贡嘎山高山树线动态及其对气候变化的影响

Alpine treeline is an important ecotone, which is sensitive to climate change. So treeline ecology is of significant to study on global change. This study is a case study in Gonggashan Mountain, Southwestern China. Three possible sensitive indicators, as treeline dynamics, growth form and tree regeneration, were chose to research response of treeline to climate change. Climate change reconstructed from dendroclimatology in eastern slope and western slope of Gonggashan Mountain, and dynamics of treeline in Gonggashan Mountain and Balangshan Mountain were compared. Tree ring-width chronology was used to construct climate change. Tree regeneration dynamics was used to be indicator of treeline response to climate change. The correlation function was used to study the response of tree radial growth and climate elements. The result showed that much of tree growth variance could be accounted for by average temperature in winter (from last December to this Feburary). 200 years of range average in winter were reconstructed from 1800 to 2001. The climate change between eastern slope Hailuogou and western slope of Gonggashan Mountain over the past century were similar, however the range of climate change was higher in western slope than that in the eastern slope. The rhythm of tree regeneration in treeline was sensitive to climate change. The response of treeline dynamics was not manifested as treeline elevation but as tree density at treeline. Winter temperature is the one of the key factors controlling treeline dynamics. Treeline regeneration is a sensitive indicator of climate change.

以贡嘎山东西坡高山树线为研究对象，采用树木更新和生长型分析作为反应气候变化的敏感指标，建立树线位置动态和树木种群年龄结构序列；以活立木、寺庙建筑木或冰川埋藏木为材料，采用树木年代气候学方法建立和延伸树轮年表及重建树线过去的气候变化。揭示树线动态对气候变化的响应及敏感度，为建立树线在气候变化下的动态响应模式提供依据。