Treesearch

A modified Midwest Guardrail System (MGS) was developed by using small-diameter round wood posts. The barrier system was configured with three timber species: Douglas fir (DF), ponderosa pine (PP), and southern yellow pine (SYP). Barrier VII computer simulation, combined with cantilever post testing in a rigid sleeve and soil, was used to determine the required post diameter for each species. The recommended nominal sizes were 184 mm (7.25 in.) for DF, 203 mm (8 in.) for PP, and 190 mm (7.5 in.) for SYP. A grading criterion limiting knot size and ring density was established for each...

Global trends in pulp, paper, and paperboard have deeply affected U.S. pulpwood markets since the late 1990s. Global trends included a shift of growth in paper and paperboard production from North America to Europe and Asia over the past decade. This trend was associated with generally slower growth in U.S. industrial production and displacement of growth in print media advertising expenditures by electronic media. Wood pulp consumption in the United States was also offset by increased paper recycling since the late 1980s. The net impact of these trends was a contraction of growth in U.S....

Nondestructive evaluation (NDE) of wood quality in standing trees is an important procedure in the forest operational value chain worldwide. The goal of this paper is to investigate how a stress wave travel in a tree stem as it is introduced into the tree through a mechanical impact. Experimental stress wave data was obtained on freshly cut red pine logs in the laboratory. Three dimensional (3D) stress wave contour maps were generated using the MATLAB software. The 3D stress wave contour maps represent the wave fronts at a series of locations along the length, which can help to visualize...

Overall, despite the lack of exact input data, the use of design tools, including models, is much superior to the simple following of rules of thumbs, and a moisture analysis should be standard procedure for any building envelope design. Exceptions can only be made for buildings in the same climate, similar occupancy, and similar envelope construction. This chapter provides guidance in the use of steady-state, manual methods, and an introduction to mathematical models. A more detailed discussion of mathematical models and modeling is provided in ASTM MNL40, Moisture Analysis and Condensatio...

This study evaluated decay and termite resistance of thermally compressed pine wood panels under pressure at either 5 or 7 MPa and either 120 or 150 °C for 1 h. Wood specimens from the panels were exposed to laboratory decay resistance by using the wood degrading fungi, Gloeophyllum trabeum and Trametes versicolor. The thermal compression process caused increases in density and decreases in thickness of the panels: however, laboratory decay resistance revealed that thermally compressed wood was not resistant against the wood degrading fungi tested. More interesting results were found in...

Many litter-decay fungi secrete heme-thiolate peroxygenases that oxidize various organic chemicals, but little is known about the role or mechanism of these enzymes. We found that the extracellular peroxygenase of Agrocybe aegerita catalyzed the H2O2-dependent cleavage of environmentally significant ethers, including methyl t-butyl ether, tetrahydrofuran, and 1,4-dioxane. Experiments with tetrahydrofuran showed the reaction was a two-electron oxidation that generated one aldehyde group and one alcohol group, yielding the ring-opened product 4-hydroxybutanal. Investigations with several...

Timber can often be a cost-effective construction material for new bridges. The durability of the bridge greatly depends on proper attention to construction details and fabrication, as well as proper preservative treatment before, during, and after construction. Material repair and replacement costs for bridges are a considerable expense for highway agencies. To address these needs, the objectives of an investigation were to determine the field effectiveness of various treatment alternatives used on Iowa roadway projects and to provide information on preservative treatments, inspection...

The Centennial Year of the USDA Forest Service’s Forest Products Laboratory offers a time to reflect on significant breakthroughs and look to a future of unprecedented innovation.

At first glance, the relationship between nanotechnology and lignocellulosic biomass may seem to be unconnected or at best tenuously connected. It is important to recognize that. at a fundamental level, lignocellulosic biomass is made up of nanometer-size constitutive building block units that provide valuable properties to wood and other types of renewable lignocellulosic and cellulosic biomaterials. Other composite biomaterials, such as bone, teeth, and seashells, have been found to owe their high strength and optical properties to the nanometer dimensions of their building blocks...

In the past, gravimetric corrosion data for fasteners exposed to treated wood has been reported as a percent weight loss. Although percent weight loss is a valid measure of corrosion for comparing identical fasteners, it can distort the corrosion performance of fasteners with different geometries and densities. This report reevaluates a key report on the corrosiveness of wood treated with chromated copper arsenate (CCA) and ammoniacal copper arsenate (ACA) and converts the previous data into corrosion rates. In addition, similar experiments were run in wood treated with alkaline copper...