气候变暖背景下全球大范围内树木衰退死亡的问题受到了普遍关注，其中气候变暖带来的干旱胁迫加剧被认为是水分匮乏地区树木死亡的重要原因，但干旱导致树木衰退死亡发生的趋势以及相关机制仍不明确，亟需在气候变暖背景下开展相关生理生态学研究。本项目拟以我国北方防风固沙重点区域—科尔沁沙地的主要防风固沙树种为研究对象，依托我单位地处该区的生态研究站，通过树木水力结构及相关重要功能性状的测定分析，明确主要树种对干旱环境的适应性差异；采用树木年轮分析技术，从较长时间尺度评估主要树种对极端干旱的抵抗与恢复能力及其与树木衰退死亡间的关联；采用相关分析法，探讨树木径向生长与气候要素间的量化关系，预测气候变暖背景下科尔沁沙地防风固沙树种对气候变化的响应规律和趋势。该研究的预期成果将为我国北方水分受限区域生态建设与林业经营实践中固沙造林树种的选育、土地沙化防治等方面提供理论科学依据。

The problem about widespread tree decline and mortality across many forests of the world in the context of climate warming has received increasing attention. The increasing drought stress caused by climate warming is considered to be an important cause of tree death in water-deficient areas, but the trend and mechanisms of tree decline and mortality resulted from drought are still unclear. Therefore, it is urgent to carry out relevant physiological and ecological researches under climate warming. This proposed project is planned to study the main windbreaks and sand-fixation tree species in Horqin Sandy Land, a key area for windbreaks and sand-fixation in northern China, relying on two ecological research stations of Institute of Applied Ecology, CAS. First, the differences of the adaptation of main tree species to dry environment will be identified by investigating the hydraulic architecture and related important functional traits. Then, the resistance and recovery of major tree species to extreme drought and their relationship with tree decline and death will be assessed using dendrochronological technique from a longer time scale. Last, the quantitative relationship between tree radial growth and climatic factors will be explored using simple correlation analysis. Based on the above analyses, the features and trends of main wind-proof and sand-fixing species responses to climate change will be predicted in the Horqin Sandy Land under the background of climate warming. The expected results of this project will provide theoretical and scientific basis for the selection of sand-fixing and afforestation tree species and the prevention and control of land desertification in water-deficient areas of northern China.