祁连山东部不同树种径向生长对气候因子的响应

Species-specific growth responses to climatic factors in the eastern Qilian Mountains

为研究祁连山东部不同树种树木径向生长对气候因子响应的差异,采集青海云杉(Picea crassifolia)和祁连圆柏(Juniperus przewalskii)两个树种的树木年轮样芯,建立树轮宽度年表,并分析不同类型年表与24个时间尺度气候因子的相关性。分析年表参数发现,青海云杉的差值年表质量优于标准年表,祁连圆柏则相反。青海云杉树轮宽度年表包含的气候信息丰富度多于祁连圆柏。祁连圆柏对温度的响应要强于青海云杉,主要与前一年6—7月、前一年9月以及当年5—8月均温呈显著负相关,青海云杉对降水的响应要强于祁连圆柏,主要与前一年9月、当年7—8月累积降水呈显著正相关。两树种的径向生长均受到干旱胁迫,全球变暖背景下,这种胁迫会加剧,因此需要加强对祁连山森林的保护和管理。

To understand the growth responses of different tree species to climatic factors in the eastern Qilian Mountains,we developed tree-ring width chronologies from two dominant tree species( Picea crassifolia and Juniperus przewalskii). The correlation coefficients between chronologies and climatic factors were calculated at 24 time scales. According to the parameters of chronologies,the residual chronology of P. crassifolia had higher quality than the standard chronology,but the case was oppoiste for J. przewalskii. The responses of J. przewalskii to temperature factors were stronger than that of P. crassifolia,which showed negative correlation with mean temperature from the previous June-July,the previous September and the current May-August. The responses of P. crassifolia to precipitation factors were stronger than that of J. przewalskii,which were positively correlated with total precipitation from the previous September and the current July-August. The radial growth of both species suffered from drought stress. In the context of global warming and intensified drought stress,enhanced protection and management should be carried out.