Key types

Of the British woods composed of native trees, those with dominance or co-dominance of oak are by far the most widespread. Because of the large numbers of sites involved, it is best to deal with the purer oakwoods on their own, and to treat separately the mixed oakwoods which mostly belong to more base-rich soils in the edaphic series. The inconsistencies in ecological distribution pattern make it appropriate to deal with pedunculate and sessile oakwoods together, but the specific identity of the oak will be mentioned whenever it is clearly known.

The main directions of variation in oakwoods are climatic, and a separation can be made into western types in regions of humid climate, and eastern types existing under drier conditions. The western oakwoods are internationally important for their rich Atlantic flora, especially of bryophytes, which is more fully represented in some of the heavy rainfall districts than in any other part of Europe. Particular emphasis has been laid on identifying and selecting an adequate latitudinal series of western oakwoods, to cover the considerable south to north changes in this Atlantic flora. The eastern oakwoods show less varied floristic features, and a more widely spaced latitudinal series has been judged adequate. Considerable variations also occur according to differences in management, especially between grazed and ungrazed woods - the former tending to be upland and the latter lowland.

Western

WESTERN OAKWOODS

Although many of the important woodlands in south-west England are in upland country, they differ from many hill woods farther north in being below the limits of enclosed land and thus mostly fenced against stock. Consequently there is often little disturbance, herbs are luxuriant, and the well-developed shrub layer includes many evergreens such as holly and ivy. The most important oakwoods of this region are on the flanks of the upland areas of Dartmoor and Exmoor. The Bovey Valley woodlands (W.63, gr. i)1

1 Cross-references to key sites are identified by an initial letter (indicating habitat) and number. , • , •

include Yarner Wood on the eastern edge of Dartmoor, which is mainly a plateau sessile oakwood with rather shallow gills, and the adjoining Becka Falls-Hound Tor woods on the steeper sides of a deep glen, but including river terrace with mixed woodland as well. The woods of Holne Chase (W.64, gr. i*) a few kilometres farther south are another important complex of plateau and valley-side sessile oakwoods, but have a good deal of mixed deciduous woodland on richer soils. Dendles Wood (W.8o, gr. 2) on the southern edge of Dartmoor is a pedunculate oakwood occupying a small hill valley, and contains a good deal of planted oak and conifers. Draynes Wood (W.yS, gr. 2), on the south side of Bodmin Moor, is a gorge oakwood with a fairly rich bryophyte and fern flora, and a counterpart to the woods at Becka Falls in the Bovey Valley complex.

Wistman's Wood (W.65, gr. i), Black Tor Copse (W.66, gr. i) on northern Dartmoor, and Piles Copse (W-79, gr. 2) in the south are also of pedunculate oak, but are high-level woods on extremely rocky ground and lie in a heavy rainfall area; the depauperate, often contorted form of the trees is in contrast to the well-grown oaks of the lower woodlands. Black Tor Copse lies within the North Dartmoor grade i composite site (£-.92).

Bryophytes and ferns are well represented in these Dartmoor woodlands, and the Holne Chase woods have some nationally rare Atlantic species. On the whole, however, the Atlantic flora here is less rich than in north Wales, Lakeland or the western Highlands, as the climate is less wet. Southwest England is the warmest of the oceanic regions of Britain, but the less humid conditions also differentiate these Dartmoor woods from those of the Killarney area, in south-west Ireland, where a similarly equable temperature regime obtains.

On the north side of Exmoor, the woods of the Holnicote and Horner Water (W.69, gr. i) are one of the largest continuous blocks of sessile oakwood in Britain, showing a great variety of slope and aspect, with a wide range of management types. Mixed deciduous woodland is also well represented here. Farther west on Exmoor, Watersmeet (W.68, gr. i), above Lynton, is another complex of sessile oak and mixed deciduous woodland, and has an especially rich flora with good representation of thermophilous Atlantic species. The woods of Holford and Hodder's Combes (W.84, gr. 2) on the Quantocks, are somewhat similar to those of the Horner Water, and can be regarded as an alternative site, whilst the Heddon Valley Woods (W.82, gr. 2) west of Lynton are a second choice to Watersmeet. In Somerset, Great Breach and Copley Woods (W.86, gr. 2) form a large lowland oakwood on relatively fertile soils. Although western in geographical position, it has stronger affinities with some eastern oakwoods or mixed deciduous woods than most of those mentioned above, as has Ashen Copse (W.85,gr.2).

The south-west peninsula has a number of coastal woods of distinctive character. On the extremely exposed and windswept north Cornish coast, steep slopes above the sea at Dizzard Point (W.62, gr. i) have a dense, wind-pruned wood of pedunculate oak with luxuriant ungrazed field communities, forming one of the best examples of coastal scrub woodland in the country. Similar steep and rocky slopes above the sea at Woody Bay (W.8i, gr. 2) and Hobby Woods at Clovelly (W.83, gr. 2), and Nance Wood (W-77, gr. 2) in Cornwall, have other examples of this maritime oakwood, regarded as alternative sites to the Dizzard Wood. A different type of coastal woodland is found in the deep, sheltered inlets of the sea which penetrate the south coast of Cornwall and Devon. At the head of the Fal Estuary (W.6i, gr. i), near Tregony, salt water backs up a low valley, creating salt marsh which passes through alder-willow carr into sessile oakwood on the drier valley sides. This is probably the best example of this kind of sequence known in Britain. Merthen Wood (W-76, gr. 2) on the estuary of the Helford River, is closer to the sea, but shows less varied stages of transition from saline habitats to oakwood.

In south Wales, the valleys of the headwaters of the River Tywi hold a number of hanging sessile oakwoods famous as the nesting haunt of the red kite in its last British refuge, amongst these sequestered hills. The most important of these woods in its own right is the Cothi Tywi (W.gi, gr. i: including Allt Rhyd y Groes), which partly belongs to the Royal Society for the Protection of Birds and forms an integral part of the complex of hill farmland, woodland and open moor constituting their Gwenffrwd reserve. The upland site of Nant Irfon (W-96, gr. 2) also contains sessile oakwoods which are the nesting place of kites. Farther north, the gorge of the River Rheidol at Devil's Bridge, Cardiganshire, is thickly wooded, mainly with sessile oak but with patches of mixed deciduous wood on richer soils. Unlike most of the Welsh oakwoods, Coed Rheidol (W.go, gr. i) is ungrazed, and the field communities are less modified than usual. Alternative woodland sites to these are the oakwoods in the Elan Valley at Glannau (W.ioo, gr. 2) and Cam Gafallt (see Appendix) (W- 97, gr. 2), both of which have mixed deciduous wood, and the latter an area of alderwood as well. Farther south, in Glamorgan, the valleys of Blaenau Nedd & Mellte (W.g8, gr. 2) have mixtures of woodland which include stands of sessile oak, and the complex at Coed Aber Edw (W.ioi, gr. 2) in Radnor also has this type represented.

