Deciduous secondary forests in north-west part of european Russia: cycles of plant associations

摘要

Plant associations of birch, aspen and white alder forests were included into 6 association cycles: bilberry, wood sorrel, red grass, meadow-like, nemoral herb, moist herb. Associations within cycles were compared on the basis of species composition, dominant species and set of floristically homogeneous groups of phytosociological releves. White alder forests are absent in bilberry cycle. Meadow-like birch forest is very distinct from corresponding aspen and white alder forests. In the rest of the cycles, aspen and birch forests have very similar understory, but white alder forests are always very distinct. The associations Calluno-Betuletum, Chelidonio-Alnetum, Chaerophyllo-Alnetum, Urtico-Alnetum were not included in any cycle.