WL1C Quercus petraea – Corylus avellana woodland
Vegetation
Dense stands of Corylus avellana are a key character of this community. It often manifests as high forest with hazel forming an understorey beneath a canopy dominated by Quercus petraea or hazel may form a lower canopy on its own (mean canopy height = 15.2 m, n = 115). Fraxinus excelsior is usually present but is seldom abundant. Betula pubescens is frequent here and occasionally there may be some sparse cover of Sorbus aucuparia. Corylus is usually joined in its strata by Ilex aquifolium and frequently by Crataegus monogyna. The main species in the field layer are Dryopteris dilatata, Dryopteris affinis, Hedera helix, Lonicera periclymenum, Blechnum spicant, Oxalis acetosella, Rubus fruticosus agg., Viola riviniana/reichenbachiana and Athyrium filix-femina. Other frequent species include Circaea lutetiana and Luzula sylvatica. Hyacinthoides non-scripta may form carpets of blue flowers in the spring. In the bryophyte layer, one could expect to find Thuidium tamariscinum, Isothecium myosuroides, Eurhynchium striatum, Kindbergia praelonga and Hypnum cupressiforme.
Ecology
These are stands of well-drained mineral soils and podzols (mean organic content = 18.3%, n = 115) found on sloping ground in upland margins (mean slope = 16.2°, n = 115; mean altitude = 94 m, n = 115). Soils are rather mildly acidic and infertile.
Sub-communities
Two sub-communities are described. The Quercus petraea sub-community (WL1Ci) is the variation in which sessile oak is always present in the canopy. The Corylus avellana subcommunity (WL1Cii) is more mesotrophic and sessile oak is often absent; included here are low canopy Corylus stands on mildly acidic soils.
Similar communities
The greater abundance of Corylus avellana is the main way of differentiating between this community and others in group WL1. This community may be regarded as transitional to group WL2, and stands of WL1Cii could be confused with the hazel woodlands of WL2E. Those stands typically occur on shallow base-rich soils, however, and more frequently support a suite of species indicative of those conditions (e.g. Ctenidium molluscum, Geum urbanum, Potentilla sterilis, Fragaria vesca, Brachypodium sylvaticum).
Conservation value
This is a species-rich woodland community (total species/100 m2 = 41.1, n = 130) with a diverse bryophyte flora (bryophyte species/100 m2 = 16.0, n = 130). Stands with Quercus petraea are likely to qualify as EU HD Annex I habitat 91A0 Old oak woodlands.
Management
These woodlands are commonly grazed, particularly by deer, and overgrazing is an acknowledged problem. Locally, woods have been fenced and deer culling employed to try to promote woodland regeneration. Invasion by non-native species and woodland clearance are also threats. Rhododendron ponticum thrives in these moist, acidic conditions. Spraying with herbicide, cutting and removal of seedlings have been used to combat the spread of this species within these woods.