Woody component of tropical rainforest recovers slower from drought than the upper canopy layer and leaves

Abstract

Tropical rainforests are crucial for Earth's health, but climate change is making severe droughts more frequent. The 2015–2016 El Niño-induced drought caused significant biomass loss, yet the recovery duration of different vegetation components (woody parts, upper canopies, and leaves) remains unknown. This study employed satellite remote sensing data of L-band Vegetation Optical Depth (L-VOD), X-band VOD (X-VOD), and Enhanced Vegetation Index (EVI) from 2010 to 2022, characterized by having different sensitivities to the different vegetation components, to examine the recovery of these components in the tropical evergreen broadleaf forest (EBF) regions during the 2015–2016 El Niño-induced drought. Results showed that the woody component had the slowest recovery, particularly in Africa, which took longer to return to pre-drought conditions than South America. Key factors influencing recovery included drought severity, moisture-related climatic conditions (i.e., VPD, precipitation, and soil moisture), and seasonal variations. Moreover, the woody component of the EBF in South America showed less impact from drought, benefitted from more favorable moisture-related climatic conditions (e.g., more precipitation and lower VPD), and experienced higher seasonal variation in monthly temperature and precipitation, resulting in a faster recovery than that observed in Africa.