【摘要】 [目的]利用天山北坡中段的雪岭云杉(Picea schrenkiana)资料,建立上、下林线的树轮宽度年表,并进行树木径向生长特征分析。[方法]将下线雪岭云杉按树龄划分为幼龄组、中龄组与老龄组,计算不同树龄雪岭云杉树木胸高断面积增长量(BAI),以此建立ARIMA模型,模拟分析雪岭云杉径向生长过程。[结果]与上树线相比,下树线的树轮宽度年表中蕴含着更多的气候信息。ARIMA模型模拟的3个树龄组雪岭云杉BAI变化中,中龄组观测值与模拟值拟合效果最优(R~2=0.832)。因ARIMA模型基于单变量自身变化趋势进行建模,故结合现有气象数据进行气候突变前后生长趋势变化分析,发现幼龄雪岭云杉实测BAI总体上增长显著,但增速逐渐减缓。[结论]中、老龄雪岭云杉BAI在气温突变前呈减小趋势,在气温突变后,中龄云杉BAI趋于平稳,老龄云杉BAI由减小趋势转变为增加趋势。更多还原

【Abstract】 [Objective] In this study, we developed two tree-ring chronologies using samples of Schrenk spruce(Picea schrenkiana) that were collected from the upper and lower treeline in the middle of the northern slope of Tianshan Mountains, and analyzed the radial growth characteristics of trees. [Method] According to the tree ages, the lower treeline spruce was divided into young, middle-aged and old groups.The ARIMA model was established to simulate the radial growth of spruce at different ages based on basal area increment. [Results] The analysis results showed that the tree-ring width chronology of the lower treeline contains more climate information comparing with the upper treeline. Among the BAI changes of three tree age groups simulated by the ARIMA model, the model fitting the middle aged trees performed the best(R~2 = 0.832). Considering the ARIMA model is modeled based on the univariate self-change trend,we analyzed the radial growth trend before and after the climate change, and found that the BAI of young spruce increased significantly overall, but the growth rate slowed down gradually. [Conclusion] The radial growth of middle-aged and old spruce showed a decreasing trend before the abrupt change of temperature. But after the abrupt change of temperature, the BAI of middle-aged spruce tends to be stable and the BAI of old spruce changes from a decreasing trend to an increasing trend.更多还原