Associations between the golden metallic beetle, Buprestis aurulenta L., and wood-destroying fungi were explored with adult beetles collected from log decks. A variety of fungi were isolated from the beetle bodies by four methods. A total of 863 isolations were made from 59 females and 21 males. There was no...
The effect of supercritical fluid treatment on superficial gas permeability of Douglas-fir was investigated by using carbon dioxide either alone or amended with methanol. Permeability increased in a majority of samples, although nearly one-third of the specimens declined in permeability. Improvements in permeability appeared to be unrelated to variations in...
Adverse effects on mechanical properties from using a supercritical fluid (SCF) to increase preservative penetration of refractory woods were evaluated by treating small ponderosa pine sapwood specimens with supercritical carbon dioxide at 64 combinations of temperatures (35 to 80 C), pressure (1,000 to 4,000 psig), and time (0.5 to 2...
A new laboratory technique to simulate the initiation of wood decay and to assess the effects of incipient decay on material properties is described. Douglas-fir heartwood specimens were exposed to brown-rot (Postia placenta and Gloeophyllum trabeum) fungi for various periods. Bendlng properties were determined by nondestructive and destructive tests, and...
The effect of pretreatment of Douglas-fir flakes with CCA-C, borate, and azaconazole on properties of flakeboard was studied. Flakes had higher retention levels of CCA-C and borate in their ends than in their centers. The distribution of chemicals was uniform in panels, which indicates that the chemicals did not migrate...
The effects of moisture content, flow direction, concentration, and temperature on the diffusion of chloropicrin in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) heartwood were investigated. Diffusion coefficients were strongly affected by wood moisture content. Coefficients for radial and tangential diffusion at the fiber-saturation point were twice as high as those at...
Vapam(r) (NaMDC) is the fumigant most commonly used to arrest and control decay of utility poles. While volatile fungitoxins are detectable only 1 to 2 years after treatment, poles treated with Vapam(r) remain free of decay fungi for 6 to 17 years. Vapam(r) decomposes to produce volatile fungicides as well...
Tests were conducted to determine the effect of ACZA composition on fixation and the roles of adsorption and precipitation in fixation. The sites of copper and zinc adsorption within the treated wood and the bonding environment of adsorbed copper were also examined. The results generally support the finding that arsenic...
The relationship between moisture content and the presence of methylisothiocyanate (MITC) in wood following various applications of sodium n-methyldithiocarbamate (NaMDC) was investigated with small Douglas-fir heartwood blocks. While MITC levels were initially higher in wetter blocks, MITC levels in drier blocks remained more stable over the 8-week test period. The...
Studies of the effects of various chemicals on fungal growth are difficult to perform on filamentous fungi because of the difficulty of observing the protoplasm through the rigid hyphal wall, and because most activity occurs in the region near the hyphal tip. However, hyphae can be exposed to certain enzymes...
Differences in stain susceptibility were evaluated on sterile and unsterile samples of freshly sawn, frozen and thawed, or oven-dried and rewetted ponderosa pine sapwood. Samples treated with sterile medium or with medium inoculated with either Pseudomonas putida or Bacillus subtilis were inoculated with selected wood-staining fungi. In general, fresh unsterile...
The effects of supercritical fluid (SCF) impregnation on physical properties of composites were investigated at various pressures, temperatures, and treatment times with carbon dioxide as the fluid and tebuconazole as a biocide. In general, within the ranges tested, SCF treatment had no negative effects on modulus of rupture (MOR), modulus...
This report describes the relationship of incising-induced strength loss in bending as a function of preservative treatment and incising pattern, density, and depth of penetration for various machine stress-rated (MSR) grades of full-size 2 by 4 Douglas-fir, Hem-Fir, and Spruce-Pine-Fir (South) dimension lumber. This study may represent a worst-case "incising...
The high decay resistance of western redcedar (Thuja plicata Donn) is due to the presence of toxic extractives, called tropolones, in the heartwood. Therefore, tropolone content may be used as an indicator of decay resistance. With increment core-sized samples of western redcedar heartwood, we used gas chromatography to measure tropolone...
Preservative treatment of whole, wood-based composite products (mainly panels) has disadvantages; problems largely stem from swelling, strength loss, and incomplete or inappropriate penetration during treatment, and distortion during redrying. Pretreatment of comminuted wood prior to mat lay-up is one alternative, though the addition of chemicals may affect bonding during subsequent...
Although boron has many advantages as a wood preservative, this chemical performs poorly in leaching exposures. In this study, we investigated the potential for decreasing the leachability of boron preservatives with polyethylene glycol (PEG). Southern pine (Pinus spp.) test samples impregnated with combinations of sodium borate or boric acid and...
Heartwood durability of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) was studied as a function of vertical and radial position in boles of trees with a wide range of leaf area/sapwood area ratios. Six 34- year-old trees were harvested from each of three plots established 14 years before: very dense,...
This study examines the effects of pressure, temperature, and treatment time on supercritical fluid impregnation of such composites as plywood, particleboard, flakeboard, and medium-density fiberboard. Carbon dioxide with methanol as a cosolvent was used as the supercritical fluid, with tebuconazole as the biocide. Biocide distribution, as measured by extraction and...
The fungitoxicity of carbon disulfide (CS2), methylisothiocyanate (MITC), or a mixture of these two gases, to selected wood-degrading fungi was studied by using a fumigation apparatus. Both gases are important decomposition products of metham sodium, the most commonly used fumigant for internal treatment of large wood members. Carbon disulfide (up...
This study evaluated the effects of pretreatment incising of dry lumber and preservative treatment on the shear strength of 1980 pieces of 2 X 4 dimension lumber (nominal 50 mm X 100 mm X 3.6 m long). Three species groups (Douglas-fir, Hem-Fir. and Spruce-Pine-Fir-South) and two commercially produced machine-stress-rated grades...
Hyphal fragments and protoplasts of two wood-degrading fungi, Postia placenta and Trametes versicolor, were used to examine the effects of two fungicides, copper sulfate and azaconazole, on fungal health (as measured by oxygen consumption, glucose utilization, potassium levels, cell regeneration, and copper uptake). Although both cell systems responded to the...
Impact bending and breaking radius were used to measure loss in toughness caused by basidiomycetes isolated from wood. Small test pieces were used to accelerate testing. Wide differences were found among, and sometimes within, the 26 species tested. Brown-rot fungi tended to cause greater losses than white-rot fungi, but no...
A small block test was used in assessing whether pelletized sodium n-methyldithiocarbamate (NaMDC) would decompose and produce methylisothiocyanate (MITC) and thereby eliminate Antrodia carbonica colonies from Douglas-fir heartwood. Also evaluated were the effects of wood moisture content, dosage, incubation period, pH level, and presence of copper sulfate on percentage of...
Basamid (3,5-dimethyl-l,3,5,2H-tetrahydrothiadiazine-2-thione), a crystalline powder first used as a soil sterilant, has shown promise as a wood fumigant. This chemical decomposes to methylisothiocyanate (MITC), the primary active ingredient, as well as other products; but the rate of decomposition in wood is too slow to be effective unless certain catalysts are...
Wood that is submerged in fresh water for long periods has increased permeability and other changed properties. Wood that is submerged in salt water may absorb considerable quantities of salts, which may render the wood resistant to microbial colonization. In this report, we describe decay tests on Douglas-fir sapwood and...
The effect of various wood characteristics on decomposition of metham sodium to methylisothiocyanate in sixteen North American and Southeast Asian hardwoods and softwoods was investigated. While marked differences were noted in the degree of decomposition among some species, the relationship between decomposition and lignin content, extractive levels, wood pH, or...