Western juniper drying project summaries, 1993-96.

Abstract

Drying tests and trials for western juniper (Juniperus occidentalis Hook.) were conducted between 1993 and 1996 to (1) test and refine existing dry kiln schedules; (2) develop moisture meter correction factors; (3) test dry western juniper in different types of kilns, both by itself and with ponderosa pine (Pinus ponderosa Dougl. ex Laws.); (4) explore alternative drying techniques to minimize splitting and warping caused by inherent growth stresses; and (5) test a "saw-dry-rip" program currently used in the hardwood industry to reduce splitting and cracking. Test results over a 3-year period revealed that checking and splitting in juniper can be reduced by (1) careful selection of logs to minimize large knots, spiral grain, and excessive taper; (2) careful treatment of logs after harvest, such as end-coating and sawing logs as soon as possible after felling; (3) minimizing material with large knots (over one-half inch) and pith; (4) drying thinner and shorter boards; (5) using moderate kiln schedules (lower initial temperatures, higher initial relative humidities, and longer times); and (6) finger jointing and emphasizing products that require shorter and thinner lumber than that commonly produced in the Pacific Northwest.

Citation

Leavengood, Scott; Swan, Larry. 1999. Western juniper drying project summaries, 1993-96. Gen. Tech. Rep. PNW-GTR-475. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 8 p