The age and size of trees was sampled and measured on eight sample plots (0.2 ha each) within a Pinus sylvestris -dominated boreal forest landscape in Vienansalo wilderness, Russian Karelia. The fire history of these plots was obtained from a previous dendrochronological study. All the studied sample plots showed a wide and uneven distribution of tree ages, but the shape of the age distributions of trees as well as tree species composition varied substantially. Trees over 250 years of age occurred in every studied plot, despite its small size. This suggests that old Pinus were common and rather evenly distributed in the landscape matrix. The oldest Pinus tree was 525 years of age. The correlations between tree age and size were often weak or even nil. In Pinus the correlation between age and diameter was stronger than that between age and height. In the dominant tree species Pinus and Picea, the largest trees were not the oldest trees. The tree age distributions together with the fire history data indicated that the past fires have not been stand replacing, as many of the older Pinus had survived even several fires. Tree age classes that had regenerated after the last fire were most abundant and dominated by Picea and/or deciduous trees, while the trees established before the last fire were almost exclusively Pinus. The results suggest that periodic occurrence of fire is important for the maintenance of the Pinus-dominated landscape. This is because fire kills most Picea and deciduous trees and at the same time enhances conditions for Pinus regeneration, facilitated by available seed from the continuous presence of old fire-tolerant Pinus trees.