- 期刊
柳杉原木形質、製材率與製材品質之探討－以台大實驗林柳杉為例
Log Quality, Sawing Yield and Sawn Lumber Quality of Japanese Cedar- A Case Study of Japanese Cedar Plantation in the NTU Experimental Forest
摘要
本研究主要探討國產柳杉原木之形質、製材利用率與製材品質三者之相關性，原木形質之部分，除參照CNS 442木材之分類標準進行原木徑級與原木分等之量測外，亦探討原木尖削度因子所致影響。此外，製材品質除依據CNS 14630針葉樹結構用製材進行目視等級與機械等級區分外，亦探討透過非破壞性檢測技術（Nondestructive testing, NDT）評估其抗彎性質之可行性。研究結果顯示，本研究之製材利用率稍低，僅18.8～38.0%，其與尖削度具有顯著之高度負相關性，其r值達-0.77。另一方面，製材品之平均抗彎彈性模數（Modulus of elasticity, MOE）為5.9 GPa，但隨原木等級提高，其所生產之製材品MOE也有上升之趨勢，且1、2等原木與3等原木間具有顯著差異，此外，在各等級製材品產出率上，可見隨原木等級提高，製材品之目視與機械等級亦有上升之趨勢。最後，經過超音波法、打音法求得之動彈性模數（Dynamic modulus of elasticity, DMOE）與MOE進行相關性分析後，顯示兩者之相關性甚高，r值分別為0.957及0.961，因此非破壞性檢測技術於柳杉製材等級區分之應用上具有可行性。
並列摘要
The main purpose of this study was to investigate the correlation among the log qualities, sawing yield and sawn lumber qualities of Japanese cedar (Cryptomeria japonica) log. In addition, the log qualities, including log taper, were determined by measuring the log diameter and visual grade according to CNS 442. Furthermore, sawn lumber qualities were determined by the visual and mechanical grading systems according to CNS 14630. Then, the relationships between the bending properties and nondestructive testing (ultrasonic and tap ton methods) were investigated. The experimental results revealed that sawing yield of Japanese cedar log ranged from 18.8% to 38.0%. The well negative relationship between sawing yield and log taper of log was found, the r value was -0.77. The average MOE of Japanese cedar sawn lumber was 5.9 GPa, however, the experimental results also indicated that the higher the visual grading of logs, the higher the values of MOE in bending of the lumber. Additionally, the significantly higher MOE values were also found in the sawn lumbers produced from higher grading logs (visual graded in class 1 and class 2). Also, the ratio of higher grade of sawn lumbers increased with increasing log qualities. Finally, the correlations between dynamic modulus of elasticity (DMOE) measured form ultrasonic wave and tap tone methods and MOE of sawn lumbers were determined, the r value were 0.957 and 0.961, respectively. The results also revealed that nondestructive testing could be an effective method in grading of Japanese cedar sawn lumbers.
延伸閱讀
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- 劉正字、李文昭（1988）。速生樹種之理化學性質及膠合方法對集成材性能之影響（第五報）－柳杉、台灣泡桐、木油桐製作集成材之研究。林產工業，7(1)，109-126。https://doi.org/10.6561/FPI.1988.7(1).8
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