Detection of decay damage in iron-wood living trees by nondestructive techniques

The purpose of this study was to investigate the standard values of living, undamaged iron-wood ( Casuarina equisetifolia ) trees by different nondestructive techniques. This study also detects the transversal stress wave velocity ( V ) and tomogram, and resolves corresponding V maps of the trees with and without decay damage. First, a visual tree inspection form with seven categories of tree defects is proposed for tree hazard assessment. The range of demarcation between decay-damaged and sound wood occurred at an approximate V of 1461–1636 m/s by transversal stress wave velocity tomography. Different nondestructive evaluation parameters can serve as an index for diagnosing standard values (with or without decay). A positive significant relationship was found between the diameter and transversal minimum V of 2D in undamaged trees. Moreover, the product diameter × frequency of evaluated value by lateral impact vibration method tended to increase with increasing minimum V of 2D using tomography in undamaged and decay-damaged trees. Decay damage in iron-wood living trees could be inspected and detected by lateral impact vibration method and transversal stress wave velocity tomography for the general location and area of wood deterioration.