Eastern SPF producters experience an average value loss of $10 to $16/mbf due to drying degrade. A clear understanding of how wood characteristics influence warp will make it easier to effectively modify drying processes to reduce these losses. The goal of this study was to categorize green lumber according to its potential to warp, dry the lumber using a typical industrial kiln schedule and assess whether pieces that either warped or remained straight were correctly identified. Experimental material was a sample of 440 black spruce 8-foot 2x4's from four grain defect groups. These were : 1) control, no grain defects; 2) cross grain but no compression wood; 3) compression wood but no cross grain; and 4) both cross grain and compression wood. Methods used to select lumber with either a high or low potential to warp were successful. Warp was found to be related to the severity of compression wood and cross grain in each piece. Lumber without cross grain or compression wood dried with very little warp. Lumber with both cross grain and compression wood had the lowest quality after drying.
The objectives of this part of the project is to provide compression strength data: 1) To be able to correlate fesults obtained using "short" and "long" specimens in the in-grade compression testing program. The U.S. in-grade testing program is based on tests of two "short" specimens cut from full length dimensional lumber. 2) To be able to evaluate the influence of rate of compressi ve deformation in parallel-to-grain compression testing.