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The effect of moisture on longitudinal stress-wave velocity (SWV), bending stiffness. and bending strength of commercial oriented strandboard, plywood. particleboard. and southern pine lumber was evaluated. It was shown that the stress-wave verocity decreased in general with increases in panel moisture content (MC). At a given MC level. SWV varied with panel type and test directions. Regression equations relating SWV to MC and bending properties (modulus of elasticity [MOE] and modulus of rupture [MOR] were established for various products. Both MOE and MOR at different MCs can be estimated...

In July of 2005, U.S. airlines were losing money. Some were in bankruptcy or on the verge of bankruptcy. The world’s Number 1 auto producer, General Motors, was losing money and market share. By the end of the month sales had set records, but this was mainly because of costly sales incentives. The U.S. dollar that had been at a high point of $1.29 in exchange for the euro on January 13, 2004 was worth around 83 euro cents. Oil prices had just gone to a record level of over $60 per barrel. This does not mean that the world’s Number 1 economy is headed for disaster, but it is symptomatic of...

The purpose of this chapter is to make the reader aware of how choices in study parameters may influence the outcome of treated-wood environmental impact evaluations. Evaluation of the leaching and environmental accumulation of preservatives from treated wood is a complex process. and many factors can influence the results of such studies. In laboratory studies, the effects of specimen dimensions, wood species, treatment practices, fixation and leaching exposure must be considered. Evaluation of in-service structures introduces additional variability, with factors such as age of the...

Many of our national forests are in critical need of restoration. These forests are dense, with an abundance of small-diameter, tightly spaced trees and underbrush that can contribute to the rapid growth of fire. If economic and value-added uses for this small-diameter and unmerchantable material can be found, forest restoration costs could be offset and catastrophic wildfires would be reduced. This document tells the story of several U.S. wood product businesses that are successfully making use of this small diameter and unmerchantable material. Some stories describe how the USDA Forest...

Effective water management involves understanding the roles of siding, trim, fenestration units, flashing, and (where appropriate) caulk seals and how these entities interface with each other. Where caulk seals are used, their geometry and dimensions are important to joint performance, as is the care with which they are executed. In selection of caulking material, consideration should be given to compatibility with substrates, to ambient conditions at application and during cure, and to the skill level of the applicator. Where and when caulk seals are used, they should not be assumed to...

The white-rot basidiomycete Phanerochaete chrysosporium employs extracellular enzymes to completely degrade the major polymers of wood: cellulose, hemicellulose, and lignin. Analysis of a total of 10,048 v2.1 gene models predicts 769 secreted proteins, a substantial increase over the 268 models identified in the earlier database (v1.0). Within the v2.1 ‘computational secretome,’ 43% showed no significant similarity to known proteins, but were structurally related to other hypothetical protein sequences. In contrast, 53% showed significant similarity to known protein sequences including 87...

In this study the surface roughness of plywood treated with various fire retardants was investigated. Commercially manufactured veneer of Akaba wood (Tetraberlinia bifoliolata) was treated with borax, boric acid, monoammonium phosphate and diammonium phosphate, then experimental plywood panels were made from these veneer sheets. A stylus method was employed to evaluate the surface characteristics of the samples. Three main roughness parameters, mean arithmetic deviation of profile (Ra), mean peak-to valley height (Rz), and maximum roughness (Rmax) obtained from the surface of plywood were...

Current procedures used to sort round timber beams into structural grades rely on visual grading methods and property assignments based on modification of clear wood properties. This study provides the technical basis for mechanical grading of 228 mm (9 in.) diameter round timbers. Test results on 225 round Engelmann spruce–alpine fir–lodgepole pine beams demonstrate the conservative nature of current timber strength assignments. A good correlation was obtained between static bending strength and static modulus of elasticity (MOE), and between bending properties and dynamic MOE determined...

Particleboard and flakeboard panels were fabricated from remediated CCA-treated southern yellow pine. Treated wood, flaked or comminuted into particles, was remediated in 12-kg batches using oxalic acid extraction, followed by bioleaching with the metal-tolerant bacterium Bacillus licheniformis. Remediation resulted in removal of 80 percent Cu, 71 percent Cr, and 89 percent As for the particulate material and 83 percent Cu, 86 percent Cr, and 95 percent As for the flaked material. Particleboard and flakeboard panels were evaluated for modulus of elasticity (MOE), modulus of rupture (MOR),...

The objective of this document is to provide philosophy and guidelines for the assignment of allowable properties to visually graded dimension lumber produced from trees not grown in the United States. This document assumes, as a starting point, the procedures of ASTM D 1990.