North Wales is especially rich in oakwoods and a choice of sites has been made from a large number. As this is a district of generally heavy rainfall and one of the richest parts of Britain for Atlantic ferns, bryophytes and lichens, considerable emphasis has been placed on the representation of this floral element. Moreover, Merioneth in particular contains an exceptionally fine series of gorge woodlands, and an adequate sample of these is needed. No single wood contains anything like the full range of ecological variation characteristic of the district, and a group of sites has been selected to give this range in the aggregate. The greatest range of oakwood types is found in the Coedydd Dyffryn Maentwrog (W.io7, gr. i*) in northern Merioneth. Here, Coedydd Maentwrog represents a hanging oakwood of southern aspect, but changing at its eastern end to the rather open gorge wood of Coed Cymerau. On the opposite side of the valley, a north- to north-west-facing hanging oakwood is represented by Coed Camlyn which bends round at its western end into the deep gorge of Ceunant Llennyrch, containing a mixture of oak, mixed deciduous and birch wood. Just beyond the head of this glen, above Trawsfynydd Reservoir, Coed y Rhygen is a rocky open bryophyte-rich hillside oak- birch wood on less steep slopes but at a higher level than Coed Camlyn, and facing north to north-east. Below Ffestiniog, a second deep gorge, Ceunant Cynfal carries a good fringe of oakwood and mixed woodland, and a third gorge, Ceunant Llechrwd below Gellilydan, is similar but less deep.

Farther south in Merioneth two oakwoods are of outstanding bryological interest. The Coed Ganllwyd (W.ioS, gr. i*) north of Dolgellau surround the rather open waterfall gorge of Rhaiadr Du and have been famous for their rich Atlantic flora for over 100 years. On the opposite, western, side of the Rhinog Mountains, there are various oakwoods along the Artro valley; the best of these is Coed Crafnant (W.icx), gr. I *), one of the most natural looking of all the British oakwoods and another important Atlantic bryophyte and lichen locality. Near Harlech, Coed Llech-wedd (W.i 14, gr. 2) is mainly a mixed deciduous wood but has oakwood represented.

Although this series of grade i Merioneth oakwoods includes 7 geographically distinct sites the total area covered by these is only 370 ha. This is felt to be a reasonable requirement for grade i status in view of the wide range of aspect, slope, altitude, geology and soil type encompassed therein.

In the far south of Caernarvonshire, the woods at Hafod Garegog (W.m, gr. 2) in the reclaimed estuary of the Traeth Mawr occupy low, rounded knolls virtually at sea-level. They are good stands of oak, but with relatively little interest in the associated communities, which are of widespread types. Coed Llety Walter (W.H3, gr. 2) near Llanbedr is another Artro valley oakwood, but on less steep ground than Coed Crafnant. Near Llanberis, Coed Dinor-wig (W.io6, gr. i) is a good example of the now rare type of ungrazed hill oakwood with unmodified field communities, and although this ecosystem is well represented in several oakwoods in south-west England and on the Loch Lomond islands, it is thought desirable to include a Welsh example. Other north Wales woods, such as Coedydd Aber (W.IO4, gr. i), Coed Gorswen (part of W.IO3), and Coed Macs yr Helmau (W.H2, gr. 2) are variable woodland complexes with good stands of sessile oak of equal merit with associated mixed deciduous woodland, and the Rhinog and Cader Idris grade i upland sites contain bonus fragments of sessile oakwood. The oak-birch woods of Cannock Chase in Staffordshire (W.I22, gr. 2) are an easterly example of this western woodland type.

In north-west England, the Lake District has strong ecological similarity to north Wales, but has somewhat lower mean temperatures and thus has fewer and less abundant thermophilous organisms. The finest semi-natural upland woods, mainly of sessile oak, but usually containing some mixed deciduous species, are in Borrowdale, and here an aggregate series of sites (W.I33, gr. i*)has been selected, extending along almost the whole length of the valley

between Keswick and Seathwaite. Great Wood on a gentle slope beside Derwentwater, is important for its lichens, and is an example of valley bottom woodland on mull soils, while the Lodore-Troutdale Woods farther south have fine hanging oakwoods with serai birch, and contain the cascade ravine of Lodore Falls, famous for its Atlantic bryophytes. Castle Crag is a further example of hanging oakwoods. Johnny's Wood at Longthwaite has both north-east and south facing slopes which illustrate finely the effect of aspect on the hygrophilous component of the flora, while the Seatoller Wood still nearer the dale head demonstrates how, in favouring these plants, extreme rainfall can compensate for a sun-exposed aspect. This exceptional series of woodlands is completed by two other areas. Castle Head Wood lies at the drier end of the rainfall gradient and is well-developed sessile oak over hazel woodland. It is entirely surrounded by enclosed farmland which must have reduced the grazing pressure over a long period and enabled some natural regeneration to take place. The Ings is also ungrazed and is a very fine example of northern alderwood with a field layer which varies with the mineral/humus properties of the soil.

Elsewhere in Lakeland, Scales Wood (W.I46, gr. 2) above Buttermere, and Low Wood (W.I5O, gr. 2) above Brothers-water, are, respectively, shaded and sun-exposed alternatives to the Borrowdale Woods, but bryologically are not in the same class. Naddle Low Forest (W.I49, gr. 2) above Haweswater contains a variety of woodland, including sessile oakwood on both shaded and sun-exposed aspects, but most of the range of variation here is represented in the Borrowdale Woods, and the Atlantic bryophyte flora is also much less rich. Both the Roeburndale Woods (W.i4i, gr. i) near Lancaster and the Lyne Woods (W.I47, gr. 2) in north Cumberland contain examples of sessile oakwood in a lower rainfall district. Roudsea Wood (W.I39, gr. i) also contains sessile oakwood on acidic slates, contrasting with ash—oak wood on limestone and other examples of oakwood on drift covered limestone soils are Whitbarrow and Witherslack Woods (W.I36, gr. i) and Gait Barrows (W.I4O, gr. i) in the Morecambe Bay area. In the Grasmoor group of fells in Cumberland, Keskadale and Birkrigg Oaks (W.I34, gr. i) are two essentially similar fragments of high- level oakwood on slate scree which have become celebrated along with the high Dartmoor oakwoods as surviving remnants of this forest type near its upper altitudinal limits. They have become classic sites, but their interest resides in the trees themselves and not in the associated flora. Both lie within Buttermere Fells grade 2 upland site (U.27).

The total area of grade i oakwood sites in Lakeland is 895 ha, a modest figure in view of their diversity and importance.

In south-west Scotland, few semi-natural oakwoods remain, and there are none of first national importance. The Wood of Cree (W.ij-j, gr. 2) in Kirkcudbrightshire consists largely of coppiced oak and has minor bryological interest, while the Fleet Woodlands (W.I78, gr. 2) include Castra-mont Wood and Killiegowan Wood, also coppiced in part and with mixtures of trees locally. A coastal cliff slope oak-wood at Ravenshall (W.I79, gr. 2), in the same district, is rather similar to some of the coastal woods of steep slopes in south-west England. While none of these three woods merits grade I status, they have some national importance as representatives of the regional forest types.

