文献类型：会议论文

英文题名：Effects of machine strength grading methods on dimension lumber grades for Chinese fir plantation

作者：Zhou, H. B.[1] Ren, H. Q.[1] Lu, J. X.[1] Yin, Y. F.[1]

第一作者：周海宾

通信作者：Zhou, HB[1]

机构：[1]Chinese Acad Forestry, Res Inst Wood Ind, Beijing, Peoples R China

会议论文集：1st International Conference on Modern Bamboo Structures

会议日期：OCT 28-30, 2007

会议地点：Hunan Univ, Changsha, PEOPLES R CHINA

主办单位：Hunan Univ

语种：英文

外文关键词：Forestry - Lumber - Ultrasonic waves

年份：2008

摘要：From producing to grading there are many factors influencing on final grade distribution of dimension lumber. Grade is one of indices in which wood managers are most interested because lumber price depends on it. Lots of researchers conducted studies on application of ultrasonic wave, longitudinal vibration and transversal vibration methods on predicting the stiffness property of dimension lumber. However, compared with traditional bending method the effects of these three methods on the grade distribution are still a problem. To solve the above, logs of Chinese fir plantation from Fujian provinces of China were felled. These logs will were cut into 470 pieces of dimension lumber of 45 mm by 90 mm and dried to a targeting moisture content of 12%. Then each piece was graded respectively by ultrasonic wave, longitudinal vibration, transversal vibration and bending methods according to the suggested machine grading design value table. Different grading methods have obvious effects on characteristic values, grade distribution and yield of dimension lumber. The transversal vibration method seems to be more precise grading method though it produces the low value of Chinese fir. C3 should be greater than I., following by C2, IIc, IIIc, and C1 for visual grades and machine strength grades for Chinese fir lumber. MSR lumber from Chinese fir plantation may offer a higher value alternative to the production of visually graded lumber.