Abstract
New insight regarding the mode of action of brown rot decay of modified wood based on DNA and gene expression studies: A review
Gry Alfredsen
Modified wood shows resistance to wood deteriorating fungi, but the mechanisms are not fully understood. In this review paper, Gry Alfredsen at the Norwegian Forest and Landscape Institute summarises the molecular studies performed on modified wood with regard to brown rot decay fungi. DNA data showed that fungi are present in inoculated test samples within two weeks. Oxidative gene expression is higher in modified wood than in untreated wood and tends to increase during incubation. Based on this data it is suggested that the hypothesis that there is a lack of substrate recognition by the fungus, should be rejected. In the reviewed studies, total wood moisture content was generally not low enough to inhibit fungal colonisation. Therefore, moisture distribution within the wood needs closer study.
New insight regarding mode of action of brown rot decay of modified wood based on DNA and gene expression studies: a review. G. Alfredsen, R. Ringman, A. Pilgård and C. G. Fossdal, pp. 5–7
Next steps in developing thermally modified timber to meet the requirements of the European low carbon economy.
Andreja Kutnar
In this educational paper, Andreja Kutnar at the University of Primorska, Slovenia presents the European initiatives and strategies that must be considered in the future development of thermally modified timber and optimisation of existing commercial processes. She then goes on to discuss the next steps in developing thermally modified timber to meet the requirements of the European low carbon economy. Environmental and sustainability impacts of processing are discussed.
Next steps in developing thermally modified timber to meet requirements of European low carbon economy. A. Kutnar and D. Sandberg, pp. 8–13
Modifying wood with bio-polyesters: Analysis and performance
Marion Noël
Oligomers of lactic and glycolic acid, polybutylene succinate/adipate were impregnated into wood for dimensional stabilisation. These bio-polyesters provide bulking and lumen filling treatments. In this research, Marion Noel at Bern University of Applied Sciences, Switzerland, investigated the degree of polymerization and cell wall penetration. The results suggest biopolyster treatments can confer specific properties to suit end use applications.
Modifying wood with bio-polyesters: analysis and performance. M. Noël, W. Grigsby, I. Vitkeviciute and T. Volkmer, pp. 14–20
Comparison of EMC and durability of heat treated wood from high versus low water vapour pressure reactor systems
WimWillems
Heat treatment is a means of modifying wood to improve its properties. The heating can be carried out in a range of processes, from in vacuum to saturated steam. Little is known about the relationship between water vapour pressure and wood modification chemistry and the resulting properties of the modified wood. Wim Willems of Firmolin Technologies BV in the Netherlands in his research concludes that at a molecular level the wood reaction chemistry is independent of the process and the wood species. Furthermore properties such as EMC and fungal durability can be achieved by all processes and for all wood species. This finding does not hold for every property of thermally modified wood.
Comparison of EMC and durability of heat treated wood from high versus low water vapour pressure reactor systems. W. Willems, M. Altgen and H. Militz, pp. 21–26
UV micro-spectrophotometry: A method to prove wood modification with MMF
Karl-Christian Mahnert
One way of modifying wood is to impregnate it with resin solutions. An example is impregnation with methylolated melamine formaldehyde resin using a full cell vacuum-pressure process. However control of the final product has been difficult. Karl-Christian Mahnert at the Norwegian Institute of Wood Technology has investigated the use of UV-micro-spectrophotometry as a possible technique for quantitative analysis of wood modified this way. The results demonstrated that this is a proven technique find out the degree of curing of the resin.
UV-microspectrophotometry: method to prove wood modification with MMF? K.-C. Mahnert, S. Adamopoulos, G. Koch and H. Militz, pp. 27–30
Investigations on wood treatment by eco-friendly hydroxypolyurathanes
Stephane Dumarcay
Dimensional stability is a desirable property for most wood applications and one way of achieving it is impregnation with resins. Some of the materials used are environmentally undesirable. Stephane Dumarcay at the University of Lorraine in France has investigated an isocyanate free route based on a double impregnation after which polycondensation reactions are initiated. Tests included leaching, anti-swelling efficiency and resistance to fungal decay. The results were promising.
Investigations on wood treatment by eco-friendly hydroxypolyurethanes. S. Dumarçay, K. Laych, A. Lemor and P. Gérardin, pp. 31–35
In vitro oxidative and enzymatic degradation of modified wood
Rebecka Ringman
Fungal cellulases have been shown to be less efficient in modified wood compared to untreated wood. However it has been shown that cellulase efficacy is partly restored by pre-treatment with Fenton's reagent, thus simulating the oxidative degradation phase in initial brown rot decay. In this study by Rebecka Ringman at SP Technical Research Institute of Sweden examined whether Fenton derived hydroxyl radicals and cellulases are able to cleave polysaccharides in chemically modified wood and to what extent enzyme efficiency could be improved by this pre-treatment.
In vitro oxidative and enzymatic degradation of modified wood. R. Ringman, A. Pilgård and K. Richter, pp. 36–39