Relationship between Lidar Metrics and Aboveground Biomass in Closed-canopy Neotropical Forests

Previous studies have shown that canopy metrics from lidar data are highly correlated with aboveground biomass in a variety of closedcanopy forests, however the generality of these site-specific relationships has remained untested. In this study, we compare relationships between lidar canopy metrics and forest structural summaries from a tropical wet forest site in Costa Rica and across a series of tropical moist forest field sites in Panama. We found that in both regions lidar metrics were strongly correlated with forest structural summaries including mean stem diameter, basal area and aboveground biomass. We also showed that the relationships differed between these regions unless deciduousness of canopy trees in Panama was considered. Adjusting for leaf-drop removed statistically significant differences between the two regions in the relationships between a lidar metric and both mean stem diameter and basal area. The relationships between lidar metrics and aboveground biomass, however, remained significantly different between the two study areas because of different general allometric relationships used to estimate aboveground biomass in tropical wet forests and tropical moist forests. Future efforts should continue to examine climatic factors that may influence the generality of the relationships between lidar metrics and forest structural characteristics, and address the dearth of allometric data on the very large trees that can dominate the biomass of primary tropical forests.