In the western Highlands, oakwood is a widespread type, but few extensive areas remain, and there is often a considerable mixture of birch with the oak. The islands of the Loch Lomond group (W.i69, gr. i*), especially Inch-cailloch, have fine stands of sessile oak with ungrazed field communities which are much more luxuriant than those of most Scottish oakwoods, as on the eastern shore of the loch. There is a considerable range of aspect and soil type, and the varied history of management on the different islands is ecologically significant. Farther west, in Knapdale, the sheltered peninsula of Taynish in the sea inlet of Loch Sween has an extensive and diverse area of woodland. Taynish Wood (W.ig6, gr. i*) shows a great variety of soil types and aspect, but sessile oakwood is one of the major woodland communities and rises straight from sea-level. There is a rich lichen flora, especially of arboreal species. On the east coast of Knapdale, the hanging woods overlooking Loch Fyne between Mealdarroch Point-Skipness (W. 197, gr. i *) have been chosen for their wealth of Atlantic bryophytes and ferns. They are oak-birch woods traversed by several deep ravines with cascading streams, and contain a greater abundance of certain thermophilous species than any woods seen outside south-west Ireland. At Coille Ardura (W.2I2, gr. i), Mull, is the most extensive area of woodland of any western Scottish island. Here the complicated topographical pattern and the variations in geology and soil are reflected in the sessile oakwoods, ash-oak woods, ash and ash-hazel areas. The birch and oak woods at Kinuachdrach (W.2i8, gr. 2) on Jura are regarded as an alternative site in this respect. The oakwoods of Choille Mor (W.2I3, gr. 2), Colonsay, and Claggain-Ardmore (W.2I4, gr. 2), Islay, are not sufficiently outstanding to merit grade i status but are interesting as probably the most westerly examples of this woodland type in Britain. In the district of Lome on the Argyll mainland, the woods at Clais Dhearg (W.2I9, gr. 2) are quite extensive stands of oak on fairly gentle slopes or flat ground, but have little interest apart from the trees themselves.

The deep, sheltered sea inlet of Loch Sunart (W.igo, gr. i*) in Argyll has a good deal of oak and birch wood, but this has been fragmented and impoverished by clearance and locally replaced by conifer plantations. The largest remaining oakwood at Ariundle lies back from the sea above Strontian. This is a fairly typical hill oakwood with grazed field communities and few undershrubs, but the bryophyte flora is rich, especially for a slope of south-east aspect, whilst the more open tree growth below the main woodland towards the river carries a rich lichen flora. On the north shore of Loch Sunart, the discontinuous areas of mainly oakwood with some birch between Salen and Strontian, and the birchwoods around Laudale, Glen Cripesdale and Creag Dubh on the south shore are of international importance for their extremely rich bryophyte and lichen floras. As this interest is spread over such a large area, there is a need here

for a general policy of woodland conservation which pays heed to the requirements of the bryophytes and lichens. Farther north, fairly pure oakwoods near Arisaig have a limited range of interest in features other than the trees, and are not regarded as of national importance. The most northerly oakwood of any size in the western Highlands is at Letterewe on the north side of Loch Maree (W.2o6, gr. i*) in Ross. This site is evidently close to the climatic limits of oak, and there are interesting ecological questions in the relationship between this type and birchwood on the richer soils of the Loch Maree area, and between oak and pine wood on the poorer soils. The Letterewe woods are good examples of sessile oakwood in their own right.

The series of grade i western oakwood sites mentioned covers a total of 6560 ha. From south to north these sites occur within a wide range of climate; in south-west England they are within the rainfall range of 140-180 'wet days'; in north Wales, Lakeland and the south- west Highlands from 180-220 wet days; while Arriundle and Letterewe Woods experience over 220 wet days annually, on average. They also show a fairly even spread within the mean annual temperature range of 11 °C in the south to 8 °C in the north. Geologically, the oakwood sites cover a wide variety of sedimentary, igneous and metamorphic rocks, differing considerably in hardness, physical structure and base- status.

Eastern

EASTERN OAKWOOD

The oakwoods of lowland England overlap to a considerable extent with mixed deciduous woodland and in the majority of oakwoods the oak dominates as a result of coppice-with-standards management. The majority of such woods have been considered as mixed deciduous and only a residue of oak high forest, oak over oak and oak over hazel coppice-with-standards remain to be considered here. Furthermore, many ancient and over-mature oakwoods have been dealt with in that section, including for example Parham Park (W.i8, gr. 2), Sussex; Savernake Forest (W.3i, gr. 2), Wiltshire; Staverton Park (W-34, gr. i), Suffolk; Sherwood Forest (W.I3O, gr. 2), Nottinghamshire; and the New Forest (W.26, gr. i*), Hampshire. A number of sites chosen for other characteristics also contain a stand of oak, or oak-hazel, for example, Hatton Wood (W.45(i)(<z), gr. i) in Lincolnshire, and Ellenden Wood (W.i6, gr. 2) in Kent. In the case of the chalk beechwoods, oak woodland is often included as a type characteristic of adjacent Clay-with-Flints oaks, as in Wouldham-Detling (W.y, gr. i) in Kent, and Aston Rowant Woods (W.29, gr. 2) in Buckinghamshire- Oxfordshire.

The residue of oak high forest, oak over oak coppice-with-standards and oak over hazel woods are scattered through southern and eastern Britain, with a concentration in the south east and Midlands, where they are the prevalent type.

Oak-hazel woods are a product of intensive management and most are probably planted, even though many are on continuously wooded sites. A stand is included within Ham Street Woods (W.2, gr. i), Kent, as well as a small stand in Hatton Wood. But perhaps the best example still managed actively is Long Itchington and Ufton Woods (W.I2O, gr. i) in Warwickshire, in the central Midlands which are otherwise devoid of high grade woods. Pipewell Woods (W.I28, gr. 2) in Northamptonshire are an alternative to Ufton.

Mature oak high forest is often a product of nineteenth-century planting, but stands are selected in areas with other features of interest. A stand in the Forest of Dean (W.y3, gr. i), Nagshead, represents the range of types in that area. Waterperry (W.25, gr. i) and Windsor Forest (W.23, gr. i) are examples in the south Midlands and south where the entomological interest is high. High Halstow (C.8, gr. 2) in Kent may be regarded as an oakwood modified by invasion of elm. Foxley Wood (W-47, gr. 2) in Norfolk has an area of disturbed oak high forest.

Oak coppice and coppice-with-standards occurs sparingly in eastern and southern Britain on more acid, well-drained soils. Scords Wood (W- 4, gr. i) is selected to represent this extensive Wealden type because in this site it is associated with other types of woodland. Likewise Swan-ton Novers Woods (W-39, gr. i*) in Norfolk have a stand comprised of both species in a wood where two other important types occur. Wyre Forest (W.I2I, gr. i), Worcestershire, is a special case, with both oak coppice and high forest, with floristic features linking north and south and an oak population said to be an intermediate in some features between the western sessile oaks and the eastern pedunculate oaks; Chaddesley-Randan Woods (W.I32, gr. 2) can to some extent be regarded as an alternative to Wyre Forest. In the Habberley Valley (W.i^i, gr. 2) in Shropshire, and Downton Gorge (W.I25, gr. 2) in Hereford, sessile oak woodland is one of the two contrasting types.

In the northern half of eastern Britain, oakwoods on acidic brown earths are fairly widespread, but show a rather limited range of variation. The grazed upland examples are usually devoid of a shrub layer, and even those in the lowlands which are enclosed often have only a sparse growth of tall shrubs. There are examples on the Millstone Grit of north Derbyshire and south Yorkshire, but these do not appear to be of national importance. In north Yorkshire, Raincliffe Wood (W.I44, gr. i) contains an example of pedunculate oakwood along with mixed deciduous woodland, and in the west, Burton Wood (W.I54, gr. 2) near Lancaster is mainly a sessile oakwood which has affinities with eastern types, probably because it is in a low rainfall area compared with the Lakeland oakwoods. Near Carlisle, Orton Moss (W.I35, gr. i) is a complex of woodland on dried out peat- moss, and among the types represented is a small area of oakwood with an acidophilous flora. Holystone Woods (W.i63, gr. 2) in the Cheviots, have a good example of upland eastern oakwood, but are hardly of grade i rank. Small areas of oakwood are represented in the glens of Monk Wood (W.i 64, gr. 2) and Hesleyside Park (W.i65, gr. 2), Northumberland, but these are selected mainly for other features.

