Strength grading is an important step for the production of homogenous and high-quality solid wood material. In particular, for hardwoods, the use of non-visible characteristics is indispensable. Dynamic MOE (E_dyn) is an important parameter widely used for grading of softwoods and applicable to hardwoods as well. There are two common ways to measure E_dyn—ultrasound (US) wave propagation and longitudinal vibration (LV) method. Both methods are used in practice, however, due to the different inherent measurement techniques, the results differ. The current paper analyses the stiffness and strength coefficients of determination for several temperate European hardwood species and emphasizes the differences between the two measurement systems. The performance was analysed with regard to grading techniques, testing modes for the mechanical properties (tension and bending) and wood qualities. For more than 2861 pieces of European ash (Fraxinus excelsior), European beech (Fagus sylvatica), European oak (Quercus spp.) and maple (Acer spp.), the E_dyn was measured using both techniques, and destructive tests (tension and edgewise bending) were applied. The results show that LV has higher coefficient of determination compared to the US E_dyn. The coefficient of determination for both methods and tensile application can be increased by calculating E_dyn with average density. Furthermore, the results support species-independent strength grading of hardwoods. Further research on the effect of different wood qualities and sawing patterns is required.

强度分级是生产均质和高质量实木材料的重要步骤。特别是对于硬木来说，使用不可见特性是必不可少的。动态MOE（E _dyn）是广泛用于软木分级的重要参数，也适用于硬木。有两种常见的测量E _dyn的方法-超声波（US）波传播和纵向振动（LV）方法。两种方法都在实践中使用，但是由于固有的测量技术不同，结果也有所不同。本文分析了几种欧洲温带硬木树种的刚度和强度系数，并强调了两种测量系统之间的差异。根据分级技术，机械性能（拉伸和弯曲）和木材品质的测试模式对性能进行了分析。对于超过2861件欧洲烟灰（Fraxinus excelsior），欧洲山毛榉（Fagus sylvatica），欧洲橡木（Quercus spp。）和枫木（Acer spp。），E _dyn使用这两种技术进行测量，并进行破坏性测试（拉伸和边缘弯曲）。结果表明，与US E _dyn相比，LV具有更高的测定系数。通过使用平均密度计算E _dyn，可以增加方法和拉伸施加的测定系数。此外，结果支持硬木的物种无关强度分级。需要进一步研究不同木材质量和锯切模式的影响。