太白山林线附近太白红杉种群的生存

Survival analysis of Larix chinensis populations near timberline on Taibai Mountain in China

为了分析太白山林线区域的太白红杉种群的生存状况,在林线附近设置了1个100 m×100 m的样地,采用侧生轮枝计数或WinDENDRO系统确定个体年龄.调查数据经匀滑技术处理,编制了太白红杉种群特定时间生命表,绘制了太白红杉种群的存活曲线、死亡率曲线和消失率曲线.结果表明:林线地段太白红杉种群存活曲线位于DeeveyⅡ型和DeeveyⅢ型之间;林线地段太白红杉种群整个生长期中出现了两个死亡高峰期:一个出现在中龄时期(70～80年),另一个出现在老龄时期(180～190年).总体看来,林线区域太白红杉的幼苗很少,更新较差,种群很不稳定,应加强对该地段太白红杉种群的保护.

One plot （100 m×100 m） was investigated and analyzed to explore the survival status of L. chinensis populations on Taibai Mountain in the Qinling Mountains. Individual ages were determined using WinDENDRO system or by counting tree branches. Time-specific life tables or vertical life table curves of survival-mortality based and hazard based age structures were drawn. The results showed that the survival curve of the population tends to be the type between Deevey Ⅱ and Deevey Ⅲ; there exists two peaks of mortality in the lifespan, one being in the adult stage （70-80 years） and the other in the old stage （180-190 years）. In all, young seedling and sapling is lacking near the timberline. According to the heliophytic and xerophytic characteristics of L. chinensis, management activities near timberline, such as cutting non-target species, clearing herbs, should be undertaken, so as to promote optimal environmental conditions for seedling recruitment in the rare L. chinensis.