滇西北海拔上限大果红杉径向生长对气候变化的响应

基于树轮年代学方法,利用玉龙雪山、哈巴雪山和普达措国家公园海拔上限大果红杉树轮宽度资料,分别建立3个样点大果红杉的差值年表(RES),研究其径向生长对气候响应的异同,探讨影响滇西北大果红杉生长的关键气候因子.结果表明: 生长季初期(5月和6月)温度是影响滇西北大果红杉生长的主要因子,与3个样点的径向生长表现出显著正相关关系,同时普达措国家公园大果红杉还受生长季以前温度的影响,分别与上年7月和11月温度呈显著负相关和显著正相关;3个样点大果红杉生长对降水的响应存在差异,随着纬度升高主要由负相关转为正相关,大果红杉径向生长与降水的关系在玉龙雪山(纬度梯度最南)主要表现为与生长季初期降水量呈显著负相关,在哈巴雪山(纬度梯度中部)表现为与9月降水量呈显著负相关,在普达措国家公园(纬度梯度最北)表现为与3月降水量呈显著正相关.另外,7月降水的增多有利于玉龙雪山大果红杉的生长.基于气候模型预测,综合大果红杉对温度和降水响应模式与响应程度分析,未来气候变化有利于滇西北高原大果红杉的径向生长.

Response of radial growth of Larix potaninii var. macrocarpa to climate change at upper distributional limits on Northwestern Yunnan Plateau,China.

Based on dendrochronological methods, we established residual chronologies of Larix potaninii var. macrocarpa by using its radial growth records at upper distributional limits of three mountains (Yulong, Haba and Potatso), in order to study the growth response variation to climate change among three sites and to identity the key climatic factors that affected the radial growth of L. potaninii var. macrocarpa in Northwestern Yunnan Plateau, China. The results showed that the temperature during current early growing season (May and June) was the main factor influencing the radial growth of L. potaninii var. macrocarpa, as indicated by a significant positive correlation between them at the three sampling sites. The radial growth of L. potaninii var. macrocarpa at Potatso National Park was also affected by temperature before growing season, presenting a significant negative correlation with temperature in previous July, and a significantly positive correlation with temperature in previous November, respectively. The radial growth responses of L. potaninii var. macrocarpa to precipitation varied among the three sites, showing a pattern from a negative correlation to a positive correlation with the increase of latitude. The radial growth showed a significant negative correlation with precipitation in current early growing season in Yulong Snow Mountain (the most southern part), a significant negative correlation with precipitation in current September in Haba Snow Mountain (the middle of the latitudinal gradient), and a significant positive correlation with precipitation in current March in Potatso National Park (the most northern part), respectively. Additionally, the radial growth of L. potaninii var. macrocarpa in Yulong Snow Mountain was also positively affected by precipitation in current July. According to the prediction of climate models, the changing pattern and the degree of response of radial growth to temperature and precipitation, the future climate change would probably benefit the growth of L. potaninii var. macrocarpa in Northwestern Yunnan Plateau.