Succession of understory vegetation in managed and seminatural Scots pine forests in eastern Finland and Russian Karelia

The aim of this study was to compare the understory vegetation in chronosequences representing seminatural and managed Scots pine (Pinus sylvestris L.) forests on dryish heaths of the Vaccinium type. The data represent the middle boreal vegetation zone and were collected in eastern Finland and the Dvina area of Karelia, on both sides of the border between Finland and the Russian Federation. Species diversity and the coverage of the various life-form groups (ground lichens, mosses, liverworts, grasses, herbs, dwarf shrubs, and tree seedlings) were used to analyse the properties of the ground vegetation over the succession from open forest land to closed forest communities. The clearest differences in diversity between the seminatural forests mainly influenced by fire and managed forests occurred in the early stages of succession. Forest management appeared to increase the species richness at the beginning of succession. The seminatural stands were rich in Cladonia lichens and dwarf shrubs up until tree canopy closure; however, the abundance of mosses was lower in the seminatural stands. Forest management favoured an abundance of grasses, notably Deschampsia flexuosa, which was common after clear-cutting. The use of prescribed burning in silviculture could result in more natural vegetation succession dynamics in managed stands.