Abstract: To understand the changes of community structure and diversity of natural forests in mountainous areas of central Hainan Island, two surveys were conducted in the montane rain forest in Wuzhishan, the lowland rain forest in Jianfengling, the montane rain forest in Diaoluoshan and the cloud forest in Bawangling from 2012 to 2020. A plot with a size of 1600 m² was set up for each forest type. The temporal variations of community structure, tree growth, tree mortality and species diversity in eight years were analyzed. The results showed that from 2012 to 2020: (1) DBH size-class and tree height class of the montane rain forest in Wuzhishan and the lowland rain forest in Jianfengling showed an inverted “J” shape. DBH sizeclass of the montane rain forest in Diaoluoshan and the cloud forest in Bawangling showed an inverted “J” shape, while tree height class showed a near “L” shape. The community structure became more complex over time. (2) Height growth rate of young trees was faster. With the increase of DBH, growth rate of tree height decreased and growth rate of DBH increased. The number of dead indivi duals decreased with the increase of DBH. Young trees had a strong competition for resources, such as sunlight. (3) The change rates of population size of Pterospermum heterophyllum, Garcinia oblongifolia, Prismatomeris tetrandra and Symplocos hainanensis were higher than 5%, indicating rapidly changing populations. Pioneer species were gradually replaced by transitional species. (4) The average change rate of species diversity was +1.48%, +1.59%, +4.19%, and +12.26% in the montane rain forest in Wuzhishan, the lowland rain forest in Jianfengling, the montane rain forest in Diaoluoshan and the cloud forest in Bawangling, respectively. Most of the immigrating and exiting species were occasional species, which accounted for the changes of species diversity. Community succession of the damaged forests in the mountainous areas of central Hainan Island can be well restored, the structure complexity, species diversity and community stability of which can be effectively improved by effective enclosure.

Key words: community structure, species diversity, tree growth, tree mortality, community renewal, vegetation restoration.