Climate response of tree growth in Ethiopia along an altitudinal transect and implications on local climate and regional atmospheric circulation dynamics

埃塞俄比亚沿海拔样线树木生长的气候响应及其对当地气候和区域大气环流动态的影响

• 批准号: 42082865
• 负责人: Professor Dr. Achim Bräuning
• 金额: --
• 依托单位: Institut für Geographie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/42082865?language=en
• 关键词: Climate; response; tree; growth; Ethiopia

With the following extension proposal we intend to finalize ongoing studies on the seasonal growth dynamics of native and exotic tree species in the tropical mountain forest of Munessa, Ethiopia. High-resolution dendrometer measurements of stem diameter variations indicated different growth dynamics of evergreen conifer species (Pinus radiata, Podocarpus falcatus) und evergreen and deciduous broadleved tree species (Prunus africana, Celtis africana), respectively. Trees released from competition showed a strong stimulation of stem growth. The knowledge about seasonal wood formation and growth dynamics form the basis for the interpretation of long tree-ring series of ring width and latewood density and of the analysis of annual variations of stable isotopes of 13C and 18O in wood cellulose. Chronologies of stable isotopes of ca. 400 year-old Podocarpus-trees shall be used for the reconstruction of past variations of precipitation. In combination with an extensive tree-ring network from Asia, they shall further be used to analyse variations in the variability of the summer monsoon variability over the Indian Ocean. Furthermore, stable 13C analyses shall provide information on the physiological reaction of the studied tree species (changes of the ‚water use efficiency‘) on extreme drought events, which provides important information for the development of sustainable forest management options under climate change scenarious of increased rainfall variability.

通过以下扩展提案，我们打算完成对埃塞俄比亚穆内萨热带山林中本地和外来树种季节性生长动态的持续研究。高分辨率树木仪测量的茎直径变化表明常绿针叶树物种的不同生长动态。对辐射松、罗汉松、常绿落叶阔叶树种（非洲李、非洲朴树）分别表现出强烈的刺激作用。关于季节性木材形成和生长动态的知识构成了解释长树木年轮系列的年轮宽度和晚材密度以及分析木材纤维素中 13C 和 18O 稳定同位素的年度变化的基础。大约 400 年树龄的罗汉松树的稳定同位素将用于重建过去的降水变化，并结合亚洲广泛的树木年轮网络，进一步用于重建。分析印度洋夏季季风变化的变化 此外，稳定的 13C 分析应提供有关所研究树种对极端干旱事件的生理反应的信息（“水利用效率”的变化），这提供了重要的信息。在降雨量变化增加的气候变化情景下制定可持续森林管理方案的信息。