Effect of height of fir sample on shrinkage progression and on hygroscopic line (the fiber saturation point))

The paper deals wits the effect of height (longitudinal dimension) of fir samples on progression of shrinkage and on the fiber saturation point determined by the method of shrinkage. During the tests the samples were subjected to the conditions of microclimate at the temperature of 20 °C and at the relative humidity of 25 + - 3 %. The test proved that the intensity of shrinkage was reduced by the increasement of the sample's height, this being particularly observable in a certain area of linear dependance of shrinkage and content of moisture in wood. The marginal value of moisture content in wood at which shrinkage of wood occurs was growing up by the reduction of sample's height. On the basis of correlation between the height of the sample and volume shrinkage it can be established that higher percentages of volume shrinkage correspond to lower height of samples.