Treesearch

This study was designed to determine if steam injection pressing used for fiberboard, particleboard, and flakeboard could be adapted to the pressing of plywood. Plywood panels were fabricated with and without adhesive and then pressed to determine the effects of steam injection Lime, steam injection pressure, and press pressure on heat transfer rate, moisture distribution, thickness loss, and adhesive-bond integrity. The time to reach 220°F (104°C) in the center glueline of five-ply, 0.5-inch- (12.7-mm-) thick Douglas-fir plywood was reduced 15 percent using certain combinations of steam...

This report is an informational report about four wood-based panel industries: particleboard, oriented strandboard, medium density fiberboard, and Southern Pine plywood. Items highlighted are trends in manufacturing and new plant costs, industry manufacturing capacity, and location. Recent data show the greatest amount of growth taking place in the oriented strandboard sector. Modest rates of growth are occurring in the Southern Pine plywood, particleboard, and medium density fiberboard sectors.

Laboratory and field experiments in wood engineering often rely on different types of devices to measure strain. Each type has certain limitations and characteristics that generally dictate its applicability to wood. Some of the issues related to using traditional strain measurement devices on wood and wood-based materials are discussed in this paper.

Mechanical wounding and wounding plus inoculation with a blue-stain fungus, Leptographium abietinum (Peck), associated with the spruce beetle, Dendroctonus rufipennis (Kirby), caused an induced reaction zone or lesion around the wound sites in Lutz spruce, Picea lutzii Little, Sitka spruce, P. sitchensis (Bong.) Carr., and white spruce, P. glauca (Moench) Voss, in south-central Alaska. The effects of tree species on lesion length were nonsignificant; however, the effects of wounding versus wounding plus blue-stain inoculate were highly significant. Lesion length was significantly longer in...

Wood joints bonded with urea-formaldehyde (UF) are weakened by cyclic swelling and shrinking. To study the failure mechanisms in UF-bonded joints, specimens were bonded with unmodified, modified (amine), or phenol formaldehyde adhesive and subjected to accelerated aging. Modification of the adhesive properties increased the cleavage fracture toughness and shear strength of bonded joints and improved the resistance of joints to cyclic swell-shrink treatment and accelerated moist-heat aging. Joints bonded with some modified urea-formaldehyde adhesives were as resistant to these treatments as...

In this article we revisit a method of sample allocation that has long been known to statisticians and has recently been “discovered” by wood strength researchers. The method allocates experimental units to blocks on the basis of the values of a variable, x, that is known to be correlated with the response, y. We call this allocation method “predictor sort sampling.” We demonstrate that the associated paired T analysis recommended in statistical texts is deficient if the sample size is small and the correlation between x and y is high. We temper this criticism of standard statistical...

Maximizing the yield of taxol per tree is important for the best management of the yew resource. Therefore, the possibility of obtaining additional taxol from the wood was explored. Initial reports form our laboratory, in cooperation with the National Cancer Institute, indicated relatively high concentrations of taxol in Pacific yew heartwood. Although these taxol concentrations were only about 20% that of corresponding bark samples, the much greater mass of wood compared to bark indicated a potentially significant additional source of taxol. However, even through the initial results were...

This report shows pulpwood receipts at pulp mills in the United States for the period 1950-1989. It is a compilation of published and estimated data based on information from various sources, including the American Pulpwood Association, American Paper Institute, U.S. Bureau of the Census, and the USDA Forest Service. Trends are shown in the use of hardwoods compared to softwoods and residues compared to roundwood, by the Forest Service timber supply regions. These historical data were compiled to help develop new pulpwood supply functions for the Timber Assessment Market Model and the...

A timber bridge, once a thing of the past, is now becoming a thing of the present. Interest in timber bridges and other transportation structures has been rapidly increasing. Much of this is due to new technologies in design and construction as well as advances in material manufacturing and presevative treatments. Although timber bridges and other transportation structures are gaining in popularity, there is much to be accomplished to fully develop wood as a material for transportation structures. This report summarizes research needs determined and prioritized by public and private...

This report presents a worldwide overview of the dissolving pulp industry and highlights of this industry in Alaska. It describes trends in world markets and major end-use markets, with special emphasis on the manufacture and use of textile fibers in the United States. Figures and tables present data on production, consumption, and trade of dissolving pulp and the cellulosic fibers-rayon and acetate-produced from it. Data are also given on the production and use of competing natural and synthetic fibers, such as cotton, silk, nylon, and polyester.