Damage assessment to subtropical forests following the 2008 Chinese ice storm

Ice storm is a major form of extreme climatic event and may occur more frequently in the future under a changing climate. The 2008 Chinese ice storm provided a natural laboratory to study ecosystem responses and feedbacks to climate variability and extreme events. Four typical subtropical forests (Chinese fir plantation, pine plantation, moso bamboo plantation, and secondary mixed broadleaved forest) were selected to assess the damage caused by the ice storm. The ice damage rate of typical subtropical forests varied between 25% and 81%. The secondary broadleaved forest had most extensive damage while the Chinese fir plantation experienced the most severe damage. Exotic pine species (Pinus elliottii Engelm. and Pinus taeda Linn.) were more severely damaged than the native species, Pinus massoniana Lamb. Ice damage was also affected by tree/culm size, age, stand density, site altitude, and management practices. Large-sized trees/culms were more vulnerable to stem breakage, decapitation, and uprooting, while small-sized trees/culms were more vulnerable to bending and leaning. Younger trees/culms had the highest damage rate, and were more susceptible to bending damage. Ice damage rate increased linearly with the stand density, and higher altitude led to a significant increase of stem breakage. Oleoresin tapping aggravated the damage to pine trees. Resistance of trees to ice damage is an emergent consequence of tree attributes, species origin, site conditions, and human disturbance. Forest silviculture and management practices can play significant roles in controlling forest susceptibility to extreme events. Inappropriate utilization of non-timber forest products can reduce trees’ resistance to extreme events. For sustainable forest development, balance needs to be achieved between the high productivity of introduced exotic tree species and the resistance of native species to extreme climatic events.