Home – Home – Jornals – Contemporary Problems of Ecology 2020 number 6

In a temperate climate, temperature is a key abiotic factor controlling the decomposition of coarse wood debris, one of the components of which is the bark. Using the aspen bark (AB), we carried out a 12-month laboratory experiment at three contrasting temperatures (2, 12 and 22 °C) and constant sufficient moisture to quantify the effect of the temperature on the decomposition rate (DecR) and decay constant (k) of aspen bark. The temperature influence on the total loss of C-CO₂ and changes in the chemical composition of AB during the entire experiment were also estimated. An increase in the incubation temperature from 2 to 12 °C and from 12 to 22 °C caused a similar increase in the average (over 12 months) value of DecR: Q₁₀ values in these temperature intervals were 1.30 to 1.41, respectively. The most significant effect of temperature on the dynamics of DecR was revealed during the 1^st and 2^nd months of the experiment. The maximum losses of С-СО₂ (284 ± 16 mg С g of bark^-1 or 55.2 ± 3.2 % of the initial С content) were observed at 22 °C. The decay constants of AB calculated by the one-component exponential model increased significantly with the rising of incubation temperature: from 0.46 ± 0.01 year^-1 at 2 °C to 1.02 ± 0.09 year^-1 at 22 °C. Changes in the chemical composition of aspen bark due to the processes of biogenic decomposition included a significant reduction in alcohol-soluble organic compounds and cellulose to 18-32 % and 41-57 % of their initial amount, respectively. Lignin losses were much less and amounted to only 9-18 % of their content in AB before the incubation. The quantitative changes in the chemical composition of aspen bark were similar at 2 and 12 °C and less pronounced than at 22 °C. It may be explained by the growing activity of destructive organisms that are actively involved in the decomposition of the bark at 22 °C.