秦岭北麓油松径向生长对气候变化的响应

Responses of radial growth of Pinus tabuliformis to climate change at the northern slopes of Qinling Mountains,China

以秦岭北麓南五台油松为样本,建立油松树轮宽度标准化年表(STD),研究油松径向生长与气候因子之间的相关性。结果表明:秦岭北麓油松径向生长与前一年9月及当年5月水分因子呈显著正相关,与前一年11月温度因子呈显著正相关,与前一年10月、当年5月温度因子呈显著负相关。油松径向生长对不同气候因子响应均存在明显的滞后效应。油松径向生长与PDSI干旱指数具有较好的相关性,特别是与前一年9-12月、当年5月PDSI呈显著正相关。回归模型能较好地模拟树轮宽度指数与PDSI之间的关系,油松极宽窄轮的形成主要是干旱作用的结果。综合各种气候指标,PDSI能更好地反映研究区油松径向生长的特征。

A standard chronology(STD)was established with Pinus tabuliformis samples collected from Nanwutai at the northern slopes of the Qinling Mountains.The correlations between radial growth of P.tabuliformis and climatic factors were explored.The results showed that radial growth was positively correlated with moisture factors in previous September and current May.The radial growth was positively correlated with temperature factors in previous November and negatively with that in previous October and current May.There was significant lag effect of climatic factors on the radial growth.The radial growth of P.tabuliformis was well correlated with the PDSI drought severity index,with positive correlations being identified from September to December of the previous year and in May of the current year.The regression model was able to simulate the relationship between STD and PDSI.The formations of extremely wide and narrow tree-ring were mainly a result of drought condition.Combined with climatic factors,PDSI could better reflect the radial growth characteristics of P.tabuliformis.