Chemical factors affecting the brown-rot decay resistance of Scots pine heartwood

AbstractThe thermal degradation of wood is affected by a number of process parameters, which may also cause variations in the resistance against decay fungi. This study compares changes in the chemical composition, water-related properties and decay resistance of Scots pine sapwood that was either thermally modified (TM) in dry state at elevated temperatures (≥ 185 °C) or treated in pressurized hot water at mild temperatures (≤ 170 °C). The thermal decomposition of easily degradable hemicelluloses reduced the mass loss caused by Rhodonia placenta, and it was suggested that the cumulative mass loss is a better indicator of an actual decay inhibition. Pressurized hot water extraction (HWE) did not improve the decay resistance to the same extent as TM, which was assigned to differences in the wood-water interactions. Cross-linking reactions during TM caused a swelling restraint and an effective reduction in moisture content. This decreased the water-swollen cell wall porosity, which presumably hindered the transport of degradation agents through the cell wall and/or reduced the accessibility of wood constituents for degradation agents. This effect was absent in hot water-extracted wood and strong decay occurred even when most hemicelluloses were already removed during HWE.

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Cellular level chemical changes in Scots pine heartwood during incipient brown rot decay

Scientific Reports ◽

10.1038/s41598-019-41735-8 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 5

Author(s):

Tiina Belt ◽

Michael Altgen ◽

Mikko Mäkelä ◽

Tuomas Hänninen ◽

Lauri Rautkari

Keyword(s):

Scots Pine ◽

Brown Rot ◽

Cellular Level ◽

Chemical Changes ◽

Brown Rot Decay

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Heartwood extractives and lignin content of different larch species ( Larix sp.) and relationships to brown-rot decay-resistance

Trees ◽

10.1007/s00468-003-0300-0 ◽

2004 ◽

Vol 18 (2) ◽

pp. 230-236 ◽

Cited By ~ 55

Author(s):

Notburga Gierlinger ◽

Dominique Jacques ◽

Rupert Wimmer ◽

Luc E. P�ques ◽

Manfred Schwanninger

Keyword(s):

Lignin Content ◽

Brown Rot ◽

Decay Resistance ◽

Larch Species ◽

Brown Rot Decay ◽

Heartwood Extractives

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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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Stilbene impregnation retards brown-rot decay of Scots pine sapwood

Holzforschung ◽

10.1515/hf-2014-0251 ◽

2016 ◽

Vol 70 (3) ◽

pp. 261-266 ◽

Cited By ~ 13

Author(s):

Jinrong Lu ◽

Martti Venäläinen ◽

Riitta Julkunen-Tiitto ◽

Anni M. Harju

Keyword(s):

Scots Pine ◽

Fungal Growth ◽

Brown Rot ◽

Monomethyl Ether ◽

Wood Preservation ◽

High Concentration ◽

Brown Rot Fungi ◽

Decay Test ◽

Antifungal Efficiency ◽

Brown Rot Decay

Abstract Stilbenes are abundant in the heartwood of Scots pine (Pinus sylvestris L.) and are known to have strong antifungal efficiency. In this study, Scots pine sapwood blocks were impregnated with crude heartwood extract containing the stilbenes pinosylvin (PS) and the pinosylvin monomethyl ether (PSM). Impregnated blocks were submitted to brown-rot fungi, Coniophora puteana, Gloeophyllum trabeum, and Rhodonia (Poria) placenta, and fungal growth test and decay test were performed. Both tests showed that the impregnation with a high concentration of stilbenes (60 mg g-1 dry wood) significantly suppressed the growth of fungi and slowed down the decay process of wood blocks, especially in case of G. trabeum. However, chemical analysis showed that PS and PSM were degraded by all the three types of fungi, obviously via modification to resveratrol and methylresveratrol. Rhodonia placenta displayed the fastest rate of degradation. Thus, impregnation with biodegradable stilbenes could be a viable alternative for wood preservation only in service situations with low or transient risk of decay.

