The construction sector stands for a large amount of the global carbon dioxide emissions and reducing these is thus important to prevent global warming. One benefit with building in wood is that it has a lower climate impact than other common building materials. The reason for this is that the tree binds carbon when it grows, and this carbon is stored in the wood as long as it stays intact. However, wood is also biodegradable and if it is wet for long periods of time, it is degraded by wood-degrading fungi. Durable wood structures in moist environments thus require some kind of protection. Such protection can be provided by impregnating toxic substances into the wood. However, instead of making the wood toxic, one can try to remove something that the fungi need – water which can be achieved by changing the wood chemistry. It is since long known that the fungi need water to degrade wood, but the exact role is not yet fully clarified and to know how to best prevent degradation we need to know more about this. Previous research within the topic have mostly focussed on how much water the wood contains and less effort has been put on where the water is within the wood structure. Also, when doing experiments to check under which humidity conditions fungi can and cannot grow, the humidity conditions are generally not well-controlled. The reason for this is that it is difficult to keep a stable humidity at the high humidity levels needed by the fungi. Also, things get even more challenging since the fungus itself produce water when it degrades wood.
Our aim is to gain more knowledge on the role of water in fungal degradation. Not only in terms of how much water is needed, but also where the water is within the wood structure. To do this, we need to be able to control the humidity conditions very precisely. We have therefore developed a method that makes it possible to study fungi that degrades wood under extremely controlled high humidity conditions. We have built moisture conditioning chambers that are specialised in keeping a stable climate at the high humidity levels that fungi like. Such moisture conditioning chambers have previously been used for other research purposes but not to study fungal degradation. At the conference, we will present this set-up and the results of some first experiments that have been done.
This research is driven by curiosity, the desire to go outside of using established methods and approaching a research question from another direction.
Keywords: moisture content, water potential, pressure plate, fungal degradation, durability
Authors
Maria Fredriksson
Building Materials, Lund University, Lund, Sweden
Gry Alfredsen
Wood Technology, NIBIO, Ås, Norway
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