The presence of wood irregularities such as knots are decisive for the mechanical properties of sawn timber, and efficient utilisation of timber requires methods by which grade determining properties can be predicted with high accuracy. In the glulam and sawmilling industries today, there is a potential and a need for more accurate prediction methods. This paper concerns the performance of a set of indicating properties calculated by means of data from surface laser scanning, dynamic excitation and X-ray scanning, the latter used to obtain boards’ average density. A total number of 967 boards of Norway spruce originating from Finland, Norway and Sweden were used to determine statistical relationships between the indicating properties and the grade determining properties used to grade sawn timber into T-classes. Results show that the indicating properties give coefficients of determination to tensile strength as high as 0.70. Furthermore, results also show that laser scanning of boards with sawn surface finish give basis for almost as accurate grading as what scanning of planed boards do. The results imply that more accurate grading of timber into T-classes is possible by application of a new set of indicating properties. This paper is part one of a series of two papers. In the second paper, two models to derive settings and calculate yield in different strength classes using the indicating properties presented herein are compared and discussed.

中文翻译：

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锯材抗拉强度预测：基于表面激光扫描和动态激发的指示特性定义和性能

木节等木材不规则性的存在对于锯材的机械性能是决定性的，木材的有效利用需要能够高精度预测等级确定性能的方法。在当今的胶合木和锯木业中，有潜力并且需要更准确的预测方法。本文涉及通过表面激光扫描、动态激发和 X 射线扫描的数据计算出的一组指示特性的性能，后者用于获得板的平均密度。来自芬兰、挪威和瑞典的967块挪威云杉板被用于确定指示特性与用于将锯材分级为T级的等级确定特性之间的统计关系。结果表明，指示特性给出了高达 0.70 的抗拉强度的决定系数。此外，结果还表明，对具有锯切表面光洁度的板材进行激光扫描为几乎与刨光板扫描一样准确的分级提供了基础。结果表明，通过应用一组新的指示属性，可以更准确地将木材分级为 T 级。这篇论文是两篇论文系列中的一部分。在第二篇论文中，比较和讨论了使用此处提供的指示属性导出设置和计算不同强度等级中的屈服的两个模型。结果还表明，对具有锯切表面光洁度的板材进行激光扫描为几乎与刨光板扫描一样准确的分级提供了基础。结果表明，通过应用一组新的指示属性，可以更准确地将木材分级为 T 级。这篇论文是两篇论文系列中的一部分。在第二篇论文中，比较和讨论了使用此处提供的指示属性导出设置和计算不同强度等级中的屈服的两个模型。结果还表明，对具有锯切表面光洁度的板材进行激光扫描为几乎与刨光板扫描一样准确的分级提供了基础。结果表明，通过应用一组新的指示属性，可以更准确地将木材分级为 T 级。这篇论文是两篇论文系列中的一部分。在第二篇论文中，比较和讨论了使用此处提供的指示属性导出设置和计算不同强度等级中的屈服的两个模型。