Effects of log defects on lumber recovery.

Abstract

The impact of log defects on lumber recovery and the accuracy of cubic log scale deductions were evaluated from log scale and product recovery data for more than 3,000 logs. Lumber tally loss was estimated by comparing the lumber yield of sound logs to that of logs containing defects. The data were collected at several product recovery studies; they represent most of the major commercial softwood species in the Western United States. Defects listed in order of decreasing effect on lumber recovery are: multiple defects, ring shake, soft rot and voids, weather check, firm rot, breakage, crook and sweep, and heart check. The accuracy of cubic log scale deductions was also analyzed. The rules were considered accurate for heart check, breakage, and crook and sweep; they underestimated the impact of ring shake and soft rots and voids on lumber tally, and overestimated the impact of weather checks, firm rot, and multiple defects.

Citation

Cahill, James M.; Cegelka, Vincent S. 1989. Effects of log defects on lumber recovery. Res. Note PNW-RN-479. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 12 p