Alnus woodland on riparian and upland soils

These are riparian and land-upheaval woodlands dominated by Alnus glutinosa and/or A. incana, and sometimes Fraxinus excelsior, typically without many softwood willows in the canopy, such woodland being assessed separately as G1.1 Temp and boreal softwood riparian woodland).  This habitat also differs from riparian woodlands of the middle and lower reaches of major European rivers, which is assessed separately as G1.2b Temperate and boreal hardwood riparian forest. The non-riverine subtype of this present habitat (corresponding to the original G1.B Non-riverine alder woodland) is typical of the Baltic coast, a sea with a low level of salinity.

The stands show varying degrees of soil moisture according to the frequency of flooding in mature river valleys, depth of water table, or proximity to the coast. Moister forms can also have some Salix fragilis, Betula pubescens and Prunus padus in the canopy with S. phylicifolia beneath;  in more mesic situations, Sorbus aucuparia can appear among the trees with Juniperus communis beneath.  Other shrubs include Crataegus monogyna, Ribes alpinum, R. spicatum, Rubus caesius, R. idaeus, S. triandra and Sambucus nigra.  The field layer can be quite species-rich, especially in moister situations, when more nutrient-demanding herbs such as Urtica dioica and Filipendula ulmaria may be abundant. Other herbs then include Valeriana sambucifolia, Angelica sylvestris, Deschampsia cespitosa, Calamagrostis canescens and C. purpurea.  More mesic stands have Milium effusum, Silene dioica, Rubus saxatilis and Poa nemoralis. In the driest situations, Agrostis capillaris and Moehringia trinervia occur and even some forest dwarf shrubs but at low frequency and cover.  In the northernmost Bothnian Bay, on slightly more calcareous substrate, Geranium sylvaticum, Oxalis acetosella, Filipendula ulmaria, Geum rivale and Anthriscus sylvestris are distinctive.

Indicators of quality:

• Undisturbed natural hydrology
• Dominance of mature trees with shrubs forming a subordinate layer
• Few if any signs of exploitation for timber, fallen trees remaining in situ with ample deposition of natural organic debris from flooding in riparian sites.
• No signs of eutrophication or pollution by anthropogenically enriched flood or ground waters, for example excessive spread of nutrient-demanding weeds
• Absence of non-native tree species and absence of invasive aliens such as Reynoutria japonica or Impatiens glandulifera

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats