IMPACT OF KILN VARIABLES AND GREEN WEIGHT ON MOISTURE UNIFORMITY OF WIDE GRAND-FIR LUMBER

Eighteen kiln runs of grand-fir (Abies grandis) lumber were dried to d etermine the impact of kiln variables and green weight on moisture uni formity of grand-fir lumber. Each of the 18 kiln runs contained 52 pie ces of nominal 2-inch by 10-inch by 8-foot (38-mm by 235-mm by 2.44-m dry-dressed size) lumber, which included 4 full-length sample boards t hat were weighed prior to drying. Time schedules were employed and kil n variables such as dry-bulb temperature, maximum depression, and fan- reversal time were varied for each run. Results showed that moisture u niformity was not achieved with changes of kiln variables. However, st udy results did indicate that moisture uniformity of wide (largely hea rtwood) kiln-dried grand-fir lumber could be improved through presorti ng green lumber by weight and that drying times may be reduced for kil n runs with low-weight boards.