Subtropical vegetation damage and recovery dynamics after the great 2008 Chinese ice storm

In early 2008, an extreme ice storm struck southern China, including the subtropical Guangdong Province, causing substantial ecological damage and economic losses. Previous evaluations of vegetation damage during this event primarily focused on the immediate physical structure damage caused by ice, overlooking the delayed physiological damage from extreme low-temperature stress, especially in adjacent non-frozen regions. Combining remotely-sensed (i.e., MODIS Gross Primary Productivity (GPP) and Enhanced Vegetation index (EVI)) and in-situ data, we conducted a more complete assessment of subtropical vegetation damage and recovery following the 2008 Chinese ice storm by considering time-lag effects. We found vegetation damage and subsequent recovery exhibited distinct spatial patterns correlated to ice storm severity. Assessments that accounted for time-lag effects were more aligned with ground truth, revealing that vegetation damage signal typically lagged the event onset by 1–2 months. The time-lag effect showed distinct patterns in non-frozen regions experiencing secondary low-temperature stress (without direct ice storm exposure). Physiological damage dominated these areas, reducing GPP by 62 %. In contrast, physical structural damage caused a comparatively smaller decline (51 %) in EVI. We also found a positive correlation between frozen time and the severity of vegetation damage, with 37 % of vegetation damaged in less frozen zone versus 70 % in severe frozen zone. Subsequent recovery of GPP and EVI to pre-ice storm conditions took 4–9 months, with GPP recovering faster than EVI, especially in severe frozen forests. Such positive correlation also existed between damage severity (or recovery time) and elevation and slope, but the pattern varied across different freezing zones. Our findings highlight the delayed physiological damage from extreme low-temperature stress and provide new insights into subtropical vegetation dynamics following extreme ice storms.