DISSERTATION RESEARCH: Remote analysis of canopy gap dynamics and limiting similarity in a lowland Neotropical rain forest

冠层间隙是指与冠层形成树的断裂或死亡有关的植被高度降低。林冠间隙的分布和动态以及造成林冠间隙变化的过程一直是森林学界长期关注的问题，因为林冠间隙与树木的更新和化学物质在森林中的流动有关。本项目利用高光谱分辨率遥感测量冠层氮的变化，并利用激光雷达遥感量化林隙动态，以检验哥斯达黎加La Selva热带雨林树种动态的假设。它还将使用一大片原始森林的9年激光雷达时间序列来研究冠层间隙动态的变化。通过将氮的高光谱分析与激光雷达对冠层高度的估计相结合，可以验证一个总体假设，即在一个以原始热带雨林为主的景观中，一个关键植物功能性状（氮状态）的局部差异是树木死亡率和林隙动态的驱动因素。

A canopy gap is reduced vegetation height associated with the breakage or death of a canopy-forming tree. The distribution and dynamics of canopy gaps, and the processes responsible for their variation, have been the subject of long-term interest in forests, because gaps are associated with tree regeneration and the movement of chemicals through the forest. This project uses high spectral resolution remote sensing to measure variation in canopy nitrogen, and LiDAR remote sensing to quantify gap dynamics, to test hypotheses about tree species dynamics in the tropical rain forest at La Selva, Costa Rica. It will also examine variation in canopy gap dynamics using a nine-year LiDAR time series for a large tract of old-growth forest. By integrating hyperspectral analyses of nitrogen with LiDAR estimates of canopy height, the overall hypothesis can be tested that local variance in a key plant functional trait (nitrogen status) is a driver of tree mortality and gap dynamics across a landscape dominated by old-growth tropical rain forest.