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The efficacy of biodiesel as a co-solvent for copper naphthenate wood preservative treating solutions was evaluated using two fungal decay methodologies (AWPA E10-09, British Standard Method EN113). Four fungal species (Gloeophyllum trabeum, Trametes versicolor, Poria xantha, Postia placenta) and three wood species (Douglas fir, Southern yellow pine, Western red cedar) with six replicates were utilized in both studies. Two levels of biodiesel: diesel (30:70 and 50:50) were compared to diesel-only solvent systems for copper naphthenate treating systems and treated to AWPA recommended retentions. No differences in decay efficacy between the biodiesel blends and diesel-only treatment in either the AWPA or the EN113 decay studies were detected for either standard method. Copper distribution was evaluated using SEM-EDX and no differences were noted with either solvent system. It was determined that the presence of biodiesel did not have a negative impact upon the efficacy of copper naphthenate as a wood preservative.

The goal of this study was to undertake a microbial investigation of the Historic Huts areas on Ross Island, to gain knowledge of the fungal biodiversity and biochemical framework, focusing on the wood degrading potential of these fungi at both psychrophilic (cold) and mesophilic (moderate) temperatures. Eight hundred and forty nine samples were collected from three Heroic Era Historic Huts of Antarctica, from a variety of substrates but predominantly structural wood. The huts, Discovery Hut at Hut Point, Terra Nova Hut at Cape Evans and Nimrod Hut at Cape Royds, are located on Ross Island and were all assembled in the early 20th century by the Heroic Era explorers to house the expeditions, stores and animals. These wooden huts were abandoned when the expeditions left. The introduction of wood and other organic material to a pristine environment along with the creation of a microclimate within the harsh Antarctica environment created interesting sites for studying fungal diversity, wood decay and fungal cellulase enzymes in an extreme environment. Each hut can be classified as offering different conditions and circumstances for fungal propagules. Of the three huts, Terra Nova Hut is the only hut where there are visible fungal blooms within the hut and it, with Discovery Hut, had the greatest number of samples that contained fungi compared to Nimrod Hut which had the least. Discovery Hut, at less than 500 metres from the United States McMurdo Station, is the most visited by scientist and base staff and has been the most demonstrably affected by human impact of the three huts due to its closeness to the research stations on Ross Island To ensure a full understanding of the fungal diversity of the Historic Hut sites, a variety of sampling techniques were used along with a variety of culture media. Two thousand and seventy six isolates consisting of 1177 filamentous fungi and 899 single celled microorganisms (yeast and bacteria) were isolated; all these cultures were frozen and now form the University of Waikato Antarctic Culture Collection. Five genera dominated the fungal isolates that were identified and these were Cladosporium, Geomyces, Cadophora, Penicillium and Thelebolus. The fungal diversity of these Historic Huts' communities is low but the members present are metabolically active, consistent with other microbial communities in the Antarctic. The Historic Huts and surroundings contain a diverse array of provision in the way of wood and supplies, which provide nutrient sources for fungal growth. Endemic organisms present in the soil could have been enriched by using the introduced nutrient sources as primary and/or second metabolic substrates. In addition, fungi could have been introduced with the wooden huts and supplies when they were brought to Antarctica by the Heroic Era explorers, or introduced in the subsequent years with visitors and conservation work conducted at the sites. These introduced organisms, though, would have had to adapt to the change in climate and conditions posed by the Antarctic in order to survive and be subsequently isolated in this study. A screen for carboxymethylcellulase (CMCase) activity was done on a selection of the fungal isolates as the first step to understand the cellulytic potential of the Antarctica fungal community inhabiting the huts. One hundred and six fungal isolates from a total of 404, that were screened were deemed to be CMCase positive, 27 fungal isolates were chosen for further study including quantifying the activity of extracellular endo-1,4-β-glucanase at psychrophilic and mesophilic incubation temperatures. All but one isolate could produce endo-1,4-β-glucanase activity at 4 C and many produced more endo-1,4-β-glucanase activity at 4 C than at 15 C. Cadophora malorum 182, Cadophora malorum 242, Penicillium roquefortii 405, Penicillium roquefortii 408, Geomyces sp. 711, Geomyces sp. 824 and Cladosporium oxysporium 805 were selected for in-depth study of growth characteristics including growth temperature preferences, growth on a variety of cellulose substrates, water activity, and carbon sources, the latter done by using a commercially available microtitre plate containing 95 carbon sources. All seven of the fungal isolates were classified as psychrotolerant and produced, when cultured at either 4 C or at 15 C, cellulase, protease, amylase, xylanase, and pectinase and mannanase enzyme activities. The range of water activity that the Antarctic Penicillium roquefortii isolates could grow at was distinctive when compared with food Penicillium roquefortii isolates. The utilisation of different carbon sources showed that like many studies of Antarctica organism they have a diverse range of enzymatic activity, but interestingly the activity does not differ greatly with incubation temperature with most carbon sources being used or not used at both incubation temperatures tested. Although it took longer for the fungi to grow at the psychrophilic temperatures, the range of carbon sources they utilised was not reduced. The protein composition of the extracellular supernatants was visualised using various electrophoretic and staining techniques. The cellulase activity of the protein bands was visualised by cellulose-containing zymograms, which illustrated that the cellulase complex in all fungi tested was multi-enzyme and differed between species, isolates and temperatures of culturing. The cellulase activity of Cadophora malorum 182 was enriched by purification techniques including ion exchange chromatography and native preparative electrophoresis. The protein complex was not purified to homogeneity, but enriched for a mixture of proteins and the mixture was described as having the following properties; a temperature range of β-1,4-glucan cellobiohydrolase activity from 20 C to 80 C with the optimum activity seen at 60 C, β-1,4-glucan cellobiohydrolase activity that is stable at 4, 25 and 40 C for at least 24 hrs, lost at 50 C and 80 C within 24 hrs and 2 minutes respectively. Along with β-1,4-glucan cellobiohydrolase activity, the protein mixture contained Avicelase, CMCase, xylanase and mannanase activity. The thesis research showed that there was limited fungal diversity in the Historic Huts and artefacts (a total of five dominant genera were identified) but the fungi are actively growing and producing viable spores in the cold of Antarctica and producing the necessary enzymes for degradation of wood. Although the metabolism and growth rate is slower at psychrophilic temperatures, the fungal isolates studied as part of this thesis research could still function enzymatically at cold temperatures and this includes the degradation of wood as evidenced by in vitro wood decay studies examined by scanning electron microscopy where two isolates of one species demonstrated the ability to degrade wood. The cellulase complex of the investigated fungal isolate was multi-enzymed and although the components were not purified to homogeneity, an enriched mixture of proteins had enzyme activity and stability in a broad temperature range, and activity to a variety of cellulosic substrates. This thesis research adds to the knowledge of the fungal biodiversity in the Antarctic and increases the understanding of the biochemical framework, participating in relation to wood decay potential of these Antarctic fungal isolates.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.

