Effect of High-Temperature Setting Treatment Conditions on Internal and Surface Checks of Rectangular Timbers with Pith

Abstract

While the use of high-temperature setting method, for kiln drying green square timbers with pith at high-temperature and low-humidity conditions at the initial drying stage, has spread in Japan, there is no established optimal kiln-drying schedule for various softwood species of larger-sized rectangular timbers used for beams and girders. Therefore, we tried to determine an adequate high-temperature setting method for reducing both surface- and internal checks through analyzing the effects of temperature conditions and size of the timbers. The results suggested that moisture content after high-tem-perature setting treatment might affect the occurrences of internal checks in akamatsu（(cid:9492)(cid:9517)(cid:9522)(cid:9529)(cid:9527)(cid:9444)(cid:9512)(cid:9513)(cid:9522)(cid:9527)(cid:9517)(cid:9457) (cid:9514)(cid:9520)(cid:9523)(cid:9526)(cid:9509)） and sugi