LAUSR

The use of pyrolysis acid (PA) as a liquid by‐product of the slow pyrolysis of wood or any other lignocellulosic biomass has been widely developed in agriculture for a variety of purposes such as crop enhancement or as a pesticide. Evidence from the literature suggests that PA could be used as a sustainable wood preservative to protect against rot fungi and termites. The experimental work presented here provides one of the first investigations into the anti‐decay efficiency of PA. Crude PA acid acquired from three different types of wood at two different temperature ranges (180–280 °C and 280–350 °C) was used to impregnate beech and pine wood samples in a full‐cell process. Then, the resistance of treated samples against white and brown rot fungi was evaluated (in accordance with European standard EN 113), before and after a leaching test (European standard EN 84). It was found that, generally, higher retention of chemicals inside the wood was observed with PA obtained at 350 °C (PA‐350). The leaching rate of chemicals from the treated samples with PA obtained at 280 °C (PA‐280) was significantly higher than from those treated with PA‐350. Before leaching, no statistical difference was observed among the impregnated woods in terms of decay resistance. Although the samples treated with PA‐280 initially showed fairly good decay resistance they partially lost it after leaching. This was particularly the case with brown rot. However, the impregnation of wood samples with PA‐350 met the requirements of EN 113 as an efficient treatment against basidiomycete fungi. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd