川西高原两种针叶树径向生长对气候因子的响应

基于树轮年代学手段,建立了岷江冷杉和方枝柏树轮宽度标准年表以及混合树种年表,研究川西地区理县凉台沟两种针叶树种径向生长对气候变化的响应,为全球变暖背景下该地区森林生态系统的保护与管理提供依据。结果表明:混合年表中包含了2个单个年表的共同气候信息,其信噪比和样本总体解释量均高于单个年表。与气候因子的相关分析显示,3个年表对气候要素的响应表现出较好的一致性,均对温度响应敏感,尤其是方枝柏最为敏感。相对湿度在5、10月对两树种的限制作用明显强于降水。1994年升温突变后,岷江冷杉宽度年表与月均温的相关性变化最为明显,部分月份由负相关转变为正相关,表明岷江冷杉树木径向生长对温度的响应呈现出不稳定性,但两树种径向生长呈差异性变宽趋势,对气温响应的敏感性减弱。

Responses of radial growth of two coniferous species to climate factors in western Sichuan Plateau,China

Based on the method of tree-ring chronology, we established ring-width standard chrono-logies of Abies faxoniana and Sabina saltuaria in Liangtaigou, Lixian County, western Sichuan Province, and their regional composite chronology (RC) to study the responses of radial growth of those two coniferous species to climate change, which provided a basis for the protection and mana-gement of forest ecosystems in this region under the background of global warming. The results showed that the RC contained the common climatic information of two individual chronologies, which had higher signal-to-noise ratio and expressed population signal. The correlation analysis showed that three chronologies had a good consistency in the response to climate factors. All chronologies were significantly correlated with temperature, with S. saltuaria being more sensitive to temperature changes. Relative humidity had stronger limiting effect on both species than precipitation in May and October. After the abrupt warming in 1994, the correlation between ring-width chrono-logy of A. faxoniana and monthly mean temperature shifted obviously from negative to positive in some months, which indicated the radial growth of A. faxoniana showed unstable in response to temperature. However, the radial growth of both species showed different broadening trend and the sensitivity to temperature response was weakened.