Climatic drivers of leaf area index dynamics in the Amazon Basin: Insights from remote sensing

The Amazon Basin, a critical carbon sink, is increasingly vulnerable to climate change, yet the mechanisms governing Leaf Area Index (LAI) variability under meteorological influences remain uncertain. As a key determinant of canopy structure and productivity, LAI regulates biosphere-atmosphere interactions and regional carbon and hydrological cycles, making it vital for forest management and conservation. However, its long-term response to climate variability remains poorly characterized. This study integrates MODIS-derived LAI data (2001–2022) with meteorological records to assess how temperature anomalies, precipitation extremes, and aridity shape canopy dynamics, offering insights for adaptive forest management. A nonlinear relationship between LAI and temperature reveals a threshold of 25.3°C, beyond which LAI declines, indicating heat stress-induced canopy suppression. Precipitation positively influences LAI, with seasonal variability exerting a stronger effect than annual means, emphasizing the role of short-term hydrological fluctuations in maintaining forest productivity. The aridity index explains 23% of LAI variability, underscoring its role as a key constraint on vegetation growth. Additional meteorological factors, including water vapor pressure (R² = 0.26) and elevation (R² = 0.27), further shape LAI dynamics, reflecting interactions between land surface energy balance and atmospheric moisture availability. Post-2018 trends indicate a decline in high-LAI regions, with partial recovery by 2022, suggesting increasing climate-driven instability in Amazonian forest structure. These findings enhance understanding of tropical forest resilience, guiding conservation planning, ecosystem monitoring, and climate-adaptive management. Given the Amazon Basin’s role in global atmospheric circulation, sustained LAI monitoring is essential for refining climate-vegetation models and ensuring long-term forest stability.