长白山突变型林线岳桦对气候变化的响应

在长白山北坡局地突变型林线内选取10个样方,采用实测法测量岳桦两种生活型(灌木状和乔木状)的树高、径级,采用年轮法测定岳桦的树龄,计算分析长白山北坡2000m处48 a(1953-2000年)的积温变化.对获得的数据采用回归模型、小波分析、相关分析建立树高、径级与积温变化的关系.结果显示:对应长白山48年来积温变化的几个高温期(1960年代初、1980年代、1990年代后期),岳桦树高生长对气候变化有显著响应.灌木状岳桦在径级1～7、7 ～13、13～19和＞19 cm阶段树高生长分为适应期,弱胁迫期和胁迫期.乔木状岳桦在径级13 cm和5 cm出现增长受限和适宜生长两个拐点.高温期对应岳桦树高的快速生长,岳桦树高增长的年际变化是对气温变化的积极响应.

Climatic Response of Betula ermanii from Closed Treeline in Changbai Mountains

On the north slope of Changbai Mountain 10 quadrats were selected in local closed treeline.The tree height and size class of shrub and single tree Betula ermanii were obtained from field measured,and the tree age was determined by standard dendrochronological techniques.The relationship between the tree height and size class was established by means of the regression model against the collected data.The variation tendency of accumulated temperature in the past 48 years on the 2 000 m high of the northern sl...