Effects of selected white-rot fungi on the calorific value of beech wood (Fagus sylvatica L.)

Abstract

The emerging climate change risks have drawn increased attention to renewable energy sources, including forest biomass. However, the quality of fuelwood is often compromised by a variety of fungi. The purpose of the present study was to determine selected energy parameters of beech wood affected by four species of white-rot fungi: Grifola frondosa, Hericium coralloides, Meripilus giganteus, and Trametes gibbosa. Wood degradation was studied under laboratory conditions. On days 60 and 120 after inoculation, beech wood samples were analysed in terms of moisture content, density, elemental composition (C, H, N, S, O), ash content, as well as gross and net calorific value. Reference data were provided by measurements of healthy wood. Elemental analysis indicated small differences in absolute values between healthy and affected wood. White rot led to a slight decrease in C and H and an increase in O. In addition, a significant rise in moisture content was observed (by more than 100%). These factors reduced the net calorific value of healthy beech wood (18.37 MJ kg−1) by 0.3 MJ kg−1 (T. gibbosa) to 0.5 MJ kg−1 (H. coralloides) after 120 days of the experiment. In terms of the amount of energy contained in a unit of volume, the initial net calorific value of 11.6 GJ m-3 decreased significantly by 18.1% (H. coralloides) to 33.6% (T. gibbosa).