80/100 24 .-- Relation of the moisture content to the various strength values of spruce. FSP = fibre-saturation point.] The strengthening effects of drying, while very marked in the case of small pieces, may be fully offset in structural timbers by inherent weakening effects due to the splitting apart of the wood elements as a result of irregular shrinkage, and in some cases also to the slitting of the cell walls (see Fig. |