Abstract
The reduction of moisture in split logs of Japanese cypress (Chamaecyparis obtusa) and Japanese blue oak (Quercus glauca) was compared in two drying seasons (autumn to winter and spring to summer) under certain conditions differentiated in terms of split size (one-quarter or one-eighth) and drying circumstances (on a paved or unpaved surface, and under a roof or exposed to the outside). Regardless of the drying season, (i) Japanese cypress dried out more rapidly than oak having higher wood density, (ii) drying under paved or roofed circumstances was more effective than under unpaved or unroofed circumstances, and (iii) fine splitting enabled more rapid drying, especially in oak of higher wood density. The effect of the split size tended to be concealed during initial drying due to differences of moisture content by heartwood ratio among the sampled logs. Overall, natural seasoning from spring to summer achieved a faster and more extensive initial reduction of moisture. Nevertheless, the benefits of longer natural seasoning are apparently marginal in both drying seasons, as the drying speed of the split logs rapidly decreased during the first four weeks of drying in both seasons. And longer drying decreased the advantage of splitting.
