| Project/Area Number |
13660169
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林産学
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| Research Institution | MIYAZAKI UNIVESITY |
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Principal Investigator |
KITAHARA Ryushi Miyazaki University, Faculty of Agriculture, Professor, 農学部, 教授 (40089933)
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| Co-Investigator(Kenkyū-buntansha) |
KIJIDANI Yoshio Miyazaki University, Faculty of Agriculture, Lecturer, 農学部, 講師 (10295199)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2002: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | Cryptomeria japonica / Obi-sugi cultivars / Wood properties / Mechanical properties / Basic density / Microfibril angle |
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| Research Abstract |
There were differences in the mechanical and anatomical properties of Obi-sugi among cultivars. The maximum and minimum values of static modulus of elasticity (Es) of the mature wood among the cultivars were 13.0 Gpa and 6.6 Gpa respectively. The patterns of radial variation in Es of the wood from pith to bark were also chatacterized by the cultivars. It was suggested that these revealed characteristics of the cultivars are quite essential information to decide the suitable end use of Obi-sugi.
The information on wood properties of sugi cultivars (Cryptomeria japonica) is very important for efficient use of sugi wood. Obi-sugi is a major group of sugi cultivars planted in Southern Kyushu. However, the wood properties of Obi-sugi still have remained unclear. Therefore, the wood properties of 33-year-old Obi-sugi (15 cultivars) grown at one stand were determined. Mechanical properties were investigated by dynamic testing method (longtitudial stress-wave propagation method) for logs and compression test parallel to the grain for small clear specimens. In addition, basic density, latewood tracheid length and microfibril angle of middle layer in secondary wall (S_2) in both earlywood and latewood tracheid were examined.
Both the basic density and the S_2 microfibril angel affected the mechanical properties of Obi-sugi. Higher basic density and/or lower S_2 microfibril angle were the cause of the higher mechanical performance of mature wood of the cultivars. S_2 microfibril angle was also the most effective factor in both mature and juvenile wood.
The dynamic modulus of elasticity (Ed) of logs first increased and then decreased with height in tree stem. The maximum Ed of logs occurred in a zone between one-fourth and one-third the tree height above ground.
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