Treesearch

The different uses of wood result in a hierarchy of carbon and energy impacts that can be characterized by their efficiency in displacing carbon emissions and/or in displacing fossil energy imports, both being current national objectives. When waste wood is used for biofuels (forest or mill residuals and thinnings) fossil fuels and their emissions are reduced without significant land use changes. Short rotation woody crops can increase yields and management efficiencies by using currently underused land. Wood products and biofuels are coproducts of sustainable forest management, along with...

Recovering wood for reuse in a new house affects energy and greenhouse gas emissions. This paper finds the energy and emissions for recovering softwood framing lumber and hardwood flooring from an old house for installation in a new house. Recovering wood displaces primary production of new wood products and avoids the end-of-life (EOL) burdens for the old house. We used a cradle-to-gate life cycle analysis and examined the EOL burdens for the wood products when disposed of including the effect of biogenic CO2. Results showed that recovering softwood framing lumber and hardwood flooring...

This article describes a theoretical method of linking fastener corrosion in wood connections to potential reduction in lateral shear strength. It builds upon published quantitative data of corrosion rates of metals in contact with treated wood for several different wood preservatives. These corrosion rates are then combined with yield theory equations to calculate a loss in lateral capacity as a function of time. The calculations are straightforward and can be performed in a spreadsheet or simple computer program. They can accommodate time-dependent and moisture-dependent corrosion rates....

Sub-100 nm resolution local thermal analysis, X-ray photoelectron spectroscopy (XPS), and water contact angle (WCA) measurements were used to relate surface polymer distribution with the composition of electrospun fiber mats and spin coated films obtained from aqueous dispersions of lignin, polyvinyl alcohol (PVA), and cellulose nanocrystal (CNC). Defect-free lignin/PVA fibers were produced with radii which were observed to increase with lignin concentration and with the addition of CNCs. XPS and WCA results indicate a nonlinear relationship between the surface and the bulk compositions. A...

Douglas-fir (Pseudotsuga menziesii) forest residues were physically fractionated through sieving. The bark and wood were separated for large-sized fractions (>12.7 mm), and their contents were determined. The chemical compositions of the large fractions were calculated based on the contents and chemical compositions of the bark and wood. The chemical compositions of the fine fractions were analyzed. The bark and wood content in the fine fractions was calculated based on the measured glucan and lignin contents in each fraction. It was found that fractionation by particle/chip size can...

Rapid enzymatic saccharification of lignocellulosic nanofibrils (LCNF) was investigated by monitoring nanoscale changes in mass via quartz crystal microgravimetry and also by measuring reducing sugar yields. In only a few minutes LCNF thin films were completely hydrolyzed upon incubation in multicomponent enzyme systems. Conversion to sugars and oligosaccharides of LCNF dispersed in water occurred in about 4 h (50 °C, pH 5). In contrast, a conversion of only 57% was observed for partially crystalline cellulose (Avicel) after 9 h, under same experimental conditions. Under conditions of high...

This paper reviews recent trends and structural changes in U.S. forest product markets and projects their effects on the long-range U.S. timber market outlook. The analysis derives from the same U.S. and global economic model that produced 50-year projections for the 2010 RPA nationwide forest assessment, but analysis is revised to more accurately include the economic recession of 2007–2009, the collapse in U.S. housing construction since 2005, and expected growth in wood energy consumption. The analysis uses the 2012 USDA Baseline global macroeconomic and currency exchange rate outlook,...

Mineral scale problems are not new to pulp mills and bleach plants. The liquor recovery system ensures that white liquor is saturated in calcium carbonate, and this mineral will precipitate when heated to cooking temperatures in the digester [1,2]. The original single-vessel continuous digesters sold by Kamyr had an extra liquor heater as standard equipment to enable the mill to take one heater out of service for acid cleaning without impacting production [3]. Although lime scale in the digester is generally the most routine scaling problem in pulp mills, various other scales are common in...

The purpose of this study was to investigate the vibrational properties and corresponding anisotropicity in wood during different states of moisture sorption. Samples of maple (Acer spp.) and red oak (Quercus rubra Michx.f.) were moisture conditioned by the adsorption process from an ovendried state and by the desorption process from a water-saturated state. The dynamic modulus of elasticity (DMOE) and logarithmic decrement (δ) were examined as a function of grain orientation during moisture change processes and under constant moisture contents (MC). It was observed that regardless of...

This paper presented a modeling study on force transfer around openings (FTAO) in wood-frame shear walls detailed for FTAO. To understand the load transfer in the walls, this study used a finite-element model WALL2D, which is able to model individual wall components, including framing members, sheathing panels, oriented panel-frame nailed connections, framing connections, hold-down connections, and strap connections for reinforcing the corners of openings. The various wall models were validated through laboratory testing of 12 fullscale 2.44 X 3.66 m (8' X 12') shear wall configurations,...