UPLAND OAKWOOD (UK BAP PRIORITY HABITAT)

Summary

This is woodland on well-drained to rather poorly drained, acidic to neutral soils in the upland parts of Britain, where either pedunculate or sessile oak forms at least 30% of the canopy cover. Other tree and shrub species occur commonly, especially downy birch, silver birch, rowan, hazel and holly. Like upland birchwoods, the field layer is mostly grassy or heathy, but when very heavily grazed can be dominated by large bryophytes. Small herbs, bryophytes and ferns, including bracken, can be very common, and on rocks, banks, trees and shrubs in the west there can be a rich flora of oceanic bryophytes including some uncommon species.

Most Scottish examples of this priority habitat are on moderate to steep slopes below 300 m, with well drained brown earth or podzol soils. This priority habitat can occur in mosaics with the Upland birchwoods, Upland mixed ashwoods and Wet woodland priority habitats, as well as with open habitats including bracken, heath, cliffs, screes and acid grassland. The habitat is widespread in Scotland and in upland areas of Britain generally.

Good management for conservation in this habitat generally aims towards maintaining a good diversity of species, sizes and age classes of trees and shrubs, encouraging diversity in the structure and species composition of the ground vegetation, maintaining rich bryophyte and lichen assemblages on rocks and trees especially in the west, maintaining good quantities of standing and fallen dead wood, and controlling the extent and spread of non-native trees and shrubs, especially rhododendron, Rhododendron ponticum.

What is it?

This is woodland on well-drained to rather poorly drained, acidic to neutral soils in the upland parts of Britain, where sessile oak Quercus petraea or pedunculate oak Quercus robur forms at least 30% of the canopy cover. Other tree and shrub species occur commonly, especially silver birch Betula pendula, downy birch Betula pubescens, rowan Sorbus aucuparia, hazel Corylus avellana and holly Ilex aquifolium.

Most of the Upland oakwood has a field layer which is grassy or heathy. In grassy examples typical species include wavy hair-grass Deschampsia flexuosa, common bent Agrostis capillaris, sweet vernal-grass Anthoxanthum odoratum, tormentil Potentilla erecta and heath bedstraw Galium saxatile. In heathy examples these species can also occur in small quantity but in a sward of ling Calluna vulgaris, bilberry Vaccinium myrtillus or, on some south-facing slopes, bell heather Erica cinerea. The heathy examples are generally on strongly acid soils but moderate to heavy grazing in such places can lead to grassier – or even bryophyte dominated – field layers. On more mildly acid soils the ground flora is less heathy and small herbs are more common including wood sorrel Oxalis acetosella, common dog-violet Viola riviniana and primrose Primula vulgaris. In the damper examples of this priority habitat purple moor-grass Molinia caerulea can be abundant or dominant in the field layer.

Bryophytes and ferns are generally common throughout. Typical bryophytes include the mosses Hylocomium splendens, Pleurozium schreberi, Pseudoscleropodium purum, Rhytidiadelphus loreus, R. triquetrus, R. squarrosus, Dicranum majus, D. scoparium, Polytrichastrum formosum and Leucobryum glaucum. Bryophytes are especially plentiful and diverse on the thinner, more acidic soils. Ferns typically include hard fern Blechnum spicant, Dryopteris spp. and bracken Pteridium aquilinum: this last species can be dominant in the field layer on deep brown earth soils.

Much of this woodland is on steep slopes where the ground vegetation is broken by rock outcrops and boulders. These rocks generally support an abundance of bryophytes and in some places lichens. Their bryophyte floras are especially luxuriant and varied in the wetter west, where they include several western species such as the mosses Dicranum scottianum and Sematophyllum micans and the liverworts Scapania gracilis, Plagiochila spinulosa, P. atlantica, P. bifaria, P. punctata, Saccogyna viticulosa, Bazzania trilobata, Adelanthus decipiens, Aphanolejeunea microscopica, Drepanolejeunea hamatifolia and Harpalejeunea molleri. The western filmy ferns Wilson’s filmy-fern Hymenophyllum wilsonii and Tunbridge filmy-fern H. tunbrigense, which are small ferns looking more like bryophytes at first glance, also grow in these habitats.

The epiphytic floras on oaks and other trees in this priority habitat, especially in the west, can be rich in bryophytes including most of the western species listed above. Lichens of the Lobarion community are a particular characteristic of western woodlands, including large foliose species such as Lobaria pulmonaria, L. scrobiculata, L. virens, L. amplissima, Sticta sylvatica, S. uliginosa, S. limbata, Nephroma laevigatum and Pseudocyphellaria spp. Species of more acid bark, such as Menegazzia terebrata and Hypotrachyna taylorensis, are also often present, along with the many smaller crustose species of the Graphidion community. These communities are better developed in Scotland than anywhere else in Europe.

Scottish examples of this priority habitat have much in common with those in the rest of the UK, but compared with those in England and Wales they do not generally extend to such a high altitude and tend to have less bramble and honeysuckle.

How do I recognise it?

Differentiation from other Priority Habitats

Upland birchwoods are the most similar to the Upland oakwood priority habitat in terms of their habitat and ground vegetation, but they have a canopy including abundant to dominant birch and with little or no oak, and are restricted to the Scottish Highlands and Hebridean islands. Stands of birch further south are best regarded as cyclical or successional stages of other types of woodland, especially that belonging to the Upland oakwood priority habitat.

Lowland mixed deciduous woodland can have similar ground vegetation and an oak- dominated canopy, but generally much less rich communities of lichens and bryophytes. They generally comprise different NVC types. The only NVC overlap between these two priority habitats is the W16 community: stands of W16 containing oak are treated as Lowland mixed deciduous woodland where they occur in the lowlands but as Upland oakwood where they occur on the upland fringes.

The NVC separates Upland mixed ashwoods (W9 and certain examples of W7 and W8) from Upland oakwood which does not include W7-9.

The Upland oakwood and Wet woodland priority habitats are largely separable by NVC type, but the W4 community occurs in both. The W4c sub-community is restricted to Wet woodland. The drier W4a sub-community occurs in the Upland oakwood and Upland birchwoods habitats but not in the Wet woodland habitat. In previously published priority habitat definitions, some of the less wet examples of W4b and those which are in mosaics with drier W10e, W11, W16 and W17 woodland are considered to be best placed in the Upland birchwoods or Upland oakwood priority habitats, depending on location and canopy as described above. However, typical W4b is as wet as many other NVC communities in the Wet woodland priority habitat and is clearly different from the drier W10, W11 and W17 communities: this might suggest keeping it within the Wet woodland habitat. Using patch size as a guide is a useful approach such that a small area of W4b within a larger area of W11 would classify as Upland birchwood; whereas if the W4b is largely associated with W4c then it would classify as Wet woodland.

Definition in relation to other habitat classifications

Classification Habitat types belonging to this UK BAP priority habitat All examples of W4a, W10e, W11 and W17 in which oak forms >30% of the canopy cover. Upland fringe examples of W16 in which oak forms >30% of the canopy cover. NVC Examples of non-NVC ‘WLz’ (with very species-poor Luzula sylvatica ground vegetation) in upland or upland fringe situations, in which oak forms >30% of the canopy cover. (All of the above NVC communities are included in the Scottish Biodiversity List.)

A1: oakwood examples of W4a, W10e, W11, W17 and WLz with oak >30% of canopy cover; total canopy cover >30% Phase 1 A2: oak scrub forms of W4a, W10e, W11, W17 and WLz with oak >30% of canopy cover A3: oakwood examples of W4a, W10e, W11, W17 and WLz with oak >30% of canopy cover; total canopy cover <30% A4: recently felled W4a, W10e, W11, W17 and WLz oakwood with oak >30% of canopy cover

UK BAP broad All examples of this priority habitat belong to the broad habitat - habitat Broadleaved, mixed and yew woodland

NVC communities W11 and W17 account for most of the Upland oakwood in Scotland. The sub-communities W8e/f/g and W10e, and examples of W16 and W8d in the upland fringe, have historically been assigned to Upland priority woodland habitats. However, W8, W10 and W16 are generally lowland communities, and their flora and distribution reflect the influence of a warmer and/or drier lowland climate compared with that of their upland counterparts W9, W11 and W17. It may be preferable to consider all examples of W8/10/16 woodland in lowland Scotland as part of the Lowland Mixed Deciduous woodland habitat. The Native Woodland Survey of Scotland classified woodland to community level only, and included all examples of W8, W10 and W16 within the Lowland mixed deciduous woodland priority habitat.

Definition in relation to legislative classifications

Classification Habitat types belonging to this UK BAP priority habitat

Habitats H91A0 (all occurrences). Directive Annex I

SNH SSSI All examples of the Upland oakwood priority habitat belong within habitat features the Upland oak woodland SSSI feature type.