The hill valleys of the Southern Uplands in the eastern counties have a number of quite interesting small oakwoods, but none of national quality has yet been found, and most examples are rather like western oakwoods with a less rich bryophyte flora. In the eastern Highlands, two northern examples are regarded as worthy of grade i status. These are the woods of the Pass of Killiecrankie (W.i85) where fairly pure sessile oakwood passes into mixed deciduous woodland in the glen of the River Garry, and the small and isolated but very fine example of both pedunculate and sessile oakwood at Dinnet (W.iSo) adjoining the great Glen Tanar pinewood (W. 187(6)). In the far north east of Scotland, the Ledmore Wood, Spinningdale (W.22y, gr. 2) in Sutherland has a pure stand of oak unusual in its heather-dominated field layer; it is evidently a planted wood but has considerable interest.

3.4.2 Mixed deciduous

Mixed broad-leaved deciduous woodland occupies the median position in the field of variation in British woodland, and is the most widespread of all woodland types in this country, being especially characteristic of soil types which fall between the extremes of acidity and alkalinity, or dry skeletal brown earths and waterlogged peats. This woodland type probably comes closer than most others to primaeval woodland in floristic composition; this is especially true of woodlands on sites that have never been cleared.

These woodlands are extremely variable. Since this variation is continuous, however, only arbitrary subdivisions can be made within them. Some of this variation is structural and results from management; much of the diversity, however, is in the composition of the tree and shrub layers. High forest and park woodlands are widespread but the majority have been managed as coppice with or without standards; following neglect or as a result of deliberate management, many of the coppice woods, whilst retaining some of their coppice features, are developing towards high forest. Because oak was the normal standard, these may have been previously described as oakwoods. However, with changing forestry practices and the felling of the big timber during and since the World Wars, many have lost their dominant oak and it now seems more realistic to consider them as mixed deciduous.

The central floristic type consists of mixtures of oak, ash and hazel, usually also with wych elm and sometimes birch (particularly in northern and western areas) and field maple (in the south and east). There are woods in which one or more of these species is absent, or present in very small numbers but, with one exception, those with at least two of these species forming a significant proportion of the standing crop are treated as mixed deciduous woods. The exception is an oak-hazel mixture in which hazel forms a distinct layer beneath the oak, and which is therefore considered as oakwood. Mixed deciduous woods with more than 20 different native tree and shrub species are common, and many species normally present as a minority element may in some woods be dominant or co-dominant. In addition, woods in which more than five species are co-dominant, though uncommon, are widespread, and the number of possible combinations of species is very large. Three floristic variants from the central facies are considered sufficiently distinctive to justify separate consideration: these are mixed deciduous woodland in which small-leaved lime or hornbeam is abundant, and similar woodland in which sweet chestnut, an introduced species, is abundant as a result of management. Even so, many intermediates can be found between these and the central type.

Mixed deciduous woods contain, in aggregate, a very large number of herbaceous species in the field layer as well as a rich variety of native trees and shrubs. Those which have been managed as parkland are generally poorer, except in epiphytic lichens and wood-boring invertebrates. Conversely, woods managed as coppice, whilst rich in field layer species and bird and insect populations, are poor in epiphytes, and the bryophytes which need continuity of shade and humidity are generally of more limited interest. Even in the relatively dry and warm climate of East Anglia, however, a few rare and hygrophilous bryophyte species occur sparingly and coppice stools are important habitats for some mosses.

Mixed deciduous woodlands are prevalent in the English lowlands but, whilst they are much less extensive in the north and west, some important examples occur in these areas. The northern examples, from Lakeland northwards, are the most uniform in both structure and floristics. Many western oakwoods contain examples of oak-ash-wych elm woodland, varying in size from fragments of less than half a hectare along watercourses and in flushed situations to large stands of scores of acres. Except where these are large and well defined, they will not be mentioned again in the present section, as they have been treated in the account of oak-woods (pp. 105-9).

In the selection of sites containing mixed deciduous woodland an attempt has been made to reflect their wide geographical/climatic spread and the full range of associated soil types. The central type is included throughout its range, and examples of major variants (edaphic, biogeogra-phic and management-induced) are selected in districts where these are particularly obvious. A number of examples have been selected in some districts, partly because individual woods are small and the full range of variation may not be present in one wood, but also because each separate wood exhibits different aspects of the impact of past and present management on the existing woodland. A relatively large number of sites is included in the south- west of England where there is a considerable range of soil types. In some areas these woods grow on fertile soils which, but for past land settlement and use factors, would be cultivated today. This is particularly so in arable eastern England where the permanent woods are almost the only sites in which undisturbed profiles of the widespread soil types can be studied, and where in consequence it is considered justifiable to select a relatively large number of sites. In situations where only one of a number of woods could justifiably be chosen to represent a variant, the final choice of site was determined by the presence of rare species or a relatively large number of species. Some sites are included because they exemplify certain particularly important special features.

South & east

THE CENTRAL FACIES

SOUTH AND EAST

In southern England, mainly in the south-east, there is an enormous variety of mixed deciduous woodland. Most types occur on sands, gravels and clays, but a particularly important type on Chalk has oak- ash-maple woodland with other species such as hornbeam but without beech, over a deep calcareous loam on the steep Chalk scarp. This is a situation normally covered by beech over a thin soil, and it is possible that these sites, Alkham Valley (W-3, gr. i) in Kent, and Gopher Wood (see L.26) in Wiltshire, represent a soil condition pre- dating that associated with the widespread beechwoods. Woodland on Chalk at Wye and Crundale Downs (L-3) appears to represent a similar mixed type of a secondary nature.

In the High Weald outcrops of sandstone in wooded gills are associated with the occurrence of plants normally regarded as Atlantic in distribution, notably the ferns Dryopteris aemula and Hymenophyllum tunbrigense and certain bryophytes. These woods are normally oak, beech and ash with alder along springlines and on low ground, and often have mature trees and a rich flora. The best of these outcrops is in Wakehurst and Chiddingly Woods (W.I2, gr. i), and the Fairlight, Ecclesbourne and Warren Glens (W.I4, gr. i), also in Sussex, are almost as rich, the latter site having a number of rare bryophytes and a coastal situation rare in lowland English woods. Saxonbury Hill/Eridge Park (W.g, gr. i*) also has an example of this community which grades into woodland with a rich ground flora over Wadhurst Clay.

The western Weald, one of the most densely wooded areas of Britain, has a distinctive type of mixed deciduous woodland characterised by oak standards over mixed coppice of hornbeam, ash and hazel. The ground flora is moderately rich, and there may be many tree and shrub species, though the commercial species are strongly dominant. Few of these woods are individually outstanding, but the area as a whole is extraordinarily rich, particularly in insect species. In these circumstances it is better to consider the area as a whole and, with few exceptions, make no attempt to select individual sites. Thus only Ebernoe Common (W.i i, gr. i) and The Mens and The Cut (W.i3, gr. i) have been listed, with the sole addition of Glover's Wood (W.2i, gr. 2) which is both representative of the hornbeam and mixed coppice of this area, and has a complicated development.

