WL2E Corylus avellana – Potentilla sterilis woodland
Vegetation
Corylus avellana dominates the low canopy of this diverse woodland community (mean canopy height = 12.3 m, n = 68). Crataegus monogyna usually joins the hazel or persists beneath, frequently in a spiny understorey with Prunus spinosa. Fraxinus excelsior is also frequent, occurring as young trees or saplings, or sometimes as emergents above the hazel. Spindly shrubs of Euonymus europaeus may also be found here. In the field layer, the constants are Rubus fruticosus agg., Hedera helix, Viola riviniana/reichenbachiana, Potentilla sterilis, Geum urbanum and Fragaria vesca. Frequent forbs include Geranium robertianum, Oxalis acetosella, Arum maculatum, Circaea lutetiana, Veronica chamaedrys, Primula vulgaris and Sanicula europaea. The chief ferns are Dryopteris filix-mas, Polystichum setiferum and Phyllitis scolopendrium. There is usually a luxuriant bryophyte layer coating the ground, rocks and lower trunks, primarily consisting of Thuidium tamariscinum, Eurhynchium striatum, Thamnobryum alopecurum, Plagiomnium undulatum, Kindbergia praelonga, Rhytidiadelphus triquetrus, Hylocomium brevirostre, Plagiochila asplenioides and Ctenidium molluscum.
Ecology
This is a base-rich scrub woodland community primarily associated with well-drained mineral soils (mean organic content = 21.6%, n = 72). It is found on flat or sloping ground in the lowlands (mean slope = 11.1°, n = 72; mean altitude = 57 m, n = 72), often where there is outcropping limestone. Soils are of fairly average fertility.
Sub-communities
Two sub-communities have been described for this community. The Ctenidium molluscum – Epipactis helleborine sub-community (WL2Ei) largely represents species-rich stands associated with limestone pavement complexes. Ctenidium molluscum, Epipactis helleborine, Tortella tortuosa, Lejeunea cavifolia, Fissidens taxifolius and Plagiochila asplenioides are more frequent in this sub-community, as are a number of the forb species listed above. The Fraxinus excelsior – Ilex aquifolium sub-community (WL2Eii) represents a more general assemblage with fewer karst indicators.
Similar communities
Hazel-dominated stands are also included within community WL1C but those occur on more acidic soils and generally lack the suite of forbs occurring in the present community that are indicative of basic conditions.
Conservation value
This is quite a species-rich woodland community (total species/100 m2 = 37.5, n = 102) with a fairly diverse bryophyte flora (bryophyte species/100 m2 = 13.3, n = 102). Stands do not qualify as any of the EU HD Annex I woodland habitats, but stands on thin soils occurring in association with karst limestone could be considered under habitat 8240 Limestone pavement*.
Management
One of the main threats to these woodlands is woodland or scrub clearance. Conversely, abandonment of grazing in some areas has led to significant increases in hazel scrub. These stands may be grazed by livestock (often cattle) or feral goats and overgrazing can be an issue. Sites can also be lost due to quarrying of limestone.