Increased drying temperature - Its influence on the dimensional stability of wood

The dimensional changes of heat treated wood exposed to cyclic climate periods, were measured. Two slices from each of 11 planks of Norway spruce (Picea abies L. Karst.) were cut. One set of the slices were dried at 50 degrees C (LT-treated), and the other at 110 degrees C (HT-treated), in 96 hours. Thereafter, all slices were exposed to five climate cycles. These cycles consisted of one wet (20 degrees C, 85% rel. air hum.) and one dry (30 degrees C, 30% rel. air hum.) climate. During the climate changes the dimensions and weight of the slices were measured. The results show that the moisture content is lower and the dimensional changes smaller in MT-treated wood compared with LT-treated wood. It seems that the difference in dimensional changes between HT- and LT-treated wood is the same in the fifth cycle as in the first.