The experimental basis for testing the biological durability of wood are often incubation experiments with wood-destroying basidiomycetes. Numerous parameters can affect the mass loss by fungal decay (MLF) in laboratory durability tests and therefore being decisive for the resulting durability classification. Among others, the dimension of the wood specimen and the time of incubation impact on fungal decay. Hence both parameters were examined within this study systematically using 19 different specimen formats and four different incubation times. Specimens made from Larch heartwood (Larix decidua Mill.) and incubated with pure cultures of the brown rot fungus Coniophora puteana. Scots pine sapwood (Pinus sylvestris L.) was used as a reference. The wood specimens’ format turned out to significantly affect both, mass loss by fungal decay MLF and resulting x-values when MLF of Larch was compared with that of the reference Scots pine sapwood. Both measures were highest for specimen formats with moderate surface-volume ratios. MLF and x-values depended on specimen size and shape as well as on the time of incubation. Reducing the specimen volume did lead to higher MLF at a given incubation time, but prolonging incubation times led to higher x-values and thus to lower durability expressed as DCs. In summary, it appeared highly questionable that results of basidiomycete durability tests can be easily transferred to each other when specimen format and/or incubation time deviate from the standard conditions.

Download document (464 kb)
free for the members of IRG. Available if purchased.

Purchase this document