Study on population structure and seedling regeneration of Hopea hainanensis Merr. & Chun under ex situ conservation in Xishuangbanna Tropical Botanical Garden

An investigation of a Hopea hainanensis population was conducted in a 500 m² plot in the Xishuangbanna Tropical Botanical Garden (XTBG), Chinese Academy of Sciences. The diameter-level structure was used instead of the age-level structure to analyze the structural characteristics of the population. At the same time, a static life table was compiled to analyze the survival rate, mortality rate, and disappearance rate of the population. Results showed that the ex situ cultivated H. hainanensis population had no individuals with large diameter, although most of adult individuals are capable of blossoming, fruiting, and naturally regenerating. The seedling density of H. hainanensis was 19 550 plants per hm², accounting for 86.00% of total individuals. Based on the static life table, the lowest mortality rate was observed in age class Ⅱ, while the highest was observed in age class Ⅲ. The population survival curve was categorized as the Deevey-Ⅲ type. Changes in mortality and loss rate curves showed the same trend. Results indicated that ex situ conservation of H. hainanensis in XTBG has achieved initial success, as evidenced by its population increase and germination stability. Enhanced management of seedlings and saplings could further improve survival rates and promote seedling to sapling, treelet, and tree progression, thereby expanding its population.