There are mires in Finland, as the rainfall is higher than the amount of water that evaporates. Mires make the microclimate in forests more humid, and they are important grazing areas for reindeer and moose. Early in the morning in spring, the singing of a polyphonic choir of birds echoes at mires.
Most of the mires in Hossa are small but still, about one third of the national park’s territory consists of various types of mires. Most of them are open mires and pine bogs.
Amongst the most special moist places in Hossa are aro wetlands that dry out in summer and are often flooded again in autumn, due to a heavy rainfall. Their vegetation is often similar to that of open mires.