Estimating the impact of peatland forest management on heterotrophic carbon dioxide emissions in southern Finland

Peatland forest management using different harvesting methods, such as rotation forestry (RF) and continuous cover forestry (CCF), affects soil organic matter decomposition and greenhouse gas emissions. In this study, a process-based model, Estimate Carbon in Organic Soils – Sequestration and Emissions (ECOSSE), developed for organic soils was applied to simulate the impact of stand harvesting on heterotrophic carbon dioxide emissions (R h -CO 2 ) in two Norway spruce dominated drained peatland forests in southern Finland (Ränskälänkorpi and Lettosuo). Both forests were split into a control area and two differently harvested areas: a clear-cut representing RF, and a selection harvest representing CCF. The output from the model simulation was evaluated against field measurements (2020–2022 in Ränskälänkorpi and 2020–2021 in Lettosuo), and the model was further applied to assess the long-term (50 years) impacts of the harvesting methods on R h -CO 2 in future climatic conditions. Results from the simulation showed that the model accurately estimated the trends in R h -CO 2 at the two sites across different management practices, with correlation coefficients ranging from 0.7 to 0.99. There was no significant model bias between the modelled and measured values from the two sites. In Lettosuo, CCF and RF initially produced higher R h -CO 2 levels compared to the non-harvested control, but these levels declined steadily over time. In Ränskälänkorpi, CCF area resulted in higher R h -CO 2 levels after 20 years compared to the control and RF areas. By the end of the simulation, R h -CO 2 levels from CCF and RF were lower compared to the control. These findings highlight the long-term and varied impacts of peatland forestry management practices in reducing R h -CO 2 .