| 概要 |
種々の木材性質は，木材の加工・処理性に深くかかわっている．一方，心材の生材含水率および心材色は木材の重要な基本性質とみなされている．そこで，この研究では，同一林分で生育したスギ6品種を対象にして，主に樹幹胸高部位での心材の生材含水率，および温水抽出物，さらにはまさ目面における気幹状態の明度を測定した．樹幹横断面内で，放射方向の生材含水率の推移をみるとき，含水率は辺材で高く，白線帯では低い値を示した...が，心材では品種や個体によっていくつかの異なるパターンが認められた．また，温水抽出物は，辺材と白線帯では少ないが，心材では生材含水率，温水抽出物および明度の値は異なっていた．特に，クモトオシでは，他の品種に比べてて心材の生材含水率が高く，温水抽出物が多く，明度が低い傾向を認めた．一方，ヤブクグリでは，これら3つの測定値に大きなバラツキがみられた．温水抽出物と心材の生材含水率，温水抽出物と明度，および心材の生材含水率と明度との間に，それぞれ有意な相関関係が認められた．このことから，心材の生材含水率と心材色の違いは，抽出物が品種間や個体間で異なることに起因すると推定された．また，心材の生材含水率を推定する指標に，心材色を採用できる可能性が推論された．
Six cultivars of sugi(Cryptomeria japonica) which were grown in the same stand, that is Ayasugi, Obiaka, Kumotooshi, Measa, Yaichi and Yabukuguri, were presented for this study. The disks were taken from the brest height of each tree, and the moisture content of green wood, the hot water extractives and the lightness of radial section at the air-dry condition were measured. The results were as follows ; 1) In the sapwood and the intermesiate wood, much difference of the moisture content was not observed amoung the cultivars or individual trees. Neverthless in the heartwood there were four patterns in the distribution of the moisture content in the radial direction of the stem, that is, Type 1-Green moisture content was low constantly, Type 2-high constantly, Type 3-high near the pith but decreasing to the raddial direction, Type 4-low near the pith, increasing to the radial direction and decreasing near the intermediate wood. 2) The amounts of the hot water extractives in both the sapwood and the intermesiate wood did not differed in the cultivars, while in the heartwood, the patterns in the distributtion of the hot water extractives were similar to those of the green moisture content. 3) The green moisture content, the hot water extractives and the lightness of the heartwood differed in the cultivars. Particularly, for kumotooshi, the moisture content and the hot water wxtractives were high, and the lightness was low, compared with the other cultivars. Those for Yabukuguri showed broader variation. 4) In the heartwood, the significant correlation were observed between the hot water extractives and the green moisture content, between the hot water extractives and the lightness, futhermore between the green moisture content and the lightness. It was supposed that the hot water extractives significantly influenced both the moisture content and the lightness.続きを見る
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