The possibility of application of three non-destructive methods was examined for evaluation of bending strength of ezomatsu (Picea jezoensis CARR.) with white pocket rot. As non-destructive methods, the measurements of ultrasonic wave propagation time, impact-induced stress wave propagation time and penetration depth of pin of "PILODYN Wood Tester" were applied to compare with visual evaluation of degree of white pocket rot. The modulus of elasticy in bending, bending strength and stress at proportional limit in bending were decreased according as increase of the degree of white pocket rot evaluated visually, even at "slight and superficial" rot. High correlations were observed between dynamic modulus of elasticity calculated through ultrasonic wave propagation time or stress wave propagation time and modulus of elasticity in bending, and between dynamic modulus of elasticity and bending strength. The penetration depth of pin and modulus of elasticity in bending or bending strength were correlated as well. Based on the results obtained by this experiment, these three non-destructive methods were serviceable to evaluate modulus of elasticity in bending and bending strength of ezomatsu with white pocket rot, same as visual evaluation.

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