Growth behavior of wood-destroying fungi in chemically modified wood: wood degradation and translocation of nitrogen compounds

Abstract Chemical wood modification has been used to modify wood and improve its decay resistance. However, the mode of protective action is still not fully understood. Occasionally, outdoor products made from chemically modified timber (CMT) show internal decay while their outer shell remains intact. Hence, it was hypothesized that wood decay fungi may grow through CMT without losing their capability to degrade non-modified wood. This study aimed at developing a laboratory test set-up to investigate (1) whether decay fungi grow through CMT and (2) retain their ability to degrade non-modified wood. Acetylated and 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) treated wood were used in decay tests with modified ‘mantle specimens’ and untreated ‘core dowels’. It became evident that white rot (Trametes versicolor), brown rot (Coniophora puteana) and soft rot fungi can grow through CMT without losing their ability to degrade untreated wood. Consequently, full volume impregnation of wood with the modifying agent is required to achieve complete protection of wooden products. In decay tests with DMDHEU treated specimens, significant amounts of apparently non-fixated DMDHEU were translocated from modified mantle specimens to untreated wood cores. A diffusion-driven transport of nitrogen and DMDHEU seemed to be responsible for mass translocation during decay testing.

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

Forests ◽

10.3390/f11010041 ◽

2019 ◽

Vol 11 (1) ◽

pp. 41 ◽

Cited By ~ 2

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.

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Mode of action of brown rot decay resistance in modified wood: a review

Holzforschung ◽

10.1515/hf-2013-0057 ◽

2014 ◽

Vol 68 (2) ◽

pp. 239-246 ◽

Cited By ~ 66

Author(s):

Rebecka Ringman ◽

Annica Pilgård ◽

Christian Brischke ◽

Klaus Richter

Keyword(s):

Cell Wall ◽

Mode Of Action ◽

Wood Decay ◽

Brown Rot ◽

Decay Resistance ◽

Hydroxyl Groups ◽

Decay Fungi ◽

Brown Rot Decay ◽

Thermally Modified Wood ◽

Modified Wood

Abstract Chemically or physically modified wood materials have enhanced resistance to wood decay fungi. In contrast to treatments with traditional wood preservatives, where the resistance is caused mainly by the toxicity of the chemicals added, little is known about the mode of action of nontoxic wood modification methods. This study reviews established theories related to resistance in acetylated, furfurylated, dimethylol dihydroxyethyleneurea-treated, and thermally modified wood. The main conclusion is that only one theory provides a consistent explanation for the initial inhibition of brown rot degradation in modified wood, that is, moisture exclusion via the reduction of cell wall voids. Other proposed mechanisms, such as enzyme nonrecognition, micropore blocking, and reducing the number of free hydroxyl groups, may reduce the degradation rate when cell wall water uptake is no longer impeded.

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Combined effect of boron compounds and heat treatments on wood properties: Boron release and decay and termite resistance

Holzforschung ◽

10.1515/hf.2006.072 ◽

2006 ◽

Vol 60 (4) ◽

pp. 455-458 ◽

Cited By ~ 12

Author(s):

S. Nami Kartal

Keyword(s):

Brown Rot ◽

Wood Properties ◽

Decay Resistance ◽

Heat Treatments ◽

Coptotermes Formosanus ◽

White Rot ◽

White Rot Fungus ◽

Termite Resistance ◽

Brown Rot Fungus ◽

Decay Tests

Abstract The decay and termite resistance of boric acid (BA)- and di-sodium octoborate tetrahydrate (DOT)-treated sugi sapwood was tested in the context of additional heat treatments at two temperature levels. Heat treatments had no effect on boron release and almost all boron was leached from specimens during a 10-day weathering period. Decay tests with the brown-rot fungus Fomitopsis palustris and the white-rot fungus Trametes versicolor and a 3-week termite resistance test with the subterranean termite Coptotermes formosanus were performed. Heat treatments did not increase the decay resistance of either BA- or DOT-treated specimens against the brown-rot fungus. However, the decay resistance of BA-treated specimens against the same fungus increased after heat treatment at 220°C for 2 h. Heat treatments at 180°C for 4 h and 220°C for 2 h also resulted in increased decay resistance of DOT-treated specimens against T. versi-color. Increased resistance against termite attack was observed only in DOT-treated specimens heated at 180°C for 4 h or at 220°C for 2 h. Accordingly, a synergistic effect between heat and DOT treatments was observed for resistance against white-rot decay and termites.