Where is it?

Most Scottish examples of this priority habitat are on moderate to steep slopes with well drained brown earth or podzol soils. Within larger areas of woodland this priority habitat can occur in mosaics with the Upland birchwoods priority habitat, more flushed areas with the Upland mixed ashwoods priority habitat or wetter areas with the Wet woodland priority habitat. It can also occur in mosaics with open habitats including bracken, heath of the Upland heathland priority habitat, cliffs and screes of the Inland rock outcrop and scree habitats priority habitat and acid grassland. Most sites are found below 300 m in altitude.

With the inclusion of W10e the habitat range of this priority type is broadened to include lowland woodland on well-drained soils on sloping to gently undulating ground among enclosed, intensively managed farmland. As a general rule of thumb these sub-communities would be classified as upland if they occur in the uplands/north-west of Scotland and as lowland if they occur in the lowlands/south-east of Scotland. These are transitional communities which could equally well fit into either upland or lowland woodland habitats.

The Upland oakwood priority habitat is widespread in upland areas of Britain, and with the inclusion of the W10e sub-community it extends into northern and western lowland areas. In Scotland this priority habitat is most common in the southern and western parts of the Highlands, especially Argyll, Lochaber and around Loch Lomond, and on the eastern sides of the larger Inner Hebridean islands. In the northernmost parts of the Highlands Upland oakwood is rare and most of the semi-natural woodland belongs to the Upland birchwoods priority habitat (which also occurs throughout the Highlands). In 2008 the total extent of Upland oakwood in Britain is estimated to be between 70000 and 100000 ha (UK BAP 2008). The Native Woodland Survey of Scotland (2014) gives the area of this priority habitat in Scotland as 19,474ha. For reference see the National Report at p22 Table 3 http://www.forestry.gov.uk/PDF/FCMS126.pdf/$FILE/FCMS126.pdf .

What is special about it?

Some species of special conservation status recorded in this priority habitat in Scotland are listed below.

Wildlife EC Scottish and UK BAP Habitats Bio- Red Country- Common priority Directive diversity Data side Act Group name Latin name list Annex II List List (1981) shining guest Formicoxenus ant y y ant nitidulus lesser beetle Calosoma inquisitor y y searcher bird tree pipit Anthus trivialis y y y Coccothraustes bird hawfinch y y y coccothraustes bird cuckoo Cuculus canorus y y y spotted bird Muscicapa striata y y y flycatcher bird wood warbler Phylloscopus sibilatrix y y y bird song thrush Turdus philomelos y y y pearl- butterfly bordered Boloria euphrosyne y y y fritillary small pearl- butterfly bordered Boloria selene y y fritillary chequered Carterocephalus butterfly y y y skipper palaemon flowering juniper Juniperus communis y y plant flowering small cow- Melampyrum y y y plant wheat sylvaticum scottish yellow fly Lipsothrix ecucullata y y splinter northern fly Lipsothrix errans y y yellow splinter orange fungus Cantharellus friesii y y chanterelle blackening Cantharellus fungus y y chanterelle melanoxeros Hydnellum fungus velvet tooth y y spongiosipes fungus a tooth fungus Phellodon confluens y y golden gilled fungus Phylloporus pelletieri y y bolete fungus oak pdolypore Piptoporus quercinus y y y fungus a tooth fungus Sarcodon scabrosus y y lichen a lichen Arthonia invadens y y Arthothelium lichen a lichen y y y dictyosporum lichen a lichen Buellia violaceofusca y y y lichen a lichen Calicium diploellum y y y lichen a lichen Catillaria alba y y y Chaenotheca lichen a lichen y y y gracilenta Chaenotheca lichen a lichen y y y laevigata lichen a lichen Collema fasciculare y y y Fuscopannaria lichen a lichen y y y y ignobilis Wildlife EC Scottish and UK BAP Habitats Bio- Red Country- Common priority Directive diversity Data side Act Group name Latin name list Annex II List List (1981) Fuscopannaria lichen a lichen y y y sampaiana Hypotrachyna lichen a lichen y taylorensis lichen a lichen Lecania chlorotiza y y y Lecanographa lichen a lichen y y y amylacea Lecanora lichen a lichen y y y cinereofusca lichen a lichen Lecanora quercicola y y y lichen a lichen Leptogium brebissonii y y y lichen a lichen Lobaria amplissima y lichen a lichen Lobaria pulmonaria y lichen a lichen Lobaria scrobiculata y lichen a lichen Lobaria virens y Megalospora lichen a lichen y y y tuberculosa lichen a lichen Menegazzia terebrata y lichen a lichen Nephroma laevigatum y lichen a lichen Pannaria rubiginosa y lichen a lichen Parmeliella testacea y y y lichen a lichen Pertusaria velata y y y Polychidium lichen a lichen y y y dendriscum lichen Yellow Pseudocyphellaria y

