辽东山区天然次生林雪／风灾害成因及分析

对2003年春发生在辽东山区的森林雪/风灾害的成因、过程、受灾情况、造成的危害、与林分结构特征的关系以及对未来次生林生态系统的影响等进行了调查分析。结果表明，雪/风的发生是在一个大的降水天气过程基础上，由于气温的异常变化形成的，受灾严重区多分布于海拔高、坡度大，林型比较单一的桦树、柞树、色树、胡桃树和杨树等林分，林分密度和受灾率及土层厚度和受害株数均呈显著的线性负相关；受灾数量与径级和树高分别呈指数负相关和指数正相关，同时探讨了雪/风害对天然次生林生态系统内病虫害发生、林下植被、生境因子和建群种变化产生的可能影响。

Snow/wind damage in natural secondary forests in Liaodong mountainous regions of Liaoning Province

In early spring of 2003,the secondary forests at the Qingyuan Experimental Forests (QEF) of the Institute of Applied Ecology,Chinese Academy of Sciences suffered from the damage caused by snow and wind (snow/wind damage).This damage occurred at 800 m above sea level was the most serious one since 1949 In order to make clear its occurrence and process and to analyze its possible influences on the secondary forest system,comprehensive investigations were conducted soon after the snow/wind damage.The results showed that the occurrence of this damage was due to the special site conditions (higher sea level and steeper slopes) and air temperature,which suited the wet snow formation and the snow accumulation on trees after a large scale of precipitation.The more seriously damaged areas were those with the stands of Acer mono,Juglans mandshurica,Populus spp. and so on.The ratio of damaged trees was negatively correlated with stand density,soil depth and size class of diameter,and positively correlated with tree height.Based on these results,the likely influences of snow/wind damage,i.e.,the happening of diseases and insect pests,the vegetation changing under forests,and the factors of habitat and dominant species in natural secondary forests were also discussed.It is significant that to do observation and basic research on damaged forests will provide reasonable strategies for management of natural secondary forests.