The Specific and Total CO₂ Emission Activity of Wood-Decaying Fungi and Their Response to Increases in Temperature

The CO₂ emission activity of xylotrophic fungi responding to an increase in temperature in the range of 10-30 °C with pure dikaryotic cultures of Fomes fomentarius s. str., F. inzengae, Fomitopsis betulina, F. pinicola, and Phellinus igniarius was analyzed. Emission activity was assessed by the difference in CO₂ concentration in 0.5 L exposure chambers with Petri dishes with mycelium growing on agar at the beginning of exposure and an hour later using a Gasmet DX-4030 FTIR spectrometer (Gasmet Technologies Oy, Finland), error measurements ±50 ppm. Specific (μg CO₂/cm²/h) and total (μg CO₂/h) emission activity and its relationship with temperature and size (area) of the mycelium were assessed. It is shown that in the range of 10-30 °C, the specific and total CO₂ emission activity of the mycelium is closely and positively related to temperature. Specific emission, which is an indicator of the respiratory activity of the mycelium, does not depend on its size; its only driver is temperature, the relationship with which is linear: an increase in temperature by 10 °C causes an increase in the specific emission activity of the mycelium by 1.7 times. The total CO₂ emission activity, which is an indicator of the total amount of CO₂ emitted, is directly proportional to the specific emission activity and the size of the mycelium. In the range of 10-30 °C, an increase in temperature causes an almost equal increase in both the specific emission activity of the mycelium (Q₁₀ 1.7) and its growth (Q₁₀ 1.5) and causes an exponential increase in the total emission of CO₂. This must be taken into account when predicting CO₂ emissions from woody debris under climate change, as it could potentially contribute to accelerating climate change.