The effect of blue stain on shear strength of cold-set polyurethane resin (PUR) bonds was investigated using lodgepole pine lumber with varying degrees of stain and two different wood grain orientations. While blue stain was associated with definite differences in wood permeability, it had no negative effect on shear strength...
The potential effects of plant derived oils on survival of dampwood termite (Zootermopsis augusticollis) workers was explored on western white pine sapwood blocks. All of the oils rapidly affected protozoa in the hindgut of termite workers and protozoa loss was closely followed by worker mortality. The effects were most rapid...
The potential for using pretreatment with cinnamon leaf oil or juniper foliage oil to improve the durability of viscoelastic thermal compression (VTC)–treated hybrid poplar was explored in a field termite test and a laboratory mold test. The addition of oils prior to VTC processing had variable effects on resistance to...
Wood shear walls are the main lateral force-resisting system for wood-frame construction. Water intrusion and subsequent decay around connections can significantly impact shear wall behavior, but these problems are seldom studied. In this study, effects of water intrusion and fungal attack on shear wall capacity were examined using small-scale (610-...
The potential for preservative migration from treated wood exposed in or above aquatic environments has become a major concern in some parts of the United States. Best management practices (BMP) were designed to decrease the potential environmental footprint of treated wood, but there are few studies assessing the efficacy of...
Wood I-joists are often left uncovered and exposed to the weather during construction, allowing the oriented strandboard and laminated veneer lumber in these systems to be adversely affected by water absorption. Manufacturers typically specify that these materials be protected from wetting, but this can be difficult in wetter climates. There...
Red oak, Douglas-fir, and ponderosa pine lumber was treated with a silicon/paraffinic system to assess the ability of the treatment to limit dimensional changes and moisture uptake during changes in temperature or relative humidity. The treatment initially had little effect on either property, but the magnitude of weight gain and...
Routine inspection of wood utility poles to detect internal decay involves drilling holes at or about the ground line. While these holes are useful for detecting internal decay, their presence raises concern among engineers about their potential effects on pole flexural properties. The effect of inspection holes on flexural properties...
The specification, inspection, and remedial treatment of utility poles are addressed. Included are discussions of enhancing specifications for improved performance, techniques for detecting decay and other defects, and chemical treatments available for arresting decay of poles in service.
The ability of natural and synthetic hinokitiol, as well as a water soluble derivative (hinokitiol sodium salt), to protect wood against fungal attack was examined. Synthetic and natural hinokitiol provided similar protection. All three materials exhibited similar antifungal activity against Aspergillus niger and Penicillium citrinum on yellow poplar wafers at...
The ability of selected plant extracts from wood and foliage to inhibit mold regrowth on fungal colonized wood was evaluated on Douglas-fir sapwood. Most foliage extracts produced some inhibition of Graphium or Trichoderma species, but isolations of other fungi increased following treatment. Five out of eight wood extracts produced 50%...
Bacillus subtilis and essential oils have been explored separately for their ability to limit colonization by wood stain and mold fungi, but neither approach has been completely effective. One alternative strategy would be to combine the bacterial biocontrol with one or more natural products extracts. In this report, the ability...
Assessing the impact of fungal decay in wood structures poses a major challenge for building inspectors. Although models have been developed to predict degradation rate of building components in varying climatic conditions, most are hampered by the lack of fundamental data on effects of fungal attack on engineering properties. Developing...
The effect of metal end plates on reducing checking of pentachlorophenol-treated Douglas-fir crossarms was evaluated over 13 wet–dry cycles. Check development was variable over the first three to four cycles, and then steadily increased for both plated and nonplated ends of arms; however, both the number of checks and the...
Preservative treatments are required whenever glued laminated beams are exposed outdoors. Treatments can be either water-based systems applied to individual laminations prior to layup or organic solvent–borne systems applied after the beams are fabricated. Water-based systems are not recommended for posttreatment because of concerns over checking and the potential for...
The resistance of three naturally durable heartwood species and a stranded giant bamboo product to fungal and termite (Coptotermes formosanus) attack was evaluated at a test site located near Hilo, Hawaii. Merbau (Intsia bijuga or I. palembanica) and ipe (Tabebuia spp.) were both exceptionally resistant to fungal and termite attack,...
A solid, crystalline fumigant (dazomet) with and without a supplemental copper compound was evaluated as an internal decay control treatment on Douglas-fir poles in two long-term field tests. Methylisothiocyanate (MITC), the decomposition
product of dazomet, was used as a measure of effectiveness. MITC levels in the wood were above the...
The amounts of treated wood present at a wood recycling center in western Oregon were surveyed over a 10-year period. Treated wood was found at 106 of 112 inspections, but the levels never exceeded 2 percent of the volume present. The amount of treated wood averaged 0.15 percent of the...
An aging electricity distribution system and reduced availability of naturally durable tropical hardwoods in Australia will
combine in the next decade to produce a major shortage of poles. One approach to mitigating this shortage is to utilize lower
durability species and improve the penetration of preservatives into the refractory heartwood...
While wood plastic composites have gained an increasingly large share of the market for decks and other outdoor structures, there are many questions about the long-term potential for biodeterioration of these materials. While the plastic does appear to retard moisture uptake, thereby slowing the rate of degradation, a number of...