Wood Quality of Sugi(Cryptomeria japonica D.Don) Boxed Heart Square Timbers Treated by Smoke-Heating System with Far-Infrared Radiation -On Moisture Content, Surface Check, Dynamic Young's Modulus-
Andoh Minoru; Ishiguri Futoshi; Nakamura Moritoshi; Yoshizawa Nobuo
Abstract:Boxed heart square timbers of sugi (Cryptomeria japonica D. Don) were treated by smoke heating system with increased far infrared radiation for about 50 hours at a temperature inside the square timbers of 70 deg. 80 deg.. After smoke heat treatment (SHT), wood qualities (moisture content, surface check, dynamic Young's modulus) were examined. Average moisture contents of boxed heart square timbers were largely decreased by SHT, but moisture contents near the pith still remained high. No surface checks occurred in 29 specimens (24.8%) of 117 square timbers smoke heated. In addition, decrease of dynamic Young's modulus by SHT was not recognized. The results obtained indicate that SHT has effect on pre drying of square timbers, without any damages, followed by kiln drying. Key Words:sugi(Cryptomeria japonica D. Don), boxed heart square timber, smoke-heat treatment, moisture content, moisture gradient, surface check, dynamic young's modulus