Fire history and forest age distribution of an unmanaged Picea abies dominated landscape

We examined fire history and forest age distribution in an unmanaged, Picea-dominated landscape in the Paanajarvi wilderness, located in northeastern Fennoscandia and northwest Russia. Maximum tree age was determined in 61 systematically located study plots in an area of about 6600 ha. Fire scars were examined in living and dead trees in the study plots and elsewhere in the study area. Charcoal and pollen analyses of peat were performed on samples from two locations. Fires had been rare in the landscape. Nearly half of the dendrochronologically dated fires occurred in a distinct and short period, from 1859 to 1889, in the northeastern part of the area. This nonrandom occurrence of fires, together with the observed signs of past human influence, suggests an anthropogenic origin for the majority of the fires. The fact that 95% of the study area consisted of forests older than 120 years reflects the end of the occurrence of fires in the 1880s. Pollen analysis from the southwestern part of the study area showed that the site had been dominated by Picea at least during the last millennium. Charcoal analysis from the same site indicated that likely more than 1000 years had elapsed since the last fire. In general, the results suggest that the abundance of old forests, with the oldest trees being approximately 300 years of age, belongs to the natural state of a Picea-dominated landscape.