长白山北坡沿海拔梯度岳桦径向生长对气候的响应

Climatic Response of Betula ermanii Tree-ring Growth Along an Altitudinal Gradient on the Northern Slope of the Changbai Mountains

为了解树轮生长与气候间的关系是否受到海拔因素的影响,运用树木年代学方法,研究了长白山北坡沿海拔梯度岳桦径向生长与气候因素间的关系.响应分析结果显示,岳桦在其低海拔林线处(1 700 m a.s.l.)径向生长与当年1月月平均温度负相关,与上年9月月总降水量正相关(P<0.05).在中海拔森林内部(1 850 m a.s.l.)径向生长与上年6月、7月月平均温度负相关(P<0.05),与降水之间的响应关系不明显.高海拔林线处(2 000 m a.s.l.)岳桦径向生长与上年7月月平均温度负相关,与上年9月月平均温度正相关,与当年3月温度负相关,与当年7月温度呈正相关(P<0.05),此外,与当年6月降水量呈正相关(P<0.05).因此,随海拔梯度升高,岳桦年表中包含的气候信息量增加,岳桦径向生长对气候的敏感性增强.

In order to explore climate-growth relationships at different elevations, tree-ring width chronologies of Betula ermanii were developed from three sampling sites on the northern slope of the Changbai Mountains, northeastern China. Monthly mean temperature and monthly total precipitation were used for the analysis. The study found more climatic signals revealed by statistical characteristics of the tree-ring chronologies in higher elevations. Response function analysis indicated that on the lower tree-line site （1 700 m a.s.l.）, radial growth of Betula ermanii was negatively correlated with temperature of January, but positively correlated with precipitation of previous September （P 〈 0.05）. On the mid-elevation interior forest site （1 850 m a.s.l.）, growth of Betula ermanii responded negatively to temperature of previous June and July （P 〈 0.05）. On the upper tree-line site （2 000 m a.s.l.）, tree-ring growth of Betula ermanii was negatively correlated with temperature of March and previous July, but positively correlated with that of June and previous September （P 〈 0.05）. Besides, on upper tree line, growth of Betula ermanii benefited from high level of precipitation during current June. Our results suggested that along the altitudinal gradient, Betula ermanii tree-ring growth responds differently to local climatic conditions. In general, the climatic sensitivity of Betula ermanii chronologies increases with the elevation.