How Bound Water Regulates Wood Drying

Water extraction from plants by evaporation is ubiquitous in nature, and essential for most uses of wood-based products, yet little is known about the internal drying mechanisms. The authors use NMR and x-ray computed tomography to observed the effects of drying at different length scales. In typical porous media drying is due mainly to capillary effects, but in wood the structure's bound water controls extraction of free liquid from pores, throughout the process. Transfers between bound and free water seem to play a major role in the interaction of plantlike systems with water, and this study provides sound concepts for modeling and controlling the drying properties of such materials.