胡杨作为干旱地区生态环境变化的指示物种，对于维持区域脆弱生态系统稳定性作用不可替代，目前针对胡杨树干空穴化形成机制研究尚属空白。本项目基于树木雷达扫描技术结合野外定位观测和室内分析，研究塔里木河中下游——英巴扎、英苏和阿拉干3个典型断面胡杨树干空穴化现象，旨在：1）利用空洞调查指标（洞口直径、空洞率）和树木长势指标（树高、胸径、冠幅、年龄、树冠疏失度）分析不同年龄级胡杨空腐分布特征，结合种群样方数据计算各断面各样地内出现空心树的概率；2）通过比较各断面各空腐程度胡杨木腐菌性质、多样性及差异，评价木腐菌对胡杨空腐的影响；3）量化地下水埋深、土壤理化性质和树木自身因素（胸径、冠幅、年龄结构）与胡杨空腐程度的关系；4）综合探究树干空腐与各因子的关系，揭示胡杨树干空腐形成机理及影响因素。本项目研究成果不仅有助于深入理解胡杨树干空穴化成因及其内在机理，同时可为珍稀胡杨林资源保育和管理提供科学依据。

Populus euphratica Oliv., as an indicator species of eco-environmental changes in arid areas, plays an irreplaceable role in maintaining the stability of regional fragile ecosystem. Currently, there is a research gap regarding the mechanism of stem cavitation formation of Populus euphratica. In this project, the stem cavitation of Populus euphratica population at the three typical transects (Yingbaza, Yingsu, Arghan) along the middle and lower reaches of the Tarim River will be studied based on the Tree Radar scanning technique (TRU) combined with field positioning observation and laboratory analysis. The research work will mainly be conducted from four aspects as following: 1) The distribution characteristics of cavity trees of Populus euphratica at different ages will be analyzed by using the cavitation survey index (number of cavities, types, height of entrance, diameter of entrance, orientation of entrance as well as rate of cavitation) and tree vitality parameters (tree height, DBH, crown size, age and crown loss), and also the probability of hollow trees appearing with different monitoring plots at each transects will be determined; 2) The effect of wood-rot fungi on stem cavitation of Populus euphratica trees will be evaluated by comparing the differences in species diversity and characteristics of wood-rot fungi in different cavity degrees of Populus euphratica trees at different transects; 3) Quantify the relationship between groundwater depth, soil physical and chemical properties as well as tree parameters (DBH, crown, age structure) and the degree of stem cavitation; 4) The mechanism and dominant factors of the stem cavitation of Populus euphratica will be revealed by analyzing the relationship between the cavitation degree and aforementioned factors comprehensively. The results of this project not only help to understand the causes of stem cavitation and its internal mechanism, but also provide scientific basis for the conservation and management of Populus euphratica forest resources.