Abstract Climate change brings about more frequent short-term waterlogging leading to unfavorable conditions for tree growth. Poplar is a preferred tree species for fast-growing plantations. Although limited short-term comparative studies exist with poplars that examine clonal variation in growth and physiological responses to waterlogging, a comprehensive assessment on growth performance, crown structure and wood property of poplar clones is lacking from a long-term study. This study compares the clonal variations in survival rate, growth, crown structure, stem form and wood property of poplar clones to better match the genotype with specific site. In line with the result of the preliminary evaluation, 17 poplar clones were harvested to further investigate crown structure, stem form and wood property after 24 growing seasons. A significant difference in tree growth was observed among the clones, ranging from 1.08 to 2.64 m3 for tree volume, whereas male clones generally had a better growth performance than the female. Hierarchical cluster analysis indicated the 17 poplar clones can be classified into three distinct groups in term of mean values of branching angle, branch numbers and branch base diameter. There existed visible differences in breast-height form factor and height-diameter ratio among the poplar clones, and four distinct groups can be divided based on Euclidean distance of stem form indexes. Significant clonal variations in wood basic density (WD) and microfibril angle (MFA) were observed among the sampled clones, and the mean clonal WD and MFA at breast height ranged from 0.325 to 0.390 g/cm3 and 11.8 to 16.7° respectively. Based on the TOPSIS method, a comprehensive assessment of adaptability and prioritization of the 17 clones was made from tree volume growth, stem form, branching traits and wood density, and some superior poplar clones were recommended for future applications in the similar lowland sites.

中文翻译：

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引进杨树无性系的生长性能、树冠结构、茎形状和木材特性的评估：来自低地场地长期田间试验的结果

摘要 气候变化导致更频繁的短期内涝，给树木生长带来不利条件。杨树是速生种植园的首选树种。尽管对杨树生长的克隆变异和对涝渍的生理反应进行了有限的短期比较研究，但长期研究缺乏对杨树无性系生长性能、树冠结构和木材特性的综合评估。本研究比较了杨树无性系在存活率、生长、树冠结构、茎形和木材特性方面的克隆变异，以更好地将基因型与特定位点相匹配。根据初步评价结果，收获17个杨树无性系，在24个生长季节后进一步考察树冠结构、茎形和木材特性。在无性系之间观察到树木生长的显着差异，树木体积从 1.08 到 2.64 m3 不等，而雄性无性系通常比雌性具有更好的生长性能。层次聚类分析表明，17个杨树无性系在分枝角度、分枝数和分枝基部直径均值上可分为三个不同的组。杨树无性系在胸高形态因子和高径比上存在明显差异，根据茎形态指标的欧氏距离可划分为4个不同的群体。在采样的克隆中观察到木材基本密度 (WD) 和微纤维角 (MFA) 的显着克隆变化，胸高的平均克隆 WD 和 MFA 分别为 0.325 至 0.390 g/cm3 和 11.8 至 16.7°。基于 TOPSIS 方法，