Influence of moisture sorption history on the swelling of sugar maple wood and some tropical hardwoods

Summary Samples of nine tropical hardwoods from Peru and sugar maple wood from Quebec were selected to perform moisture sorption tests associated with swelling tests at 25 °C. The results demonstrate that, for a given equilibrium moisture content, tangential and radial dimensions, and hence the volume of wood, are greater after desorption than after adsorption. The importance of these differences, so-called second-order effects of moisture sorption, varied with the species and with the direction of swelling. These effects are proportionally greater in the tangential direction of wood than in its radial axis. Finally, two types of samples showed similar swellings for three equilibrium moisture contents.The author wishes to thank Professor M. Goulet for his support and help. This research was supported by the Canadian International Development Agency and the Natural Sciences and Engineering Research Council of Canada