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Differences in Resin Acid Concentration between Brown-Rot Resistant and Susceptible Scots Pine Heartwood

Holzforschung ◽

10.1515/hf.2002.074 ◽

2002 ◽

Vol 56 (5) ◽

pp. 479-486 ◽

Cited By ~ 24

Author(s):

A. M. Harju ◽

P. Kainulainen ◽

M. Venäläinen ◽

M. Tiitta ◽

H. Viitanen

Keyword(s):

Moisture Content ◽

Equilibrium Moisture Content ◽

Scots Pine ◽

Abietic Acid ◽

Resin Acid ◽

Brown Rot ◽

Decay Resistance ◽

Resin Acids ◽

Hydrophobic Properties

Summary The concentration of individual resin acids and the equilibrium moisture content at a relative humidity of 100% were studied in brown-rot resistant and susceptible Scots pine (Pinus sylvestris L.) heartwood. About 90% of the resin acids in the heartwood were of the abietane type, abietic acid being the most abundant. The concentration of resin acids was higher in the decay-resistant heartwood than in the decay-susceptible heartwood. Resin acids are presumably in part responsible for the decay resistance of Scots pine heartwood. However, no clear relationship was found between the concentration of resin acids and the equilibrium moisture content. The role of resin acids may also be ascribed to mechanisms other than their hydrophobic properties alone. The reasons for the slight differences in moisture content between the decay classes require further study.

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Genetic variation in the decay resistance of Scots pine wood against brown rot fungus

Canadian Journal of Forest Research ◽

10.1139/x01-059 ◽

2001 ◽

Vol 31 (7) ◽

pp. 1244-1249 ◽

Cited By ~ 11

Author(s):

Anni M Harju ◽

Martti Venäläinen ◽

Egbert Beuker ◽

Pirkko Velling ◽

Hannu Viitanen

Keyword(s):

Genetic Variation ◽

Mass Loss ◽

Scots Pine ◽

Brown Rot ◽

Decay Resistance ◽

Phenotypic Variance ◽

Increment Core ◽

Genetic Components ◽

Brown Rot Fungus ◽

The Mean

The role of genotype in the durability of Scots pine (Pinus sylvestris L.) wood against decay by brown rot fungus (Coniophora puteana (Schum. ex Fr.) Karst. (strain Bam EBW 15)) was studied in a laboratory test. The wood material was obtained from 32-year-old half-sib progenies of Scots pine. The increment core samples of sapwood and juvenile heartwood were decayed using a modification of the standardized EN 113 method. The mean densities of the sapwood and heartwood samples were 391 and 337 mg·cm3, respectively, and the mean mass losses were 114 and 80 mg·cm3, respectively. The additive genetic components were small compared with the total phenotypic variance, which resulted in small narrow-sense heritabilities in mass loss. The most marked feature was the wide phenotypic variation in mass loss observed in heartwood (range 199 mg·cm3) compared with sapwood (range 72 mg·cm3) samples. Low heritability, together with the relatively high coefficient of additive genetic variation (CVA) in heartwood mass loss, suggests that advances in breeding can only be made through intensive testing in the environments which the studied experiment represents.

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Effects of white rot and brown rot decay on the drilling resistance measurements in wood

Holzforschung ◽

10.1515/hf-2017-0204 ◽

2018 ◽

Vol 72 (10) ◽

pp. 905-913 ◽

Cited By ~ 3

Author(s):

Evgenii Sharapov ◽

Christian Brischke ◽

Holger Militz ◽

Elena Smirnova

Keyword(s):

Scots Pine ◽

Free Water ◽

Brown Rot ◽

European Beech ◽

White Rot ◽

Drilling Tool ◽

Significant Difference ◽

Brown Rot Decay ◽

Drilling Resistance ◽

The Impact

AbstractAn IML-RESI PD 400 drilling tool and a standard spade drill bit (IML System GmbH, Wiesloch, Germany) were used to study the impact of white and brown rot decay on drilling resistance (DR) measurements in wood. In total, 720 drillings were made in specimens of Scots pine (Pinus sylvestrisL.) heartwood and sapwood, European beech (Fagus sylvaticaL.) and English oak (Quercus roburL.), which were decayed byConiophora puteanaandTrametes versicolor. Drillings were made with specimens conditioned in normal climate (20°C/65% RH) and with specimens vacuum-impregnated in water. DR and feeding force (FF) were negatively correlated with mass loss (ML) due to fungal decay. The intensity of reduction was higher for DR than for FF with increasing ML for all decay types and moisture contents (MCs). A significant difference (at 95% confidence level) in DR was found between decay types using water-saturated (WS) Scots pine specimens (3–35% ML). In most cases, DR revealed a higher predictive power of the models for ML prediction than FF. Free water in decayed specimens significantly reduced the DR and FF. Hence, the effect of ML on DR and FF of decayed and WS wood was less prominent.

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