella, Artocarpus chaplasha and Cynometra polyandra were five most dominant and important species in the tropical secondary forest. The girth size of all species combined followed the reverse-J-curve, typical of uneven-aged mixed forests. Interpretation: The present study could be useful for understanding the changes in the species composition during the course of development in a secondary tropical forest dominated by Palaquium polyanthum (Sapotaceae).