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Recently, increased attention has been drawn to the greenhouse gas emissions of the Land use, Land use Change and Forestry (LULUCF) sector. In the Finnish LULUCF sector, the soil-originated emissions from the after-use of cutover peatland have become a more relevant question. This is due to the rapid increase in the number of former peat-harvesting sites, caused by the decline in the combustion of energy peat due to its high CO 2 emissions. We conducted a nationally representative survey to study which after-use options of cutover peatlands are preferred by landowners. Based on the preferred after-use options, we estimated their impact on the national greenhouse gas emissions in the Finnish regions in 2035, and what factors influence the landowners' choice of after-use options. We found that the four most popular after-use options for landowners were afforestation (71%), agriculture (24%), production of wind and solar power (22%) and rewetting (18%) when the respondent chose the three most attractive options. However, there were clear regional differences in the preferred after-use options, which might lead, if realized, to different soil-originated emissions at the regional level. The preferred after-use options could produce emissions of 0.35 million tonnes of carbon dioxide equivalent a year (Mt CO 2 eq y−1) by 2035 in Finland. Most of these emissions (30.1%) would come from South Ostrobothnia in western Finland, mainly due to the indicated high interest in agricultural after-use. Most landowners prefer financially profitable after-use options, such as forestry, agriculture, as well as wind and solar energy production in cutover peatlands. However, environmentally oriented landowners favour many kinds of actions to support biodiversity, carbon sequestration, and water protection in cutover peatlands. It is crucial that economic productivity and the greenhouse gas sinks of cutover peatlands be considered simultaneously to meet the climate targets of the LULUCF sector in Finland. • The landowners' perspective of using cutover peatland was studied. • The landowners prefer financially profitable after-use options. • Forestry, agriculture, and wind and solar energy were the most popular options. • Landowners' choices would increase the soil originated GHG emissions nationally. • Strengthening the dialogue between the landowners and climate policy is needed. [ABSTRACT FROM AUTHOR]

Drainage for forestry purposes changes the conditions in the peat and leads to increased growth of shrubs and trees. Concurrently, the production and uptake of the greenhouse gases carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are likely to change: due to the accelerated decomposition of oxic peat, drained peatlands are generally considered to loose peat carbon (C). We measured CO2 exchange with the eddy covariance (EC) method above a drained nutrient-poor peatland forest in Southern Finland for 16 months in 2004-2005. The site, classified as a dwarf-shrub pine bog, had been ditched about 35 years earlier. CH4 and N2O fluxes were measured at 2-5 week intervals with the chamber technique. Drainage had resulted in a relatively little change in the water table level, being on average 40 cm below the ground in 2005. The annual net ecosystem exchange was -870 g CO2 m-2 yr-1 in the calendar year 2005, varying from -810 to -900 g CO2 m-2 yr-1 during the 16 month period under investigation. The site was a small sink of CH4 (-0.12 g CH4 m-2 yr-1) and a small source of N2O (0.10 g N2O m-2 yr-1). Photosynthesis was detected throughout the year when the air temperature exceeded -3 °C. As the annual accumulation of C in the above and below ground tree biomass (550 g CO2 m-2) was significantly less than the net exchange of CO2, about 300 g CO2 m-2 yr-1 (~80 g C m-2) was likely to have accumulated as organic matter into the peat soil. This is a higher average accumulation rate than previously reported for natural northern peatlands, and the first time C accumulation has been shown, by EC measurements, to occur in a drained peatland. Our results suggest that forestry-drainage may significantly increase the CO2 uptake rate of nutrient-poor peatland ecosystems. [ABSTRACT FROM AUTHOR]

Northern peatlands cover approximately 4% of the global land surface area. Those peatlands will be particularly vulnerable to environmental and climate change and therefore it is important to investigate their total greenhouse gas (GHG) budgets, to determine the feedback on the climate. Nitrogen (N) is known to influence the GHG budget in particular by affecting the methane (CH4) balance. At two peatland sites in Scotland and Finland GHG fluxes of carbon dioxide (CO2), methane and nitrous oxide (N2O) and nitrogen fluxes were measured as part of the European project 'NitroEurope'. The Scottish site, Auchencorth Moss, was a GHG sink of −321, −490 and −321 g CO2 eq m−2 year−1 in 2006, 2007 and 2008, respectively, with CO2 as the dominating GHG. In contrast, the dominating GHG at the Finnish site, Lompolojänkkä, was CH4, resulting in the site being a net GHG source of +485 and +431 g CO2 eq m−2 year−1 in 2006 and 2007, respectively. Therefore, Auchencorth Moss had a negative global warming potential (GWP) whilst Lompolojänkkä had a positive GWP over the investigated time period. Initial results yielded a positive N budget for Lompolojänkkä of 7.1 kg N ha−1 year−1, meaning the site was gaining nitrogen, and a negative N budget for Auchencorth Moss of −2.4 kg N ha year−1, meaning the site was losing nitrogen. [ABSTRACT FROM AUTHOR]

Fluxes of greenhouse gases (GHG) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were measured during a two month campaign at a drained peatland forest in Finland by the eddy covariance (EC) technique (CO2 and N2O), and automatic and manual chambers (CO2, CH4 and N2O). In addition, GHG concentrations and soil parameters (mineral nitrogen, temperature, moisture content) in the peat profile were measured. The aim of the measurement campaign was to quantify the GHG fluxes during freezing and thawing of the top-soil, a time period with potentially high GHG fluxes, and to compare different flux measurement methods. The forest was a net CO2 sink during the two months and the fluxes of CO2 dominated the GHG exchange. The peat soil was a small sink of atmospheric CH4 and a small source of N2O. Both CH4 oxidation and N2O production took place in the top-soil whereas CH4 was produced in the deeper layers of the peat, which were unfrozen throughout the measurement period. During the frost-thaw events of the litter layer distinct peaks in CO2 and N2O emissions were observed. The CO2 peak followed tightly the increase in soil temperature, whereas the N2O peak occurred with a delay after the thawing of the litter layer. CH4 fluxes did not respond to the thawing of the peat soil. The CO2 and N2O emission peaks were not captured by the manual chambers and hence we conclude that high time-resolution measurements with automatic chambers or EC are necessary to quantify fluxes during peak emission periods. Sub-canopy EC measurements and chamber-based fluxes of CO2 and N2O were comparable, although the fluxes of N2O measured by EC were close to the detection limit of the system. We conclude that if fluxes are high enough, i.e. greater than 5-10 μg N m-2 h-1, the EC method is a good alternative to measure N2O and CO2 fluxes at ecosystem scale, thereby minimizing problems with chamber enclosures and spatial representativeness of the measurements. [ABSTRACT FROM AUTHOR]