Abstract
It has been known that there is a relationship between wind-falls of trees and such defects as cavities or decays within their trunks. However, up to now, no such methods or devices have been developed that can estimate the defects within a trunk with a certain level of accuracy without damaging the trunk. With the suggested method, the defects within a trunk can be estimated by analyzing the diagnostic slapping sounds which are got when hitting the trunk with a wooden hammer. Those diagnostic slapping sounds are analyzed by the wavelet analysis and the obtained power spectrum are utilized to estimate the defects. First of all, the measure for estimating the defects within a trunk is got by utilizing the wavelet analysis results of 15 logs and 702 trees whose conditions have been known. Then, the suggested method based implementing the obtained measure is tested to the estimation of the defects of 23 trees. As a result, all the estimations “with defects” are coincided with those of a tree doctor and 17 of them actually have defects. Adding to this, in the application to 6 trees including a healthy tree, all the estimation results coincided with the actual cross section conditions.
