德令哈地区柏树山不同生境气候对祁连圆柏径向生长的影响

Impacts of climate on the radial growth of Sabina przewalskii in different habitats in Baishu Mountain,Delingha region,China

为探究德令哈地区柏树山不同生境气候对祁连圆柏(Sabina przewalskii)径向生长的影响,在该区域设置3个采样点(S1:地势较低的陡坡地,S2:坡度缓和的凹形坡地,S3:地势较高的陡坡地),运用树木年轮学方法收集了58棵祁连圆柏共113根样芯。通过建立3个样点的祁连圆柏差值年表,分析在半干旱区不同生境内祁连圆柏径向生长对气候响应的特征以及气候因子对祁连圆柏径向生长的贡献。结果表明:不同生境的祁连圆柏径向生长对降水的响应基本一致,对温度的响应则存在显著差异,其中当年5月的降水对不同生境祁连圆柏径向生长的贡献作用最大(P<0.01),当年6月的降水次之(P<0.05)。温度对S1和S3祁连圆柏径向生长的贡献均不显著(P>0.05)。当年9月的平均最高温对S2祁连圆柏径向生长有显著的贡献作用(P<0.05),低温对其的贡献并不显著(P>0.05)。研究结果论证了受地形差异的影响,不同生境下的气候对树木径向生长的影响具有多样性。因此,在研究树木生长与气候的关系时,应综合考虑不同生境的特点,以选取适宜的生境进行科学研究。

We set up three sampling sites(S1:steep hillslope with lower terrain,S2:hollow hillslope with gentle slope,S3:steep hillslope with higher terrain)and collected a total of 113 cores from 58 Sabina przewalskii using dendrochronological methods in Baishu Mountain of the Delingha region to investigate the impacts of climate on the radial growth of S.przewalskii in different habitats.By establishing the residual chronologies of S.przewalskii at the three sampling sites,we analyzed the response characteristics of the radial growth of S.przewalskii to climate and the contribution of the climate factors to the radial growth of S.przewalskii in different habitats in the semi-arid area.Results revealed that the radial growth of S.przewalskii in different habitats had basically same response to precipitation,but the response to temperature was of significant difference.The precipitation in May of the current year contributed the most to the radial growth of S.przewalskii in different habitats(P<0.01),followed by the precipitation in June of the current year(P<0.05).The contribution of temperature to the radial growth of S.przewalskii at S1 and S3 was not significant(P>0.05).The mean maximum temperature in September of the current year had a significant contribution to the radial growth of S.przewalskii at S2(P<0.05),while the contribution of low temperature to it was not significant(P>0.05).The results demonstrated that the effects of climate in different habitats on the radial growth of trees were diversified under the influence of the difference in topography.Therefore,the characteristics of different habitats should be considered comprehensively before studying the relationship between tree growth and climate to select suitable habitats for scientific research.