Forest sample plots data of National Park of Hainan Tropical Rainforest in 2003, 2008, 2013,2018 and 2022.

The research area of this study is National Park of Hainan Tropical Rainforest. From February 20, 2022 to July 30, 2022, the investigators went to National Park of Hainan Tropical Rainforest to conduct a forest resources survey. The scope of the investigation includes Jianfengling Branch of Hainan Tropical Rainforest National Park Administration, Maorui Branch of Hainan Tropical Rainforest National Park Administration, Wuzhishan Branch of Hainan Tropical Rainforest National Park Administration, Diaoluo Mountain Branch of Hainan Tropical Rainforest National Park Administration, Limushan Branch of Hainan Tropical Rainforest National Park Administration, Bawangling Branch of Hainan Tropical Rainforest National Park Administration and Yingge Ling Branch of the Hainan Tropical Rainforest National Park Administration. In order to be consistent with the size of forest sample plots in the Hainan Continuous Forest Inventory, the forest sample plots investigated in this study was 25.8m × 25.8m. The distance between two forest sample plots was about 4 kilometers. A total of 98 forest sample plots were investigated, of which 64 were reviewed and 34 were supplementary. The investigators mainly investigated the tree species, DBH, tree height of trees with diameter above 5 cm in the forest sample plots. At the same time, data such as latitude, longitude, climate, slope gradient, slope direction and altitude of the forest sample plots were collected. In addition, this study combined with the data of the sixth, seventh, eighth and ninth Hainan Continuous Forest Inventory in the National Park of Hainan Tropical Rainforest included 64 forest permanent sample plots. In principle, the National Continuous Forest Inventory should be conducted every five years. Every year, the competent forestry authorities under the State Council shall uniformly arrange provinces to carry out National Continuous Forest Inventory. The review shall be conducted in the same year and the results shall be reported to the competent forestry authority under The State Council two years later.