Vulnerability of timber in ground contact to fungal decay under climate change

Attack of decay fungi on wood-based material depends primarily on the natural durability of wood, the local climatic conditions, and the likely climatic change. This study investigates the vulnerability of wood and structural timber in ground contact to decay fungi under high and medium emissions scenarios specified by the Intergovernmental Panel on Climate Change, and a future scenario in which the global emissions have been limited to 550 ppm through a range of successful intervention schemes. Nine general circulation models are applied to project the local climates of Brisbane, Sydney, and Melbourne in Australia. It was found that, under the three emissions scenarios, the median decay rate of wood by 2080, relative to that in 2010, could increase up to 10 % in Brisbane and Sydney, but could decrease by 12 % in Melbourne. For timber of less durable wood species 50 years after installation, the residual strength under climate change could be almost 25 % less than that without climate change. The coefficients of variation (COVs) of decay rate of wood are in the vicinity of 1.0 regardless of wood species. For residual strength of timber pole after 50 years of installation, the COVs range from 0.2 to 1.1, depending on the natural durability of timber and the site location. The high COVs due to the variability of natural durability of wood and of climate change, in combination with the likely changes in median residual strength of structural elements, will cause significant structural reliability issues of wood construction and need to be addressed in engineering design codes.