气候变暖背景下杉木年轮密度对气候因子的响应

Response of tree ring density to climatic factors of Cunninghamia lanceolata under climate warming

为探讨杉木年轮密度与气候因子的响应关系,采用树木年轮学方法,以60年生杉木种源林为研究对象,测定杉木整轮密度、早材密度、晚材密度、晚材最大密度和早材最小密度,分析在气候变暖条件下主要气候因子(温度、降水、相对湿度)对杉木年轮密度及其生长的影响。结果表明:杉木不同年轮密度指标均受到温度、降水和相对湿度的显著影响。早材密度与当年夏季最高温度、当年5月降水量,最大密度与当年10月、当年秋季降水量,最小密度与前一年秋季降水量、最小相对湿度呈显著负相关。滑动相关分析表明气候因子在短时间尺度上对杉木生长影响的稳定性有显著影响,其中杉木年轮最大密度与当年10月、秋季的平均相对湿度和最小相对湿度,最小密度与当年2、3月的平均相对湿度和前一年秋季的平均相对湿度、最小相对湿度、降水量的负相关关系最为稳定。杉木年轮最小密度对前一年气候要素的响应存在滞后效应,且晚材密度对当年春季的气候要素响应也存在滞后效应。研究结果对开展亚热带针叶树种年轮生态学和年轮气候学研究具有重要参考价值,建议选择武夷山的天然林获取更长年表用于重建古气候。

The objective of this study was to investigate the relationship between tree ring density and climatic factors of Chinese fir.The tree ring chronology methods were used to study 60 years old Chinese fir provenance forest in Sanming.The whole round density,earlywood density,latewood density,latewood maximum density and earlywood minimum density of Chinese fir were measured,and the effects of main climatic factors(temperature,precipitation and relative humidity)on the tree ring density and growth of Chinese fir were analyzed.The results showed that the tree ring density of Chinese fir was significantly influenced by temperature,precipitation and relative humidity.The earlywood density was negatively correlated with the highest temperature in summer and precipitation in May;the latewood maximum density was negatively correlated with precipitation in October and autumn;and earlywood the minimum density was negatively correlated with precipitation and minimum relative humidity in autumn.The sliding correlation analysis also showed that climate factors had a significant effect on the stability of Chinese fir growth in short time,in which the maximum density was related to the average relative humidity and the minimum relative humidity in autumn of the current year,while the negative correlation between the minimum density and the mean relative humidity in February and March of the current year as well as the mean relative humidity,the minimum relative humidity and the precipitation in autumn of the previous year.The response of earlywood minimum density of Chinese fir to climatic factors in previous year had lag effect,and the response of latewood density to climatic factors in spring of the current year also had lag effect.The results of this study have important reference value for the study of tree ring ecology and climatology of subtropical coniferous tree species.It is suggested that natural forests in Wuyi Mountain should be selected to obtain a longer chronology for paleoclimate reconstruction.