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Decay resistance of anhydride-modified Corsican pine sapwood exposed to the brown rot fungus Coniophora puteana

Holzforschung ◽

10.1515/hf.2006.105 ◽

2006 ◽

Vol 60 (6) ◽

pp. 625-629 ◽

Cited By ~ 30

Author(s):

Callum A.S. Hill ◽

Michael D. Hale ◽

Graham A. Ormondroyd ◽

Jin H. Kwon ◽

Simon C. Forster

Keyword(s):

Brown Rot ◽

Pinus Nigra ◽

Decay Resistance ◽

Exposure Test ◽

Weight Percentage ◽

Coniophora Puteana ◽

Chemically Modified ◽

Brown Rot Fungus ◽

The Relationship ◽

Modified Wood

Abstract Corsican pine (Pinus nigra) sapwood was chemically modified with acetic or hexanoic anhydride to a variety of weight gains. The modified wood was exposed to the brown rot fungus Coniophora puteana, and the relationship between weight loss due to decay and weight percentage gain, or degree of hydroxyl substitution, was determined in a 16-week exposure test. The effect of exposure time and the strain of C. puteana upon the decay protection threshold of acetylated Corsican pine was also examined.

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Gene Expression Analysis of Three Putative Copper-Transporting ATPases in Copper-Tolerant Fibroporia radiculosa

Frontiers in Microbiology ◽

10.3389/fmicb.2020.586940 ◽

2020 ◽

Vol 11 ◽

Author(s):

Katie M. Ohno ◽

Amy B. Bishell ◽

Glen R. Stanosz

Keyword(s):

Treated Wood ◽

Untreated Wood ◽

Brown Rot ◽

Wood Products ◽

Copper Tolerance ◽

Decay Fungi ◽

Putative Gene ◽

Gene Annotations ◽

Decay Test ◽

Copper Tolerant

Copper tolerance of brown-rot basidiomycete decay fungi can lessen the efficacy of copper-containing wood preservatives for wood products in-service. The purpose of this study was to evaluate wood mass loss and differential expression of three genes that have putative annotations for copper-transporting ATPase pumps (FIBRA_00974, FIBRA_04716, and FIBRA_01430). Untreated southern pine (SP) and SP treated with three concentrations of ammoniacal copper citrate (CC, 0.6, 1.2, and 2.4%) were exposed to two copper-tolerant Fibroporia radiculosa isolates (FP-90848-T and L-9414-SP) and copper-sensitive Gloeophyllum trabeum isolate (MAD 617) in a 4-week-long standard decay test (AWPA E10-19). Decay of copper-treated wood was inhibited by G. trabeum (p = 0.001); however, there was no inhibition of decay with increasing copper concentrations by both F. radiculosa isolates. Initially, G. trabeum and one F. radiculosa isolate (L-9414-SP) highly upregulated FIBRA_00974 and FIBRA_04716 on copper-treated wood at week 1 (p = 0.005), but subsequent expression was either not detected or was similar to expression on untreated wood (p = 0.471). The other F. radiculosa isolate (FP-90848-T) downregulated FIBRA_00974 (p = 0.301) and FIBRA_04716 (p = 0.004) on copper-treated wood. FIBRA_01430 expression by G. trabeum was not detected, but was upregulated by both F. radiculosa FP-90848-T (p = 0.481) and L-9414-SP (p = 0.392). Results from this study suggest that all three test fungi utilized different mechanisms when decaying copper-treated wood. Additionally, results from this study do not provide support for the involvement of these putative gene annotations for copper-transporting ATPase pumps in the mechanism of copper-tolerance.

