Habitat account - Forests


9190 Old acidophilous oak woods with Quercus robur on sandy plains 

Background to selection

Distribution of SACs/SCIs/cSACs with habitat 9190 Old acidophilous oak woods with Quercus robur on sandy plains.  Click image for enlarged map.
Distribution of SACs/SCIs/cSACs with habitat 9190 Old acidophilous oak woods with Quercus robur on sandy plains. Click image for enlarged map.

Description and ecological characteristics

 

This habitat type comprises ancient lowland oak woodland on acidic, sandy or gravelly substrates. Veteran trees are relatively abundant in UK stands compared to examples in continental Europe, and are often associated with assemblages of notable lichens, fungi and invertebrates.

 

The ground flora is generally species-poor, and comprises calcifuge sub-shrubs such as bilberry Vaccinium myrtillus and heather Calluna vulgaris, grasses such as wavy hair-grass Deschampsia flexuosa and creeping soft-grass Holcus mollis, and herbs such as heath bedstraw Galium saxatile and common cow-wheat Melampyrum pratense, together with acidophilous bryophytes. Bracken Pteridium aquilinum can become dense where the sands are deep and loose. It is broadly equivalent to NVC type W16 Quercus spp. – Betula spp. – Deschampsia flexuosa woodland and some stands of W10 Quercus robur – Pteridium aquilinum – Rubus fruticosus woodland.

 

The floristics of UK examples are typical for the type, apart from the absence of a few more continental species such as May lily Maianthemum bifolium. The type is limited to the south and east of Britain because to the west the oakwoods start to acquire a more oceanic character that places them within 91A0 Old sessile oak woods with Ilex and Blechnum in the British Isles.

European status and distribution

 

Old acidophilous oak woods are found on highly acidic and impoverished soils derived from siliceous sedimentary rocks or very often from aeolian, fluvio-glacial or morainic deposits across the Baltic and North Sea plain. They occur from Poland through Germany and into the Netherlands, with more local areas in the Ardennes, middle Rhine, northern France and Paris Basin. Across their range, these woods are now extremely local.

UK status and distribution Click to view UK distribution of this habitat

 

Old acidophilous oak woods are limited to the south and east of England. Many examples are secondary, having developed on, for example, former heathland.

Site selection rationale

 

Sites selected encompass the limited range of geographical and ecological variation shown by this habitat type in the UK. Selection centred on large ancient woodlands, particularly those with veteran trees important for their lichen, fungi or invertebrate assemblages. Secondary woodlands were not selected, as the conservation priority is usually to restore former heathland where trees have encroached.

 

Two sites, the New Forest and Windsor Forest and Great Park, were identified as of potential international importance for their saproxylic invertebrate fauna by the Council of Europe (Speight 1989).


Site accounts

Birklands and Bilhaugh Derbyshire and Nottinghamshire
Birklands and Bilhaugh is the most northerly site selected for old acidophilous oak woods and is notable for its rich invertebrate fauna, particularly spiders, and for a diverse fungal assemblage, including Grifoa suphurea and Fistulina hepatica. Both native oak species, Quercus petraea and Quercus robur, are present, with a mixture of age-classes, so there is good potential for maintaining the structure and function of the woodland system and a continuity of dead-wood habitats.
Staverton Park and The Thicks, Wantisden East Anglia
This site is representative of old acidophilous oak woods in the eastern part of its range, and its ancient oaks Quercus spp. have rich invertebrate and epiphytic lichen assemblages. Despite being in the most ‘continental’ part of southern Britain, the epiphytic lichen flora of this site includes rare and Atlantic species, such as Haemotomma elatinum, Lecidea cinnabarina, Thelotrema lepadinum, Graphis elegans and Stenocybe septata. Part of the site includes an area of old holly Ilex aquifolium trees that are probably the largest in Britain. The site has a very well-documented history and good conservation of woodland structure and function.
The New Forest Gloucestershire, Wiltshire and Bristol/Bath area, Hampshire and Isle of Wight
The New Forest is representative of old acidophilous oak woods in the southern part of its UK range. It is the most extensive area of active wood-pasture with old oak Quercus spp. and beech Fagus sylvatica in north-west Europe and has outstanding invertebrate and lichen populations. This site was preferred over other sites that lack a succession of age-classes because, although scattered over a wide area, the oak stands are found within a predominantly semi-natural landscape with a more balanced age-structure of trees. The traditional common grazing in the Forest by cattle and ponies provides opportunities to explore the impact of large herbivores on the woodland system. The New Forest has been identified as of potential international importance for its saproxylic invertebrate fauna by the Council of Europe (Speight 1989).
Windsor Forest and Great Park Berkshire, Buckinghamshire and Oxfordshire, Surrey, East and West Sussex
Windsor represents old acidophilous oak woods in the south-eastern part of its UK range. It has the largest number of veteran oaks Quercus spp. in Britain (and probably in Europe), a consequence of its management as wood-pasture. It is of importance for its range and diversity of saproxylic invertebrates, including many rare species (e.g. the beetle Lacon querceus), some known in the UK only from this site, and has recently been recognised as having rich fungal assemblages. Windsor Forest and Great Park has been identified as of potential international importance for its saproxylic invertebrate fauna by the Council of Europe (Speight 1989).

SACs/SCIs/cSACs where this Annex I habitat is a qualifying feature, but not a primary reason for site selection

Dorset Heaths Dorset and Somerset
Dorset Heaths (Purbeck and Wareham) and Studland Dunes Dorset and Somerset
West Dorset Alder Woods Dorset and Somerset
 

Many designated sites are on private land: the listing of a site in these pages does not imply any right of public access.