specklebelly crocata ragged Pseudocyphellaria lichen pseudocyphell y y y y lacerata aria Norwegian Pseudocyphellaria lichen y y y specklebelly norvegica lichen a lichen Pyrenula dermatodes y y y Ramonia lichen a lichen y y y chrysophaea lichen a lichen Ramonia dictyospora y y y lichen a lichen Rinodina degeliana y y y lichen a lichen Rinodina isidioides y y y Schismatomma lichen a lichen y y y graphidioides lichen a lichen Sclerophora pallida y y y lichen a lichen Sticta canariensis y y y lichen a lichen Sticta fuliginosa y lichen a lichen Sticta limbata y lichen a lichen Sticta sylvatica y lichen a lichen Usnea florida y y lichen a lichen Vulpicida pinastri y y y lichen a lichen Wadeana minuta y y y Wilson's liverwort Acrobolbus wilsonii y y pouchwort Dumortier`s liverwort Dumortiera hirsuta y y y liverwort Carrington`s liverwort Radula carringtonii y y y scalewort mammal hedgehog Erinaceus europaeus y mammal wildcat Felis silvestris y y y y mammal pine marten Martes martes y y y y mammal noctule Nyctalus noctula y y y y soprano mammal Pipistrellus pygmaeus y y y pipistrelle brown long- mammal Plecotus auritus y y y y eared bat mammal red squirrel Sciurus vulgaris y y y green shield- moss Buxbaumia viridis y y y y y moss moss Irish daltonia Daltonia splachnoides y y y pied tineid moth Nemapogon picarella y y moth spider a money- Monocephalus y y Wildlife EC Scottish and UK BAP Habitats Bio- Red Country- Common priority Directive diversity Data side Act Group name Latin name list Annex II List List (1981) spider castaneipes Philodromus spider a crab spider y y margaritatus

Many other species of interest occur in this habitat but are not included in the above list because they do not have any of those particular conservation designations. However they are still of importance. They include many western bryophyte species (some of these listed above in the Description section) and additional birds such as pied flycatcher and redstart.

How do we manage it?

Good management for conservation should aim towards the following:

 Encourage regeneration to ensure a continued canopy and diversity of species, sizes and age classes of trees and shrubs

If felling or thinning takes place this should ideally not reduce the variation in species, sizes and age classes of trees and shrubs. In many woods natural regeneration can be encouraged, generally by at least a temporary reduction or removal of grazing, as a means of increasing the numbers of young trees, thereby helping to maintain the woodland in the long term. Ash, rowan, sycamore and birch regeneration often develops more quickly and abundantly than that of oak, elm and hazel. Where beech is present this species can also regenerate plentifully. The benefits of management for natural regeneration should of course be balanced against any possible detrimental effects. An increased height and density of ground vegetation can lead to reductions in populations of insects and small plants. A very dense tree/shrub canopy can outshade light-demanding species such as many lichens. It can be good to keep some glades open, to provide general habitat diversity and because glades can be important for groups such as insects, birds and, on trees at edges of glades, lichens. Enclosing woodlands to encourage regeneration can lead to dense thicket regeneration however it may be the only option available to allow regeneration to take place effectively and retain woodland at a site.

 Encouraging diversity in the structure and species composition of the ground vegetation

If grazing is only light to moderate this can allow some tree and shrub regeneration to take place and also allow good flowering and seed-setting of ground flora plants including dwarf shrubs. Heavy grazing can lead to extensive carpets of mosses becoming dominant or co-dominant on the ground, as vascular cover becomes shorter and sparser. This has led some people to think that moderate to heavy grazing is needed in order to maintain bryophyte abundance and diversity, but the main bryological interest in these woods is not on the ground but on rocks and trees.

