The mode of action of modified wood has long been discussed but is still unsolved. A better understanding of decay resistance mechanisms facilitates improvements of wood protection processes and product properties. Brown rot fungi degrade wood through chelator mediated Fenton (CMF) degradation, where hydroxyl radicals (∙OH) depolymerise polysaccharides and modify lignin, and enzymatic degradation, where cellulases and hemicellulases hydrolyse the polysaccharides. The aim of this study was to investigate the expression of Postia placenta wood degradation genes in thermally modified wood and to correlate gene expression to mass and strength loss. The results indicate that once mass loss is detected, P. placenta degrades thermally modified wood in a similar manner to untreated wood. However, the onset of degradation seems to be delayed and the rate of degradation, once started, seems to be lower than in untreated wood. We therefore conclude that the key to understanding degradation resistance in thermally modified wood lies within the time frame before mass loss is detectable.
Keywords: Brown rot, chelator mediated Fenton degradation, Pinus sp., thermally modified wood
Authors
Pilgård A.
Technische Universität München, München, Germany.
Wood Technology, SP Technical Research Institute of Sweden, Borås, Sweden
Ringman R.
Wood Technology, SP Technical Research Institute of Sweden, Borås, Sweden
Kölle M.
Thünen-Institute of Wood Research, Hamburg, Germany
Brischke C.
Leibniz University Hannover, Faculty of Architecture and Landscape Sciences, Institute of Vocational Sciences in the Building Trade (IBW), Hannover, Germany
Richter K.
Chair of Wood Science, Technische Universität München, München, Germany
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