不同海拔温度和降水对新疆阿尔泰山西伯利亚落叶松径向生长的影响

为定量并分离关键气候因子对新疆阿尔泰山不同海拔树木径向生长的影响,通过对高、中和低海拔的西伯利亚落叶松(Larixsibirica)树轮宽度标准年表与气候因子分别进行相关、多元线性回归等统计分析,并进一步计算了线性模型中不同气候因素的绝对和相对贡献率。结果表明,高海拔地区,当年6月温度和上年7月降水分别与径向生长呈显著正相关和负相关,两者共同解释西伯利亚落叶松径向生长变异的33.1%,相对贡献率分别为66.2%和33.8%;中海拔地区,当年6月温度和上年6月降水分别与径向生长呈显著正相关和负相关,两者共同解释径向生长变异的26.8%,相对贡献率分别为40.1%和59.9%;低海拔地区,上年6月温度和7月降水分别与径向生长呈显著负相关和正相关,两者共同解释径向生长变异的29.4%,相对贡献率分别为31.9%和68.1%。这表明限制树木径向生长的主要影响因子随海拔的不同而异,在高海拔地区,温度是主要限制因子;而在低海拔地区,降雨是主要限制因子。

Effect of Temperature and Precipitation on Radial Growth of Larix sibirica along Altitudinal Gradient on Altay Mountains, Xinjiang, China

In order to quantify and separate the effects of key climatic factors on the radial growth at different altitudes in Altay Mountains of Xinjiang, China, the correlation analysis and multivariate linear regression analysis between the standard chronologies of Siberian larch (Larix sibirica), at high-, mid-and low-altitude stands, and climate factors were studied. The absolute and relative importance of different climate factors in the linear model were further calculated. The results showed that the radial growth of trees were significantly correlated with the current-June temperature (positive) and last-July precipitation (negative) at high altitude, which explain 33.1% of the total variance in tree radial growth and the relative contribution rate was 66.2% and 33.8%, respectively. The radial growth of trees were significantly correlated with the current-June temperature (positive) and last-June precipitation (negative) at mid-altitude, which explain 26.8% of the total variance in tree radial growth and the relative contribution rate was 40.1% and 59.9%, respectively. The radial growth of trees were significantly correlated with the last-June temperature (negative) and last-July precipitation (positive) at low altitude, which explain 29.4% of the total variance in tree radial growth and the relative contribution rate was 31.9% and 68.1%, respectively. So, it was suggested that the main climatic factors affecting the radial growth in Altay Mountains varies with altitude. The temperature and precipitation were the main limiting factors at high and low altitude, respectively.