 Maintaining rich assemblages of bryophytes and lichens on rocks and trees, especially in the west

To a large extent this means maintaining shaded conditions so that shade- and humidity-demanding bryophytes and lichens, including many uncommon species, do not suffer from too much exposure to sunlight and wind. However, this also means guarding against overshading because many of these species are intolerant of heavy shade. Where felling or thinning is planned in western woods it is best to assess the richness of the trees and shrubs concerned, and that of nearby rocks, and to carry out the planned management only where these epiphytic and saxicolous floras are not especially rich or do not include species of special interest.

 Maintaining good quantities of standing and fallen dead wood

Dead wood is best left in the woodland because it is an important habitat for birds, insects and, on fallen rotting logs, bryophytes, especially liverworts. Fallen dead wood also helps to provide variety in habitat structure on the ground, and the additional shade and shelter close to fallen timber helps to maintain the humid conditions needed by some woodland species.

 Controlling the extent and spread of non-native trees and shrubs, especially Rhododendron ponticum

Non-native trees and shrubs can occur in this habitat as a result of deliberate under- or inter- planting, or by seeding in from nearby sources. The commonest of such species here are conifers such as spruces, firs, pines, larches and western hemlock Tsuga heterophylla, together with beech Fagus sylvatica, sycamore Acer pseudoplatanus and rhododendron. All of these except larch have the potential to grow thickly and cast such heavy shade and leaf litter as to impoverish the native woodland ecosystem. Sycamore tends to be less overshading than beech, rhododendron and evergreen conifers. Control of these species is desirable in order to prevent ecological impoverishment of the habitat. Rhododendron ponticum is the most serious of these alien woody species because it can invade an area in a relatively short time forming such dense thickets that almost all plant life is overshaded and smothered by leaf litter. Worst of all, rhododendron is especially common and invasive in the types of humid western woodland, including many belonging to this priority habitat, which are of international importance for the oceanic bryophyte, lichen and fern floras. Removal of rhododendron is therefore desirable from such woods and their surroundings. The most important things to note are:

• there are several techniques available, and each site should be evaluated to determine which would be most appropriate. • cut and burn is historically most popular in Scotland but is generally not the most effective, • stem injection is extremely effective, although it takes longer for the results to show, • mechanical removal (inc Lever and Mulch ™) can also be very effective, but requires considerable skill, and • follow-up treatment and long-term monitoring are essential to ensuring success.

References, links and further reading

Averis, A., Averis, B., Birks, J., Horsfield, D., Thompson, D., & Yeo, M. 2004. An Illustrated Guide to British Upland Vegetation. Peterborough, JNCC http://jncc.defra.gov.uk/page-2463

Ellis, N.E. and Munro, K. 2004. A preliminary review of the distribution and extent of BAP priority habitats across Scotland. Scottish Natural Heritage Commissioned Report No.044 (ROAME No. F00NA02). https://www.nature.scot/information-library-data-and-research/information-library

Forestry Commission. 2003. The management of semi-natural woodlands. Practice Guide series of seven booklets (one for each woodland UK BAP priority habitat). Edinburgh, Forestry Commission.

Rodwell, J.S., ed. 1991a British plant communities Volume 1: Woodlands and scrub. Cambridge, Cambridge University Press

Rodwell, J.S., Dring, J.C., Averis, A.B.G., Proctor, M.C.F., Malloch, A.J.C., Schaminee, J.H.J. & Dargie, T.C.D. 1998. Review of coverage of the National Vegetation Classification. Joint Nature Conservation Committee contract report F76-01-170. Coordinated by the Unit of Vegetation Science, Lancaster University.

UK BAP 2008 http://jncc.defra.gov.uk/pdf/UKBAP_BAPHabitats-63-UplandOakwood.pdf

Usher, M.B., Bain, C. and Kerr, A. eds. 2000. Action for Scotland's Biodiversity. Scottish Biodiversity Group. Edinburgh, The Scottish Executive and The Stationery Office.

Common Standards Monitoring guidance http://www.jncc.gov.uk/page-2199

Native Woodland Survey of Scotland http://scotland.forestry.gov.uk/supporting/strategy- policy-guidance/native-woodland-survey-of-scotland-nwss

Managing native woodlands http://scotland.forestry.gov.uk/supporting/strategy-policy- guidance/biodiversity/native-woodlands

Managing invasive rhododendron: http://www.forestry.gov.uk/fr/rhododendroncontrol

National Biodiversity Network (NBN) Gateway https://data.nbn.org.uk/

Scottish Natural Heritage website: http://www.nature.scot

UK BAP information on JNCC website: http://jncc.defra.gov.uk/default.aspx?page=5155