不同生境祁连圆柏径向生长对气候变化的响应

通过在青海都兰曲什岗地区建立不同生境的祁连圆柏树轮宽度年表及分析，揭示了不同微环境下祁连圆柏的径向生长对气候变化的响应。从标准轮宽年表的统计特征来看，森林中部年表的平均敏感度、标准差以及序列间的相关系数等统计量均高于其他地点，而凹地年表的上述统计量都较低；各序列之间的相关分析表明，无论在高频变化还是在低频变化上，森林上限年表与其他各采样点的年表均存在较大差异，这种差异在低频变化上尤为明显；采样点轮宽年表与气候资料的相关分析表明，森林中部、下限及水分条件相对较好的凹地，树木径向生长主要与当年6月份降水量之间存在显著的正相关关系，而与同期月平均最高温度之间存在显著的负相关关系。值得提出的是，森林上限祁连圆柏的径向生长与当年7月份温度之间存在极显著的正相关关系。该研究所揭示的不同生境树木生长特性及其对气候响应的差异，一方面对于模拟不同微环境下树木生长对全球变化的响应具有重要意义，另一方面对于利用同一地区的树轮资料重建不同气候要素提供了依据。 

Response of radial growth of Qilian juniper to climatic change under different habitats

Tree-ring width chronologies of Qilian juniper(Sabina przewalskii Kom.) at Qushigang of Dulan County,Qinghai Province are developed and analyzed to reveal the response of tree radial growth to climatic changes under different habitats.The mean sensitivity,standard deviation and correlation of chronology at the middle elevation sites are at the highest level among these sites,while those statistical parameters of chronology at the low elevation sites are at the lowest level.The results of correlation analysis among chronologies show that the chronology at the high elevation sites is quite different at both high and low frequency from other sites,especially the low frequency.The radial growth of Qilian juniper has significantly positive correlation with precipitation in June and significantly negative correlation with temperature in the same time at the middle,low and high elevation sites.It is worthy to be pointed out that radial growth of Qilian juniper has significantly positive correlation with temperature in July at the high elevation sites.The results of this study are important to simulate tree growth and its response to climatic changes under different habitats and they provide the bases for reconstructing different climatic variables at the same region.