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    小兴安岭不同海拔臭冷杉年轮-气候关系及大尺度气候影响

    Climate-growth relationships of Abies nephrolepis and its connection with large-scale climate change in Xiaoxing’an Mountains, northeastern China

    • 摘要: 以丰林自然保护区臭冷杉为样本,运用树木年轮气候学方法,建立了不同海拔3个臭冷杉树轮宽度年表,并分析其与该区温度、降水及大尺度气候因子的关系。结果表明:丰林自然保护区臭冷杉的径向生长主要受温度制约,与降水相关性较弱。3个臭冷杉年表均与当年生长季的最低温度、平均温度显著负相关(P0.01),与当年3月降水量显著负相关 (P0.05)。不同海拔臭冷杉径向生长对温度、降水的响应存在差异,高海拔谷地和坡上臭冷杉受气候(温度、降水)影响明显强于低海拔臭冷杉。丰林自然保护区臭冷杉径向生长与大西洋多年代际振荡(Atlantic Multidecadal Oscillation, AMO)和太平洋年代际振荡(Pacific Decadal Oscillation, PDO)的相关分析表明,该区臭冷杉径向生长还可能与大尺度气候变化存在联系,AMO对低海拔臭冷杉生长影响较大,而PDO对高海拔臭冷杉影响更强。小兴安岭谷地臭冷杉衰退可能与AMO、PDO的相位转变存在一定关联,AMO和PDO影响小兴安岭地区温度、降水,改变了山谷地带的水分可利用性。大尺度气候变化导致本区最低温度显著升高,树木光合作用下降,呼吸作用加强,又促使这一现象加剧。

       

      Abstract: Three tree-ring standard chronologies of Abies nephrolepis at different elevations in Fenglin National Nature Reserve from Xiaoxing’an Mountains of northeastern China were developed by using standard dendrochronological methods. Relationships between these three chronologies and local (mainly temperature and precipitation) and largescale climatic factors were analyzed. Results showed that radial growth of A. nephrolepis in this region was mainly limited by air temperature, while the effect of precipitation was relatively weak. Three A. nephrolepis chronologies were negatively correlated with minimum and mean temperatures in the current growth season (P0.01) and total precipitations in March (P0.05). Radial growth of A. nephrolepis in different elevations, however, responded differently to monthly mean temperatures and total precipitations. The effects of climatic factors (monthly temperature and precipitation) on tree growth in high elevations were significantly stronger than that in low elevations. Correlation analysis between three A. nephrolepis chronologies and the index of Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) indicated that radial growth of A. nephrolepis could be connected with large-scale climate changes in Pacific and Atlantic. A greater effect of AMO on tree growth appeared in low elevation sites, while greater effect of PDO on tree growth was in two high elevation sites. The decline of valley spruce-fir forests in this region in recent years could be related to the phase changes of AMO and PDO, which changed the regime of temperature and precipitation in this region. Higher minimum temperatures in growing season caused by large-scale climate (AMO and PDO) changes decreased net photosynthesis and increased respirations of A. nephrolepis in this area. Thus, the physiological recession of tree growth will appear. In addition, higher temperature may result in the disappearance of patchy permafrosts in valleys, which will decrease water availability of soil in growing seasons. Therefore, spruce-fir forest declines in valleys in this region will occur.

       

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