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Untersuchungen zum Einfluss der Wärmebehandlung auf die Beständigkeit von Fichtenholz gegenüber holzzerstörenden Pilzen | Examination of the influence of heat treatment on the resistance of spruce timber to wood decaying fungi

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2004.0548 ◽

2004 ◽

Vol 155 (12) ◽

pp. 548-554 ◽

Cited By ~ 1

Author(s):

Fritz Bächle ◽

Peter Niemz ◽

Markus Heeb

Keyword(s):

Heat Treatment ◽

Mass Loss ◽

Ph Value ◽

Treated Wood ◽

Untreated Wood ◽

Brown Rot ◽

Nitrogen Atmosphere ◽

White Rot ◽

Heat Treated ◽

Blue Stain

Spruce wood that was heat treated in rape oil (laboratory scale) and in an autoclave with a nitrogen atmosphere (industrial scale), respectively, was tested according to EN 113 for its resistance to basidiomycetes (4 brown and 1 white rot). In addition,resistance to blue-stain fungi was tested according to EN 152 and pH-values were measured in an outdoor ageing process. Influenced by the thermal treatment a clear decrease of mass loss induced by brown rot can be seen. There is an obvious influence of the kind of fungi and the level of treatment. Inoculated with Trametes versicolor (simultaneous white rot) a higher mass loss can be seen in the heat-treated specimens than in the untreated specimens. The big differences in the results between the fungi show that the type of fungi plays a role in the degree of influence. It would therefore seem that tests using only one fungus are insufficient. Similar results were achieved by testing previously weathered samples. The tendencies are not always similar. Blue-stain was occasionally detected near the surface of heat-treated wood. The pH-value of wood treated in an autoclave is clearly lower than that of untreated wood. The colour of the heat-treated wood is not UV stable. However, the colour achieved by the oil-heat-treatment is more stable than that achieved by a treatment in an autoclave.

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Cell Wall Bulking by Maleic Anhydride for Wood Durability Improvement

Forests ◽

10.3390/f11040367 ◽

2020 ◽

Vol 11 (4) ◽

pp. 367 ◽

Cited By ~ 3

Author(s):

Mingming He ◽

Dandan Xu ◽

Changgui Li ◽

Yuzhen Ma ◽

Xiaohan Dai ◽

...

Keyword(s):

Cell Wall ◽

Maleic Anhydride ◽

Wood Cell Wall ◽

Brown Rot ◽

Decay Resistance ◽

White Rot ◽

White Rot Fungus ◽

Hydroxyl Group ◽

Hydroxyl Groups ◽

Decay Fungi

Wood is susceptible to swelling deformation and decay fungi due to moisture adsorption that originates from the dynamic nanopores of the cell wall and the abundant hydroxyl groups in wood components. This study employed as a modifier maleic anhydride (MAn), with the help of acetone as solvent, to diffuse into the wood cell wall, bulk nanopores, and further chemically bond to the hydroxyl groups of wood components, reducing the numbers of free hydroxyl groups and weakening the diffusion of water molecules into the wood cell wall. The derived MAn-bulked wood, compared to the control wood, presented a reduction in water absorptivity (RWA) of ~23% as well as an anti-swelling efficiency (ASE) of ~39% after immersion in water for 228 h, and showed an improvement in decay resistance of 81.42% against white-rot fungus and 69.79% against brown-rot fungus, respectively. The method of combined cell wall bulking and hydroxyl group bonding could effectively improve the dimensional stability and decay resistance with lower doses of modifier, providing a new strategy for wood durability improvement.

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The Resistance of Heat-Modified Fast Growing Woods Against Decay Fungi

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/891/1/012009 ◽

2021 ◽

Vol 891 (1) ◽

pp. 012009

Author(s):

T Priadi ◽

W Suhailiyah ◽

L Karlinasari

Keyword(s):

Wood Species ◽

Heating Temperature ◽

Schizophyllum Commune ◽

Brown Rot ◽

Decay Resistance ◽

Fungal Resistance ◽

White Rot ◽

Gas Chromatography Mass Spectrometry ◽

Decay Fungi ◽

Fast Growing

Abstract Fast growing woods from plantations forest generally have low quality and require improvement to resist degrading organisms. This study aimed to evaluate the resistance of heat-modified sengon, jabon, mangium, and short rotation teak woods against decay fungi. Heat treatment was applied at two different temperatures (150 °C and 180 °C) and for three different times (0, 2, and 6 hours). The decay resistance test used white rot (Schizophyllum commune Fr) and brown rot (Tyromyces palustris) fungibased on modified SNI 01-7207-2014 standard. The chemical analysis of heat-modified wood used Gas Chromatography-Mass Spectrometry. The results showed that the white rot fungal resistance was significantly affected by the interaction of wood species, temperature and period of heating, while the brown rot fungal resistance was significantly affected by the interaction of wood species and heating temperature. Heating at 180 °C for 6 hours increased the fungal resistance of sengon, jabon and mangium woods. However, the fungal resistance of teak wood improved by heating at 150 °C for 6 hours. The durability improvement of the heat-modified woods were suspected due to the appearance or increase of antifungal substances such as benzoic acid, sinapaldehyde, vanillin and 2-methylantraquinone.

