Spatial response patterns of subtropical forests to a heavy ice storm: a case study in Poyang Lake Basin, southern China

In early 2008, an unexpected ice storm hits southern China, severely affected the subtropical forest ecosystems. We used the moderate resolution imaging spectroradiometer products of Enhanced Vegetation Index (EVI) corroborated with information gathered from field investigations to analyze the spatial patterns of forest damage in Poyang Lake Basin. The results showed that forests on windward aspects and 400-1,000 m elevation zones are sensitive to ice storm. The spatial pattern of forest damage after the ice storm can be understood in light of topographical sheltering effect. Due to the mountains of the basin blocked the cold flow and wind, the damage on windward aspects showed more severity than other aspects, which was similar like previous studies in North America. The most severe canopy loss beyond 63 % (EVI loss 0.085) occurring on 400-800 m elevation zones. The secondary severe forest damage was on 800-1,500 m elevation zones with canopy loss 33 % (EVI loss 0.035), which unlike previous studies in North American that found damage was rapidly decreased at these elevations. This observation fits the ecological disturbances theory suggests that ice storms generating greater damage in forests which less frequently impacted by ice disturbance events. There appears to be a broader pattern of forest damage associated with ice storm in subtropical forests than in temperate regions. This implies that the subtropical forests are more vulnerable than temperate forests to ice storm disturbance.