scholarly journals Effect of the degree of decay on the electrical resistance of wood degraded by brown-rot fungi

2019 ◽  
Vol 49 (2) ◽  
pp. 145-153 ◽  
Author(s):  
Shan Gao ◽  
Xiaoquan Yue ◽  
Lihai Wang
Keyword(s):  
Moisture Content ◽  
Mass Loss ◽  
Electrical Resistance ◽  
Dominant Role ◽  
Treated Wood ◽  
Wood Decay ◽  
Brown Rot ◽  
Brown Rot Fungi ◽  
Study Results ◽  
Significant Difference

There have been limited efforts to investigate the association between wood decay and electrical resistance; consequently, we have examined the change in the electrical resistance of wood progressively decayed by brown-rot fungi to elucidate the effect of the degree of decay. The rate of mass loss of wood was used as an indicator of the degree of fungal decay. The changes in the moisture content and ion concentrations were measured at various decay stages. The results showed a significant difference in the electrical resistances of sound wood and fungal-treated wood after 24 weeks. The electrical resistance significantly decreased with the exposure time. The degree of decay increased as the mass loss increased, resulting in the severe breakdown of cell walls and the accumulation of fungal mycelia. Empirical models related to the rate of mass loss and the percent decrease in the electrical resistance were established. The moisture content and cation concentrations increased to various degrees in decayed wood. This increase in the cation concentration was considered to play a dominant role in the decrease in the electrical resistance. The study results provide valuable information for developing an electrical resistance based method coupled with ion content measurements for incipient wood decay detection.

scholarly journals Effect of Concrete on the pH and Susceptibility of Treated Pine to Decay by Brown-Rot Fungi

Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 41 ◽  
Author(s):  
Darrel Nicholas ◽  
Amy Rowlen ◽  
David Milsted
Keyword(s):  
Treated Wood ◽  
Untreated Wood ◽  
Brown Rot ◽  
Consistent Difference ◽  
Ground Contact ◽  
Decay Fungi ◽  
Brown Rot Fungi ◽  
Organic Systems ◽  
Decay Tests ◽  
Copper Azole

Treated wood timbers employed in ground contact are often installed with a cement collar to firmly fix the structural wood post in place. Few prior studies have determined the effect of concrete on decay efficacy on treated wood, however. Treated wood nominal 4 × 4 posts were installed at four locations, with the upper ground-contact portion of each post encased in concrete, and the samples removed at various times for pH measurements. The wood alkalinity quickly increased at all four sites for the portion of the treated wood in concrete contact compared to the wood in ground contact without concrete. In laboratory decay tests employing three decay fungi, untreated wood which was first exposed or unexposed to concrete had no consistent difference in decay susceptibility. For wood treated with three different commercial copper/organic systems, cement exposure had no effect on wood treated with an amine copper azole system, while treatment with amine copper quat showed a statistically significant fungal efficacy enhancement for cement-exposed samples with both copper-tolerant fungi. Conversely, with a micronized copper azole preservative, cement exposure resulted in reduced fungal efficacy compared to treated samples which were not cement-exposed for all three decay fungi.

Variation in germination percentage of basidiospores collected successively from wood decay fungi in culture

1983 ◽  
Vol 61 (1) ◽  
pp. 171-173 ◽  
Author(s):  
E. L. Schmidt ◽  
D. W. French
Keyword(s):  
Spore Germination ◽  
White Rot Fungi ◽  
Wood Decay ◽  
Brown Rot ◽  
Germination Percentage ◽  
White Rot ◽  
Malt Extract ◽  
Decay Fungi ◽  
Brown Rot Fungi ◽  
Wood Decay Fungi

Successive collections of basidiospores, produced in culture from the same hymenial areas of four species of wood decay fungi, were tested for spore germination percentage on malt extract agar under controlled conditions. Spores from white rot fungi retained high germination levels after 5 weeks of spore production, but germination averages for brown rot fungi decreased by more than 50%. Such variation should be considered in wood pathology research using spore germination bioassay.

