The quality of dimension lumber (2 by 4 lumber) was preliminarily investigated in four common Mongolian softwoods: Pinus sylvestris L., Pinus sibirica Du Tour, Picea obovata Ledeb., and Larix sibirica Ledeb. to produce high quality dimension lumber for structural use. In total 61, 39, 67, and 37 pieces of lumber were prepared for Pinus sylvestris, Pinus sibirica, Picea obovata, and L. sibirica, respectively. The lumber was visually graded and then tested in static bending to obtain the 5% lower tolerance limits at 75% confidence level (f0.05) of the modulus of elasticity (MOE) and the modulus of rupture (MOR). In addition, the effects of sawing patterns on bending properties were also analyzed. The f0.05 of the MOE and MOR were 4.75 GPa and 15.6 MPa, 3.39 GPa and 11.0 MPa, 3.78 GPa and 11.7 MPa, and 6.07 GPa and 22.3 MPa for Pinus sylvestris, Pinus sibirica, Picea obovata, and L. sibirica, respectively. These results suggested that with a few exceptions, characteristic values of MOR in the four common Mongolian softwoods resembled those in similar commercial species already used. In visual grading, over 80% of total lumber was assigned to select structural and No. 1 grades in Pinus sylvestris and Pinus sibirica, whereas approximately 40% of total lumber in L. sibirica was No. 3 and out of grades. Sawing patterns affected bending properties in Pinus sylvestris and L. sibirica, but did not affect Pinus sibirica and Picea obovata. Dynamic Young's modulus was significantly correlated with bending properties of dimension lumber for the four species. Based on the results, it was concluded that dimension lumber for structural use can be produced from the four common Mongolian softwoods.

中文翻译：

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蒙古四种普通软木规格材质量的初步评价。

在蒙古的四种常见软木中初步调查了规格木材（2比4的木材）的质量：樟子松，西伯利亚松图尔，白云杉和西伯利亚落叶松。生产用于结构用途的高质量尺寸木材。总共为樟子松，西伯利亚松，白云杉和西伯利亚落叶松分别准备了61、39、67和37件木材。对木材进行视觉分级，然后进行静态弯曲测试，以在弹性模量（MOE）和断裂模量（MOR）的75％置信度（f0.05）下获得5％的较低公差极限。此外，还分析了锯切模式对弯曲性能的影响。樟子松的MOE和MOR的f0.05为4.75 GPa和15.6 MPa，3.39 GPa和11.0 MPa，3.78 GPa和11.7 MPa，以及6.07 GPa和22.3 MPa，西伯利亚松，白云杉和西伯利亚乳杆菌。这些结果表明，除少数例外，四种常见的蒙古软木的MOR特征值类似于已经使用的类似商品树种的MOR特征值。在视觉分级中，樟子松和西伯利亚松中有超过80％的木材被指定为结构等级和第一等级，而西伯利亚落叶松中约40％的木材为3级及以上等级。锯切模式影响樟子松和西伯利亚落叶松的弯曲特性，但不影响西伯利亚松和云杉云杉。动态杨氏模量与这四个物种的尺寸木材的弯曲性能显着相关。根据结果​​得出的结论是，可以使用蒙古的四种常见软木生产用于结构用途的尺寸木材。