Crushing Strength Sampling With Minimal Damage to Taiwania (Taiwania Cryptomerioides) Using a Fractometer

Cheng-Jung Lin, Song-Yung Wang, Chih-Ming Chiu


The Fractometer is a device that stresses radial increment cores in the direction of the fiber to measure crushing strength, which can provide a direct wood quality indicator for structural lumber. This study analyzes the pattern of the radial variation in Taiwania (Taiwania cryptomerioides Hay.) trunk wood crushing strength to explore its effect on the precision and efficiency of the sampling procedure in the outer increment core zone as an alternate nondestructive sampling method. A pith-to-bark 0.5-cm caliber core was extracted at breast height (1.3 m above the ground) from each tree and was separated into individual section groups. Then individual crushing strengths were determined using the Fractometer.

In this study, the variation in crushing strength in the transverse direction increased from the pith outward to the bark side. An analysis of variance and correlation analysis were used to evaluate the data. The magnitude of the radial variation in crushing strength was smaller than the tree-to-tree variation. Including samples of at least 7.2 cm, 5.4 cm, and 2.4 cm near the bark side was found to be acceptable for the assessment of wood crushing strength for trees of Type A (DBH > 27 cm), Type B (DBH = 23~27 cm), and Type C (DBH > 23 cm), respectively.


Taiwania (Taiwania cryptomerioides Hay.);crushing strength;sampling efficiency;analysis of variance;partial core sample;Fractometer

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