Tree mortality and damage links in tropical forests / Quantifying spatial and temporal variation in canopy tree mortality and branchfalls in a tropical forest using repeat drone photogrammetry

About the talk

Tree mortality and damage links in tropical forests

Daniel Zuleta

Large uncertainties remain on how tropical forests will respond to a rapidly changing climate. This uncertainty is primarily attributed to spatial variation in woody residence times (i.e., biomass losses via tree mortality and branchfall), which occur more abruptly than tree growth and recruitment. We used data from the ForestGEO annual monitoring program to study the relative importance of multiple tree-level factors involved in tree death, their physiological consequences, and their implications for aboveground biomass dynamics. While tree-level damage is the most common condition preceding death in tropical trees, non-lethal damage can contribute to significant amounts of aboveground biomass losses that are not necessarily captured by studies focused only on tree mortality. Ongoing efforts to resolve the timing of lethal and non-lethal biomass losses, their climatic drivers, and physiological consequences will improve our understanding of carbon woody residence time and predictions of the fate of forests in vegetation models.

Quantifying spatial and temporal variation in canopy tree mortality and branchfalls in a tropical forest using repeat drone photogrammetry

Helene Muller-Landau

Tropical tree mortality and branchfall rates vary widely among sites and over time, in part in relation to climate. However, we still have a relatively poor understanding of the drivers of tree mortality and branchfall, because their rates are low, requiring frequent and large-scale observations to quantify variation, which is infeasible with labor-intensive traditional field methods. We used repeat drone photogrammetry to quantify temporal and spatial variation in canopy tree mortality and branchfall at high resolution and over large scales at Barro Colorado Island, Panama. We documented high temporal and spatial variability, and found that temporal variability was related to strong rainfall events whereas spatial variability was related to soil type, topography, and stand age.