Question: When evaluating forests in terms of their biodiversity, distinctiveness and naturalness, the affinity of the constituent species to forests is a crucial parameter. Here we ask to what extent are vascular plant species associated with forests, and does species’ affinity to forests vary between European regions?Location: Temperate and boreal forest biome of Northwestern and Central Europe.Methods: We compiled EuForPlant, a new extensive list of forest vascular plant species in 24 regions spread across 13 European countries using vegetation databases and expert knowledge. Species were region‐specifically classified into four categories reflecting the degree of their affinity to forest habitats: 1.1, species of forest interiors; 1.2, species of forest edges and forest openings; 2.1, species that can be found in forest as well as open vegetation; and 2.2, species that can be found partly in forest, but mainly in open vegetation. An additional “O” category was distinguished, covering species typical for non‐forest vegetation.Results: EuForPlant comprises 1,726 species, including 1,437 herb‐layer species, 159 shrubs, 107 trees, 19 lianas and 4 epiphytic parasites. Across regions, generalist forest species (with 450 and 777 species classified as 2.1 and 2.2, respectively) significantly outnumbered specialist forest species (with 250 and 137 species classified as 1.1 and 1.2, respectively). Even though the degree of shifting between the categories of forest affinity among regions was relatively low (on average, 17.5%), about one‐third of the forest species (especially 1.2 and 2.2) swapped categories in at least one of the study regions.Conclusions: The proposed list can be used widely in vegetation science and global change ecology related to forest biodiversity and community dynamics. Shifting of forest affinity among regions emphasizes the importance of a continental‐scale forest plant species list with regional specificity.

1 Species cover was tested during a 10-year fertilization experiment in the low-alpine Cetrarietum nivalis community and the middle-alpine Phyllodoco-Juncetum trifidi community in the Dovre mountains of south-central Norway. Nitrogen was added at 7, 35 and 70 kg N ha⁻¹ year⁻¹, with the highest dose corresponding to approximately 3.5 times the annual deposition in south-west Norway. 2 Both communities are dominated by lichens (Cladonia spp. and Cetraria spp., respectively), have a patchy structure and are ‘conservative’ as regards species content. 3 Lichens, which showed a decrease in cover and size, and after some years developed discoloured thalli, are the best organisms for monitoring changes in alpine vegetation that is exposed to increased nitrogen deposition. The most sensitive species in Cetrarietum nivalis appeared to be Alectoria nigricans and Cetraria ericetorum, but more abundant species (Cladonia mitis, C. stellaris and Cetraria nivalis) are likely to be more reliable indicators. Cetraria delisei seems to be a reliable indicator species for monitoring in Phyllodoco-Juncetum trifidi. 4 Fertilization had no significant effect on the vascular plants (dwarf shrubs and a few graminoids) in either community, except for Festuca ovina, the cover of which increased slightly. 5 Nitrogen pollution may affect oligotrophic, alpine communities differently, depending on their species composition and horizontal structure (patchiness). 6 It is suggested that other factors, such as climate, soil properties and community structure, may be more important than long-range nitrogen pollution for determining species composition and species cover in many of the oligotrophic, alpine communities in southern Norway. However, in lichen-rich communities, critical loads have already been exceeded in the most polluted areas of south-west Norway.

Decisions regarding forest typology, management and protection are often based on the structures of present-day forests, ignoring their successional history. Forests growing on kames, eskers and various moraine hillocks common in regions with Holocene glaciation are good examples of this approach. In Estonia, these forests locally persist as fragments of continuous primary forest, but usually they are situated on former slash-and-burn areas (bushlands) or reforested agricultural land. Our aim was to elucidate the strength of the effect of long-term land-use history on the present-day vegetation compositions of mature hillock forests and their soil chemistry. It appeared that even the mature secondary hillock forests are still distinct from historically continuous stands in terms of species composition. We discovered connections between stand history and species content in hillock forests as well as transformed soil properties. The carbon and nitrogen contents in the humus horizons of secondary forests are lower while their carbon–nitrogen ratios are higher than in continuous forests. The relationship between vegetation and stand history is demonstrated by the higher proportions of anthropophytic and apophytic species in the herb layer of the secondary forests. The presence of species that are tolerant of anthropogenic impact on the secondary hillock forests floor can also be partly explained by the effect of different species in the tree and shrub layers, gaps in the tree canopy, and the boundary effect caused by the small areas of forest patches, neighboring grasslands or fields. The extinction debt in secondary communities should also be considered.