Habitat account - Forests
91J0 Taxus baccata woods of the British Isles * Priority feature
Background to selection
|Distribution of SACs/SCIs/cSACs with habitat 91J0 Taxus baccata woods of the British Isles. Click image for enlarged map.|
Description and ecological characteristics
Yew Taxus baccata woodland occurs on shallow, dry soils usually on chalk or limestone slopes, but in a few areas stands on more mesotrophic soils are found. The habitat is classified as NVC type W13 Taxus baccata woodland. Within this community yew tends to be overwhelmingly dominant and is usually associated with a very sparse shrub and tree layer. Only a few species, such as dogís mercury Mercurialis perennis, can survive beneath the dense shade cast by the canopy of mature yew trees. Association with beech Fagus sylvatica and holly Ilex aquifolium is less common than in mainland Europe.
Ecological variation arises according to the nature of the yew wood. In the south this type may be either the senescent phase of beech woodland supporting clusters of yew after the fall of beech, or primary woodland developing on unstable slopes. Very locally, box Buxus sempervirens may occur below the yew. Eventually individual ash Fraxinus excelsior or beech trees may grow through in gaps to recreate an overstorey. More northerly examples tend to be associated with ash and elm Ulmus spp., and in these situations yew is more likely to remain as the main overstorey species.
Stands of yew woodland frequently form mosaics with calcicolous scrub and grassland, including 6210 Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco-Brometalia).
European status and distribution
Yew is a broadly Atlantic tree with a wide but local distribution through western and central Europe, where it is most abundant in beech woods. Pure yew woods are relatively rare in Europe. Taxus baccata woods of the British Isles is restricted to the UK and Ireland.
UK status and distribution Click to view UK distribution of this habitat
Yew woodland is scattered, predominantly on calcareous substrates, in the south of the UK, and to a lesser degree in northern England. The only significant stand in Scotland, on Loch Lomond, is considered to have been planted.
Site selection rationale
The largest yew woodlands in Britain have been included within the SAC series. Sites have also been selected to encompass the geographic range and ecological variation of the habitat type, e.g. to represent examples on both chalk and limestone substrates, and in both southern and northern England. The selected sites include extensive pure yew Taxus baccata stands and also yew groves occurring as distinct communities within larger woodland blocks, so that the range of structural and functional relationships between yew and other woodland types is represented.
|Butser Hill||Hampshire and Isle of Wight|
|The combes of the south-east flank of Butser Hill support dense yew Taxus baccata woodland in association with scrub and chalk grassland. The yew is regenerating into the grassland and shows the classic interaction of these habitats in relation to grazing pressure.|
|Castle Eden Dene||Tees Valley and Durham|
|Castle Eden Dene in north-east England represents the most extensive northerly native occurrence of yew Taxus baccata woods in the UK. Extensive yew groves are found in association with ash-elm Fraxinus-Ulmus woodland and it is the only site selected for yew woodland on magnesian limestone in north-east England.|
|Great Yews||Gloucestershire, Wiltshire and Bristol/Bath area|
|Great Yews represents yew Taxus baccata woods in the south-west of the habitatís range. Although it is the smallest example of the habitat within the SAC series, it is important for the presence of about 300 old trees. It probably originated as yew wood following beech Fagus sylvatica or ash Fraxinus excelsior. It has some regeneration and so has the full structural and functional range expected of yew stands.|
|Hartslock Wood||Berkshire, Buckinghamshire and Oxfordshire|
|The bulk of this site lies on a steep slope above the River Thames. Recent storms and landslips have resulted in a diverse age-structure for the yew population. Open patches show a rich flora including local species such as southern wood-rush Luzula forsteri, wood barley Hordelymus europaeus and narrow-lipped helleborine Epipactis leptochila.|
|Kingley Vale||Surrey, East and West Sussex|
|Kingley Vale is one of the sites representing yew Taxus baccata woods on chalk, in the central southern part of its UK range. It has been selected primarily because of its size, as it is the largest area of yew woodland in Britain. It also shows excellent conservation of the full range of habitat structure and function.|
|Mole Gap to Reigate Escarpment||Surrey, East and West Sussex|
|At Mole Gap to Reigate Escarpment yew Taxus baccata woodland has been formed both by invasion of chalk grassland and from development within beech Fagus sylvatica woodland following destruction of the beech overstorey. Yew occurs here in extensive stands, with, in places, an understorey of box Buxus sempervirens at one of its few native locations.|
|Morecambe Bay Pavements||Cumbria, Lancashire|
|Morecambe Bay Pavements is an example of yew Taxus baccata woods in north-west England. The site is similar to the nearby Roudsea Wood and Mosses. These yew woods are on the northern Carboniferous limestone and, as in the Wye Valley, yew occurs both as dense groves and as scattered trees in the understorey of ash or ash-elm Fraxinus-Ulmus woodland. Yew woodland here represents the development of long-established stands on unstable scree and rocky slopes.|
|North Downs Woodlands||Kent|
|Yew Taxus baccata woodland at this site is associated with 9130 Asperulo-Fagetum beech forests, scrub and small areas of unimproved grassland on thin chalk soils. Where the shade is not too dense dogís mercury Mercurialis perennis predominates in the ground flora. The site is the most easterly of those selected.|
|Roudsea Wood and Mosses||Cumbria|
|The yew Taxus baccata woods of Roudsea Wood have strong similarities with the yew stands at the nearby Morecambe Bay Pavements. They are both on the northern Carboniferous Limestone, and as in the Wye Valley yew occurs both as dense groves and as scattered trees in the understorey of ash or ash-elm Fraxinus-Ulmus woodland.|
|Wye Valley Woodlands/ Coetiroedd Dyffryn Gwy||Gloucestershire, Wiltshire and Bristol/Bath area, Herefordshire, Worcestershire and Warwickshire, West Wales and The Valleys|
|Wye Valley is representative of yew Taxus baccata woods in the south-west of the habitatís range. It lies on the southern Carboniferous limestone, and yew occurs both as an understorey to other woodland trees and as major yew-dominated groves, particularly on the more stony slopes and crags.|
|Extensive yew Taxus baccata groves occur on the slopes and crags of Yewbarrow in association with 91A0 old sessile oak woods and invasive beech Fagus sylvatica stands on acidic substrates. Over much of the site, where light conditions allow, grasses such as wavy hair-grass Deschampsia flexuosa and creeping soft-grass Holcus mollis predominate with bracken Pteridium aquilinum. There are also some base-rich flushes along the stream-sides.|
SACs/SCIs/cSACs where this Annex I habitat is a qualifying feature, but not a primary reason for site selection
|Coedwigoedd Penrhyn Creuddyn/ Creuddyn Peninsula Woods||West Wales and The Valleys|
|East Hampshire Hangers||Hampshire and Isle of Wight|
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