Continues cover forestry on drained peatland

Challenges: Almost 50% Finnish peatland (4.95 Mha) has been drained for forestry (nearly 25% forest area). Drained peatland forests are a net carbon sink due to their trees (12.9 Mt CO₂ eq.), their soils are a carbon source (6.9 Mt CO₂ eq.). Rotational even-aged forestry is the conventional forest management method in Nordic countries. 60–100-year-long stand rotation is followed by clearcutting and e.g. ditch network maintenance (NTM), ensuring regeneration of the next tree stand. NTM lowers the water table level (WL) in soil for a long time and low WL increases aerobic decomposition, leading to increased soil CO₂ emissions; conversely, a high WL increases methane (CH₄₎ and nitrous oxide (N₂O) emissions.

Solutions: Continuous cover forestry (CCF) harvesting (e.g. strip cutting, selective cutting) has greater potential to maintain carbon sink potential in fertile peatland forests than even-aged forestry. In CCF, a forest canopy with post-harvest tree carbon storage and sink functions are maintained. Greenhouse gas emissions (GHGE) and soil greenhouse gas balance, the vegetational composition and microbial community will be studied.

Outcomes: By controlling the number of growing trees, GHGE are affected through vegetation-driven WL regulation. It has been calculated that if WL remains 30 cm deep, CH₄ emissions (25x more potent than CO₂) is prevented. GHGE are estimated to reduce by >10% compared to clearcutting. The first estimates indicate no economic disadvantage to CCF.