The role of fire in the carbon dynamics of a mire, eastern Finland

The fire history and the effect of fires on the long-term (apparent) rate of carbon accumulation (LORCA) in the Patvinsuo mire complex, eastern Finland, were determined through stratigraphic and pollen analyses of 98 peat cores. The peat cores were characterized by a large number of charcoal layers and the age of the basal peat varied between 57 and 10 500 years. Mire fires slowed down the progress of vertical peat accumulation and resulted in great carbon losses. The average LORCA in the Patvinsuo cores was clearly lower, 9.2 ± 1.0 (SE) g m-2 yr-1, compared to the average value for all mire sites in the southern half of Finland, 17.7 ± 0.6 (SE) g m-2 yr-1. The average rate of carbon loss in Patvinsuo mire complex was 9.5 ± 1.0 (SE) g m-2 yr-1 and the mean carbon loss in an individual fire was estimated to be 2.5 kg m-2.