三種非破壞檢測儀器應用於柳杉造林木立木材質之評估

Property Evaluation of the Plantation Trees (Japanese Cedar) by using Three Nondestructive Testing Techniques

詹明勳(Ming-Hsun Chan) ； 曾郁珊(Yu-San Tseng) ； 蔡明哲(Ming-Jer Tsai) ； 高毓謙(Yu-Chien Kao) ； 李佳韋(Chia-Wei Lee) ； 郭佩鈺(Pei-Yu Kuo) ； 黃憶汝(Yi-Ru Huang)

《國立臺灣大學生物資源暨農學院實驗林研究報告》 19卷3期 (2005/09) Pp. 207-216

https://doi.org/10.6542/EFNTU.200509_19(3).0003

摘要

本研究應用非破壞檢測儀器Sylvatest超音波檢測儀、DmP鑽孔抵抗儀及ARBOTOM®非破壞檢測系統等，針對台大實驗林溪頭營林區第六林班長期試驗地，所種植之柳杉(Cryptomeria japonica)進行非破壞檢測，以究明柳杉木材材質之變化及不同撫育措施對柳杉木材材質之影響。非破壞檢測之柳杉分為種子苗林木與插條苗林木，且於1968年及1974年進行A、B、C、D四種不同強度的疏伐（A為輕度疏伐，C為重度疏伐，B和D介於兩者間，其中B為下層疏伐，D為上層疏伐）。研究結果顯示柳杉實生林的橫向及縱向超音波速皆較柳杉插條林的來得快，由此推知實生林的材質稍好，但兩者無顯著差異。柳杉實生林及插條林的縱向及橫向超音波及應力波速度，在四種疏伐度間皆無顯著差異。因此推估，疏伐作業如果超過10年可能對林木的效益影響較有限。又以DmP和ARBOTOM®輔助與比對超音波試驗結果，初步發現ARBOTOM®是適宜評估木材內部材質的非破壞檢測系統，對於木材內的腐朽、空洞或不良的品質可適切的檢測出，同時利用圖譜的呈現讓檢測者更易判讀。本研究於冬季進行的生長錐取樣發現，樹蕊的邊材含水率（約為170%）低於心材（約為190%），兩者有顯著的差異存在，而對於季節的變化，以超音波與應力波檢測的結果顯示出如下的趨勢：冬天波速最快，其次為秋天，夏天最慢，但三者間無顯著差異存在。

關鍵字

應力波 ； 超音波 ； 柳杉 ； 種子苗 ； 插條苗 ； 疏伐

並列摘要

We used ultrasonic instrument, DmP and ARBOTOM® to investigate the wood properties of Japanese cedar (seedling grown and cutting grown) under different seasons and 4 thinning treatments (from 1968 to 1974) in 6(superscript th) stand of Shitou (the experimental forest of National Tai-Taiwan University). Results showed that the transverse and longitudinal ultrasonic velocities of seedling grown Japanese cedar were faster, though not reached significance level, than those of cutting grown Japanese cedar. It indicated seedling grown trees might have better properties than cutting grown trees. Comparing 4 kinds of thinning treatments, the transversal and longitudinal ultrasonic velocities of seedling and cutting grown trees revealed no significant difference. It was assumed that thinning treatment might restrict its effects on wood properties after 10 years. It also found that DmP and ARBOTOM® were two applicable instruments which assisted with ultrasonic instrument for investigation of wood properties. In winter, the moisture content of sapwood (170%) was lower than heartwood (190%). By using ultrasonic waves and stress waves to investigate wood properties during different seasons, the velocity of ultrasonic and stress wave was fastest in winter, second in fall, and slowest in summer. However, it did not reach significance level.

並列關鍵字

Stress wave ； Ultrasonic wave ； Japanesecedar ； Seedling grown trees ； Cutting grown trees ； Thinning