Assessment of soil CO2, CH4, and N2O fluxes and their drivers, and their contribution to the climate change mitigation potential of forest soils in the Lublin region of Poland

Abstract Forests can play a key role in the mitigation of climate change, although there have been limited regional scale assessments that account for variations in soil type and tree species. Most of the focus has been on their ability to sequester atmospheric CO 2 , while there is less information on the two other major greenhouse gases (GHGs), N 2 O and CH 4 . We examined the GHG budgets of ten forest soils in Poland, considering all three major GHGs, where no previous long-term measurements had been made, which encompassed different tree species, stand age, and contrasting edaphic conditions. In addition to the quantification and assessment of seasonal variability in the major soil GHG fluxes over two years, the aims of the present study were (i) the identification of the main drivers of the soil-based GHG fluxes, (ii) the determination of the contribution of each gas to the Global Warming Potential (GWP), and (iii) to assess the mitigation potential of these fluxes over different forest systems. All the forest soils were sources of CO 2 and N 2 O and sinks for atmospheric CH 4 with pronounced seasonal variations in CO 2 and CH 4 driven by soil moisture and temperature. The soils showed significant differences in annual GHG fluxes, with average values of 16.7 Mg CO 2 ha −1 , − 3.51 kg CH 4 ha −1 , and 0.95 kg N 2 O ha −1 . The annual total GWP ranged from 13.1 to 22.0 Mg CO 2 eq ha −1 with CO 2 making the highest contribution , and forest-specific CH 4 uptake resulting in a reduction in GWP, ranging from − 0.08% (in the youngest forest) to -0.97% (in the oldest forest). Mixed forests showed the greatest potential for climate change mitigation, with the highest soil C sequestration, and the lowest GWP values when compared to sites with monocultures. The results suggest that a mixture of tree species could eventually be incorporated into management plans to increase the effectiveness of forests in climate change mitigation.