Climate, or weather, is the most important allogenic factor controlling bog fire activity, but the vegetation composition determines the spatial spread and severity of fires. Severe fires induce changes in bog microtopography, hydrology, vegetation and peat properties, which should be taken into consideration when studying past climate dynamics from bog archives. In this paper we aim to define fire patterns and frequencies of two boreal bogs, one in Estonia and one in Finland, in relation to paleoclimate and, to determine the nature and time-scale of post-fire vegetation succession. During the last 5000 years both peatlands experienced several fire events. A typical pre-fire vegetation community consisted of dry hummock Sphagna, often accompanied by Calluna vulgaris. We found that only the most severe occasional fires resulted in a dramatic change to the vegetation composition. In these cases, a wet shift, where the pre-fire hummock community was replaced by a wet hollow community, occurred. Even after a long-lasting wet phase, the post-fire disturbance succession led towards a dry hummock community characterised by Calluna. Therefore, Calluna appeard to be a key species in both pre- and post-fire vegetation dynamics. The recovery time of dry microtopes following severe combustion and subsequent hydrological change could take up to 350 years. Fires have been a regular phenomenon in boreal bogs even in the regions with a rather low human impact. The fire history records did not indicate any direct link to the regional long-term climate.