Treesearch

Recent research on the release of wood preservatives from treated wood used in sensitive environments has not considered the potential contribution from construction residues. This study sought to develop leaching rate data for small construction debris and compare those to the release rate from treated wood itself. Western hemlock boards were pressure treated with chromated copper arsenate Type C (CCA-C), and then common construction tools were used to generate sawdust or shavings from those boards. These wood particles were then leached in deionized water, and the leaching rate was...

Trends in demand for lumber and panel products in packaging and materials handling are examined both for the past and the future. Effects of recent technological developments and innovations such as molded particleboard pallets, medium-density fiberboard pallets, and plywood pallets, are analyzed. Increased use of pallets is seen as the main reason for the expected increase in wood products consumption. Use of the slip-sheet is considered competition for the wood pallet. Projections are made for lumber and board use in the 1980as.

This report presents experimental results of modulus of rupture and shear strength tests on unsplit, green, sawn Douglas-fir lumber. Five different size-matched specimens, ranging from nominal 2-by 4-in (standard 38- by 89-mm) to nominal 4- by 14-in (standard 95-by 343-mm), were tested in third-point bending and five-point beam shear. A total of 120 bending and 160 shear specimens, as well as shear blocks cut from each beam, were tested. Results adjusted to 12 percent moisture content are compared with results from prior research on Douglas-fir glued-laminated timber beams. Statistical...

Some building codes require wood shingles to be fire-retardant treated. Because exterior fire-retardant treatments are subjected to weathering, treatment durability and leach resistance are critical for insuring adequate fire protection. We examined the effectiveness of various fire-retardant treatments on wood after 0, 2, 5, and 10 years of outdoor exposure. We used a Class C burning-brand test (ASTM E 108) and a Schlyter flamespread test to evaluate effectiveness. Most shingle treatments evaluated were either pressure impregnated or coated at the Forest Products Laboratory; however, a...

In 1982, 175 softwood plywood plants operated in the United States with a combined production capacity of nearly 23.1 billion square feet (ft2 ) (3/8-in. basis) per year, 60 percent greater than in 1965. The West was the region with largest capacity in 1982--12.5 billion ft2. The South had 10.5 billion ft2 and the North less than half a billion ft2. Approximately 1.1 billion cubic feet (roundwood equivalent) of peeler logs were consumed in 1982 to produce 15.1 billion ft2 of softwood plywood. Domestic softwood plywood consumption in 1982 was 14.6 billion ft2, with residential construction...

Large amounts of lumber and wood panel products are used annually for the repair and remodeling of residential structures and properties in the United States. In response to the need by government and industry for detailed information on this important market for timber products, a study was conducted by the Timber Demand and Technology Assessment Research Work Unit of the USDA Forest Service at the Forest Products Laboratory, Madison, Wisconsin, and the Wood Products Promotion Council, with additional support from the American Plywood Association, Tacoma, WA. Results of this study...

This paper reports results of a cooperative study by the USDA Forest Service, Southern Illinois University at Carbondale, and Tuskegee Institute. The study was designed to provide statistically reliable information on national and regional use of wood in pallets, by species and pallet type. An estimated 17 fbm of wood was required to produce a finished pallet; the finished pallet contained 12.7 fbm of wood. This is less wood per pallet than had previously been thought. Significant differences in wood use exist between regions. Pallets from the Northeast and North Central regions contain...

The Hoffman Run bridge, located just outside Dahoga, Pennsylvania, was constructed in October 1990. The bridge is a simple-span, single-lane, stress-laminated deck superstructure that is approximately 26 ft long and 16 ft wide. It is the second stress-laminated timber bridge to be constructed of hardwood lumber in Pennsylvania. The performance of the bridge was monitored continually for approximately 32 months, beginning shortly after installation. Performance monitoring involved gathering and evaluating data relative to the moisture content of the wood deck, the force level of steel...

A previous paper presented a reliability-based model to predict the strength of glued-laminated timber beams at both room temperature and during fire exposure. This Monte Carlo simulation procedure generates strength and fire endurance (time-to-failure, TTF) data for glued- laminated beams that allow assessment of mean strength and TTF as well as their variability. This paper reports an effort to validate model predictive capability through an independently fabricated set of 21 glued-laminated beams. Based upon the available data for the model input parameters on lumber strength and...

From a starting universe of approximately 1,300 Canadian and American sawmills, 149 were permanently closed between 1996 and 2003. This figure does not include small portable or part-time operations. These mills represented 17.6 million m3 of capacity, nearly 12% of the 1995 industry total. On the other hand, 25 new mills brought on-line have offset 4.9 million m3 of lost production potential. Further, upgrades to existing sawmills have added 31 million m3 of capacity. The region most severely impacted by closures was the U.S. West, which accounted for over half of all the capacity lost....