Journal of Wood Science

, Volume 52, Issue 2, pp 111–114 | Cite as

Effects of high temperature kiln drying on the practical performances of Japanese cedar wood (Cryptomeria japonica) II: Changes in mechanical properties due to heating

  • Eiichi ObatayaEmail author
  • Sakae Shibutani
  • Kensuke Hanata
  • Shuichi Doi
Original Article


Japanese cedar wood specimens were steamed at 80°, 100°, and 120°C over 14 days, and their equilibrium moisture content (M) at 20°C and 60% relative humidity, longitudinal dynamic Young’s modulus (E), bending strength (σmax), and breaking strain (εmax) were compared with those of unheated specimens. Steaming for a longer duration at a higher temperature resulted in a greater reduction in M, σmax, and εmax. The E of wood was slightly enhanced by steaming at 100°C for 1–4 days and 120°C for 1–2 days, and thereafter it decreased. The slight increase in the E of sapwood was attributable to the reduction in hygroscopicity, while sufficient explanation was not given for a greater increase in the heartwood stiffness. Irrespective of the steaming temperature, the correlations between M and the mechanical properties of steamed wood were expressed in terms of simple curves. M values above 8% indicated a slight reduction in E and s max, whereas M values below 8% indicated a marked decrease in the mechanical performances. In addition, the e max decreased almost linearly with a decrease in the value of M. These results suggest that hygroscopicity measurement enables the evaluation of degradation in the mechanical performances of wood caused by steaming at high temperatures.

Key words

Kiln drying Steaming Japanese cedar Thermal degradation Hygroscopicity 


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Copyright information

© The Japan Wood Research Society 2006

Authors and Affiliations

  • Eiichi Obataya
    • 1
    Email author
  • Sakae Shibutani
    • 2
  • Kensuke Hanata
    • 2
  • Shuichi Doi
    • 1
  1. 1.Graduate School of Life and Environmental SciencesUniversity of TsukubaTsukubaJapan
  2. 2.Institute of Wood TechnologyAkita Prefectural UniversityNoshiroJapan

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