Reduction in kiln-drying time for black cherry lumber

Green No. 1 and No. 2 Common black cherry 4/4-inch-thick lumber was dried using carefully selected kiln schedule modifications. The lumber was inspected for end checks, surface checks, shake, twist, bow, cup, and crook prior to kiln-drying. Once inside the kiln, the lumber was dried using a conventional kiln schedule or one of three modified kiln schedules. Kiln schedule modifications included adjusting wet-bulb (WB) and dry-bulb (DB) temperatures at approximately 3 percent moisture content (MC) intervals between 30 percent and 15 percent MC instead of standard 5 percent MC intervals. Modification to the conventional kiln schedule reflected the same equilibrium moisture content at the end of the standard 5 percent MC intervals. This kiln schedule modification method was used to determine if drying time could be reduced without inducing a large amount of additional drying defects compared to the conventional kiln schedule. After drying, the lumber again underwent a close inspection for drying-induced defects. Pre- and post-drying defects were recorded for each modified kiln schedule for use in comparison with similar data for a conventional kiln schedule. Results of the kiln schedule modifications indicated that the drying time for No. 1 and No. 2 Common black cherry lumber may be reduced from approximately 20 to 43 percent to between 30 percent and 15 percent MC, while still providing usable lumber for hardwood dimension products. Using the modified kiln schedules, No. 1 Common black cherry lumber tended to have more twist and bow, while No. 2 Common black cherry lumber had a tendency to have more twist and shake than similar grade black cherry lumber dried with a conventional kiln schedule.