Effects of an impregnation procedure for prevention of wood cell wall damage due to drying

Drying of wood may lead to readily observable macroscale cracks. Recently o bservations were made indicating that also at the level of cell walls, dama ge occurs due to drying. A method is presented where green wood is impregna ted using a solution of water and a bulking compound such as glycerol. Tens ile strength parallel to the grain for wood impregnated in the green state was compared with that for ordinary dried wood and for wood impregnated aft er drying. Data demonstrate significantly higher strength for wood impregna ted in the green state. It is postulated that this is due to damage in the cell walls of non-impregnated wood where the damage is induced by the dryin g stresses. Support for this hypothesis is also presented in the form of fr actography results. For wood impregnated in the green state, damage develop ment during drying is limited. This is because the impregnating chemical (g lycerol in the present case) in the cell wall substitutes some of the moist ure and therefore limits the drying stresses.