Ice storm damage to oak forests in subtropical China

Ice storms, as important sources of frequent and injurious disturbances, drive forest dynamics in the Northern Hemisphere. However, stand-level differential vulnerability to ice storms and the associated factors that predis-pose forest stands remain unclear. This is particularly concerning in the subtropics where the frequency of ice storms is predicted to increase with global warming. Here we assessed how the impact on three forest stands (early and late secondary-growth forests, and old-growth forests) differed after an extreme ice storm during 20-21 March 2022, and identified the abiotic and biotic factors that determine the damage intensity in the Shennongjia World Natural Heritage Site, a biodiversity conservation hotspot in central China. We found a stand-specific 'mid-domain effect' where the late secondary-growth forest sustained the most severe damage, the early secondary-growth forest sustained the least, and the old-growth forest suffered an intermediate amount. 'Crown broken' was the most severe damage type across all three forest stands, although the proportion of 'branch broken' was also high in the old-growth forest. Topography played a significant role in determining the vulnerability of the early secondary-growth forest to severe ice storms whereas the forest structure and composition were important factors in explaining the damage rates in the old-growth forest, although they differed among the damage cat-egories. In contrast, topography, forest structure and composition generally explain the intensity of damage in the late secondary-growth forests. Our results highlight that, in subtropical forests, the intensity of damage caused by severe ice storms and related determining factors are stand-level dependent. We also suggest exploring potential management strategies (e.g., slow-growing hardwood species that can resist storms should be the main species for reforestation in early secondary-growth forests) to mitigate the risk of future severe ice storms, as well as other wind-related climatic extremes.