Treesearch

The study described in this report was conducted to examine the flexural properties of laminated veneer lumber (LVL) manufactured from red maple veneer. Ultrasonically rated veneer, which was peeled from low value red maple saw-logs, was fabricated into 1/2-in.-(1.3-cm-) and 2-in.-(5-cm-) thick LVL billets. The flexural properties of the billets and of corresponding small specimens cut from the billets were determined through flatwise and edgewise static bending tests. Ultrasonic wave propagation time and corresponding dynamic modulus of elasticity of red maple veneer were found to be well...

Peroxidase/H2O2-mediated radical coupling of 4-hydroxycinnamaldehydes produces 8–O–4-, 8–5-, and 8–8-coupled dehydrodimers as has been documented earlier, as well as the 5-5-coupled dehydrodimer. The 8–5- dehydrodimer is however produced kinetically in its cyclic phenylcoumaran form at neutral pH. Synthetic polymers produced from mixtures of hydroxycinnamaldehydes and normal monolignols provide the next level of complexity. Spectral data from dimers oligomers and synthetic polymers have allowed a more substantive assignment of aldehyde components in lignins isolated from a CAD-deficient...

Although wood was one of the earliest materials to be adhesively bonded, the factors that contribute to strong wood bonds are still not well understood. Wood is a very complex substrate in that it is non-uniform in most aspects. On the macro scale, it is a porous structure with different sized and shaped voids for fluid flow. The structural cells contain four different wall layers, and there is a middle lamella region between the cells. Each cell wall layer is made up of different amounts of three structural components: cellulose, mostly present as a crystalline and rigid polymer; hemicellu...

The unmitigated pest risk potential for the importation of unprocessed logs and chips of 18 species of eucalypts (Eucalyptus amygdalina, E. cloeziana, E. delegatensis, E. diversicolor, E. dunnii, E. globulus, E. grandis, E. nitens, E. obliqua, E. ovata, E. pilularis, E. regnans, E. saligna, E. sieberi, E. viminalis, Corymbia calophylla, C. citriodora, and C. maculata) from Australia into the United States was assessed by estimating the likelihood and consequences of introduction of representative insects and pathogens of concern. Twenty-two individual pest risk assessments were prepared,...

We made a series of aspen fibre medium density fibreboard panels adding various levels of chicken feather fibre to determine the relative effect of the feather fibre-wood fibre mixtures on composite panel properties. Chicken feathers are a waste product left over after processing chickens for meat. The feather fibre amounts used ranged from 20% to 95% and a 5% concentration of phenol formaldehyde resin was used as the adhesive. The panels were tested for mechanical and physical properties as well as decay. Initial mechanical properties show some loss in strength and stiffness for feather...

Creosote has a long history of use as a preservative, particu-larly in industrial wood products. However, its use has come under increasing scrutiny as a result of concerns about ptential effects on aquatic and terrestrial non-target organ-isms. Despite the long use of creosote, there is relatively little data on the rates of creosote loss in many exposures, including aquatic applications. To address this concern, the Federal Highway Administration has funded a series of studies to evaluate the environmental impact of creosote-treated wood used in timber bridges. In the study reported...

The value of small-diameter grand fir round stock could be increased if this material could be successfully treated with preservatives and marketed as posts and poles. This paper reports the treatability of suppressed-growth grand fir posts with several common preservatives. Ammoniacal copper zinc arsenate (ACZA) and oilborne copper naphthenate were found to provide adequate treatment. Acceptable treatment was not achieved with chromated copper arsenate (CCA). The pattern of preservative penetration was erratic, especially with CCA.

Controlling erosion is a serious and challenging task. Annually, erosion is responsible for billions of dollars of damage worldwide. Erosion control mats (ECMs) were developed to control erosion and provide soil stability until vegetation can be established. There are hundreds of products in the erosion control market. Erosion control mats are made from organic materials, synthetic materials, and sometimes a combination of the two. This study is a market analysis of ECMs based on a telephone survey of nine manufacturers and a literature search. The objective of the market analysis was to...

The objective of this research was to develop a stable process for compound ultra-pure cellulose fibers into polyamides. This has been a difficult procedure and has taken years of trial and error to understand the viscosity shear heating effects associated with compounding cellulose into high-melting point engineering thermoplastics. The evolution of the low temperature compounding (LTC) technique is ongoing, and the ongoing development of new process stabilizers for cellulose-polyamide composites will help facilitate the commercial use of these new materials for industrial applications.

The RPA Timber Assessment projects, over the next 50 years, the likelihood of increasing relative use of imported forest products versus U.S. roundwood harvest to meet U.S. consumption needs, although our projected consumption needs are now estimated to be lower than we projected in 1993. The projected higher imports relative to U.S. roundwood harvest is due in part to slower projected increase in available hardwood inventory and harvest in the South. Softwood harvest is projected to increase notably with increasing area and management intensity for plantations in the South, and we project...