Acidophilous Quercus woodland

These are oak-dominated woodlands typical of acidic, free draining soils with mor humus on sandstones, lime-poor metamorphic and igneous rocks and sandy and gravelly soils through the nemoral zone. Extending from the Atlantic fringe of northern Portugal and Spain, across north-west and central Europe into southern Scandinavia, the northern Balkans and on into Russia, the habitat occurs often very fragmentary and scattered now in the prevailingly agricultural semi-natural landscape. Variations in climate across this wide overall range, from extreme Atlantic on the western fringes of Ireland and the British Isles, Lusitanian in northern Iberia, through Continental to Boreal in the east and sub-Mediterranean in the south, have an effect on the associated flora, even though this is not in general very rich.

 The characteristic oaks here are Quercus robur and Q. petraea, often occurring with a subordinate proportion of Betula pendula and/or B. pubescens, which can be pioneers in this habitat following fire or clear-felling, are relatively short-lived survivors in mature forest and which have been selected against in the coppice manage-ment or timber extraction often imposed on these woodlands. Through much of the range in central and north-western Europe, Fagus sylvatica is a potential competitor for canopy dominance even on mineral-poor, sandy soils. On acidic, mineral-rich soils with moder humus co-dominant Fagus-Quercus canopies are better classified under G1.6b Fagus woodland on acid soils. On highly acidic soils to the Boreal east of the range, Pinus sylvestris replaces the oaks as the dominant tree in woodlands with much the same field layer. In central European mountain ranges on shallow siliceous soils Pinus sylvestris can also be present in the canopy in lower proportions. Overall, other associated trees and shrubs are typically very few in this habitat: Sorbus aucuparia and Frangula alnus occur through much of the range, Castanea sativa, Sorbus torminalis and Pyrus cordata in the Sub-Atlantic heartland and, to the west, Ilex aquifolium can be abundant.

 The field layer is generally rather species-poor with calcifuge sub-shrubs, herbs and cryptogams most characteristic and lending a heathy appearance, especially under lighter shade and where grazing is absent. Constant through much of the range are Vaccinium myrtillus, Calluna vulgaris (in more open places), Deschampsia flexuosa, Agrostis capillaris, Anthoxanthum odoratum, Festuca ovina agg., Holcus mollis, Carex pilulifera, Potentilla erecta, Hieracium sabaudum, this sometimes tall and dense on less shallow soils. The commonest bryophytes overall are Polytrichum formosum, Hypnum jutlandicum, Pleurozium schreberi and Leucobryum glaucum.

 Regional variations in the flora in relation to climatic differences can be seen in each of the layers of the vegetation moving away from the Sub-Atlantic woodlands of central and western France, the lower Rhineland and north-east Italy/south-west Switzerland. In the more Atlantic climate of the north-west, there is a further contingent of herbs such as Galium saxatile, Teucrium scorodonia, Hypericum pulchrum, Luzula sylvatica and Blechnum spicant and to the western seaboard of Ireland and the UK an extraordinary additional richness in cryptogams and ferns which, with annual precipitation up to 3000 mm, lends this habitat a great luxuriance. It is this vegetation which forms the richer core of Annex 1 91A0 Sessile Oakwoods in the British Isles.

 On the Atlantic fringe of Portugal and Spain, with annual precipitation up to 2000 mm but with warmer summers and milder winters, Quercus petraea tends to be less prominent than further north but there is often some Q. pyrenaica along with Betula pubescens spp. celtiberica and Arbutus unedo. Cytisus scoparius, Ulex gallii and Erica arborea enrich the sub-shrub layer, with the lianas Rubia peregrina and Tamus communis. Herbs such as Pseudarrhenatherum longifolium, Potentilla montana, Daboecia cantabrica, Crepis lampsanoides, Luzula forsteri, Euphorbia dulcis, Melitis melissophyllum, Silene nutans, Polygonatum odoratum, Galium rotundifolium, Arenaria montana, Genista florida, Rumex papillaris give a South Atlantic or more Mediterranean feel to the flora.

 In northern Europe and southern Scandinavia, some Eurasian Temperate and Boreal species such as Vaccinium vitis-idaea, Maianthemum bifolium and Luzula pilosa begin to appear in these woodlands and examples on the Baltic-North Sea plain form the core of the Annex 1 9190 Old acidophilous oakwoods with Quercus robur on sandy plains.

 Further east, through Germany, Poland, Belarus, Ukraine and into Russia, where Pinus sylvestris begins to challenge the dominance of Quercus spp. on impoverished acid soils, Juniperus communis and Euonymus verrucosa are additional woody species and, among the herbs, Trientalis europaea, Rubus saxatilis, Pyrola rotundifolia, Orthilia secunda, Calamagrostis arundinacea. At the extreme east of the range, where there is usually less than 800mm precipitation and winter temperatures down to -12°C, Carex digitata, Galium schultesii and Chamaecytisus ruthenicus are characteristic. Among the bryophytes Dicranum polysetum, Eurhynchium angustirete and Rhodobryum roseum are distinctive here.

 Further south, at the eastern sub-Mediterranean limit of this habitat in Austria, the northern Balkans and Romania, the warmer climate is reflected in the appearance of Quercus cerris, Q. dalechampii and Q. polycarpa in the canopy, Pyrus communis and Euonymus verrucosa among the shrubs and Genista tinctoria, G. germanica, Cytisus nigricans, Rubus hirtus and Vincetoxicum hirundinaria in the herb layer. Castanea sativa woods are inlcuded in this forest type as well because of their  species-poor and calcifuge vegetation.

Indicators of good quality:

• Sufficient proportion of historically old (ancient) woodland with corresponding species diversity
• Presence of old trees and a variety of dead wood (lying and standing) and the associated flora, fauna and fungi
• Sufficient structural diversity/ complexity including (semi)natural age structure
• Maintenance of humidity beneath an intact canopy where a rich fern and bryophyte component is typical (e.g. for Annex 1 91A0)
• Typical flora and fauna composition of the region
• Absence of non-native tree species (such as Pseudotsuga menziesii) and absence of invasive aliens in all layers (fauna, flora)
• No signs of eutrophication or pollution with e.g. pronounced invasion on nutrient-demanding herbs
• Presence of gradients or mosaics with heathland or acidic grassland at the landscape level (not isolated within plantation forests).

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats