As tree mortality increases throughout the Amazon, researchers in Brazil are working to more accurately assess and better understand carbon budgets, climate change effects, and other factors in the world’s largest and most biodiverse tropical rainforest.
According to a study, published in Scientific Reports, tree mortality can be attributed to “greater climate variability and feedbacks from faster growth and mortality. This has effectively shortened tree life cycles."
Led by Ricardo Dal’Agnol, an environmental engineer and researcher in the Earth Observation and Geoinformatics Division of Brazil’s National Space Research Institute, who co-authored the study, researchers collected data via airborne lidar, using pulsed laser light to survey topography and study the structure of vegetation. For this study, lidar coverage extended to remote parts of the Amazon, “where fieldwork is very difficult and satellite images can be imprecise,” thanks to heavy cloud coverage. The data was collected over the course of more than 600 flights.
Specifically, the researchers were able to map gaps in the Amazon rainforest and identify factors that contribute to tree mortality. They found that water stress, soil fertility, and human-induced forest degradation have the most influence on gap dynamics. The spatial patterns of dynamic gaps were “notably consistent with field mortality patterns,” according to the study. Past research has already pointed to the influence of climate change, namely rising temperatures and drier weather, on tree mortality in tropical forests. Reference: R. Dal’Agnol et al., Sci. Rep. (2021); doi.org/10.1038/s41598-020-80809-w.