区域气温和降水对关帝山不同海拔华北落叶松径向生长的耦合效应

为揭示区域气温和降水在不同海拔对山地林区林木径向生长的耦合效应,在关帝山林区孝文林场和庞泉沟国家自然保护区外围4个不同海拔选取立地条件相似的华北落叶松(Larix principis-rupprechtii Mayr.)人工林设置调查样地,采集典型样木样芯,采用建立年表的方法,获取年轮宽度指数,结合区域气温和降水进行相关性分析和单年分析。结果表明:在研究地区4个海拔上华北落叶松的径向生长均与区域气温和降水量有密切关系,但不同海拔响应机制不同;在1600 m海拔处,年轮宽度指数与当年4月气温极显著负相关,与当年9月降水量显著正相关;在1800 m海拔处,年轮宽度指数与上年6月气温显著负相关,降水量显著正相关;在2000 m海拔处,年轮宽度指数与当年9月气温和当年3月降水量显著负相关;在海拔2200 m处,年轮宽度指数与上年8月气温显著正相关,降水量显著负相关;随着海拔的升高,气温逐渐降低,降水量增加,两者对华北落叶松径向生长的耦合效应也发生变化,当海拔到达2000 m时,生长季降水量的增加使耦合效应关系发生转换。

Coupling effects of regional temperature and precipitation on radial growth of Larix principis-rupprechtii at different altitudes in Guandishan.

To reveal the coupling effects of regional temperature and precipitation on the radial growth of trees in mountainous forests at different elevations,we collected tree cores of typical sample woods from Larix principis-rupprechtii plantations with similar conditions across four elevations in the Xiaowen Forest Farm of Guandishan forest region and the Pangquangou National Nature Reserve.We established chronology to obtain the annual ring width index and conducted correlation analysis and single-year analysis combined with regional temperature and precipitation.The results showed that radial growth of Larix principis-rupprechtii was closely related to regional temperature and precipitation on the four elevations,but with different response mechanisms.At the altitude of 1600 m,annual ring width index was significantly negatively correlated with temperature in April,and positively correlated with precipitation in September.At 1800 m,annual ring width index was significantly negatively correlated with temperature and positively correlated with precipitation in June of last year.At 2000 m,annual ring width index was significantly negatively correlated with temperature in September and precipitation in March.At 2200 m,annualring width index was significantly positively correlated with temperature and negatively correlated with precipitation in August of last year.With increasing altitude,the temperature decreased and precipitation increased.Moreover,the coupling effect of temperature and precipitation on the radial growth of Larix principis-rupprechtii was changing.When the altitude reached 2000 m,the increase in precipitation in the growing season altered the coupling effects.