2024 Volume 23 Issue 1 Pages 13-28
The Ryuunohige sugi cultivar, which is grown in the Kumamoto and Oita prefectures in Kyushu Island, has a moderate rate of growth, straight stems and good resistance to the damage by the strong winds of typhoons.However, little is known of its wood properties. In this study, thirty trees were sampled from a forest stand in Kikuchi, Kumamoto prefecture, and logs and wood discs were cut from 0.6 to 8.0 m height, to evaluate the variation of the wood properties among and within the tree stems. It was found the wood has high density and stiffness, with a high percentage of latewood and low microfibril angle, compared with those properties reported for other sugi cultivars. The tangential and radial shrinkage of the wood was relatively high, compared with other sugi cultivars.The heartwood of the green logs had a low moisture content (except at the base of the stem), which reduces the energy required for kiln-drying, and the air-dry heartwood color had high lightness (L*), average redness (a*) and high yellowness (b*). There was low variation in wood properties among the trees, and similar within tree stem patterns for all the trees. The Ryuunohige cultivar has a favorable combination of wood properties, which together with its good stem form and resistance to wind damage, should make it desirable cultivar for plantation use in Japan.
