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    吉林北部山区长白落叶松林径向生长对气候干暖化的响应

    Growth responses of Larix olgensis forests to climatic drying-warming trend in the northern mountainous region of Jilin Province, northeastern China

    • 摘要:
      目的中国东北地区的气候干暖化对长白落叶松林构成了严重威胁,有待进一步探究林分因子(如林龄、密度、蓄积量等)如何与气候条件共同作用、影响树木径向生长对气候变化响应的相关机制。
      方法本研究基于吉林长白山北部余脉至老爷岭间的长白落叶松林的树轮宽度标准年表,分析了气候条件及林分因子对长白落叶松林的年轮—气候关系中的相对作用大小,以研究长白落叶松在气候变化下的响应机制。
      结果近30年来,研究区气候干暖化趋势显著,长白落叶松的生长明显受到气候变化的影响,气候条件和林分因子共同作用于年轮—气候关系,但前者的影响要大于后者。Palmer干旱指数对主成分第1轴的解释力为50.27%,表明水分条件的影响更为重要;林分因子中的林龄有显著作用,林龄大的林分更易受到温度升高的限制作用,其余林分因子则在本研究中没有表现出显著影响。
      结论在未来气候干暖化情境下,林龄较小的长白落叶松的生长会得到一定促进,但若林龄过大则会受到温度上升导致水分亏缺的限制作用,所以有必要采取经营措施以减小升温对林分的不利影响,以保证林分的持续发展。

       

      Abstract:
      ObjectiveLarix olgensis forest in northeastern China has been threatened by significant climatic drying-warming trend. So we need to figure out how stand factors (i.e. forest age, density, volume, etc.) and climatic conditions affect forest growth-climate relationship together.
      MethodOur study area was located in Jilin Province, between the northern part of Changbai Mountain and Laoyeling Mountain of northeastern China. We analyzed the relative effects of climatic conditions and stand factors on the growth-climate relationship of Larix olgensis forests with dendrochronological method, in order to study the mechanism regulating the response of L. olgensis forests to climate change.
      ResultThe results showed that, in the past 30 years, it had a clear drying-warming trend in the study area, and the growth of L. olgensis forests was significantly affected by changing climate. The growth-climate relationship was affected both by climatic and stand factors, but the influence of climate factors was much stronger. Palmer drought severity index (PDSI) explained 50.72% of variations in growth-climate relationship in PCA 1, indicating that the effects of water were more important than temperature. Stand age also showed a significant effect, stands with older age were more susceptible to growth limitation caused by increased temperature. Other stand factors (e.g. density and volume) did not show significant effects in this study.
      ConclusionUnder a drier and warmer future climate, the growth of young L. olgensis forests may be promoted. But the growth of older stands might be limited by the water deficit caused by climate warming. Thus it is necessary to use examined forest management methods to alleviate the vulnerability to climate change, so as to ensure the sustainable development of the L. olgensis forests.

       

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