Real-time RT-PCR was used to assess the effects of interspecific microbial interactions on the expression of genes associated with lignin peroxidase, manganese peroxidase and alcohol oxidase production during the wood decay process. Expression levels of genes encoding the selected lignolytic enzymes were quantitated in one-, two- and multiple-organism interaction tests with the basidiomycetes Trametes elegans, Phanerochaete chrysosporium, Gloeophyllum sepiarium and Gloeophyllum trabeum. Compression strength loss was measured for each decay sample and correlated with gene expression data for each species. Soil microflora actively producing lignolytic enzymes during wood decay were also assessed and identified using degenerative PCR coupled with denaturing gradient gel electrophoresis, cloning and cycle sequencing. Differential expression was detected in three genes in the two-organism interaction tests: manganese peroxidase in T. elegans interactions, lignin peroxidase A in P. chrysosporium interactions and alcohol oxidase in G. sepiarium interactions. A positive linear correlation was observed between lignin peroxidase A expression and compression strength loss in P. chrysosporium interactions.

The use of near infrared (NIR) spectroscopy for predicting levels of degradation in laboratory soil block tests was investigated. Calibrations were developed for mass loss, compression strength, and exposure period using data measured from the prior methods, and untreated and mathematically treated (multiplicative scatter correction and first and second derivative) NIR spectra from various spans of wavelengths by partial least squares regression. Strong correlations were obtained from each study conducted, while calibrations developed from NIR spectra from the cross-sectional face of southern yellow pine presented the strongest predictions. Of them, calibrations for mass loss resulted in the strongest predictions. Calibrations constructed from spectra obtained from the radial face of southern yellow pine also produced strong predictions, where the strongest model was for exposure period. While, calibrations developed for cottonwood presented the weakest statistics, the strongest calibration found was for exposure period.

