秦岭南坡油松树轮碳稳定同位素对气候因子的响应

Responses of δ13C in Pinus tabuliformis Tree Rings to the Changes of Climatic Factors in the Qinling Mountains

根据树木年轮气候学原理,运用相关分析和多元回归分析方法,研究陕西秦岭南坡油松(Pinus tabuli formis)树轮碳稳定同位素(δ^13C)对气候变化的响应。结果表明,树轮δ^13C含有丰富的气候信息,低海拔(1250m)的油松δ^13C与前一年的4月温度显著正相关(P<0.05),与当年10月降水显著正相关(P<0.05);中海拔(1450m)的油松δ^13C与当年2月温度显著正相关(P<0.05),同时也与5月的极端高温显著正相关(P<0.05);高海拔(1650m)的油松δ^13C与当年10月温度显著负相关(P<0.05),与1月相关湿度显著正相关(P<0.05)。1978、1990年夏、冬季气温的偏低和秋季气温偏高,7月温度低于8月,4-9月降水波动太大,这些反常的气候变化扰乱了油松正常的生理活动,破坏了油松的光合作用过程,造成δ^13C值的异常降低。

Based on the principles of dendroclimatology,responses of δ^13 C in Pinus tabuliformis tree rings to the changes of climatic factors in the south slope of the Qinling Mountains were examined by using the analyses of correlation and multiple regression.The results showed that sufficient climate information was retrieved from the δ^13 C data set of the tree rings.At low elevation (1 250 m),δ^13 C in P.tabuliformis was significantly and positively correlated with temperature in April of the previous year ( P <0.05),and likewise with precipitation in October of the same year ( P <0.05).At mid elevation (1 450 m),δ^ 13 C was not only positively correlated with temperature in February of the same year ( P <0.05) but also with extreme high temperature in May ( P <0.05).At high elevation (1 650 m),δ^13 C was negatively correlated with temperature in October the same year ( P <0.05),and positively correlated with the relative humidity in January the same year ( P <0.05).Since spring temperatures clearly impacted carbon uptake and fixation of P.tabuliformis ,this tree species rings thus offered considerable potential for robustly inferring past climatic variability of the Qinling Mountains.