三峡库区秭归县不同海拔马尾松径向生长对气候的响应

Responses of Ring Width of Pinus massoniana to the Climate Change at Different Elevations in Zigui County,Three-Gorge Reservoir Area

利用采自三峡库区秭归县不同海拔高度的马尾松树轮样芯,分别建立树木年轮宽度年表,包括标准年表和差值年表,并对2种年表进行比较。运用相关函数及单年分析等树木年轮学方法,研究秭归县马尾松在不同海拔高度处的径向生长与气候变化的关系。最后通过多元回归得出不同海拔高度处马尾松年轮指数与气候因子的关系模型。结果表明:在正常的气候条件下,海拔300m处马尾松生长受上年6和10月份降雨量和湿润指数的影响,与当年气候因子的关系不显著;海拔600m处马尾松生长与上年6月份温度呈显著相关,还受当年7月份的月平均降雨量和湿润指数的影响;海拔900m处马尾松生长不仅与当年2月份温度呈显著相关,还受当年12月份月平均降雨量和湿润指数的影响,单年分析进一步印证了这种关系。

Tree-ring cores of Pinus massoniana were collected from different elevations of Zigui County, Three-Gorge reservoir area in China. Tree-ring width chronologies including RES and STD were established using standard dendrochronological methods, respectively. The relationship of P. massoniana radial growth with climatic factors of different elevations was assessed by dendrochronological techniques including correlation functions and single-years analysis. Finally the correlation model between tree-ring width index and climatic factors in the different elevations was simulated by multi-factor regression. The results showed that the character of ring width index of P. massoniana was different for the altitude gradients due to complex topographic. The ring growth in different elevations had a significantly different response to temperature and precipitation. In normal climatic conditions, the growth at 300 m elevation was significantly affected by mean monthly precipitation and humid index in previous June and October. There was no significant correlation to climatic factors of the current year. The growth at 600 m elevation was significantly correlated to temperature in previous June and mean monthly precipitation and humid index in current July. At 900 m the growth was not only affected by temperature of current February, but also affected by mean precipitation and humid index of this December. The relationship was verified by single year analysis.