Treesearch

This report describes 53 taxa of hardwoods of North America, which are organized alphabetically by genus. Descriptions include scientific name, trade name, distribution, tree characteristics, wood characteristics (general, weight, mechanical properties, drying, shrinkage, working properties, durability, preservation, toxicity and uses) and additional sources for information. Data were compiled from existing literature, mostly from research done at the U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI.

Research results from the value-added research and demonstration program for western hardwoods are summarized in this report. The intent of the program was to enhance the economy of the Pacific Northwest by helping local communities and forest industries produce wood products more efficiently. Emphasis was given to value-added products and barriers to increased utilization. The program was coordinated by the Pacific Northwest Research Station, the Pacific Northwest Region of State and Private Forestry, and the Forest Products Laboratory.

This document summarizes accomplishments of USDA Forest Service researchers in the area of recycling. Specifically, it describes work in economic assessment, paper recycling, recycled housing and industrial applications of recycled materials, other recycling applications, and technology transfer. The literature list includes the references cited in the text and additional publications regarding Forest Service recycling research.

The development of standardized timber bridge plans and specifications is a key element in improving design and construction practices. The bridge plans presented were developed as a cooperative effort between the USDA Forest Service, Forest Products Laboratory (FPL); the University of Alabama; and the Southern Pine Council and are the first step in developing standardized designs for the southern United States where Southern Pine is the primary structural wood species group. This publication contains standardized designs and details for three timber bridge superstructure types, including...

Resin acids in the diethyl ether extracts of Picea glauca, Pinus ponderosa and Pinus banksiana seed cones were identified by gas-liquid chromatography of their methyl-ester derivatives. For these seed cones, abietic, dehydroabietic and isopimaric acids comprised 63.7-80.5 % of the total resin acids identified. In P. banksiana, the resin acid composition of the seed cones was shown to be significantly different from that in either the leaves, bark or wood. Investigation of the role of resin acids in the apparent decay resistance of woody conifer tissues to white-rot fungi involved the...

In this paper, we consider the fatigue strength of wood structural members. That is, we develop a mathematical model for time-dependent strength under sinusoidal load. This work extends the model for time-dependent strength under constant load and ramp load derived previously by two of the authors. It is based on the statistical theory of the absolute reaction rate in a version favorably reviewed in the literature. Under the isothermal condition, the model predicts that the time at fracture is independent of stress frequency. The need to evaluate experimentally some of the model parameters...

Recycled newspaper fibers (ONP) are potentially outstanding nonabrasive reinforcing fibers with high specific properties. In this study, a high energy thermokinetic mixer was used to mix these fibers in a polypropylene (PP) matrix, and the blends were then injection molded in order to observe the tensile and impact strengths of the composites. A 40% (weight) of ONP in PP resulted in a tensile strength of 34.1 MPa and an unnotched Izod impact strength of 112 J/m. Small quantities of maleic anhydride-grafted polypropylene (MAPP) and acrylic acid-grafted polypropylene (AAPP) were used to...

Numerous organizations have conducted research to develop nondestructive testing (NDT) techniques for assessing the condition of wood members in structures. A review of this research was published in 1991. This is an update of the 1991 report. It presents a comprehensive review of published research on the development and use of NDT tools for in-place assessment of wood members. It examines the fundamental hypothesis behind NDT of wood, reviews several widely used NDT techniques, and summarizes results of projects that focused on laboratory verification of the fundamental hypothesis....

This work demonstrates the complexity of modeling wall and corner fires in a compartment. The model chosen for this purpose is the Ohio State University (OSU) room fire model. This model was designed to simulate fire growth on walls in a compartment and therefore lends itself to direct comparison with standard room test results. The model input were bench-scale data obtained from the ASTM Test Method for Heat and Visible Smoke Release Rates for Materials and Products (E 906). Six wood materials were tested in the bench-scale test and also in an ASTM room fire test (proposed method). The...

Phenol-formaldehyde (PF) resin is a widely used adhesive in the manufacture of wood composites. However, curing behaviour of the resin under various environmental conditions is not well known. A differential scanning calorimeter was employed to characterize the degree of resin cure in this study. Resin-impregnated glass cloth samples with varied moisture contents (0,31,71%) were exposed to an environment of controlled temperature (105,115,125,140°C) and relative humidity (41,75,90%) for a series of time periods (0-20 min). The samples were next conditioned to different levels of relative...