One other mixed wood on Weald Clay, Staffhurst Wood (W. 19, gr. 2), is included partly to enlarge the geographical coverage but mainly as a representative of a different structural type. It is a common wood of oak, beech, hornbeam and ash with a mixture of age classes, including large, ancient trees with rich epifloras, and a range of field layer communities.

The Gault Clay woodlands are a related type distinguished by the influence of rich calcareous downwash from the Chalk and consequent floristic differences. They are typically oak standards over ash- hazel-hornbeam coppice

Regional diversity and selection of key sites and, being fairly close ecologically to the western Weald Clay woods, only one site is included. This is Asholt Wood (W.5, gr. i) in Kent, one of the most diverse of the type and probably the best remaining, now that Ryarsh Wood has been partly converted to conifers.

A distinctive feature of the Weald is the occurrence of alder on springlines and low-lying ground in mixed deciduous woodland, associated with a field community including both Chrysosplenium spp. This is represented in many sites chosen for other features, e.g. Wakehurst and Chiddingly Woods and Scords Wood. Nevertheless, an additional site, Colyers Hanger (W.2O, gr. 2) in Surrey, is included partly because it has a good stand of alder but also because it is an excellent example of the zonation of woodland types determined by soil conditions: oakwood occurs on dry, sandy soil and mixed wych elm- ash-maple woodland on base rich soil. More extensive Wealden alder carrs occur elsewhere but the type is adequately represented by Colyers Hanger.

One other site in the Weald, Scords Wood (W-4) is included as a representative of oak woodland (discussed elsewhere), but it also has a variety of woodland types corresponding with differences in underlying geology. The valley contains mixed deciduous woodland of beech, ash, maple, wych elm and oak, and an alder carr on clay at the bottom. Corresponding changes in the field layer emphasise the close correlation with underlying geology, and it is mainly for the clarity of this relationship that this particular wood is selected.

The south Region contains few important mixed deciduous woodlands: much of the land is chalk and the main woodland types are beech, oak and oak-hazel. Selborne Common, with recently developed oak-ash- hawthorn-hazel woodland, is included in the Selborne Hanger (W.2y, gr. i) beechwood site to add diversity and a sample of plateau woodland. Cranborne Chase (W-32, gr. 2) in Wiltshire also includes chalk plateau woodland - mainly oak -but is selected to include an unusual ash-maple wood on Chalk, which has limited quantities of oak, beech, yew and holly and a rich epiphytic flora. A further site at Wychwood (W.24, gr. i) in Oxfordshire is included (even though the present woodland is largely the product of planting in the last century) because it is a reasonably rich example of mixed deciduous woodland in an area otherwise almost devoid of scientifically valuable woodland. It also has an interesting range of other habitats including scrubby woodland edge, broad rides, springs and flushes, ponds and grassland. Waterperry Wood (W.25, gr. i), although much of it has been felled and replanted, is also included as an example.

The mixed deciduous woodlands of East Anglia, Lincolnshire and the east Midlands are typically coppice-with-standards of oak, ash, hazel and maple on calcareous clay with a rich variety of shrubs and field- ground layer species. The field and ground flora varies according to soil base-status and drainage conditions but the tree and shrub layers are at least partly the product of past management. Clear geographical groups can be distinguished on the basis of

certain species of local occurrence, e.g. hornbeam (treated as a separate type), oxlip in East Anglia, bird-cherry in Norfolk and, to some extent, lime in Lincolnshire (also treated separately).

Selection of sites here has to take into account a number of features, in addition to the need for geographical scatter. The average type must be well-represented, as well as the main variants, and woodlands intermediate between it and other types. Since their character has been modified by management, a range of past and present management types must be included and distinct phytogeographical types such as oxlip woods should also be represented.

The average type is represented by a series of sites. Monks Wood (W- 42, gr. i) and Castor Hanglands (W-44, gr. i), are both rich floristically and faunally, the former showing a variety of management types and the latter crossing a series of geological boundaries. Sites which may be regarded as alternative to Monks Wood and Castor Hang-lands are Whittlewood Forest (W.I29, gr. 2) in Northamptonshire — an area of entomological importance — Leighfield Forest (W.i2y, gr. 2), Leicestershire, and the Kesteven group (W-58, gr. 2) of Dole Wood, Dunsby Wood, Kirton Wood and Sapperton- Pickworth Woods. Although alternative in general terms, these enlarge both the geographical range and the range of management variants in selected areas. The Kesteven Woods are included as a series to represent variation within a geographical group (cf. limewoods in central Lincolnshire, oakwoods in north Wales, Scottish pinewoods). King's Wood (W.5I, gr. 2), Bedfordshire, is in part an alternative to the grade i sites here.

In many cases these woods are infiltrated by narrow-leaved elms to the extent that elm woodland is produced. This is often the case in re-established woods (a series of these is included at Hintlesham Woods) but also occurs in some permanent woods. Hayley Wood (W.4O, gr. i) in Cambridgeshire has small examples of this, but a further site is added at Overhall Grove (W-56, gr. 2) as an example of the advanced form of this change with many peculiar features. At Dunsby Wood a similar process is apparent, but the species here is English elm.

On the drier more sandy soils oak woodland may occur, but in some sites the mixed deciduous character is retained with abundant birch. Hintlesham Woods (W-33, gr. i) in Suffolk exhibit this well, in addition to numerous other features. Similar effects are also represented in Foxley Wood (W-47, gr. 2), Norfolk, and Newball and Hardy Gang Woods (see W.45(i)(6), gr. i), Lincolnshire. Although many sites have valuable features showing the interaction of past and present management with the natural flora and fauna, these features are of outstanding interest in only a few, notably Felshamhall and Monks Park Woods (W-35, gr. i*), Hintlesham Woods, Swanton Novers Woods (W-39, gr. i*) and Hardwick Wood (W-57, gr. 2).

Three important variants are recognised with, respectively, oxlip, alder and bird-cherry as important constituents. The oxlip woods selected cover a range of variants within the type: Hayley Wood and Felshamhall and Monks Park Woods are actively managed still, whilst Canfield Hart Wood (W-53, gr. 2) in Essex is the most southerly and a good example of this variant. Overhall Grove has been mentioned as an example of narrow-leaved elm woodland and Hardwick Wood has an area of planted wych elm. Surprisingly for woods so commonly wet for long periods of each year, alder is often completely absent. Sites where it occurs may be of particular significance in understanding the management modifications resulting from many centuries of coppice management. Felshamhall and Monks Park Woods are the main representative, but it is also well developed in Foxley Wood and in parts of Swanton Novers Woods. Bird-cherry is more or less confined to Norfolk woods, where there is an outlying population from the centre of occurrence in north and western Britain. Wayland Wood (W- 48, gr. 2) is selected because bird-cherry is an abundant component of the coppice layer. Likewise a small portion of Swanton Novers Woods has coppice of this species mixed with alder.

