Fall 1995
Engineered Wood Products
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Changing Resources, New Products, Increased Use of Hardwoods
The changing forest resource is accelerating the use of engineered wood products around the world. Initially, the engineered wood industry in North America used primarily softwoods as their raw material of choice, but now more manufacturing plants are being constructed that utilize soft hardwoods. What impact this acceleration in the manufacture and use of engineered wood products has on the hardwood industry is an unanswered question only beginning to be asked. With planned, new, engineered wood products plants being located in hardwood producing areas to utilize what are considered underutilized species such as Aspen, Poplar and other soft hardwoods, the impact of engineered wood products could be significant on sawmills and manufacturers dependent on soft hardwoods and lesser used species.
During the past 10 years sawmills have turned to using more second growth logs, as timber became scarcer, and higher priced. In addition, sales of timber from government owned lands in the west declined due to various set-asides, and environmental considerations. Because of the decline of old growth timber harvests, and the use of more second growth timber, the size of timber being delivered to the mills has declined rapidly. Today, many of the newer softwood sawmills are designed to saw small logs at extremely high rates of speed. These mills sort logs by diameter and often cannot efficiently handle logs much bigger than 12 to 15 inches in diameter.
As the recovery of fiber became a real issue, the attractiveness of engineered wood became apparent. Normally sawmill recovery has been only about 40% of the log by weight. With the advent of engineered wood, recovery increased to from 52% to 75%, depending upon the product being manufactured. It is obvious that as logs became smaller, larger sized timbers and dimension becomes more difficult to supply. After all, most sawmills have a tough time sawing 2 x 10's out of 10-12' logs. The advent of engineered wood has made it possible to manufacture timbers up to virtually any size with assurance of structural strength, since many of the defects are eliminated in the manufacturing process.
Just what is engineered wood? Some processes are old, such as laminated beams, where selected dimension lumber is glued together, often in arches used in roof applications. Engineered wood includes Oriented Strand Board (OSB), particleboard and other panel products as well as laminated products solids and veneers. In this article we will deal with Laminated Veneer Lumber and its variations, since LVL production could have the most impact on traditional hardwood sawmills.
Laminated Veneer Lumber (LVL)
This is structural lumber made by gluing up a number of layers of veneer with the train going one way. LVL, by eliminating many of the defects found in trees in the veneer manufacturing process, can convert small logs into long-length, wide width dimension lumber. In essence the product is similar to plywood, but by laying up the veneers in one direction and using a continuous press there is no limit on length, except what can be handled. LVL is purchased for its structural properties and dimension, with less importance given to species. Aspen and Poplar are increasingly being used in the manufacture of LVL. The most common species used in North American are Douglas Fir, Southern Pine, Spruce and Aspen. New plants using Poplar signal the increasing use of hardwoods in engineered wood applications. In North America there are presently in excess of 20 LVL plants in operation. In West Virginia and in North Carolina 2 new LVI. plants have recently opened, operated by Truss Joist MacMillan and Georgia Pacific Corporation.
In a report prepared for equipment maker Durande-Raute in 1993, Len Guss and Associates of Bellevue, Washington, estimated that from 1987, with three plants and a production level of 200 million board feet, production of LVL increased to 10 plants and production of 340 million fbm by 1993. By the year 2002 this is expected to triple to 1 to 1.25 billion board feet, and the number of plants was expected to double. The properties of LVI are superior to glu-lam and machine stress rated (MSR) lumber. One innovation in manufacturing the veneer that goes into LVI has been the advent of spindleless lathes, which allows small logs to be peeled down to 2" in diameter. The process of manufacturing LVL increases the yield by weight to over 52% as compared to 40% for a sawmill. Once LVL lumber is manufactured, other products such as wood I-beams can be manufactured. The use of LVL manufactured from other hardwoods can be utilized in the furniture and millwork industry.
Parallel Strand Lumber (PSI)
Parallam�, Truss Joist MacMillan's registered trade name, is made by peeling logs into veneer sheets, cutting them into long, thin strands of 4 to 8 foot lengths and bonding them parallel to one another to create a structural wood product that is superior even to dimension lumber milled from old-growth timber. PSL is available in dimension up to 11 x 17 inches and length up to 66 feet. With the unique parallel grain of PSL it can be left exposed as a design element. The manufacturing process converts 64 percent of a log into Parallam� whereas traditional sawmill methods convert only 40 percent of a log into lumber.
Laminated Strand Lumber (LSL)
Is the newest technology in engineered lumber. In this process, which uses as much as 75 percent of a log, woods such as Aspen and Poplar can be utilized. The timber is cut into strands up to 12 inches long, dried and treated with a polyurethane resin. The treated strands are aligned parallel to each other, which takes better advantage of wood's natural strength. The strands are pressed into solid billets, blocks of wood 35 feet tong, 8 feet wide, and up to 5-1/2 inches thick. They can then be cut and sanded to exact customers specifications. LSL is in many respects similar to OSB and is made in very much the same way, except that the strands are 12 inches long instead of 4 inches as in OSB. In North American Truss Joint MacMiJlan's LSL lumber is marketed under the trade name of TimberStrand�.
The use of engineered wood products has been phenomenal. The market has now spread across the country and today an estimated 25% of US builders use both LVL and engineered wood I-Joists.
Marketing has been the major focus of most manufacturers of the above products. Third party inspection and engineering standards assure the buyers of high quality products. The manufacturers also offer computer software programs to architects and builders in order to increase the understanding of how engineered wood components can be used.
These new competitive products will find their way into many of traditional hardwood markets and will compete for raw material, which may impact our industry in the future, perhaps positively. If the demand for these items grows as expected, the less profitable species sawn at many sawmills might then become more profitable to sell the LVL plants in log form, allowing sawmills to cut only the more desired species. While a significant impact felt throughout the industry is a long way off, it is important to realize that some change in the competitive picture for hardwood logs could come over the horizon.