Variation in Veneer Properties with the Radial Direction in Logs and Effect of Pruning on Japanese Larch ( Larix kaempferi ) Planted in Hokkaido

Abstract

We investigated the relationship between quality of veneers of Japanese larch (Larix kaempferi) and their radial locations in logs. In addition, we investigated the effect of pruning on veneer quality. There was a positive correlation between the moduli of elasticity of logs determined by the longitudinal vibration method and those of veneers determined by the ultrasonic velocity method. The moduli of elasticity of veneers increased with the distance from the center of the veneer lathe spindle. This tendency was marked for pruned logs. When we separated juvenile from mature veneers at 15 annual rings from the pith, the average modulus of elasticity of mature veneers was 60% higher than that of juvenile veneers. The ratio of mature veneers rapidly increased when the veneers were cut outside of 10 cm from the center of the spindle, which indicated that high-strength veneers could be obtained by separating the veneers at this distance. In pruned logs, there were almost no knots in veneers cut from more than 12 cm from the center of the spindle indicating that veneer quality was improved by pruning.