Towards a better understanding of wood decay

The German standard DIN 68800 defines that wood used in construction shall not be allowed to have a moisture content of more than 20% for a longer period of time in order to avoid damage by wood destroying fungi. In fact, the growth of wood destroying fungi depends on the conditions of moisture, temperature and type of wood, and may already be possible at the fixed 20% moisture level. In an interdisciplinary project the growth performance of wood destroying fungi under different substrate, temperature and moisture conditions is investigated employing the isopleth system approach. The so called "isoplethe - system" was originally used by mycologists to describe the specific reaction of growth and germination of different mould species to different combinations of temperature and relative humidity and water activity, respectively (e.g. Snow, 2001; Ayerst, 1969; Smith and Hill, 1982), Data of building relevant species have been collected and used to define a "lowest isopleth for mould" (LIM 0) (Sedlbauer (2001), which describes the border conditions for any mould growth at optimal media.