Changes in Carbon Sequestration in Wood During Decay by Brown- and White-Rot Fungi

2020 ◽  
Vol 14 (3) ◽  
pp. 414-419
Author(s):  
Huadong Xu ◽  
Jiedong Wei ◽  
Yanan Di ◽  
Ruixia Qin ◽  
Zonglin Zhen
Keyword(s):  
Carbon Sequestration ◽  
Mass Loss ◽  
Decay Time ◽  
Carbon Emission ◽  
Wood Decay ◽  
Brown Rot ◽  
White Rot ◽  
Korean Pine ◽  
Decay Test ◽  
The Absolute

Wood decay is a releasing process of carbon fixed in the wood. The study on carbon sequestration change caused by decay can provide a theoretical basis for wood preservation and utilization. At present, there are few reports on decay influence on wood carbon emission and no corresponding quantitative data. Therefore, one broad-leaved species, Poplar, and one coniferous species, Korean pine, were selected as the research object, and brown rot fungus (Gloeephyllum trabeum) and white rot fungus (Coriolus versicolor) were used to conduct accelerated decay test on wood samples in the laboratory. During decay, specimens were taken out in different periods to measure chemical properties, mass loss and carbon sequestration. The influence of decay time on carbon sequestration, chemical component and mass loss were then analyzed and the change rule of carbon sequestration were finally studied. The results showed that with increasing decay time, the relative carbon sequestration content of wood affected by different types rot fungi decreased, which was consistent with the change rule of mass loss, indicating that decay would lead to a loss of wood mass and affect its carbon sequestration. However, the absolute carbon sequestration (measured value of carbon sequestration) after brown rot treatment did not decrease but increased slightly, which was different from previous expectation. According to the analysis, with increasing brown rot time, the absolute content and proportion of lignin in wood samples increased slightly, while the corresponding value of holocellulose (including α-cellulose and hemicellulose) decreased significantly. The carbon content of lignin per unit mass is higher than that of holocellulose (Poplar 64.08% > 37.38%; Korean pine 66.37% > 35.94%), resulting in absolute carbon sequestration in wood increases instead of decreases. In conclusion, the change of lignin proportion during the process of brown rot is the decisive factor affecting the change of absolute carbon sequestration. This study focused on two aspects of wood decay and wood carbon sequestration, systematically analyzed the change rule and internal mechanism of wood carbon sequestration with the increase of wood decay degree, and accumulated basic data for wood carbon emission reduction and wood prevention.

scholarly journals Localizing gene regulation reveals a staggered wood decay mechanism for the brown rot fungusPostia placenta

2016 ◽  
Vol 113 (39) ◽  
pp. 10968-10973 ◽  
Author(s):  
Jiwei Zhang ◽  
Gerald N. Presley ◽  
Kenneth E. Hammel ◽  
Jae-San Ryu ◽  
Jon R. Menke ◽  
...  
Keyword(s):  
Cell Walls ◽  
Plant Biomass ◽  
Wood Decay ◽  
Brown Rot ◽  
Glycoside Hydrolases ◽  
Ros Generation ◽  
Rna Seq ◽  
Postia Placenta ◽  
Brown Rot Fungi ◽  
Whole Transcriptome

Wood-degrading brown rot fungi are essential recyclers of plant biomass in forest ecosystems. Their efficient cellulolytic systems, which have potential biotechnological applications, apparently depend on a combination of two mechanisms: lignocellulose oxidation (LOX) by reactive oxygen species (ROS) and polysaccharide hydrolysis by a limited set of glycoside hydrolases (GHs). Given that ROS are strongly oxidizing and nonselective, these two steps are likely segregated. A common hypothesis has been that brown rot fungi use a concentration gradient of chelated metal ions to confine ROS generation inside wood cell walls before enzymes can infiltrate. We examined an alternative: that LOX components involved in ROS production are differentially expressed by brown rot fungi ahead of GH components. We used spatial mapping to resolve a temporal sequence inPostia placenta, sectioning thin wood wafers colonized directionally. Among sections, we measured gene expression by whole-transcriptome shotgun sequencing (RNA-seq) and assayed relevant enzyme activities. We found a marked pattern of LOX up-regulation in a narrow (5-mm, 48-h) zone at the hyphal front, which included many genes likely involved in ROS generation. Up-regulation of GH5 endoglucanases and many other GHs clearly occurred later, behind the hyphal front, with the notable exceptions of two likely expansins and a GH28 pectinase. Our results support a staggered mechanism for brown rot that is controlled by differential expression rather than microenvironmental gradients. This mechanism likely results in an oxidative pretreatment of lignocellulose, possibly facilitated by expansin- and pectinase-assisted cell wall swelling, before cellulases and hemicellulases are deployed for polysaccharide depolymerization.

Composition and diversity of fungi on decaying logs in a New Zealand temperate beech (Nothofagus) forest

2000 ◽  
Vol 30 (7) ◽  
pp. 1025-1033 ◽  
Author(s):  
Robert B Allen ◽  
Peter K Buchanan ◽  
Peter W Clinton ◽  
Angela J Cone
Keyword(s):  
New Zealand ◽  
Moisture Content ◽  
Habitat Heterogeneity ◽  
Nutrient Concentration ◽  
Brown Rot ◽  
Brown Rot Fungi ◽  
Early Stages ◽  
Cation Concentration ◽  
Nothofagus Forest ◽  
Dominant Pattern

Saprobic fungal taxa on decomposing mountain beech (Nothofagus solandri var. cliffortioides (Hook. f.) Poole) logs were investigated in relation to properties of logs including stage of decay, size, nutrient concentration, and moisture content. We also determined whether logs become increasingly heterogeneous in nutrient concentration and moisture content with decay and also whether log heterogeneity related to fungal taxa diversity. Sporocarps were collected from the same 75 logs in spring (November 1995, 80 taxa) and autumn (May 1996, 151 taxa). For both seasons the dominant pattern in fungal taxa composition was only weakly related to measured properties of logs; however, a secondary pattern was found related to a fungal taxa succession reflecting stage of decay. In the autumn collection, Biscogniauxia capnodes (Berk.) Y.-M. Ju & J.D. Rogers and Schizopora nothofagi (G. Cunn.) P.K. Buchanan & Ryvarden occurred on small logs in the early stages of decay, with relatively low N. Decayed logs, with relatively high N, were characterized by Marasmius otagensis G. Stev. and Athelia epiphylla Pers. Our observations were not consistent with previously described successional trends from soft- to white- and brown-rot fungi as logs decay. The number of fungal taxa increased with log volume, and, additionally for the autumn collection, with heterogeneity in cation concentration suggesting habitat heterogeneity may be a factor in explaining log fungal taxa diversity.

Comparative Morphology of Early Stages of Brown-Rot Wood Decay

IAWA Journal ◽  
1993 ◽  
Vol 14 (2) ◽  
pp. 127-138 ◽  
Author(s):  
W. Wayne Wilcox
Keyword(s):  
Wood Decay ◽  
Brown Rot ◽  
Comparative Morphology ◽  
Diagnostic Feature ◽  
Postia Placenta ◽  
Brown Rot Fungi ◽  
Early Stages ◽  
Poria Placenta ◽  
White Fir ◽  
Early Progression

Early stages of decay by two brown-rot fungi in two woods were studied by light and scanning electron microscopy. The earliest diagnostic feature to appear was hyphae in the earlywood lumina. The earliest effect on cell walls was the loss of birefringence in the earlywood; Poria placenta (syn. Postia placenta) caused this loss at the earliest stage of decay observed, in both Douglas-fir and white fir, while Gloeophyllum trabeum caused significant weight loss before loss of birefringence was visible. Attack on the latewood progressed from the earlywood, and was different in pattern among the wood/fungus combinations. Hyphal and bore hole diameter increased throughout the early progression of decay and would be useful in evaluating the stage of decay, if the starting diameter of hyphae could be determined. Separation between cells was not observed until moderate stages of decay and, therefore, was not useful in diagnosing early stages of decay.

scholarly journals Efficacy of Caffeine Treatment for Wood Protection—Influence of Wood and Fungi Species

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3758
Author(s):  
Miloš Pánek ◽  
Vlastimil Borůvka ◽  
Jana Nábělková ◽  
Kristýna Šimůnková ◽  
Aleš Zeidler ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Beech Wood ◽  
Ecological Integrity ◽  
Treated Wood ◽  
Physical And Mechanical Properties ◽  
Brown Rot ◽  
European Beech ◽  
Brown Rot Fungi ◽  
Wood Protection ◽  
Caffeine Treatment

