Wood and bark residues in Oregon : trends in their use

The forest-products industries are most important to the state of Oregon. Oregon leads the nation in the production of plywood, lumber, and particle board. More than half of softwood plywood production in the United States came from Oregon at the time of this survey, and more than a fifth of the lumber and about a third of the particle board were produced in Oregon. Over 90 percent of the logs harvested in the state at the time of this survey were destined for sawmills and plywood plants. In producing lumber and plywood from logs, less than half of the entering log volume emerges as the finished primary product. That portion of the log remaining consists of such items as bark, sawdust, shavings, slabs; veneer trim, plywop-dArim, cores, and sander dust. This portion that remains after primary manufacture frequently is called residue.f Ouch of this residue formerly was considered waste and usually was disposed of by burning. But now a large portion of this residue material is recovered for other uses-primarily as raw material for paper and wood-composition board manufacture. If residue is not used, it presents a problem of disposal within allowable limits of pollution ! Because these residue materials are a valuable raw material, we conducted a survey of virtually all sawmills and plywood plants in the state to determine how these residues were being used; to point out what quantities might be available for future use; and to note the changes that had occurred in residue usage since previous surveys. An additional objective was to obtain information on a material balance' for sawmill and plywood plants, so that conversion factors could be developed for estimating average quantities of different types of residue generated from a given production of lumber or plywood. From these conversion factors, the average amount of a given type of residue that might be expected in producing a given board footage of lumber or a given square footage of plywood can be estimated