2024

Ekman, Ellinoora; Minkkinen, Kari; Putkinen, Anuliina; Siira, Olli-Pekka; Hautala, Roosa; Kübert, Angelika; Li, Xuefei; Ojanen, Paavo; Raivonen, Maarit; Rinne, Erkka; Lohila, Annalea

Session 6. Greenhouse gas fluxes at high latitudes and climate/human induced feedbacks Peatlands are huge carbon storages, but due to human activities, part of this carbon is released to the atmosphere intensifying global warming. In Finland, circa half of the peatland area is drained for forestry. Drainage, together with intensive harvesting, alters water table level (WTL), and further leads to soil CO2 emissions, especially in nutrient-rich sites. Rewetting causes CH4 emissions but eventually the soil becomes a carbon sink again, and the accumulation of carbon will exceed the warming effect of CH4 emissions. It is not yet fully understood how rewetting temporally affects ecosystem processes as well as carbon and greenhouse gas (GHG) balance in different peatland forest ecosystems. A forestry-drained peatland site in Tammela, Southern Finland, is currently being rewetted. With various measurements using the eddy covariance technique, closed chambers, soil incubation experiments, water table loggers and sap flow sensors we want to understand how rewetting affects GHG-fluxes both at the ecosystem and the soil level, the surface energy balance and tree water consumption. Most of the measurements started two years ago and will be ongoing several years after the rewetting. This study will produce new knowledge about the local and global climate impacts and about the hydrological effects of rewetting in peatland forest ecosystems. Here, we present the site and the measurement set-up with some preliminary results from the ecosystem GHG flux measurements and the incubation experiments before the rewetting.