Tracking Amazon forest succession after large-scale windthrow events

Abstract Understanding the resistance and resilience of the vast Amazon rainforest to disturbances other than deforestation is critical, particularly for natural events like windthrow. Strong winds uproot and snap trees, and such events are increasing in frequency across the Amazon basin. These disturbances lead to long-lasting changes in forest structure and species composition, often observed as an increase in vegetation greenness post-event. Our study tracked the temporal response of vegetation using Landsat enhanced vegetation index (EVI) over 32 years after windthrow. We analyzed 166 large-scale (⩾30 ha) windthrow events that occurred in the 1990s throughout the Amazon. To quantify the affected area, we compared EVI responses within the central disturbed zones, as mapped in the windthrow inventory database (WInD V.1), to those from adjacent undisturbed areas. Following an initial, sharp EVI decrease, the affected forest typically undergoes a decade-long ‘greening’ phase. During this period, EVI steadily increases, often peaking 20% above the EVI of undisturbed forest, before a gradual, longer-term decline. The timing and magnitude of EVI changes vary regionally, influenced by the spatial occurrence of windthrow (high, moderate, low) and the initial windthrow severity (extreme, high, moderate, low). For instance, minimum EVI values generally occurred within 0–1 year post-event across all sites. However, the time to reach maximum EVI ranged from 6 ± 2 years for extremely damaged areas in high-occurrence windthrow regions to 18 ± 7 years for less severe damage in moderate-occurrence regions. We also assessed tree mortality beyond the central disturbed zone, where more scattered damage was evident. EVI dynamics captured temporal shifts in functional groups and a biomass reduction of approximately 25% compared to old-growth forest, as confirmed by chronosequence data from Brazil. These findings highlight the spatial and heterogeneity and ecological importance of windthrow disturbance in Amazonian forest ecosystems.