丽江老君山海拔上限长苞冷杉(Abies georgei)和云南铁杉(Tsuga dumosa)径向生长对气候变化的响应

基于树木年轮学方法，利用丽江老君山海拔上限长苞冷杉（Abies georgei）和云南铁杉（Tsuga dumosa）树轮宽度资料，构建差值年表，运用响应函数和滑动响应分析研究树木径向生长与气温和降水的相关关系及其稳定性，进而阐明影响该区域2个针叶树种径向生长的主要气候要素。结果表明：2个树种对降水累积效应的响应较为一致，对逐月气候因子的响应存在差异，相关关系较为稳定，具体表现为（1）上年11月平均温升高和当年生长季盛期（7-8月）降水增加有利于老君山海拔上限长苞冷杉生长；（2）云南铁杉径向生长与当年3月、树木休眠期（1-3月）、生长季盛期（7-8月）的降水表现为显著正相关关系，与上年7月与当年5月的气温及当年生长季末期（9-10月）降水呈显著负相关；（3）上述相关关系的稳定性较强，在全部或大部分分析时段（1951-2017）内达到显著相关，云南铁杉的稳定性更强。研究结果可为气候变化背景下滇西北高原树木生长的管理及森林生态系统的保护提供理论依据。

Response of radial growth of Abies georgei and Tsuga dumosa to climate change at upper distributional limits on Laojun Mountain, Lijiang, Yunnan, China

Based on the dendrochronological method, tree width data of Abies georgei and Tsuga dumosa at their upper distributional limit in Laojun Mountain were used to develop tree-ring residual chronologies. In order to clarify the main climatic factors affecting the radial growth of two conifer species, we used response function and moving interval analysis to study relationships between chronologies and temperature and precipitation, and the stability of the relationships. The results showed that the response of the two tree species was consistent in cumulative effects of precipitation, but different in monthly climatic factors, and the relationships were stable. The detail results were as follows: (1) November mean temperature in last year and growing season (July-August) precipitation in current year promoted the radial growth of A. georgei at the upper distributional limit. (2) The radial growth of T. dumosa was significantly and positively correlated with the precipitation in March, the dormant period (January-March) and growing season of current year, but the growth was significantly and negatively correlated with July temperature in last year, May temperature and post-growing season (September-October) precipitation in current year. (3) The relationships between radial growth and climatic factors were stable by presenting significant correlations in most or whole analysis periods (1951-2017), and the stability of T. dumosa was stronger than A. georgei. The result of this paper can provide a theoretical basis for the prediction of tree growth and the management and protection of forest ecosystems in the northwestern Yunnan Plateau under the background of climate change.