Trends in Lumber Processing in the Western United States. Part II: Overrun and Lumber Recovery Factors

This article describes trends in three measures of lumber recovery for sawmills in the western United States: lumber overrun (LO), lumber recovery factor (LRF), and cubic lumber recovery (CLR). All states and regions showed increased LO during the last three decades. Oregon and Montana had the highest LO at 107 and 100 percent, respectively. Alaska had the lowest LO at 31 percent, followed by the Four Corners Region (i.e., Arizona, Colorado, New Mexico, and Utah). Because sawmills in the western United States use the Scribner Log Rule (SLR) as the unit of log input, higher LO is not a clear indication that mills are using improved sawing technology and techniques. At best, LO is an imprecise measure of production efficiency. Better measures of lumber output per unit input include LRF and CLR. These measures are substantially better than LO because they are based on the cubic volume of solid wood fiber in a log, thus eliminating a number of the problems associated with the SLR. Oregon, followed by Washington, had the highest LRF (8.67 and 8.43 board feet lumber tally per cubic foot of logs, respectively) and the highest CLR (52% and 50%, respectively). Alaska had the lowest LRF and CLR. Changes in LRF and CLR suggest that sawmills in the western United States have used improved sawing technology and techniques to increase the volume of lumber recovered even as log sizes have decreased.