Treesearch

The increased interest in copper-based wood preservatives has hastened the need for understanding why some fungi are able to attack copper-treated wood. Due in part to accumulation of oxalic acid by brown-rot fungi and visualization of copper oxalate crystals in wood decayed by known copper-tolerant decay fungi, oxalic acid has been implicated in copper tolerance by the formation of copper oxalate crystals. Nineteen isolates of the brown-rot fungus Wolfiporia cocos were evaluated for oxalic acid production and weight loss on wood treated with 1.2% copper citrate. Twelve of 19 isolates that...

Bioremediation of chromated copper arsenate-treated waste wood with one or more metal-tolerant bacteria is a potential method of naturally releasing metals from treated wood fibre. Sampling eight environments with elevated levels of copper, chromium, and arsenic resulted in the isolation of 28 bacteria with the capability of releasing one or more of the components from chromated copper arsenate-treated wood. The isolates represent 13 species of 8 different genera of soil-inhabiting bacteria. Three isolates, Acinetobacter calcoaceticus FN02, Aureobacterium esteroaromaticum VV03, and...

Recovery of chromated copper arsenate (CCA)-treated wood for reuse has been the focus of several international research groups due to the imminent disposal problem created when large quantities of CCA-treated wood ultimately come out of service. Bioleaching with Bacillus licheniformis CC01 and oxalic acid extraction are two methods known to remove significant quantities of metals from CCA-treated wood. Remediated particulate CCA-treated southern pine was reassembled into particleboard (PB) using 10% urea-formaldehyde resin. Particleboard panels were evaluated for internal bond (IB),...

This paper compares two new formulations of creosote and one pigment-emulsified creosote (PEC) with a formulation of creosote that met requirements of the AWPA standard P1/P13. Two softwood and two hardwood species were treated to four retention levels with each formulation. The evaluation of the four creosote formulations was done using (1) soil-block tests, (2) fungal cellar tests, and (3) field tests. This paper briefly discusses results from the soil-block tests, and updates previous reports to three years of fungal cellar tests and five years of field exposure in Saucier, Mississippi....

Since the 1920s creosote has been used extensively in the United States for treatment of construction timbers, poles, and posts. However, creosote has the tendency to exude or bbleedc from some treated commodities, producing a tar-like covered surface. In the United States, creosote-treated products exhibiting cleaner dried surfaces and a reduced tendency to bleed have been achieved through reduction of the xylene-insoluble carbonaceous fraction in creosote. In Australia, pigment-stabilized creosote emulsion formulations have been designed and developed to blockc the oil phase within the...

At very early stages of decay of wood by basidiomycete fungi, strength loss can be measured from wood before any measurable weight loss. Therefore, strength loss is a more efficient measure of incipient decay than weight loss. However, common standard decay tests (e.g. EN 113 or ASTM D2017) use weight loss as the measure of decay. A method was developed that allowed progressive removal of samples so that all stages of colonisation and decay could be monitored by strength testing, weight loss determination and chemical analysis. Our results indicated that substantial and rapid decay (90%...

A recently discovered coupling agent, hydroxymethylated resorcinol (HMR), based on resorcinol-formaldehyde, can greatly enhance wood-to-epoxy resin bond durability in exterior applications. However, for HMR to be most effective, it needs to be prepared a few hours before it is applied to the wood surface. In this study, carbon-13 nuclear magnetic resonance (NMR) spectroscopy was used to monitor composition of HMR as a function of time to characterize which chemical groups are present in solution when HMR is applied. A quantitative assessment of formaldehyde-derived groups required the use...

Indoor air quality problems resulting from the emission of volatile organic compounds (VOCs) have become an issue of increasing concern. Emissions from building and furnishing materials, which are frequently constructed from particleboard and medium density fiberboard (MDF), are a potentially important contributor of indoor VOCs. In this research, VOC emissions from particleboard and MDF were measured in small (53-L) stainless steel chambers for 4 days. Samples were collected from 53 of the 61 U.S. mills that produce particleboard and MDF. Each mill identified the predominant tree species...

Biomechanical pulping of whole logs pretreated with Phlebiopsis gigantea was investigated in several studies using loblolly and red pine. Results from these studies showed P. gigantea was able to colonize 90 to 100% of the freshly cut logs after 8 weeks, with little variation between replicate treatments. Up to a 59% decrease in resinous wood extractives was observed in loblolly and red pine logs inoculated with P. gigantea as compared to noninoculated logs. Simonsa staining, used to evaluate cell wall changes in mechanically refined pulp fibers during biological pulping processes, showed...

Mycelial interactions and allozyme analysis for glucose&phosphate isomerase activity were used to evaluate compatibility of pairings of single spore isolates (SSIs) within and between Laetiporus restriction groups (LRGs). SSIs from six collections of LRG II were completely compatible. SSIs from four LRG III collections from western North America were completely compatible, but those from a fifth collection of LRG III, from Michigan, were only partially compatible with those from the western LRG III collections. LRG II SSIs were incompatible with LRG III SSIs, and SSIs of these LRGs were...