Three kinds of woodland intermediate between this central type and the oak, hornbeam and lime woods can be recognised. Some woods, though mainly mixed deciduous, have small stands of oak, e.g. Foxley Wood, whilst Wayland Wood differs from oak-hazel coppice-with- standards only in having a proportion of bird-cherry in the coppice layer. Four woods have small areas of lime; Felshamhall and Monks Park Woods, Hintlesham Woods, Kirton Wood and Dole Wood. Hatfield Forest (W-54, gr. 2) in Essex is included as both a variant of the basic type in which oak is unusually poorly represented and as a type intermediate with the hornbeam woods.

In Suffolk and Essex it is extremely difficult to define the boundaries between the central ranges of variation of oak, hazel, ash, maple and birch, and the hornbeam and lime facies. There are, however, still a large number of woods with a variety of these coppice types, and collectively these amount to a considerable range of more or less clear-cut types and intermediate combinations. Hintlesham Woods have been selected as a site with a wide range of variation in a relatively undamaged state, but many other woods exhibit other aspects of this variation. Had all these woods been surveyed in detail, further grade I or 2 sites might have been selected. The following woods are the most promising on present knowledge: Elmsett Park Wood in Suffolk, and, in Essex, Quendon Wood, Hempstead Wood, East End Wood, Coggeshall Woods and Hockley Wood. In addition, Hales Wood National Nature Reserve (NNR) is a relatively small piece of woodland which is only a small remnant of what was once a much larger wood whose chief features are better represented in, for example, Hayley Wood. However, for the time being Hales Wood is retained as a grade 2 site

(W.52).

A group of sites is included to represent multiple mixtures of more than four main species of tree or shrub. Bedford Purlieus (W-43, gr. i) and Swanton Novers Woods are of this type and also have numerous rare species. Felshamhall and Monks Park Woods can also be included here, as can the more mixed parts of Newball Wood and Wickenby Wood (see W-45(ii)).

West & north

WEST AND NORTH

Mixed deciduous woodlands in western and northern Britain occur in lowland country but are perhaps more characteristic of the lower hill slopes. They occur on a wide variety of parent materials, but notably on those which are moderately base-rich, such as calcareous igneous rocks, shales, grits and sandstones. Sometimes, on hillsides, they occupy the middle or lower enriched zone of a catena, or they may be associated with flush lines. They are also highly characteristic of stream ravines, but it is noticeable that, except on completely acidic rocks such as granite and quartzite, these stream gorges, very typically, have mixtures of both sessile oakwood on leached brown earths and mixed deciduous wood on more fertile mull soils.

Floristically, these western and northern mixed deciduous woods are poorer in tree and tall-shrub species than those of the south and east, and in particular the number of species representing these life forms decreases with distance north. Hornbeam, sweet chestnut, small- leaved lime, field maple and Sorbus spp. (except S. aucuparia) gradually drop out but gean remains widespread (though usually sparse) and bird-cherry is a species mainly found in the north and west. The number of field layer species also tends to decrease in the same directions, but bryophytes increase in number and luxuriance with distance west, and some extreme western mixed deciduous woods are rich in Atlantic species. The most typical examples have a near dominance of ash, with a variable understorey of hazel, and a constancy of oak, wych elm and birch. This grades into purer ashwood (often still with wych elm) on definitely calcareous soils, and into pure oakwood on markedly base-deficient soils. The field layer is composed largely of basiphilous species, but the upland woods are usually grazed and show predominance of grasses at the expense of forbs.

Numerous examples of mixed deciduous wood occur within woodlands chosen as representatives of oak or ash wood in the west and north, and in many districts there is no need to add further examples. In south-west England the Bovey Valley Woods (W.63, gr. i), Holne Chase (W.64, gr. i*) and Avon Gorge (Leigh Woods) (W.yo, gr. i) have mixed deciduous wood grading into oakwood, whereas Asham Wood (see W.ji(b), gr. i) grades from this type into ashwood. Weston Big Wood (W.87, gr. 2) is included as a mixed deciduous wood in its own right. In the hill country of south Wales, Coed y Cerrig (W.Q2, gr. i), Coed Rheidol (W.go), Cam Gafallt (W.Q7) and Blaenau Nedd & Mellte (W.gS) all have examples of the central type, while Tarren yr Esgob (see U.8, gr. 2) has an atypical high-level scrub woodland which includes ash, birch, willow, rowan and hawthorn.

In the west Midlands several mixed woods have been chosen which are intermediate in character between the lowland and upland types. These, which in places have affinity with ash—wych elm wood on calcareous soils, mostly occur on fairly steep slopes and they are floristically rich in both woody and herbaceous species. The sites, which themselves represent a range of variation are, Tick Wood (W.I 19 gr. i), Halesend Wood (W.n6, gr. i), Hill Hole Dingle (see Appendix) (W.n8, gr. i), and Habberley Valley (W.i3i, gr. 2). The Wye valley on the borders of south Wales and Gloucestershire/Herefordshire has one of the most varied and important complexes of woodland in Britain, mainly on Carboniferous Limestone where soil conditions vary according to topography. In the Wye valley complex, mixed deciduous wood with little oak and a usual admixture of beech, small-leaved lime, ash and wych elm is represented within three separate sites, namely Blackcliff-Wyndcliff- Pierce Woods (W-94, gr. i), Lady Park Wood (see W.Q5, gr. i*) and Hudnalls (W.y5, gr. i). Four other sites in the same area, Coombe Woods (W. 102, gr. 2), Dingle Wood (see W-73, gr. i), Downton Gorge (W.I25, gr. 2) and Bushy Hazels and Cwmma Moors (W.I26, gr. 2) are of this type but with different structural and floristic features which merit their inclusion in the national series. Salisbury Wood (W-93, gr. i) has a mixture of species and characteristics of both upland and lowland coppices.

In north Wales, the Conwy valley has good upland examples of mixed deciduous woodland on calcareous pumice tuffs, or mixed drifts giving fairly base-rich soils. These are of the hanging type at Coed Dolgarrog (see W. 103, gr. i), and the gorge type in the adjoining ravine of Ceunant Dulyn, while Coedydd Aber (W. 104) has a combination of both types and Coed Gorswen (W. 103(6)) is on gentle slopes and grades into alder-oak wood. The cliff fragment of this type at the existing NNR of Cwm Glas Crafnant is not considered to rate more highly than grade 3, but Coed Tremadog (W.IO5, gr. i) is important and includes cliff, scree and scrub habitats. The Merioneth gorge woods of Ceunant Llennyrch (see W.i 07), Ceunant Cynfal (W.io- j(dJ), Coed Ganllwyd (W.i 08), Coed Macs yr Helmau (W.i 12) and Ceunant Llechrwd, Gellilydan (W.ioy(<»)) all have this kind of woodland as a bonus. On the Creuddyn limestone, Bryn Maelgwyn and Gloddaeth (W.no, gr. 2) is a western lowland example of mixed deciduous woodland with a rich flora.

