Incipient brown rot decay in modified wood: patterns of mass loss, structural integrity, moisture and acetyl content in high resolution

2017 ◽  
Vol 8 (3) ◽  
pp. 172-182 ◽  
Author(s):  
Rebecka Ringman ◽  
Annica Pilgård ◽  
Christian Brischke ◽  
Elizabeth Windeisen ◽  
Klaus Richter
Keyword(s):  
High Resolution ◽  
Mass Loss ◽  
Structural Integrity ◽  
Brown Rot ◽  
Acetyl Content ◽  
Brown Rot Decay ◽  
Modified Wood

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

Holzforschung ◽  
2014 ◽  
Vol 68 (2) ◽  
pp. 239-246 ◽  
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.

Degradation of chemically modified Scots pine (Pinus sylvestris L.) with Fenton reagent

Holzforschung ◽  
2015 ◽  
Vol 69 (2) ◽  
pp. 153-161 ◽  
Author(s):  
Yanjun Xie ◽  
Zefang Xiao ◽  
Carsten Mai
Keyword(s):  
Fenton Reaction ◽  
Oxidative Degradation ◽  
Brown Rot ◽  
Fenton Reagent ◽  
Wood Degradation ◽  
Weight Percentage ◽  
Brown Rot Fungi ◽  
Minor Losses ◽  
Brown Rot Decay ◽  
Modified Wood

AbstractThe Fenton reaction is supposed to play a key role in the initial wood degradation by brown rot fungi. Wood was modified with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) and glutaraldehyde (GA) to various weight percentage gains in order to study if these types of modifications are able to reduce wood degradation by Fenton reagent. Veneers modified with higher concentrations (1.2 and 2.0 mol l-1) of both chemicals exhibited minor losses in mass and tensile strength during treatment with Fenton reagent, which shows restrained oxidative degradation by hydroxyl radicals. The decomposition rate of H2O2was lower in the Fenton solutions containing modified veneers than in those containing unmodified controls. More CO2evolved in systems containing unmodified veneers than in systems with modified veneers, indicating that modification protected wood from mineralisation. The reason for the enhanced resistance of modified wood to the Fenton reaction is attributed to impeded diffusion of the reagent into the cell wall rather than to inhibition of the Fenton reaction itself. The results show that wood modification with DMDHEU and GA is able to restrain the degradation of wood by the Fenton reaction and can explain why modified wood is more resistant to brown rot decay.

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.

The role of chemical transport in the brown-rot decay resistance of modified wood

2016 ◽  
Vol 7 (2) ◽  
pp. 66-70 ◽  
Author(s):  
S. L. Zelinka ◽  
R. Ringman ◽  
A. Pilgård ◽  
E. E. Thybring ◽  
J. E. Jakes ◽  
...  
Keyword(s):  
Brown Rot ◽  
Chemical Transport ◽  
Decay Resistance ◽  
Brown Rot Decay ◽  
Modified Wood

Mode of action of brown rot decay resistance in phenol-formaldehyde-modified wood: resistance to Fenton’s reagent

Holzforschung ◽  
2016 ◽  
Vol 70 (3) ◽  
pp. 253-259 ◽  
Author(s):  
Reza Hosseinpourpia ◽  
Carsten Mai
Keyword(s):  
Cell Wall ◽  
Mode Of Action ◽  
Fenton Reaction ◽  
Phenol Formaldehyde ◽  
Brown Rot ◽  
Weight Percent ◽  
Fenton’S Reagent ◽  
Fenton's Reagent ◽  
Brown Rot Decay ◽  
Modified Wood

Abstract The mode of action of phenol-formaldehyde (PF)-modified wood has been investigated with respect to its resistance to brown rot decay. The Fenton reaction is assumed to play a key role in the initial brown rot decay. Pine microveneers were modified to various weight percent gains (WPG) with low molecular weight PF and exposed to a solution containing Fenton’s reagent. The mass loss (ML) and tensile strength loss (TSL) as well as the decomposition of hydrogen peroxide within the incubation time decreased with the increasing WPG of the veneers. Incubation of untreated and PF-modified veneers in acetate buffer containing ferric ions without H2O2 revealed that the modification strongly reduces the uptake of iron by the wood cell wall. Further studies indicated that lignin promotes the decay of wood by Fenton’s reagent. The reason for the enhanced resistance of modified wood to the Fenton reaction is attributable to the impeded diffusion of iron ions into the cell wall rather than to the blocking of free phenolic sites of lignin, which accelerate redox cycling of iron.

scholarly journals Experimental evidence that fungal symbionts of beetles suppress wood decay by competing with decay fungi

2019 ◽  
Author(s):  
James Skelton ◽  
Andrew Loyd ◽  
Jason A. Smith ◽  
Robert A. Blanchette ◽  
Benjamin W. Held ◽  
...  
Keyword(s):  
Mass Loss ◽  
Wood Decay ◽  
Brown Rot ◽  
Inhibitory Effects ◽  
Ambrosia Beetles ◽  
Decay Fungi ◽  
Bark And Ambrosia Beetles ◽  
Symbiotic Fungi ◽  
Brown Rot Decay ◽  
Forest Biology

Throughout forests worldwide, bark and ambrosia beetles inoculate dead and dying trees with symbiotic fungi. We experimentally determined the effects of three common and widely distributed ascomycete symbionts, and one introduced Asian basidiomycete symbiont on the decay of pine sapwood. Ascomycetes caused less than 5% mass loss and no structural degradation, whereas the basidiomycete Flavodon ambrosius caused nearly 15% mass loss and visible degradation of wood structure. In co-inoculation experiments, the beetle symbionts Ophiostoma ips and Raffaelea fusca reduced white and brown rot decay through competition with Ganoderma curtisii and Phaeolus schweinitzii, respectively. The inhibitory effects of O. ips and R. fusca on decay were negated when co-inoculated with F. ambrosius, suggesting that widespread introduction of this beetle symbiont could alter forest carbon fluxes. In contrast to the predominant forest biology narrative, most bark and ambrosia beetles introduce fungi that delay rather than facilitate tree biomass recycling.