In the future, we can expect increased requirements to the health and ecological integrity of biocides used for the protection of wood against bio-attacks, and it is therefore necessary to search for and thoroughly test new active substances. Caffeine has been shown to have biocidal efficacy against wood-destroying fungi, moulds and insects. The aim of the research was to determine whether the effectiveness of caffeine, as a fungicide of natural origin, is affected by a different type of treated wood. Norway spruce mature wood (Picea abies), Scots pine sapwood (Pinus sylvestris), and European beech wood (Fagus sylvatica) were tested in this work. The samples were treated using long-term dipping technology or coating (according to EN 152:2012) and then tested against selected wood-destroying brown rot fungi according to the standard EN 839:2015, wood-staining fungi according to EN 152:2012, and against mould growth according to EN 15457:2015. The penetration of caffeine solution into wood depth was also evaluated using liquid extraction chromatography, as well as the effect of the treatment used on selected physical and mechanical properties of wood. The test results showed that the type of wood used and the specific type of wood-degrading agent had a significant effect on the effectiveness of caffeine protection. The most resistant wood was the treated spruce, whereas the most susceptible to deterioration was the treated white pine and beech wood. The results of the work showed that caffeine treatment is effective against wood-destroying fungi at a concentration of 2%, and at 1% in some of the tested cases. It can be used as an ecologically acceptable short-term protection alternative against wood-staining fungi in lumber warehouses and is also partially effective against moulds. It also does not have negative effects on changes in the physical and mechanical properties of the tested wood species.

scholarly journals Effects of Wood Moisture Content and the Level of Acetylation on Brown Rot Decay

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 299 ◽  
Author(s):  
Samuel L. Zelinka ◽  
Grant T. Kirker ◽  
Amy B. Bishell ◽  
Samuel V. Glass
Keyword(s):  
Moisture Content ◽  
Mass Loss ◽  
Linear Trend ◽  
Fungal Growth ◽  
Weight Percent Gain ◽  
Brown Rot ◽  
Weight Percent ◽  
Wood Moisture Content ◽  
Wood Moisture ◽  
Brown Rot Decay

Acetylation is one of the most common types of wood modification and is commercially available throughout the world. Many studies have shown that acetylated wood is decay resistant at high levels of acetylation. Despite its widespread use, the mechanism by which acetylation prevents decay is still not fully understood. It is well known that at a given water activity, acetylation reduces the equilibrium moisture content of the wood cell wall. Furthermore, linear relationships have been found between the acetylation weight percent gain (WPG), wood moisture content, and the amount of mass loss in decay tests. This paper examines the relationships between wood moisture content and fungal growth in wood, with various levels of acetylation, by modifying the soil moisture content of standard soil block tests. The goal of the research is to determine if the reduction in fungal decay of acetylated wood is solely due to the reduction in moisture content or if there are additional antifungal effects of this chemical treatment. While a linear trend was observed between moisture content and mass loss caused by decay, it was not possible to separate out the effect of acetylation from fungal moisture generation. The data show significant deviations from previously proposed models for fungal moisture generation and suggest that these models cannot account for active moisture transport by the fungus. The study helps to advance our understanding of the role of moisture in the brown rot decay of modified wood.

Wood decay by indoor basidiomycetes at different moisture and temperature

Holzforschung ◽  
2014 ◽  
Vol 68 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Tristan Stienen ◽  
Olaf Schmidt ◽  
Tobias Huckfeldt
Keyword(s):  
Moisture Content ◽  
Pinus Sylvestris ◽  
Mass Loss ◽  
Wood Decay ◽  
Metal Ring ◽  
Wood Moisture ◽  
Erlenmeyer Flask ◽  
Moisture Flow ◽  
Moisture Source ◽  
Coniophora Puteana

Abstract Some of the most important indoor wood-decay basidiomycetes were investigated in Erlenmeyer flask experiments, in which 50 Pinus sylvestris sapwood samples with moisture content (MC) of 16% were piled, in view of the parallel influence of wood moisture and temperature on decay in buildings. In the piles, the moisture flow from the liquid at the bottom was interrupted by a metal ring at layer 7. Laboratory incubations with Antrodia xantha, Coniophora puteana, Donkioporia expansa, and Gloeophyllum abietinum over the temperature range of 10°C–25°C showed that fungi are able to colonize, moisten, and thereafter degrade wood samples below fiber saturation, if a moisture source nearby is available. In extreme cases, mycelium grew on wood with 17.4% final MC, and wood mass loss of more than 2% occurred at 24.6% moisture.

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