Fungal moisture demands for colonization and decay of wood
Regarding wood decay by fungi there are still open questions, like their ability to transport water, to produce it by their metabolism and to infect and decay dry wood. Few laboratory investigations were already done using piled wood samples. The aim of this study was to get data on three common indoor wood decay basidiomycetes on different wood substrates regarding growth, moisture demands and wood decay. Small wood blocks from Scots pine sapwood (Pinus sylvestris) and English oak sap wood and heartwood (Quercus robur) were piled in Erlenmeyer flasks. Metal rings between the samples inhibited the capillary water diffusion from sample to sample. The flasks were supplied with nutrient agar and were inoculated with the brown-rot fungi Coniophora puteana, Serpula lacrymans and the white-rot species Donkioporia expansa. Different harvest times were used according to the different colonization time of the piles. Results revealed that the fungi were able to transport water from the agar to the piles and within them and to colonize wood even from 15.1% to 21.8% moisture content. Regarding minimum moisture for decay, e.g. D. expansa degraded the oak heartwood at even 17.9% moisture. Depending on wood species and distance between the samples the fungi showed different growth behaviour.