天山中西段不同地区雪岭云杉径向生长对气候变暖的响应差异

为研究乌苏和石河子地区雪岭云杉（Picea schrenkiana）径向生长对气候变暖的响应差异状况,利用响应函数及滑动相关分析等树轮气候学方法,研究了2个地区森林下限雪岭云杉径向生长与气候因子的响应关系。结果表明：乌苏和石河子地区雪岭云杉生长均与生长季的气候因子呈显著相关关系。但乌苏和石河子地区雪岭云杉生长对当地气候因子的响应也存在差异,乌苏地区雪岭云杉径向生长与上一年7、9月平均气温呈显著负相关,与当年8月降水、上一年9月及当年8月平均相对湿度和上一年7~10月的scPDSI呈显著正相关。石河子地区雪岭云杉径向生长与当年1月平均湿度和当年1、2月的scPDSI呈显著正相关。此外,乌苏地区树轮宽度指数具有与温度升高而下降的“分离现象”,而石河子地区树轮宽度指数具有与温度升高相一致的趋势。升温导致的水分胁迫是造成乌苏地区雪岭云杉径向生长与温度变化趋势相反的重要因素。生长季的温度和降水的增加对石河子地区雪岭云杉径向生长有促进作用。乌苏地区雪岭云杉径向生长对5~7月平均气温和降水量变化敏感性上升;石河子地区雪岭云杉径向生长对5~7月降水量变化敏感性上升,而对5~7月平均气温变化敏感性下降。结果显示,气候变化的区域差异是造成乌苏和石河子地区雪岭云杉径向生长趋势不同以及各年表序列对温度和降水变化敏感性变化的主要气候因素。

Response Differences of Radial Growth of Picea schrenkiana to Climate Warming in Midwestern Tianshan Mountains

The experiment was conducted to study the response differences of radial growth of Picea schrenkiana to climate warming in Wusu and Shihezi regions. Dendrochronological methods including response function and evolutionary intervals analysis method were applied to study the relationships between radial growth and climatic factors of P.schrenkiana at the lower forest border of the two regions. The radial growth of P.schrenkiana at two regions was significantly correlated to the local climatic factors in the growing season, but the differences in response were statistically significant. In Wusu, the radial growth of P.schrenkiana was significantly negatively correlated to the average temperature in previous July and September but significantly positively correlated to precipitation in current August, the average relative humidity in previous September and current August, and scPDSI from July to October last year. In Shihezi, the radial growth of P.schrenkiana was significantly positively correlated to the average relative humidity in current January, and scPDSI in current January and February. The tree ring width index in Wusu showed a decreasing trend namely "separation phenomenon" with the increasing of temperature, while that in Shihezi was increased with the increasing temperature. For P.schrenkiana in Wusu, water stress caused by temperature rising was the main factor causing the opposite tendency between radial growth and temperature change. The increase of temperature and precipitation in the growing season mutually enhanced the P.schrenkiana growth in Shihezi. The sensitivity of radial growth of P.schrenkiana to average temperature and precipitation from May to July was increasing in Wusu. The sensitivity of radial growth of P.schrenkiana to precipitation from May to July was increased in Shihezi, while the sensitivity to average temperature was decreased from May to July. Therefore, the regional differences in climate change were the main factor in the radial growth difference at two regions and the sensitivity change to temperature and precipitation in chronological series.