Detection of Discoloration and Decay in Living Trees and Utility Poles

摘要

Decay of wood is a major cause of damage to all species of trees and to all wood products throughout the world. A method is described for detecting discoloration and decay in trees and utility poles. The electrical resistance to a pulsed current is less in decayed wood than in sound wood. A meter has been developed, a 'Shigometer', that delivers a pulsed current and measures the resistance to it. A probe attached to the meter by a flexible cable is inserted into a hole 2.4 mm in diameter made by long drill bits into the wood. When the probe tip is pushed inward and it moves from sound wood to discolored wood that is above the fiber saturation point, the resistance measured in ohms on the meter decreases abruptly.