Measuring the effect of internal log defect scanning on the value of lumber produced
2009
Chang, Sun Joseph | Gazo, Rado
In this article, we report on the effect of internal log defect scanning on the gain in lumber value recovery for five hardwood species, consisting of black cherry, hard maple, yellow poplar, red oak, and white oak logs. A total of 29 logs, 6 logs per species and 2 logs each for log Grades 1, 2, and 3, were scanned with a medical X-ray computed tomography scanner to acquire their cross-sectional images. The one exception being for red oak logs, for which we scanned two Grade 1 logs, one Grade 2 log, and two Grade 3 logs. These logs were then sawn in the sawmill to determine the actual value recovered from each log. Virtual logs constructed with the scanning images of these logs were then sawn on the computer using the TOPSAW software. Based on simple live sawing simulations, overall the average value gain for all species and grades was 46%, while the gains for black cherry, hard maple, yellow poplar, red oak, and white oak were 42, 33, 83, 24, and 60 percent, respectively. The average gains for Grades 1, 2, and 3 logs were 27, 47, and 97 percent, respectively. Regression analysis of the gains indicated that while there are no significant differences among the species, the gain for Grade 3 logs was significantly different from other log grades.
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