基于无人机的喀斯特退化天坑地下森林树高特征研究

基于无人机提取喀斯特退化天坑地下森林的树高特征，探索乔木树高的生长策略与天坑局部圈闭化生境的关系，研究退化天坑作为物种避难所的价值。通过无人机遥感技术对退化天坑进行三维重建，提取退化天坑内外的树高信息。结果表明：退化天坑地下森林平均树高较地表高出约5 m。地下森林平均树高为10.47 m，地表平均树高为5.43 m，地表南坡平均树高为5.75 m，坑内树高的分布特征受海拔影响显著。在喀斯特天坑微生境的作用下，与坑外地表相比，坑内地下森林在树高方面具有显著的优势，光照是地下森林乔木类植物种内和种间竞争的主要因子，垂直梯度是退化天坑植被树高分布格局的首要特征。无人机遥感技术能够快速地获取退化天坑地下森林的树高信息，具有推广潜力。

Tree-height Characterization of Karst Degraded Tiankeng Underground Forests Using Unmanned Aerial Vehicles

Based on UAV extraction of tree height characteristics of underground forests in graded karst Tiankeng， we explored the relationship between the growth strategy of tree height and the local enclosure habitat of graded Tiankeng， and studied the value of graded Tiankeng as a refuge for species. The graded Tiankeng was reconstructed in three dimensions by unmanned aerial remote sensing technology to extract tree height information inside and outside the graded Tiankeng.The results showed that the average tree height in the underground forest of degraded Tiankengs is about 5m higher than the surface. The average tree height in the underground forest is 10.47 m； the average tree height on the surface is 5.43 m； and the average tree height on the south slope of the surface is 5.75 m. The distribution characteristics of tree height in the Tiankeng are significantly influenced by elevation. Under the effect of karst Tiankeng microhabitats， the underground forest in the Tiankeng has a significant advantage in tree height compared with the surface outside the Tiankeng. Light is the main factor of intra- and interspecific competition among tree species in the underground forest， and vertical gradient is the primary feature of tree height distribution pattern of degraded Tiankeng vegetation. UAV remote sensing technology has the potential to be promoted as it can quickly obtain information on tree height in degraded Tiankeng underground forests.