伏牛山龙池墁南坡油松径向生长对气候变化的响应

树龄是森林结构、成分变化的重要诱导因素，它极大地影响着森林的生长动态乃至分布格局，因此不同年龄尺度的树木径向生长对气候变化的响应研究，对全球气候变化背景下的森林保护和管理有着十分重要的科学意义。油松是我国的特有树种，在我国北方地区广泛分布，河南西部伏牛山地处南北气候过渡的敏感地带，是油松分布的南界。以伏牛山地区龙池墁南坡原始森林的油松树轮为研究对象，依据系统聚类分析将样芯宽度序列分为两个年龄组，最终建立了整体及不同树龄的树轮宽度标准年表（STD）。研究结果表明：（1）树轮标准年表的信噪比SNR和样本总解释量EPS值都较高，说明年表含有较丰富的环境信息；（2）当年5月的水热因子是龙池墁油松径向生长的主要限制因子；（3）老龄油松和幼龄油松的树轮宽度生长变化均呈下降趋势，但是幼龄树的树轮宽度下降幅度远大于老龄树；（4）建立了不同分组油松的生长模型，并基于模型确定了树轮生长的最显著因子，同时也发现幼龄油松对气象因子响应敏感，受到的抑制作用也较为强烈。因此随着全球气候变暖趋势增大，龙池墁低海拔地区将更加不利于幼龄油松的生长，这将影响油松的抚育更新及油松种群在低海拔地区生态群落中的地位，甚至造成油松将向更高海拔地区迁移，这一研究结果也为伏牛山地区的森林管理和抚育更新提供了科学依据。

Climate-growth response of Pinus tabulaeformis in the south slope of Longchiman, Mt. Funiu, central China

Tree age is a significant inducer factor in the change of forest structure and composition and it greatly affects the growth dynamics and distribution pattern of forests. So, the study has very important scientific implications to forest protections and managements under the background of global climate change based on the responses of radial growth of trees to climate change on different age scales. Pinus tabulaeformis carr. is an endemic species to China and widely distributed in northwestern, northeastern and northern China. Mt. Funiu in western Henan Province is located in the sensitive zone of climate transition from north subtropical to south warm temperate in eastern China, which is considered as the southern boundary of Pinus tabulaeformis distribution in eastern China. Although some studies on the relationship between tree growths and climate change had been carried out in Mt. Funiu, there are few studies on the response of tree growths to climate change on different age scales. In this paper, tree rings of Pinus tabulaeformis from the southern slope of the primeval forest in Mt. Funiu were taken and the samples were divided into two age groups based on systematic cluster analysis. Finally, different tree ring-width standard chronologies (STD) for the whole and different tree-ages were developed. The study results showed that:(1) these standard chronologies had higher value of signal-to-noise ratio (SNR) and expressed population signal (EPS),so they indicated that these contained a variety of environmental information; (2) The main limiting factors for the radial growth of Pinus tabulaeformis in Longchiman were the hydrothermal factors in May of the current year; (3) The tree-ring width growths of both older and younger Pinus tabulaeformis showed a decreasing trend, but the decreasing amplitude of the tree ring width of younger trees was much greater than that of the older; (4) The growth models of different groups of Pinus tabulaeformis were established and the most significant limiting factor of each group was determined based on models. Also the study found that the radial growth of younger Pinus tabulaeformis was more sensitive response to climate factors and more inhibited. Hence, with the global warming increasing, the growth of younger Pinus tabulaeformis will be more unfavorable in the lower altitude area of Longchiman and affect the tending and regeneration and the status of Pinus tabulaeformis population in the ecological community of the low altitude area, at last even may cause Pinus tabulaeformis to migrate to higher altitude or colder area. The results also provide some scientific basis for forest management and tending and regeneration in Mt. Funiu.