Landscapes are comprised of multiple ecosystems shaped by disturbances varying in severity and source. Moderate disturbance from weather, pathogens, insects, and age-related senescence, in contrast to severe disturbances that fell trees, may increase standing woody debris and alter the contribution of coarse woody debris (CWD) to total ecosystem respiration (RE). However, woody debris dynamics are rarely examined following moderate disturbances that substantially increase standing dead wood stocks. We used an experimental manipulation of moderate disturbance in an upper Great Lakes forest to: 1) examine decadal changes in CWD stocks through a moderate disturbance; 2) quantify in situ CWD respiration during different stages of decay for downed and standing woody debris and; 3) estimate the annual contribution of CWD respiration to the ecosystem C balance through comparison with RE and net ecosystem production (NEP). We found that the standing dead wood mass of 24.5 Mg C ha-1 was an order of magnitude greater than downed woody debris stocks and a large source of ecosystem C flux six years following disturbance. Instantaneous in situ respiration rates from standing and downed woody debris in the earliest stages of decay were not significantly different from one another. Independently derived estimates of ecosystem CWD respiration of 1.1to 2.1 Mg C ha-1 yr-1 six years following disturbance were comparable in magnitude to NEP and 12.5 % to 23.8 % of RE, representing a substantial increase relative to pre-disturbance levels. Ecosystem respiration and NEP were stable following moderate disturbance even though ecosystem CWD respiration increased substantially, suggesting a reduction in the respiratory C contribution from other sources. We conclude that CWD is an essential component of the ecosystem C balance following a moderate forest disturbance.

In many regions of North America, Europe, and Australia, wood utility poles are used as main and secondary structural members for the support of electrical distribution and transmission lines. In the province of Ontario alone there are over 40000 H-frame, 6000 Gulfport, and thousands of single pole structures constructed of over 2 million wood utility poles (Pandey et al. 2010b). Currently, utility companies report an increasing number of woodpecker damage incidents on in-service utility poles (HONI 2010). In addition, many aging poles have woodpecker damage in combination with wood decay. Both these forms of degradation cause strength reductions in utility poles, making their structural integrity questionable. This has raised concerns regarding the safety of utility maintenance workers and the public, and the dependability of the electrical network. In response to these concerns, Hydro One Networks Incorporated (HONI) initiated a research project on the effect of woodpecker damage and wood decay on wood utility pole strength. The objective of the research was to develop methods of quantifying the strength reduction caused by woodpecker damage and wood decay. This information was then used to develop in-service assessment methods for determination of whether pole replacement is necessary when specific levels of woodpecker damage and wood decay are present. By developing better assessment methods, in-service utility poles will not be unnecessarily replaced, reducing maintenance costs. In this study, three analytical models were developed that predicted the theoretical cross-sectional strength reduction caused by the presence of woodpecker damage. A bending failure model was developed since, in the structural design of utility poles, bending moment stresses are known to be the critical design parameter. It was decided that the significance of shear stress in a cross-section should also be considered since the presence of woodpecker damage could cause shear stresses to be a significant parameter. As a result, a shear-bending and a shear failure model was developed to determine the significance of shear stress on cross-section behaviour. These models were developed for analysis purposes and were verified by the subsequent experimental program. A total of 28 new and in-service utility poles were received from HONI for experimental testing. The new poles were received in as-new condition, while the in-service poles received had varying levels of woodpecker damage and wood decay. The poles received were cut into 4.25 m lengths for beam testing. A single new pole and in-service specimen from each pole was tested as a control specimen without woodpecker damage to obtain reference utility pole bending strengths. The remainder of the new pole specimens were mechanically introduced with woodpecker damage, while the remainder of the in-service specimens were tested with natural woodpecker damage. The tested specimens were analyzed and the results were compared with the woodpecker damage analytical model predictions. Results indicated that the effect of woodpecker damage is well modelled by the woodpecker damage analytical models. Overall, the bending failure analytical model was preferable for cross-section analysis due to the accuracy of the model predictions and the simplicity of required calculations. It was evident from the experimental program that the presence of woodpecker damage can severely reduce the strength of utility poles, making replacement necessary according to CSA C22.3 No. 1 Cl. 8.3.1.3 (2006a). In-service specimen experimental results indicated that if wood decay is detected in wood utility poles, severe reduction in wood strength has occurred and the utility pole should be replaced. Analytical and experimental results were used to develop three application methods for determining whether utility pole replacement is necessary due to the presence of woodpecker damage. These three methods include the simplified method, the chart method, and the case-specific method. The simplified method allows determination of whether a utility pole should be replaced based only on knowledge of the most severe level of woodpecker damage present in a pole. The chart method takes into account additional factors such as the diameter of the pole at the location of the woodpecker damage and the width of the hole opening. The case-specific method is advantageous since it accounts for the parameters used in the chart method and allows the location of woodpecker damage along the length of a pole to be accounted for. The simplified and chart methods are preferable since they are relatively simple and easy to implement in the field. The case-specific method requires a full structural analysis of the utility pole in question to be undertaken and is useful for more accurately assessing whether replacement is necessary. These three methods show how the research completed can be used for improved assessment of in-service utility poles resulting in reduced unnecessary pole replacement and maintenance costs.