Uncommon vascular plant species in an East-Central Swedish forest area-a comparison between young and old stands

Abundance of uncommon vascular plant species (indicator species and red-listed species) was recorded in 120 circular (12.6 m²) random plots in young (10–24 years after deal-cutting) and old (>80 years) forest stands, respectively, in the forest area of Vällen (2 600 ha), ca. 80 km north of Stockholm, Sweden. Factors describing stand density, field-layer and soil moisture were recorded. A total of 16 species were observed and of these 14 were found in old and 9 in young stands. Seven species occurred exclusively in the old stands and two in the young stands. The total number of species records was significantly higher in young than in old stands, 80 and 71, respectively. Mean number of records per ha was ca. 530 for the young stands and ca. 470 for the old. Of the five species common enough to be tested, a difference was only found for Paris quadrifolia , which was significantly more frequent in young than old stands. Galium odoratum, Hepatica nobilis, Lathyrus vernus and Paris quadrifolia grew in significantly more sheltered sites, e.g. beneath other herbs and grasses or close to shrubs and trees in young compared to old stands. Nested subset analysis showed that the whole data-set had a nested structure. Galium odoratum was significantly nested and thus indicated rich plant assemblages. In this calcareous area with nutrient-rich forest soils, there evidently is a potential for at least some uncommon vascular plant species to survive the phases following clearcutting. The study indicates that green-tree retention at final fellings and avoidance of heavy shrub removal during cleaning are beneficial to the flora.