Tangential and radial shrinkage variation within trees in sugi (Cryptomeria japonica) cultivars

Abstract

The transverse shrinkage variation within trees was examined for five sugi cultivars. The within-tree trends of tangential shrinkage (αT) were different by cultivar, whereas radial shrinkage (αR) increased from pith to bark in most cultivars. The tangential/radial shrinkage ratio (αT/αR) decreased from pith to bark in most cultivars, because the radial variation of αR was larger than that of αT. The cultivars showed significant differences among cultivars in αT, αR, and αT/αR, but the difference among cultivars for αT/αR was smaller. The relationships between transverse shrinkage and microfi bril angle (MFA), basic density (BD), tree ring parameters, and modulus of elasticity were examined. The αT and αR showed positive relationships with BD, latewood percentage, latewood density, and modulus of elasticity, and negative relationships with MFA and ring width. The relationships with earlywood density were weak. Sugi exhibited variation in transverse shrinkage within stem and among cultivars, with the variation affected by MFA, density, and tree ring parameters. © The Japan Wood Research Society 2009.