Changes in Vibrational Properties of Wetwood of Japanese Fir (<i>Abies Sachalinensis</i> Mast) with Time During Drying


  • Hisashi Ohsaki
  • Yoshitaka Kubojima
  • Mario Tonosaki
  • Masamitsu Ohta


Wetwood, Japanese fir, vibrational properties, high-temperature drying


Temporal changes in vibrational properties of wetwood of Japanese fir (Abies sachalinensis Mast.) during a drying process were investigated. Specimens were cut from wetwood defined as heartwood with extremely high moisture content and normal wood whose moisture content was not so high, and matched in the R-direction. Green and water-saturated wood specimens were prepared. The specimens and the vibration testing system were put in an electric drying oven, where a free-free vibration test was conducted at intervals of 5 to 20 minutes. When the green specimens were used, the resonance frequency and loss tangent of both wetwood and normal wood reached the minimum and maximum, respectively, early in the drying. The minimum and maximum of the wetwood were smaller and larger than those of the normal wood. These differences between the wetwood and normal wood were mainly caused by the differences in initial moisture content because such differences, which existed in the green wood, disappeared once a water-saturated condition was reached.


Hokkaido Prefecture, ed. 2000. Annual report on forest management in Hokkaido 1999-2000.nKitamura, Y. 1941. Properties of wetwood. Bulletin Hokkaido Forestry Experiment Station.27:1-19.nKubojima, Y., M. Wada, and M. Tonosaki. 2001. Real-time measurement of vibrational properties and fine structural properties of wood at high temperature. Wood Sci. Technol.35:503-515.nOhsaki, H., Y. Kubojima, M. Tonosaki, and M. Ohta. Vibrational properties of wetwood of Todomatsu (Abies sachalinensis Mast.) at high temperature. J. Wood Sci. (accepted.)nOno, T., and A. Kataoka. 1979. The frequency dependence of the dynamic Young's modulus and internal friction of wood used for the soundboards of musical instruments. II. Mokuzai Gakkaishi25(8):535-542.nTakizawa, T., N. Kawaguchi, and M. Takahashi. 1976. The observation of the wetwood of Todomatsu (Abies sachalinensis Mast.). J Hokkaido Forest Products Research Inst294:6-11.nYano, H., M. Norimoto, and T. Yamada. 1986a. Changes in acoustical properties of Sitka spruce due to acetylation. Mokuzai Gakkaishi32(12):990-995.nYano, H., T. Yamada, and K. Minato. 1986b. Changing in acoustical properties of Sitka spruce due to formaldehyde. Mokuzai Gakkaishi32(12):984-989.nYano, H., H. Kondou, and Y. Kimura. 1992. Enhancement of the physical properties of wood by resorcin/formaldehyde treatment. Mokuzai Gakkaishi38(12):1119-1125.nYoshimoto, M., and S. Shida. 2001. Observation and mechanical properties of wetwood in Todomatsu (Abies sachalinensis Mast.). Bull. Tokyo Univ. For.106:91-139.n






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