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Current grading standards for logs used in log home construction use visual criteria to sort logs into either “wall logs” or structural logs (round and sawn round timbers). The conservative nature of this grading system, and the grouping of stronger and weaker species for marketing purposes, probably results in the specification of logs with larger diameter than would be required if a more precise grading method were available. This study evaluated the relationships between log strength and stiffness as a basis for a mechanical grading system. A sample of 120 logs, 4.9-m (16-ft.) long, was...

The purpose of this study was to evaluate two groups of composite panels made from two types of underutilized natural fiber sources, kenaf bast fiber and office wastepaper, for their suitability in composite panels. All panels were made with 5% thermosetting phenol-formaldehyde (PF) resin and 1.5% wax. Also, an additional 10% polypropylene (PP) thermoplastic resin was used in half the panels. The PP was added to determine the effect it had on the mechanical and physical properties of the panels. The resin and wax were applied with a pneumatic spray gun while tumbling the fiber in a rotary...

Certain issues in recent softwood lumber trade negotiations have centered on the method for converting estimates of timber volumes reported in cubic meters to board feet. Such conversions depend on many factors; three of the most important of these are log length, diameter, and taper. Average log diameters vary by region and have declined in the western United States due to the growing scarcity of large diameter, old-growth trees. Such a systematic reduction in size in the log population affects volume conversions from cubic units to board feet, which makes traditional rule of thumb...

Kiln drying at high temperature may reduce warp in dimension lumber sawn from small-diameter trees. In this study, we examined the effect on warp of high drying temperatures in conjunction with top loading immediately after drying and after storage in typical conditions that result in further moisture loss. Eight-foot-long 2- by 4-in. (2 by 4) boards sawn from open-grown, 30- to 35-year-old, 9-in.-diameter at breast height ponderosa pine trees were kiln dried at three temperatures, 160°F, 230°F, and 280°F. Crook, bow, and twist were measured and compared. Total grade loss from exceeding...

The inadequate transportation infrastructure and undeveloped markets for sawmill residues in southeast Alaska are among the factors that limit the use of this forest resource. This study considers the potential use of sawmill residues to supply two bioenergy systems that would produce thermal energy for (1) community heating and (2) a lumber dry kiln in Hoonah, Alaska. The proposed community heating system would be a direct combustion system, burning approximately 1,450 green tons (1.315 green metric kilotons) of wood fuel per year to provide heating for seven centrally located buildings...

Timber rivet connections, originally developed for use with glulam construction, may be a viable option for use with structural composite lumber (SCL) products. Tests were conducted on small samples to assess the performance and predictability of timber rivet connections in parallel strand lumber (PSL) and laminated strand lumber (LSL). The test joint configurations were designed to exhibit rivet failures some combination of rivet yield and bearing deformation in the composite as opposed to wood failure modes, such as block-shear tear-out or splitting. Results suggest that per-rivet design...

This is a directory of companies involved in wood-framed building deconstruction, dismantling and reused building materials, with an emphasis on those that use, resell, and/or re-manufacture salvaged wood. Companies in this directory range in scope from those that carryout targeted building removals, such as historic barns, strictly for the purpose of harvesting the antique wood in these buildings, to companies that conduct residential and commercial demolition where the primary goal is building removal, and the recovery of materials is conducted opportunistically as a by-product. The bulk...

This study reviewed the literature on static and impact withdrawal of nails driven into the end grain of wood members. From this, an empirical relationship was created relating the specific gravity of the wood, the diameter of the nail, and the depth of penetration of the nail to the static withdrawal capacity of nails driven into the wood and withdrawn immediately. Areas of additional research are identified for end-grain nailing in wood members.

In recent years, computers, sensors, microelectronics, and communication technologies have made it possible to automate the way materials are tested in the field. It is now possible to purchase monitoring equipment to measure weather and materials properties. The measurement of materials response often requires innovative approaches and added expense, but the instrumentation vastly improves the quantity and quality of the data that can be obtained. Data on weather and materials can be linked to a computer system, either at the field site or through a communications link back to the...

There is a growing need to find a rapid, inexpensive, and reliable method to distinguish between treated and untreated waste wood. This paper evaluates the ability of near infrared (NIR) spectroscopy with multivariate analysis (MVA) to distinguish preservative types and retentions. It is demonstrated that principal component analysis (PCA) can differentiate lumber treated with CCA, ACZA, or ACQ preservatives. Furthermore, separation according to wood species and assay zone was also observed. Within the range of preservative concentrations available, partial least squares (PLS) regression...