Drying properties of Cunninghamia lanceolata grown in Japan (part 1): Fundamental drying characteristics measurement and drying schedule estimation for kiln drying
2019
Di, S. (the University of Tokyo (Japan). Graduate School of Agricultural and Life Sciences) | Maeda, K. | Shida, S. | Kamoda, S. | Saito, S.
The objective of this study is to reveal drying characteristics of Chinese fir (Cunninghamia lanceolata), which is a well-known wood as one of the fast-grown species. In this paper, measurement of fundamental drying properties was carried out and drying schedule of Chinese fir was estimated based on results of 100℃ test of several conversion of flat-sawn grain board. The highest moisture content of green Chinese fir was almost 200% observed in sapwood and lower in heartwood. The anisotropy of shrinkage equals to the literature value of Japanese cypress. After 100℃ test, drying rate of heartwood specimens with less than 1 mm ring width was significantly slow. A heartwood with almost 10 mm ring width contained both severe inner checks and a large bobbin winding-shaped deformation. This deformation was also found in the boundary of sapwood and heartwood. The probable reason seems to be the drying stress between them caused by differences of their drying rate, although main reason is collapse. In all moisture content region, the estimated drying schedules of Chinese fir were milder than that of Japanese cedar.
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