Impact of Former Peat Extraction Field Afforestation on Soil Greenhouse Gas Emissions in Hemiboreal Region

The reduction of greenhouse gas (GHG) emissions and climate change mitigation are global issues. Peatlands in Europe are widely distributed in the Nordic-Baltic region, and Baltic countries are some of the largest peat suppliers for horticulture in Europe. However, there is no sustainable substitute for peat in the horticulture industry. Therefore, it is necessary to identify suitable re-cultivation types for former peat extraction fields, because knowledge about the effect of re-cultivation on annual carbon and GHG budgets is limited. Ecosystem GHG (CO2, CH4, N2O) exchange measurements, environmental parameter assessment and sampling in the study were conducted in a hemiboreal vegetation zone for 24 consecutive months in former peat extraction fields with different re-cultivation management strategies (land use types). The aim of the study was to assess the influence of diverse re-cultivation management strategies on the GHG emissions of former peat extraction fields. The most suitable re-cultivation management is afforestation with Scots pine (Pinus sylvestris) in order to obtain the lowest annual CO(2)eq values and ensure additional carbon sequestration in living tree biomass. The developed linear mixed-effect models showed a good model fit ((RCO2)-C-2 = 0.80, (RCH4)-C-2 = 0.74) for the analyzed land use types, and thus can be used for CO2 and CH4 emissions estimation.