Modelling timber decay caused by brown rot fungi

Decay models are key elements for service life prediction and performance classification of wooden products and timber structures. Available models differ in terms of data sources used and prevailing decay types considered. Comparative studies on performance models are therefore rare. In this study we applied data sets from field tests dominated by brown rot decay to a model developed on the basis of white and soft rot decay. Differences in time till colonization, onset of decay and subsequent decay progress between the rot types were found. Brown rot decay turned out to be initiated earlier and proceed faster compared to white and soft rot decay. Microclimate was influenced by shading within this study, whereby the moisture and temperature induced dose was affected as well as the progress of brown rot decay itself. Consequently, for obtaining a more conservative decay model only data sets dominated by brown rot and unaffected by shading were used. The brown model shortened the expected lifetime by 50 % compared to the previous white and soft rot model for a given dosage.