In northern England many of the sessile oakwoods of Lakeland contain examples of oak-ash-wych elm-hazel wood, usually on base-rich beds in the predominantly acidic rocks, and especially where there is also flushing. The mixed type is, however, equally well represented with oakwood in Seatoller Wood (see W.I33) and Low Wood (W.i5o) (in both there is a close approach to limestone ashwood); and in Lodore- Troutdale Woods (W.i^(dJ) and Naddle Low Forest (W.I49), the mixed woodland occupies the more basic soils at the gentler foot of steep slopes with hanging oakwood. Two woods on limestone just south of Lakeland are intermediate between the richer kind of northern oak- wood and more typical mixed deciduous woodland; they are at Whitbarrow and Witherslack Woods (W.I36) and Gait Barrows (W.i4o). Gowbarrow Park (W.I48, gr. 2) includes a fine example of mixed woodland on the crags on the north side of Ullswater. Eaves Wood (W.I53, gr. 2) in the same area has a rather artificial appearance with various non-native species, but is important for its rich field layer. Two rather similar complexes of sessile oak and mixed deciduous wood in river glens south and north of Lakeland are Roeburndale Woods (W.I4I, gr. i) and its alternative site Lyne Woods (W.I47, gr. 2). Thornton and Twisleton Glens (W.i57, gr. 2) have ashwood grading into a more mixed type.

The above woods are all in the west of northern England. In the centre, in Teesdale, Shipley Wood (W.I45, gr. i), is a fine example of mixed deciduous wood with a rich flora. The valleys of the North York Moors in the east of northern England have varied woodlands which range from oak to mixed types on fairly rich soils, and the best remaining examples are Raincliffe Wood (W.I44), Ashberry and Reins Woods (W.I58, gr. 2) and Beckhole Woods (W.I59, gr. 2). This last group has stronger affinities than the other woods in northern England with the mixed deciduous woods of the south and east, but the sites mentioned are all valley-side woods. The once fine woods of Newtondale in the same area of Yorkshire were recently subjected to extensive felling and can no longer be considered. In Durham, Castle Eden Dene (W. 162, gr. 2) is a good example of mixed deciduous wood in a glen of Magnesian Limestone. Beast Cliff (W.i6o, gr. 2) is an example of oak-ash wood that has developed on slipped Jurassic strata on the Yorkshire coast.

In southern Scotland, the prevailing Ordovician and Silurian greywackes and shales give a prevalence of base-rich soils well suited to the development of mixed deciduous woodland and this type is extremely widespread in the region, especially in stream gorges. Very few outstanding examples are known, however, and only one site has been rated as grade i for this woodland type. This is one of the Clyde valley ravine woods at Avondale (W.i7o), and the nearby sites of Hamilton High Park (W.I75) and Nethan Gorge (W.i76) are regarded as grade 2 alternatives. On the Scar Water in Dumfries-shire, Chanlock Foot (W.I72) and Stenhouse Wood (W.i73) are also rated as grade 2 to represent examples not in gorges; the first is on steep slopes and the second on gentler ground. The Maidens to Heads of Ayr (W.i74, gr. 2) represent mixed deciduous woodland on coastal cliffs of Old Red Sandstone. It is possible that further survey in this region may disclose more valuable sites, but present views are that the range of variation is adequately represented in northern England and Avondale.

In the eastern Highlands, mixed deciduous woods appear to be few, and only three examples have been chosen, all in river gorges. The first, at Killiecrankie (W.i85), occupies the rather open gorge of the River Carry, together with oakwood. The second, in Glen Tarff (W.i84, gr. i), lies in a deep, long glen on the Fort Augustus side of the Monadh- liath. The third clothes the precipitous sides of a cascading stream ravine at Keltney Burn (W.iSg, gr. 2) in the Breadalbane Hills.

Mixed deciduous woods are extremely widespread in the western Highlands, especially in river gorges, though they are replaced on exposed coasts of the west mainland and Hebrides by hazel scrub and in the far north by birchwood rich in herbs. Probably the best gorge wood of this type is on Inverneil Burn (W.igS, gr. i*) in Knapdale, a site also very rich in bryophytes. Other very fine gorge examples are Allt nan Carnan (W.205, gr. i), and Corrieshalloch W.2O9, gr. i) in Ross, and Geary Ravine (W.2O2 gr. i) in Skye. The Glasdrum Wood (W.I93, gr. i*) in Argyll grades from ash—hazel to more mixed wood with much oak, and the Doire Donn (W.2i6, gr. 2), Loch Linnhe, Loch Moidart (W.22I, gr. 2), Ben Hiant (see W.igo, gr. i*) and Glendaruel Woods (W.2iy, gr. 2), Cowal, show some affinities to this same type, but are on less calcareous soils. The hazel scrub at Drimnin (W.ig2, gr. i) in Morvern grades into taller woodland in sheltered places and is best placed in the present group; it has a rich and luxuriant field layer, an unusual feature in hill woods. Further good examples of this type of woodland probably remain to be discovered in the region, especially in river gorges, where survey is far from complete. There are numerous areas of hazel scrub on the Isle of Mull, and bonus examples are represented on the Ross of Mull (C.ioo) and Ardmeanach (U-95).

3.4.3 Lime

Woodlands in which lime is dominant occur in England and Wales where they are mostly confined to a broad belt from Lincolnshire, Nottinghamshire and Norfolk through the Midlands to the Welsh borderland, south Wales and parts of Gloucestershire and Somerset, with outlying concentrations in south Lakeland and the Pennines, Essex and Suffolk and north Wales, and only rare occurrences of no more than a few individuals in the south-east and southern counties. In all these areas Tilia cordata is the usual species and only rarely is T. platyphyllos present in significant quantities. T. x europaea occurs in small numbers in woods in which T. cordata is the most abundant lime, but in some woods it is the most abundant species. It is probable that many if not most occurrences of the hybrid are plantings, but the occurrence of natural hybrids is not fully understood.

The greatest concentration of almost pure limewoods is in Bardney Forest (W-45). These Lincolnshire Limewoods grow mainly on neutral or acid, poorly drained boulder clay, with some areas on Kimmeridge and Ampthill Clays or sandy gravels. Most appear to be primary woodland which has been managed as coppice-with-standards since at least the eleventh century, but many woods are now slightly larger than their minimum extent. In such expanded woods the primary woodland is often distinguished by the presence of lime and wild service tree, whilst the secondary woodland is generally dominated by ash and oak without lime. Although the general silvicultural system was pedunculate oak standards over lime coppice, there are areas where hazel, ash, maple and oak form the principal coppice species. Associated with these are numerous shrub and tree species, including Midland hawthorn, hawthorn, blackthorn, willow and holly. In some woods, exotic strains of Ulmus have become established.

The ground flora reflects the variation in the quantity of clay and sand in the soil. Where sand is prevalent, Pteridium aquilinum, Convallaria majalis, Potentilla erecta, Corydalis claviculata, Succisa protends and other species of well-drained soils are found. On clay soils, communities dominated by Geum rivale and G. urbanum occur, together with typical clay ground flora species such as Primula vulgaris, Sanicula europaea, Platanthera chlorantha and Galeobdolon luteum. Mercurialis perennis occurs in some woods, but is evidently absent from others. In areas apparently disturbed in the past, the ground flora is dominated by Lonicera periclymenum and Rubus fruticosus. The rides and the wood margins, which normally reveal a mediaeval bank and ditch, add appreciably to the floristic diversity.

