Swelling and shrinkage of wood
Swelling and shrinkage behaviour
in the main directions of the wood
In the three main anatomical directions of the wood, in the fibre direction (=longitudinal), in the wood ray direction (=radial) and in the annual ring direction (=tangential), there are great differences with regard to the swelling and shrinkage behaviour. In general, swelling is most pronounced in the tangential direction, while in the longitudinal direction it is rather negligible. However, swelling and shrinkage varies from species to species. In general, it increases with increasing density, as the proportion of cell walls (wood fibres) in the total volume increases.