Occurrence of Fires in the Eastern Saariselkä Area, North-West Russia

Fire is the most signifi cant natural factor controlling succession in boreal forests (Zackrisson 1977). Small and large fi res of varying intensity control the age structure of forests, their species composition, and nutrient cycling (Lehtonen and Kolström 2000). Fire creates a mosaic of burned and unburned forest patches, thus maintaining vegetation diversity at the landscape level. Patchiness is also found within a single fi re-affected area, because large fi res seldom if ever kill all vegetation within the main fi re perimeter (Eberhart and Woodard 1987). From the biodiversity point of view, fi re history information is an important aspect in the management of protected areas and in maintaining and restoring the features of pristine forests in managed stands. The occurrence of wildfi res in Finland has decreased considerably during the past one hundred years because of effi cient fi re prevention and control systems. The number of fi res has been very low for a long time (Zackrisson 1977, Lehtonen and Huttunen 1997), and the median size of burns has markedly decreased. The oldest statistics in Finland on the numbers of forest fi res and on the areas swept over by them go back some 130 years (Saari 1923). In the 19th century, forest fi res were common on crown land. The median size of burns was 131 ha in 1865–1870, but early in the 20th century it was reduced to 40 ha in North Finland and 18 ha in South Occurrence of Fires in the Eastern Saariselkä Area, North-West Russia