The visual assessment of tree vigour before partial cutting is a key element of the long-term sustainability of managed hardwood forests. Several classification systems have been developed and applied to perform this task during the tree marking process. They segregate trees in different vigour classes based on the presence and severity of stem and crown defects. Yet, the relevance of using these defects to assess tree vigour has rarely been empirically validated. In this study, we analysed the relationships between quantitative vigour indicators and a full range of individual defects using 336 sugar maple and 84 yellow birch trees. Among the tested defects, the tree crown density showed the best ability to identify slow growing, non-vigorous sugar maple trees, regardless of their size. However, none of the stem-related defects, such as bark aspect, the presence of cambial necrosis or conks and stromata were strongly related to our quantitative vigour indicators. For yellow birch, none of the stem defects and crown conditions were found to be related to our vigour indicators. We conclude that, pending longitudinal studies that will provide a full empirical validation of classification systems, crown density should be used to assess recent growth and vigour of sugar maple trees and guide tree marking.

中文翻译：

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相关的茎和冠缺陷估计北部硬木森林树木的活力

在部分砍伐之前对树木的活力进行目测评估是管理硬木森林的长期可持续性的关键要素。已经开发了几种分类系统并将其应用于在树标记过程中执行此任务。他们根据茎和树冠缺陷的存在和严重程度将树木分为不同的活力等级。但是，使用这些缺陷评估树木活力的相关性很少得到经验验证。在这项研究中，我们使用336棵糖枫树和84棵黄桦树分析了定量活力指标与各种个体缺陷之间的关系。在测试的缺陷中，树冠密度显示了识别缓慢生长，无力的糖枫树的最佳能力，无论其大小如何。但是，没有茎相关的缺陷，例如树皮方面，冈比亚坏死或浓缩和基质的存在与我们的定量活力指标密切相关。对于黄桦，没有发现茎部缺陷和冠状状况与我们的活力指标相关。我们得出的结论是，在进行纵向研究以提供分类系统的完整实证验证之前，应使用树冠密度评估糖枫树的近期生长和活力并指导树的标记。