Prediction model based on chemical composition change for the mechanical degradation of Korean pine (Pinus koraiensis) after brown-rot fungi (Gloeophyllum trabeum) invasion

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lipeng Zhang ◽  
Qifang Xie ◽  
Liujie Yang ◽  
Yajie Wu ◽  
Xingxia Ma
Keyword(s):  
Chemical Composition ◽  
Mass Loss ◽  
Decay Time ◽  
Brown Rot ◽  
Strength Loss ◽  
Gloeophyllum Trabeum ◽  
Korean Pine ◽  
Composition Change ◽  
Brown Rot Decay ◽  
Loss Rates

Abstract In order to predict the mechanical properties of Korean pine after brown-rot decay based on its chemical composition change, 252 samples were prepared and exposed to a 14-week accelerated laboratory decay test using the brown-rot fungus Gloeophyllum trabeum. The mass loss, parallel-to-grain compressive strength, parallel-to-grain tensile strength and bending strengths were tested. Then chemical components and scanning electron micrograph analysis were conducted every two weeks. Results indicated that the mass loss rates of the samples increased with the increasing decay time and were negatively correlated with the sample volume. The strength loss rates were positively correlated with the decay time and mass loss rates. After 14 weeks the average strength loss rates of the parallel-to-grain compressive, tensile and bending samples reached 32%, 41% and 41%, respectively. Strengths degradation was found sensitive to the change of cellulose and hemicellulose contents. Further, mathematical regression models were proposed based on the content changes of the cellulose and hemicellulose to quantitatively predict the degradation of the strengths of Korean pine after brown-rot decay.

scholarly journals Experimental evidence that fungal symbionts of beetles suppress wood decay by competing with decay fungi

2019 ◽  
Author(s):  
James Skelton ◽  
Andrew Loyd ◽  
Jason A. Smith ◽  
Robert A. Blanchette ◽  
Benjamin W. Held ◽  
...  
Keyword(s):  
Mass Loss ◽  
Wood Decay ◽  
Brown Rot ◽  
Inhibitory Effects ◽  
Ambrosia Beetles ◽  
Decay Fungi ◽  
Bark And Ambrosia Beetles ◽  
Symbiotic Fungi ◽  
Brown Rot Decay ◽  
Forest Biology

Throughout forests worldwide, bark and ambrosia beetles inoculate dead and dying trees with symbiotic fungi. We experimentally determined the effects of three common and widely distributed ascomycete symbionts, and one introduced Asian basidiomycete symbiont on the decay of pine sapwood. Ascomycetes caused less than 5% mass loss and no structural degradation, whereas the basidiomycete Flavodon ambrosius caused nearly 15% mass loss and visible degradation of wood structure. In co-inoculation experiments, the beetle symbionts Ophiostoma ips and Raffaelea fusca reduced white and brown rot decay through competition with Ganoderma curtisii and Phaeolus schweinitzii, respectively. The inhibitory effects of O. ips and R. fusca on decay were negated when co-inoculated with F. ambrosius, suggesting that widespread introduction of this beetle symbiont could alter forest carbon fluxes. In contrast to the predominant forest biology narrative, most bark and ambrosia beetles introduce fungi that delay rather than facilitate tree biomass recycling.

scholarly journals Properties of modified wood according to treatment technology and thermo-vacuum process for birch (Betula pendula Roth) veneers

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 4150-4164
Author(s):  
Anete Meija-Feldmane ◽  
Ignazia Cuccui ◽  
Ilze Irbe ◽  
Andris Morozovs ◽  
Uldis Spulle
Keyword(s):  
Mass Loss ◽  
Betula Pendula ◽  
Brown Rot ◽  
Strength Loss ◽  
Decay Resistance ◽  
Treatment Technology ◽  
Betula Pendula Roth ◽  
Treatment Regimes ◽  
Brown Rot Fungus ◽  
Modified Wood

Thermally modified birch (Betula pendula Roth) veneers that had been subjected to wood treatment technology (WTT) or thermo vacuum (TV) processes were compared in this study. After modification of veneers in the range of temperatures from 160 °C to 218 °C and times from 0.5 h to 3 h, the color, mass loss, density, tensile strength, hygroscopicity, and decay resistance against brown rot fungus Coniophora puteana were determined. Treatment regimes with the greatest mass loss were at 217 °C for 3.0 h in TV (7.8%) and 160 °C for 0.8 h in the WTT (6.7%). As expected, wood mass loss correlated well with moisture exclusion efficiency (MEE) in all relative humidity (RH) environments (r = 0.95 to 0.99). Strength loss in the WTT was considerable compared to the TV process (57% and 40%, respectively). The resistance against brown rot fungus was moderate with a mass loss of 12% to 33%. Among the investigated samples, the regime 217/3.0/TV showed the best resistance against brown rot fungus and acceptable other properties.

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