中文摘要：

根据川西卧龙地区岷江冷杉（Abies faxoniana）的年轮宽度资料,分析了该地区树木生长特征及对气候响应在最近53年（1956–2008年）的异质性特征。结果表明,在1956–1976年时段,树木生长速率较快,晚冬至早春（1月到4月）温度对树木生长有着明显的促进作用,而春末5月份的高温对于树木生长有限制性影响,而与日照时数关系不大;在1977–2008年时段,树轮生长主要受冬季（11月到1月）低温的限制,另外,日照时数对于树木生长的限制性影响明显增强。秋季到早冬（9–12月）降水在两个时段上对树木生长均有一定的限制性影响。树轮指数在1956–1976年时段与温度序列吻合较好,而在1977–2008年时段树轮指数明显偏低,与温度序列出现了明显的分离。1977–2008年时段内云层覆盖量增加导致太阳辐射量显著下降,进而树木可利用的光合有效辐射也相应地降低,这可能是树木生长速率在此时期明显较慢的主要原因。

英文摘要：

Aims It is generally assumed in dendroclimatological studies that the approximate relationship between tree growth and the limiting climatic factors is stable over time. However,observed spatial and temporal instabilities in growth-climate relationships suggest diverse growth responses expected to be triggered by unprecedented climatic changes in the future may greatly complicate dendroclimatic reconstructions of past climate histories. We test the stability of the growth-climate relationship using tree ring-width data of Abies faxoniana in Wolong National Natural Reserve of western Sichuan,China to provide qualitative verification for regional paleoclimatic studies and dynamic vegetation models for carbon uptake. Methods Standardized dendroecological methods were used to study the effects of climatic variability on radial growth of A. faxoniana,a subalpine conifer that was the dominant and economically most important tree species in this region. Fifty-two increment cores of A. faxoniana were sampled in a pristine forest site at 2 750 m and sev-eral statistics were used to identify common patterns of interannual growth variability. A shift in climate facilitated comparison of growth-climate relationships during two distinct periods：1956–1976 and 1977–2008. Tree radial growth was correlated against monthly total precipitation,sunshine time and mean,minimum,and maximum temperature from the nearby meteorological station. Important findings Tree radial growth showed time-dependent relationships to interannual climate variation. For 1956–1976,tree growth showed a positive growth response to temperature in late winter to early spring （prior December to current April）,whereas high temperature in late spring （May） negatively impacted tree growth. For 1977–2008,tree growth responded more strongly to sunshine time （positive） and winter temperature （negative）. In addition,tree growth showed an internally consistent positive response to precipitation in autumn to early winter （prior September to D