Abstract: Studies on the relationship between forest gap spatial pattern and understory woody species diversity are of great significance for understanding species coexistence, biodiversity maintenance and sustainable development of forest ecosystems. In this study, we used the airborne Lidar to collect cloud data from a 24 hm² permanent forest dynamic monitoring plot in Jinzhong Mountain Nature Reserve of Guangxi, extracted forest gaps, and calculated shape complexity index of each forest gap by R programming language. Correlation analysis was conducted to quantify the relationship between forest gap characteristics and understory woody species diversity. The results showed that the forest gap rate in the study area was 6.16%, the gap density was 15.5·hm^-2, the average gap area was 39.72 m², and the gaps were mainly small and middle sized. The spatial distribution pattern of forest gaps had topographic differentiation, mostly distributed in low altitude and gentle slope areas. The gap shape complexity index was positively correlated with Shannon index and species richness index, which was more obvious in low altitude and steep slope areas. This study revealed the characteristics of plant regeneration in the forest gaps of subtropical forests, which has a certain guiding role for regional biodiversity conservation.

Key words: Lidar, subtropical forest, forest gap, distribution pattern, biodiversity