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Effect of phenol-formaldehyde (PF) resin oligomer size on the decay resistance of beech wood

Holzforschung ◽

10.1515/hf-2020-0020 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Vladimirs Biziks ◽

Sascha Bicke ◽

Gerald Koch ◽

Holger Militz

Keyword(s):

Phenol Formaldehyde ◽

Beech Wood ◽

Treated Wood ◽

White Rot Fungi ◽

Molecular Size ◽

Brown Rot ◽

Decay Resistance ◽

Water Soluble ◽

White Rot ◽

Vacuum Impregnation

AbstractTreating wood with water-soluble resins is a well-known and effective method to improve the durability of wood. However, there has been no systematic work to date related to the influence of average molecular size of phenol-formaldehyde (PF) resin on the decay resistance of wood, especially of hardwoods. Therefore, the goal of this study was to investigate the effect of average molecular size of PF resin treatment on the resistance of beech wood against brown- and white-rot fungi. Four different average molecular weights (Mw) of resol type resin oligomers (297, 421, 655 and 854 g/mol) were examined. Different weight percent gains (WPGs) in European beech (Fagus sylvatica) wood blocks (15 × 20 × 50 mm3) were attained through vacuum impregnation using various concentrations of aqueous-PF solutions. Afterwards treated wood blocks passed the leaching and were exposed to brown-rot fungi (Gloeophyllum trabeum; Coniophora puteana) and white-rot fungi (Trametes versicolor) for 16 weeks. No effect of oligomer size on the resistance against G. trabeum decay of wood blocks was observed, resulting in resin loadings of 7–8%. The required WPG for resistance to brown-rot decay by C. puteana increased slightly with increasing oligomer molecular size: 6, 7, 10 and 11% for wood treated with 297, 421, 655 and 854 g/mol, respectively. The extent of white-rot fungal decay resistance of treated wood was affected by the molecular size of oligomers. Resin loadings of 8% and of 17% against T. versicolor were required to attain similar durability levels for beech wood treated with Mw = 297 and 854 g/mol, respectively.

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Particleboards from Recycled Thermally Modified Wood

Forests ◽

10.3390/f12111462 ◽

2021 ◽

Vol 12 (11) ◽

pp. 1462

Author(s):

Ján Iždinský ◽

Zuzana Vidholdová ◽

Ladislav Reinprecht

Keyword(s):

Mechanical Properties ◽

Urea Formaldehyde ◽

Brown Rot ◽

Decay Resistance ◽

Raw Material ◽

Modulus Of Rupture ◽

Negative Effect ◽

Serpula Lacrymans ◽

Thermally Modified Wood ◽

Modified Wood

In recent years, the production and consumption of thermally modified wood (TMW) has been increasing. Offcuts and other waste generated during TMWs processing into products, as well as already disposed products based on TMWs can be an input recycled raw material for production of particleboards (PBs). In a laboratory, 16 mm thick 3-layer PBs bonded with urea-formaldehyde (UF) resin were produced at 5.8 MPa, 240 °C and 8 s pressing factor. In PBs, the particles from fresh spruce wood and mixed particles from offcuts of pine, beech, and ash TMWs were combined in weight ratios of 100:0, 80:20, 50:50 and 0:100. Thickness swelling (TS) and water absorption (WA) of PBs decreased with increased portion of TMW particles, i.e., TS after 24 h maximally about 72.3% and WA after 24 h maximally about 64%. However, mechanical properties of PBs worsened proportionally with a higher content of recycled TMW—apparently, the modulus of rupture (MOR) up to 55.5% and internal bond (IB) up to 46.2%, while negative effect of TMW particles on the modulus of elasticity (MOE) was milder. Decay resistance of PBs to the brown-rot fungus Serpula lacrymans (Schumacher ex Fries) S.F.Gray increased if they contained TMW particles, maximally about 45%, while the mould resistance of PBs containing TMW particles improved only in the first days of test. In summary, the recycled TMW particles can improve the decay and water resistance of PBs exposed to higher humidity environment. However, worsening of their mechanical properties could appear, as well.

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