Effects of Initial Moisture Content on Wood Decay at Different Levels of Gaseous Oxygen Concentrations

The influence of initial moisture content on wood decay at different levels of atmospheric oxygen concentration was studied. Three fungi, Coriolus versicolor (C. versicolor) a white rot, Coniophora puteana (C. puteana) a brown rot, and Chaetomium globosum (C. globosum) a soft rot, were chosen. The mycelia of the fungi were inoculated in to mini blocks of Fagus sylvatica (beech) and Pinus sylvestris (Scots pine). Incubation was conducted under four levels of oxygen concentration (1,5,10, and 21% O2) at 22o C. At low oxygen concentrations, an increase of moisture content had a negative effect on the wood decay process by both the Basidiomycetes (C. versicolor and C. puteana) in Scots pine and beech. In air, the effect of initial moisture content on wood decay by these fungi depended on the characteristics of the fungi and the wood species (such as fungal biology and physiology). When C. globosum was used as a colonizer, increasing moisture content generally increased weight loss in the wood blocks (especially in beech). When the moisture content in the wood blocks was increased, more sporulations by C. globosum were also observed on the wood samples. However, the role of oxygen in inceasing wood decay was more important than the moisture content effect.