When assessing the strength of sawn lumber for use in engineering applications, the sizes and locations of knots are an important consideration. Knots are the most common visual characteristics of lumber, that result from the growth of tree branches. Large individual knots, as well as clusters of distinct knots, are known to have strength-reducing effects. However, industry grading rules that govern knots are informed by subjective judgment to some extent, particularly the spatial interaction of knots and their relationship with lumber strength. This case study reports the results of an experiment that investigated and modelled the strength-reducing effects of knots on a sample of Douglas Fir lumber. Experimental data were obtained by taking scans of lumber surfaces and applying tensile strength testing. The modelling approach presented incorporates all relevant knot information in a Bayesian framework, thereby contributing a more refined way of managing the quality of manufactured lumber.

翻译：在评估工程用锯材强度时，木节的大小和位置是重要考量因素。木节是木材最常见的视觉特征，源于树枝的生长。已知单个大木节及多个离散木节簇均具有降低强度的效应。然而，规范木节的行业分级规则在某种程度上受主观判断影响，尤其是木节的空间相互作用及其与木材强度的关系。本案例研究报告了一项实验的结果，该实验调查并模拟了木节对花旗松木材样本的强度降低效应。实验数据通过扫描木材表面并施加抗拉强度测试获得。提出的建模方法在贝叶斯框架内整合了所有相关木节信息，从而为管理制造木材质量提供了一种更精细化的途径。