Treesearch

An extensive U.S. research program to further develop wood utilization in transportation structures is currently in progress as a joint effort of the USDA Forest Service, Forest Products Laboratory, and the U.S. Department of Transportation, Federal Highway Administration. This research is funded primarily by U.S. legislation and involves cooperative research with universities, government agencies, and private industry. Within the program, research is divided into six areas: system development and design, lumber design properties, preservatives, alternate transportation system timber...

In recent years wood strength researchers have begun to replace experimental unit allocation via random sampling with allocation via sorts based on nondestructive measurements of strength predictors such as modulus of elasticity and specific gravity. Although this procedure has the potential of greatly increasing experimental sensitivity, as currently implemented it can easily reduce sensitivity. In this paper we discuss the problem and we present solutions. Given the existence of nondestructive measurements of strength predictors, our methods can be used to reduce sample sizes. We have...

Preservative-treated wood is an economical, durable, and aesthetically pleasing building material; therefore, it is a natural choice for construction projects in our National Forests, National Parks, and other public lands. However, we need to ensure that the chemicals used in treated wood do not pose a threat to people or the environment. The purpose of this report is to provide a summary of the pertinent literature on leaching of wood preservative components and their mobility in the environment. The waterborne wood preservatives chromated copper arsenate (CCA), ammoniacal copper zinc...

Filled thermoplastic composites are stiffer, stronger, and more dimensionally stable than their unfilled counterparts. Such thermoplastics are usually provided to the end-user as a precompounded, pelletized feedstock. Typical reinforcing fillers are inorganic materials like talc or fiberglass, but materials derived from waste wood, such as wood flour and recycled paper fiber, are also effective as fillers. The goal of this project was to generate commercial interest in using waste-wood–paper- derived fillers (WPFs) to reinforce thermoplastics. The research strategy was twofold: developmenta...

The irradiance plotted as function of time to ignition for wood materials tested in the Cone Calorimeter (ASTM E1354) differs signiticantly from that tested in the Lateral Ignition and Flame spread Test (LIFT) apparatus (ASTM E1321). This difference in piloted ignitabilty is primarily due to the difference in forced convective cooling of the specimen tested in both apparatus. By calibrating for the convective heat transfer coefficient and using appropriate heat conduction analysis of the test data for both apparatus, similar values were derived for the following thermophysical properties:...

The Colville Study was developed in 1994 to identify and evaluate a series of management options for achieving ecosystem objectives in dense stands of small-diameter trees while also producing wood products. The Colville National Forest selected the Rocky II Timber Sale as an example of this type of stand that needed management to achieve the following goals: (1) create late successional forest structure, (2) decrease forest health risk from fire, insects, and disease, (3) improve wildlife habitat by providing large green trees and snags, and (4) improve stand aesthetics by decreasing...

In the past decade, bridge railing design criteria have moved away from static-load design and have focused on full-scale crash testing as a more appropriate and reliable means of evaluating bridge railings. The five bridge railing plans presented reflect the results of a cooperative research project between the Midwest Roadside Safety Facility, University of Nebraska--Lincoln; the USDA Forest Service, Forest Products Laboratory; and the Federal Highway Administration. The project objective was to develop and crash test bridge railings and approach railing transitions for longitudinal wood...

A system was developed for grouping tropical wood species for kiln drying based on similar estimated drying times. Six tropical species were subjected to drying and water soaking tests; variables were test temperature and specimen thickness. Soaking time, specimen thickness, and test temperature were used in an empirical model to predict drying times. The capability of the model to predict drying times was considered acceptable based on an adjusted coefficient of determination equal to 0.929 and an average error of 14 percent. The overall capability of the method proposed for grouping...

In recent years biological control has received increasing attention as a means of protecting wooden structures against decay fungi. This has been due, in large part, to increased public awareness and concern over the environment impact of currently used chemical wood preservatives. Laboratory studies have indicated that Trichoderma isolates are able to antagonise wood decay fungi by a number of different mechanisms. These include passive antagonism through competition for available nutrients; active antagonism through the production of soluble metabolites and volatiles and mycoparasitism...

Wood preservation based on in situ polymerization of potentially bioactive monomers has been studied. Tributyltin oxide acrylate (TBTOA) and pentachlorophenol acrylate PCPA) were synthesized. Wood samples were treated at 2%, 5%, 10%, 15% and 20% by weight solutions with varying amounts of either crosslinker (trimethylolpropane trimethacrylate, TMPTM) or methyl methacrylate (MMA) and polymerized in situ in wood samples. Soil block testing was performed on acetone leached samples using Gloeophyllum trabeum in a standard ASTM test for 12 weeks. TBTOA was effective at all levels except when...