樟子松树轮δ^(13)C对气候因子响应的方位差异

Orientation Difference of Tree Ring δ^(13)C Response to Climatic Factors for Pinus sylvestris var. mongolica

对大兴安岭北部3株樟子松树轮进行δ13C测定,分析树轮δ13C对气候因子响应的方位差异以及不同采样方位数和方位组合方式对整轮代表性的差异。结果表明:樟子松树轮不同方位δ13C的均值序列对大区域气候环境因子的响应是一致的;树轮不同方位的δ13C序列多数呈正相关,少量呈负相关,其中相关系数达到显著性水平的序列多数呈对称分布;树轮不同方位δ13C序列提取气候因子的能力和程度存在较大差异;当无法整轮周向取样时,选取3～4个方位采样既经济高效又能较完整地提取样本的δ13C变化信息;在方位组合上,应尽量避免各孔向间呈180°夹角。

Through investigation of the stable carbon isotope ratio （δ13C） of discs which were sampled from three 15- year-old trees in the north part of Daxing＇anling Mountain, we analyzed the orientation variation in tree ring δ13 C in response to climate factors and influence of sampling orientations and the sample combinations on the circumferential representative. The result showed that the impact of regional climate and environment factors on the variation in tree ring δ13C was consistent. It was found that most of the correlations between the tree ring δ13C sequences were positive, but some were negative. The sequences with significant correlation usually exhibited symmetrical or obtuse-angled distribution. The capability and extent of tree ring δ13C extracting the climate factors varied obviously among different orientations which accounted for the responses of different orientations to climate factors. The result suggests that 3 orientations provide the best and most efficient choice for extracting the information of tree ring δ13C. Sampling should avoid boring in one direction only, but should also include transversal angles.