Atlantic and Baltic broad-leaved coastal dune woodland

This is a very broadly defined habitat of Atlantic coastal dunes, comprising a diversity of relatively open to closed woodlands which develop where more stable coastal sands are invaded by broadleaved trees typical of the local soils and climatic conditions. It includes forests in dry and wet conditions, on calcareous and acidic sands and in the climatic gradient from southern Norway and the Baltics towards central Portugal. Many of these forests are indistinguishable in their floristic composition from inland examples of the same general type.

A first division can be made between forests of dry and moist soils. In moist dune slacks in the whole range of the habitat these forests are rather similar, with Betula pendula as one of the most important tree species, accompanied by Populus tremula. The understory consists of a combination of dune shrubs and common dune slack species, like Mentha aquatica, Phragmites australis, Valeriana officinalis, Cirsium palustre, Eupatorium cannabinum and Calamagrostis epigejos (alliance Ligustro vulgaris-Betulion pubescentis, sometimes considered as part of the Alnion incanae). In wetter conditions Alnus glutinosa or Betula pubescens may become dominant (Alnion glutinosae, Betulion pubescentis), with helophytic species like Thelypteris palustris and Lycopus europaeus. In some sites Sphagnum species dominate the moss layer. Rarely Salix alba will colonise wet dune slacks, forming woodlands.

The dry forests are more diverse, with Quercus robur as the dominant species in the Northwest-Atlantic and Baltic, and more thermophilous Quercus species (Q. ilex, Q. rotundifolia, Q. suber) in the warmer parts of the Atlantic coast, south of Loire estuary. In general these forests have a similar species combination to more inland forests on sandy soils, although some typical dune species like Carex arenaria and Calamagrostis epigejos will occur more frequently. The Quercus forests from the acidic dune sands in the northern and Baltic part of the range (alliance Quercion roboris) are often relatively species poor, with a heathy aspect beneath the trees, Calluna vulgaris, Empetrum nigrum, Festuca ovina, Carex arenaria, Lonicera periclymenum, Polypodium vulgare and other common species in the herb layer, and in many cases a high cover of bryophytes (Pleurozium schreberi, Hypnum spp., Dicranum scoparium, Polytrichum spp.) and lichens (Cladonia spp.). On slightly richer, more mature soils, Fagus sylvaticus may be dominant, or a combination of Quercus robur, Ulmus minor, Acer pseudoplatanus and Fraxinus excelsior (classified under Alnion incanae). The field layer may contain a set of geophytes, like Scilla non-scripta and Galanthus nivalis. Most different from inland types are the Quercus robur forests on calcareous dune sands, widespread in the central part of the Dutch dunes, but elsewhere rare. These, in many cases relatively young forests, contain a lot of shrubs, like Crataegus monogyna, Rosa spp., Berberis vulgaris, Euonymus europaeus, Ligustrum vulgare, Hippophae rhamnoides and Rhamnus cathartica. The herb layer differs, depending on the exposition of the dunes, but often includes a combination of species preferring dry, sandy soils and species of more humus- rich soils, with mixtures such as Carex arenaria, Calamagrostis epigejos, Glechoma hederacea, Polygonatum odoratum, Convallaria majalis, Geranium robertianum and Galium aparine. Sometimes rare species are found in the woodland edges, like Scrophularia vernalis. In the southern part of the distribution range more Mediterranean species are found in the canopy, like Quercus ilex, Q. suber and Q. pyrenaica sometimes mixed with Pinus pinaster, and in the understorey Ruscus aculeatus, Cistus salviifolius, Arbutus unedo, Rubia peregrina, Ligustrum vulgare and Iris foetidissima.

Because the coastal dunes of Europe have been relatively intensively used by man for many centuries, and in other parts are very dynamic, in general dune forests are relatively young and in many places also rare. Other woodlands have been created by planting, often with pine species, like dune areas between the Loire estuary and Les Landes in (South)western France. In general dune woodlands are restricted to the more inland parts of the dunes, but in some places low trees grow seawards as far as the first dune ridge, being reduced to a bonsai structure by the salty wind. Old plantations with dominance of deciduous trees with a similar structure and species composition as natural forests may be considered under this habitat. Pine forests on dunes belong to B1.7d (Baltics) or B1.7e (Mediterranean), while lower, shrubby woodlands, for example dominated by Salix cinerea in dune slacks or Crataegus monogyna on dry dunes, and Sambucus nigra woodland, in most cases growing together with Hippophae rhamnoides, are considered part of habitat B1.6a.

Indicators of good quality

These are relatively young woodlands, which often still are in a certain stage of succession. Open structures contribute to the richness of the species diversity. 

• Variety of open woodlands (with many gradients towards shrub, heathland and grassland) and closed forests (with more typical species of shaded conditions)                   

• Dominance of broad-leaved species

• Absence of non-native or nitrophilous species

• Abundance of spring-flowering geophytes

• No or a low rate of disturbance by recreation

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats