宁夏罗山油松(Pinus tabulaeformis)树轮宽度对气候因子的响应分析

 树轮样本采自宁夏罗山油松纯林的下限和上限。建立了下限和上限的树轮宽度标准化年表,分析了树轮宽度与降水、气温、湿润指数(P/T)的相关关系,结果显示,下限和上限树轮宽度指数都与当年3月、5月、春季以及年降水量显著正相关,与7月气温显著负相关;下限树轮宽度标准化年表与气候要素的相关系数一般大于上限的相关系数,而且下限树轮宽度与前一年9月、秋季降水以及夏季气温的相关也达到显著水平,表明下限树轮宽度标准化序列对降水和气温单一气候要素的变化较敏感;下限和上限的树轮宽度指数和湿润指数(P/T)呈正相关关系,而且上限树轮宽度和3—8月湿润指数的正相关达到99%的置信水平,说明罗山油松纯林上限树轮宽度标准化序列对水热组合的响应较敏感。

Response of Tree-Ring Width of Pinus tabulaeformis to Climate Factors in Luoshan Mountains of Ningxia

Tree-ring cores are sampled at lower and upper forest border of pure forests of Pinus tabulaeformis in Luoshan Mountains of Ningxia. The authors develop the tree-ring width index standard chronologies and analyze the statistical characters of two sites chronologies. After anglicizing the response relationship between tree-ring width and precipitation, temperature and moisture index (P/T), it is found out that the standard chronologies of two sites are all significantly related to March, May, spring and the annual precipitation and July temperature. There is a significant relation between the tree-ring width and the prior September precipitation, autumn precipitation and summer temperature at lower forest border. Based on the size of the correlation coefficient and the number of significant factors, it is pointed out that the tree-ring width index standard chronology at lower forest border is relatively sensitive to the precipitation and temperature than that at upper forest border. Furthermore the tree-ring width trends are all positively correlative with the humid index, and the correlation coefficient between the tree-ring width standard chronology at upper forest border and March to August moisture index reaches 99% level. The standard chronology at upper forest border is relatively sensitive to the combination of water and heat.