著者

太田 貞明 渡辺 治人 松本 勗 堤 寿一

出版者

九州大学

雑誌

演習林集報 (ISSN:03760707)

巻号頁・発行日

vol.22, pp.105-116, 1968-01

被引用文献数

2

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This paper aims at gaining informations about the "mechanical properties of juvenile wood" on stem of SUGI-trees (Cryptomeria Japonica D. Don). The test specimens were taken from disks of 12-year-old fertilized SUGI, 30-year-old irrigated SUGI and 40-year-old non-fertilized SUGI stems cut at 2.0 m above the ground. Measurments were made of the specific gravity, the dynamic modulus of elasticity and the poisson's ratio. The fibril angle of the middle layer of the secondary wall of tracheid was measured from the same test samples. The following conclusions can be deduced from the experimental findings. (1) There are distinct differences between the juvenile wood and the mature wood. The former locates within 10-15 annual ring from the pith and the later locates the outer part at given height in each SUGI stem. (2) The relationship between specific gravity and dynamic modulus of elasticity in each stem can be found a very high degree of positive correlation at late wood. But at the early wood, the positive correlation can be seen only the mature wood. (3) High degree of correlation is able to found between the fibril angle of the middle layer of the secondary wall of tracheid and the specific dynamic modulus of elasticity, It may be considered that these factors influence on the mechanical properties of wood. (4) In addition to these factors, fibril angle and specific gravity, it is sugested that the quality of the microfibril may be improved significantly through successive growth rings from the pith to bark.