Hurricane-induced structural disturbance amplifies forest vulnerability to subsequent heatwaves

Hurricane-induced structural disturbances can make forests more vulnerable to subsequent heatwaves, according to a study analyzing 21 hurricane-heatwave events. By using advanced statistical methods, researchers found that structural degradation leads to non-linear amplification of productivity loss during heatwaves. The 2018 Hurricane Michael case study showed significant negative effects on Gross Primary Productivity (GPP) during the 2019 heatwave.

Intact forests with tall, diverse canopies act as natural buffers, moderating thermal sensitivity. However, hurricanes often simplify forest structure, removing this protective canopy and exposing temperature-sensitive shaded leaves to extreme stress. The study identified a context-dependent hydraulic trade-off: while structural complexity provides shade, it also exacerbates forest sensitivity to water deficits during peak heat, with the vulnerability reversing during the recovery phase.

The magnitude of these legacy effects varies by location, with loamy-soil forests being the most vulnerable. These findings emphasize the crucial role of forest structure in how forests respond to compound disturbances. If Earth System Models do not account for these structural legacies, they may underestimate the risks to global carbon sinks.