A series of comparable specimens of hornbeam wood were submitted to pretreatments by white-rot fungi, by alkali alone, or by alkali and oxidizing agents. The pretreatments caused weight loss of wood and modified its physical properties and chemical composition. All pretreat-ments reduced markedly axial permeability of the test specimens in the wet state (w > FSP). The chemical pretreatments of the test specimens, however, increased the rate of diffusion in the direction parallel to the grain. All pretreatments made the kinetics of wood/water interactions in the initial phase much higher, especially when white-rot fungi were used. The chemical pretreatments caused extreme swelling of wood, and on the other hand, drying of the pretreated specimens to their initial moisture content resulted in extremely deep reduction of their dimen-sions. An increased rate of wood/water interactions, high uptake of water, and higher diffusion coefficients of wood pretreated by alkali may positively influence the pulping processes.