Treesearch

This review critically evaluates literature on the ways in which excessive drying (overdrying) inactivates wood surfaces to bonding, primarily for phenolic adhesives. In Part I of a two-part review, three inactivation mechanisms involving physical responses to overdrying are considered: (1) exudation of extractives to the surface, which lowers the wettability or hides the surface; (2) reorientation of wood surface molecules, which reduces wettability or places for bonding; and (3) irreversible closure of large micropores in cell walls. I believe that extensive evidence from wood bonding...

A complete annotated bibliography of all published and unpublished reports of the USDA Forest Service, Forest Products Laboratory, on the subject of tropical woods. Research on tropical woods began soon after the formation of the Forest Products Laboratory in 1910 and continues today.

Xylose is a major component of angiosperm lignocellulosic residues. It is available from a number of different sources in the forest products industry, including fiberboard manufacture, sulfite waste liquors, production of dissolving pulp, and the hydrolysis of hardwood residues. Hydrolysis of wood for the production of liquid fuels, particularly ethanol, has been proposed and practiced at various times and especially during petroleum shortages such as those that occurred in World War II or the late 1970s and early 1980s.

Recently, we showed that a biomechanical pulping process in which aspen chips are pretreated with a white-rot fungus can give energy savings and can increase paper sheet strength. To optimize this process, we need more efficient ways to evaluate the fungal treatments. Here, we examine a method that consists of treating coarse refiner mechanical pulp, refining in a PFI mill, and testing for freeness. The relative ability of a fungus to promote a decrease in pulp freeness in the PFI mill did not correlate with its ability to give energy savings in chip refining. However, it correlated with...

To gain insight into the biochemical mechanism employed by brown-rot fungi to depolymerize cellulose, we identified the end-groups of chemically pure cellulose that had been depolymerized by the brown-rot fungus, Postia placenta. The acids identified include glyceric and erythronic, indicating oxidative cleavage of the vicinal dial carbon-carbon bonds within glucosyl residues in the cellulose polymer. Gluconic and arabonic acids were also identified as major products. No uronic acids were produced in either systems.

This study explains and determines fuelwood consumption at the county level based on county economic and demographic conditions, and identifies U.S. counties where potential fuelwood use problems and benefits are greatest. The percentage of wood-burning households in a county is estimated and multiplied by estimated average wood consumed per wood-burning household in that county to produce an estimate of total county fuelwood use. Use estimates are then compared to forest inventory data to identify potential problem/benefit areas. Parameters in estimating equations are determined from...

A room test designed according to the ASTM draft standard was used to investigate the effect of various parameters on the contribution of wall and corner fires to compartment fire growth. Location of the burner (against a wall or in a corner), power program of the gas burner ignition source, and combination of wall linings were varied, An initial series of calibration tests were conducted on ceramic fiber blanket and gypsum board. These tests showed satisfactory instrumentation, good repeatability, and reliable data reduction techniques. The second series were wall and corner tests with...

This report describes methods of predicting the performance of light-frame wood structures with emphasis on floor and wall systems. Methods of predicting structural performance, fire safety, and environmental concerns including thermal, moisture, and acoustic performance are addressed in the three major sections.

Fire-retardant-treated (FRT) plywood used as roof sheathing has exhibited strength degradation in some situations. The cause appears to be certain fire retardant chemicals that are activated under environmental conditions of high temperature and moisture content. This report describes how fire retardants are made, how they work, and what causes strength degradation of FRT wood. We present guidelines for selecting and using FRT wood and precautions to follow when designing roof systems with FRT plywood.

For 65 years, the Forest Products Laboratory (FPL) in Madison, Wisconsin, has had a continuous and extensive program of research on finishing wood for outdoor use. The research has stressed the fundamental aspects of wood weathering and the interactions of pretreatments and finishes on wood surfaces. This report outlines the history of the FPL wood finishing research program, including the perspective of Dr. Frederick L. Browne, the program’s leader during the strategic years from 1922-1963. We describe the early research that established the important role of the wood substrate in finish...