Abstract
Compressed wood is used as building interior material such as the floor material after fixed permanently by such as steam treatment. However, the compressed wood is swollen by absorbing water without recovering large amount of compressed deformation, despite it was fixed permanently. The dimensional stability of compressed wood for moisture is very important for safe use of building material. Therefore, swelling behavior of cell was observed in compressed wood and the relationship between cell shape and swelling behavior of cell was discussed. The swelling in radial direction of wood compressed 50％ was four times larger than that of uncompressed wood. In the visual fields of a microscope, four different deformation types of cell lumens were observed. The increase in area of cell lumens is different among the four types. The increase in area of cell lumens is much different between S-shape cells and elongated shape of cells. In particular, the cells deformed to S-shape are hard to be increased the area of cell lumens by swelling. This result suggests that deformation types of cell lumens affect the swelling behaviors of compressed cells. From the above results, it might be possible to improve the dimensional instability of the compressed wood by giving deformations as increasing the S-shape cells.
