Abstract: A total of 13 temporary sample plots with a total area of 2800 m² were surveyed with typical sampling method to investigate Vatica mangachapoi dominant communities at different altitudes in Hainan Island.The effects of different altitudes on species composition,structure,and community characteristics of Vatica mangachapoi dominant communities were analyzed.The analysis results showed:there were significant differences on dominant species composition of Vatica mangachapoi communities at different altitudes; the changes of Vatica mangachapoi important value and community diversity for trees (DBH≥5cm)showed opposite trends as the altitude increases; tree number distributions of Vatica mangachapoi (DBH≥5cm)at different altitudes all showed inverted J-curve distribution among diameter classes,but the difference among them was significant and inverted J-curves tend to be much more flatr as the altitude increases; Vatica mangachapoi tree numbers,ratio and basal area (DBH≥5cm)decreases as the altitude increases,but average diameter of Vatica mangachapoi at breast height increases as the altitude increases.

Key words: community structure, diversity, Vatica mangachapoi, Hainan Island