The Effects of Veneer Selection by Radial Location in Logs on Strength Properties of LVL in Japanese Larch (Larix kaempferi) Planted in Hokkaido

The aim of this study was to examine the effect of the radial location of veneer on the strength properties of laminated veneer lumber (LVL) in Japanese larch grown in Hokkaido. We manufactured LVL using veneers taken from different radial locations in logs, and then examined their strength properties using bending and horizontal shear tests. In addition, we examined how annual ring width of the logs influences the modulus of elasticity of both the logs and the veneers. Our results suggested that there was a significant negative correlation (p < 0.01) between the average annual ring width and the modulus of elasticity of the logs. The modulus of elasticity of veneers (EV) increased as distance from the center of the veneer lathe spindle increased, and average EV was higher for logs with lower average annual ring width. In addition, we compared the strength properties of LVL composed of veneers sourced from the outer part of logs (>12 cm from the center of the veneer lathe spindle) with that sourced from the inner part of logs (<10 cm from the center of the veneer lathe spindle). LVL composed of the outer veneers was stronger than that composed of the inner veneers; 53% higher in modulus of elasticity, 65% higher in bending strength, and 26% higher in nominal shear strength. These results indicate that veneer sorting by radial location in logs is effective.