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Hiraiwa T.,Utsunomiya University | Ishiguri F.,Utsunomiya University | Endo R.,Japan Forestry and Forest Products Research Institute | Takeyama F.,Awa Branch Office | And 7 more authors.
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2014

The objectives of this study are to clarify the wood properties of Sanbu-sugi cultivar of sugi (Cryptomeria japonica D. Don) planted in Chiba prefecture, Japan. Stress-wave velocity (SWV) of stem, dynamic Young's modulus (DMOE) of logs, wood properties (basic density, latewood tracheid length, microfibril angle of S2 layer in latewood tracheid, and static bending properties), and bending properties of 2 by 4's were investigated for Sanbu-sugi cultivar with different 5 stand ages (11, 19, 30, 48, and 70-years-old). From obtained results, changes of wood properties due to changes of stand age were also discussed. Based on the radial variation of wood properties, juvenile wood of Sanbu-sugi existed from pith to 15th or 20th annual ring from pith. SWV of stem and DMOE of logs increased with increase of stand age up to 30 years, and then it slightly decreased. Thus, SWV of stem and DMOE of logs became stable from about 30-years-old due to increase of mature wood volume. Mean values of modulus of elasticity and modulus of rupture in 2 by 4's were 8.54 GPa and 56.2 MPa, respectively. Modulus of elasticity of 2 by 4's in mature wood was almost the same for that obtained from trees with different stand age. © 2014 The Society of Materials Science. Source

Ohno H.,Tokyo University of Agriculture and Technology | Ohno H.,Utsunomiya University | Ohno H.,Tochigi Prefectural Forestry Res Center | Kameyama Y.,Tochigi Prefectural Forestry Res Center | And 6 more authors.
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2011

The Strength properties, such as bending, shearing, and partial compression, were examined for full-size specimens 120 by 240 by 4000mm of 10-ply laminae of the same thickness 24mm of sugi Cryptomeria japonica and hinoki Chamaecyparis obtusa and 6-ply and 5-ply of hinoki laminae of the same thickness at the outer layer and different thicknesses of sugi elements 36 and 72mm For each piece of laminated lumber, two laminae of hinoki were used on both sides of the outer layer. All strength properties in all types of laminated lumber showed higher values than those of solid sugi lumber. In addition, the coefficients of variation in the modulus of elasticity and modulus of rupture were lower in the laminated lumber than in the solid sugi lumber. On the other hand, no significant differences in strength properties, except for the modulus of shearing, were found among the three types of laminated lumber, suggesting that there was no decrease in strength properties in laminated lumbers made of thick elements instead of laminae. These results indicated that the strength properties of laminated lumbers composed of laminae and elements of different thickness without finger joints were almost the same as those of laminated lumbers composed of laminae of the same thickness. © 2011 The Society of Materials Science, Japan. Source

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