Satellite observations of forest resilience to hurricanes along the northern Gulf of Mexico

As one of the most destructive natural disasters, hurricanes pose a great threat to forest ecosystems, particularly in the coastal areas. A better understanding of forest resilience to hurricane disturbances is essential for reducing hazard risks as well as sustaining forests in a time of increasing climate disasters. Although hurricane-induced forest damage has been extensively studied at both local and regional levels, the lack of large-scale assessment of post-hurricane recovery still limits our understanding of forest resilience to hurricane disturbances. In this study, we utilized four remotely sensed vegetation indices (VIs), including the normalized difference infrared index (NDII), enhanced vegetation index (EVI), leaf area index (LAI), and solar-induced chlorophyll fluorescence (SIF), to examine the forest resilience to hurricanes of different strengths by quantifying the resistance, net change, and recovery of the forest after hurricanes that made landfall along the northern Gulf of Mexico from 2001 to 2015. The results revealed that the NDII was superior in monitoring the large-scale forest resilience. SIF exhibited a performance similar to that of the EVI. Wind speed was found to be the leading factor affecting forest damage and post-hurricane recovery. The impacted forest canopy began to recover approximately one month after the landfall. Woody wetlands exhibited less VI reduction and shorter recovery time than evergreen forests for the same category of hurricanes. For regions dominated by evergreen forests, NDII values lower than the multi-year average were observed across all seasons during the year after being impacted by a major hurricane. The widespread drought of 2006/2007 has aggravated the VI decrease and substantially extended the recovery period after hurricanes Ivan and Katrina. Overall, our findings derived from satellite observations provide essential information for understanding forest resilience to hurricanes as well as implementing efficient post-hurricane forest restoration.