Wood Quality of Sugi (Cryptomeria Japonica) Grown at four initial Spacings

Abstract

Wood quality is affected by silviculture, which includes factors such as stand density control and genetics. In the present study, the effects of initial spacing on the general wood quality and lumber quality of sugi wood (Cryptomeria japonica D. Don) were examined. Logs of 35-year-old sugi were cut from four stands with different initial spacing (A: 2.6 by 2.6 m, 1,500 trees/ha; B: 1.8 by 1.8 m, 3,000 trees/ha; C: 1.3 by 1.3 m, 6,000 trees/ha; D: 1.0 by 1.0 m, 10,000 trees/ha). Trees from stand A showed significantly larger values in annual ring width than trees from the other stands. However, there were no significant differences in the wood basic density, the length of latewood tracheids, and the microfibril angle of the S2 layer among stands. On the other hand, initial spacing affected the lumber quality. The average diameter of knots was significantly larger in stand A than in the other stands. In addition, the dynamic Young's modulus, the modulus of rupture, and the modulus of elasticity in static bending increased with the decrease in the initial spacing from 2.6 by 2.6 m to 1.3 by 1.3 m.