超音波應用於香杉鼠害立木樹幹腐朽之研究

Application of Ultrasound in Detecting Wood Decay in Squirrel-damaged Standing Trees of Luanta China Fir

林振榮(Cheng-Jung Lin) ； 邱志明(Chih-Ming Chiu) ； 王松永(Song-Yung Wang)

《台灣林業科學》 15卷2期 (2000/06) Pp. 267-279

https://doi.org/10.7075/TJFS.200006.0267

摘要

超音波廣泛應用於材料非破壞性檢測評估之方法，本研究以不同程度鼠害之香杉造林木為對象，使用PUXDIT與SYLVATEST超音波儀器檢測，探討超音波穿透樹幹內部材質時間，以評估樹幹內部腐朽程度，結果顯示超音波穿透樹幹180°與90°方向時間比值為0.207-0.517，判定實際腐朽程度最嚴重。比較超音波測試同一徑級之立木時，超音波穿透時間值偏大時判斷內部材質有損壞腐朽現象。綜合上述兩項試驗結果，可作為判斷樹幹腐朽狀況參考，篩選受鼠害之香杉造林木，提供作為育林除害伐上之依據。

關鍵字

超音波 ； 非破壞性試驗 ； 穿透時間 ； 腐朽木 ； 生立木

並列摘要

Ultrasonic methods were extensively used for non-destructive evaluation of wood. In this study, various degrees of wood decay in Luanta China fir standing trees (Cunninghamia lanceolara var. Konishii form. Konishii) damaged by squirrels were assessed. Transverse traversing time was measured with on ultrasonic method using PUNDIT and SYLVATEST ultrasonic meters. Results show that the biological internal quality of standing trees can he evaluated by measuring the ultrasonic traversing time on the radial axis of tree trunks. Effects of decay on the traversing time of standing trees are discussed. Results also show that the ratio of traversing time in the 90° direction to radial (180°) direction for seriously decayed trees are between 0.207 and 0.517. If the ultrasonic traversing times are higher, then the trees are decayed within the same diameter class. Results verified that the internal decay of tree can be detected using ultrasonic measurements the radial direction. Experimental results suggest that the non-destructive testing (NDT) of standing trees can be applied to salvage cuttings, and that ultrasonic traversing time along the radial direction can serve as a guideline to distinguish the internal physical status of standing trees.

並列關鍵字

ultrasound ； non-destructive testing ； traversing time ； decayed tree ； standing tree