Description:
Oregon white oak, Quercus garryana Dougl., could have greater commercial use, but
information on its drying properties is lacking. All oaks are difficult to dry, and the initial kiln conditions are important to prevent excessive surface checking and honeycombing. This study illustrated that a maximum dry-bulb temperature of 110 F with a wet-bulb depression of 4 F is required to reduce checking and must be maintained until the average moisture content is 40 percent or lower. The second stage of drying required a dry-bulb temperature of 110 F with a depression of 6 F and is held until the average moisture content is 30 percent. The drying conditions are set to promote drying until the equalization period, which is a dry-bulb temperature of 180 F and a wet-bulb depression of 35 F. This is followed by a conditioning period, which is a dry-bulb temperature of 180 F with a wet-bulb depression of 10 F. Drying times ranged from 21 days for 4/4 (1-inch thick) lumber, to 32 days for 5/4 (1'44-inch thick) lumber, and 43 days for 6/4 (1 V2-inch thick) lumber. Air drying to an average moisture content of 15-20 percent will reduce kiln-drying time for 4/4 lumber from 4 to 5 days.