The woods are noted entomologically, especially for their Lepidoptera. Marsh fritillary and purple emperor have occurred, and recent records include white admiral, comma and five fritillaries, the small pearl-bordered, pearl-bordered, dark green, high brown and silver-washed. There is a rich fauna of more common lepidopterae. Several woods or parts of woods are considered necessary to represent the full range of structural and floristic types, but survey is continuing to determine the final selection. The range of variation is provisionally covered by two aggregate samples comprising separate parts of four woods as grade i sites, and three more sites at grade 2. The latter enlarge the range of variation represented by the grade i sites, but can also be regarded as alternatives. Hatton Wood (W- 45(i)(a)) is regarded as the best stand of high forest, particularly as parts are occupied by other woodland types, oak-ash and oak-hazel. Great West Wood and Stainton Wood are alternatives (W.45(ii)(<z) and (£>)). Newball and Hardy Gang Woods (W-45(i)(6)) are the best example of coppice, with a range of woodland types of which lime coppice is only one, and a range of soil conditions from wet clays to dry sands. It also includes a small area of coppice-with-standards. Wickenby Wood is regarded as an alternative site, but with a calcareous soil (W_45(ii)(c)). Fulnetby Wood (W-45(ii)(6)) is the best remaining stand of oak standards over lime coppice, but has a restricted flora. Stainfield and Scotgrove Woods (W-45(i)(c)) together represent the strongly acid end of the variation with poor drainage, whilst Potterhanworth Wood (W-45(i)(cf)) is included as an example of the western group with species not found in the main group. Cocklode- Spring Woods (W.45(ii)(a)) is regarded as an alternative site, with features intermediate between Newball and Potterhanworth Woods.

At the other end of the main belt of limewoods, the southern Welsh borderlands, and Somerset, Tilia is especially characteristic of base- rich soils, where it is common as a minor constituent or dominant over small areas. Such occurrences are already represented in woods selected as characteristic of other woodland types, e.g. Salisbury Wood (W.93), Holne Chase (W.64), Avon Gorge (Leigh Woods) (W.yo), Rodney Stoke (part of W.yi) and Weston Big Wood (W.8y). In the Wye valley area, though many of the woods are still unknown, two sites, Lady Park Wood (part of W-95) and Blackcliff-Wyndcliff-Pierce Woods (W-94), are selected. Both are floristically rich and include a number of woodland types. Lady Park is the only wood in which large- leaved lime Tilia platyphyllos forms an appreciable proportion of the canopy. In this area the contrasting Hudnails (W- 75) also has a good deal of lime but here it is on acidic soils. Collinpark Wood (W.y4, gr. i) is representative of sessile oak-lime woodland on poorly drained soils.

With the conversion of most of Shrawley Wood, Worcestershire, to conifers, what was the best area of oak-lime woodland in the Midlands is no longer worth including. No other comparable area of lime is known, but Habberley Valley (W. 131) includes an area of large-leaved lime, and Halesend Wood (W.n6) and Tick Wood (W.i 19) are mixed deciduous with lime one of the more abundant species. Halesend Wood is included in addition to Tick Wood partly because the lime there is T. x europaea.

Outside the main belt of limewoods, the species occurs as a minor constituent in woods selected mainly for other characteristics: e.g. Box Hill (L-7), Burton Wood (W.I54), Coed Rheidol (W.go), Cressbrook Dale (W. 115(6)), Fel-shamhall and Monks Park Woods (W-35); or as a constituent of mixed deciduous woodland, e.g. Swanton Novers Woods (W- 39), Bedford Purlieus (W-43) and King's Wood (W.Si).

3.4.4 Hornbeam

Hornbeam, like beech, has been widely planted, but its native range is restricted to southern counties. Its centre of distribution as a native species is south-east England and the Home Counties, but it extends north to Norfolk and west to Monmouthshire. Through much of this range it is a minor constituent of, for example, Chiltern beechwoods some sites in the Wye valley and mixed East Anglian woods and Midlands woods such as Chaddesley. Only in a belt from south- east Norfolk through Essex to Hertfordshire and Middlesex, and thence to Surrey, Sussex and Kent is hornbeam a major constituent of the woodlands.

Typically, these woods constitute oak-hornbeam coppice-with- standards. At the centre of the distribution there is a clear separation into stands with mainly sessile oak standards and those with mainly pedunculate oak standards. Wormley Wood-Hoddesdon Park Wood (W.i5, gr. i) in Hertfordshire is considered to be the best remaining example of the former and King's Wood, Bedfordshire, is in part an alternative here. Parts of Epping Forest (W-55, gr. 2) have been selected to represent the latter. The grading of Epping Forest below Wormley Wood-Hoddesdon Park Wood is consistent with its grading as a beech-wood site, and is justifiable because pedunculate oak- hornbeam woods are selected elsewhere at, for example, part of Ham Street Woods (W.z) in Kent. Sessile oak-hornbeam woodland is also included in Blean Woods (W.i, gr. i) which is selected in addition as a representative of sweet chestnut coppice, and Ellenden Wood (W.i6), an alternative to Blean. At the northern end of its native range (cf. Felbrigg Wood (W.5O, gr. 2), Norfolk, for beech) and in the absence of information on the majority of possible sites, Sexton Wood (W-49, gr. 2) in Norfolk is provisionally selected.

Hornbeam occurs as one of the major constituents of a number of western Wealden sites, but Glover's Wood (W.2i) is the only one selected.

3.4.5 Sweet chestnut

Though it is an introduced species planted throughout most of Britain, woods of sweet chestnut have been present since the early Middle Ages, and in some areas, notably southeast England, this tree dominates a high proportion of broad-leaved woodlands. It is present as a minor constituent of many selected sites, but in view of its abundance and long period as a denizen, it is desirable to include small samples of sweet chestnut woodland. The sites selected - Wouldham-Detling (W.y), Blean Woods (W.i) and Ham Street Woods (W.2)- are all in the south-east. They have been chosen from a large number of possible sites because sweet chestnut is only one of the woodland types present and the woods as a whole are floristically rich.

Mixed deciduous woodland: ancient parks and overmature woodland

Mixed deciduous woodland varies not only in composition but also in structure. Structural variation is important in providing a range of habitats for various components of the fauna, but it is also significant floristically in that individual mature and overmature trees provide a habitat for epiphytes, and some stands give the richest occurrences of corticolous lichen communities in the country. Woodlands composed mainly of ancient, overmature trees occur throughout most of England. They are mostly survivals of mediaeval land-uses, such as deer parks and royal forests, which have persisted with little alteration in the subsequent centuries, and which may have been formed originally on the remnants of primaeval woodland. As such they are a biologically important component of deciduous woodland and are said to be better developed here than elsewhere in Europe. It is therefore considered important that a number of sites should be included in the selection.

The significance of these overmature woodlands is threefold. First, the tree species present, though undoubtedly influenced by centuries of management, may represent survivals of primaeval woodland. Secondly, the epiphytic lichen flora is usually rich, with far more species than occur in nearby plantations and secondary woodlands, ancient coppice and coppice-with-standards woodland: these lichen communities are regarded as survivals of similar communities in the primaeval woodland on the sites. Thirdly, by possessing large quantities of dead, dying and overmature timber, these woods often contain populations of local and rare wood-boring invertebrates. These too are regarded as relict populations whose survival has only been possible through continuity of habitat.

Until very recently only a few such woods had been studied in detail and even these are known only incompletely. As a result the significance of some sites is not fully appreciated and their relative importance changes as further sites are examined. In selecting sites on the basis of existing knowledge, an attempt has been made to include examples of the main combinations of tree species and sites with the richest epiflora. Furthermore, because of the biogeographical significance of the accompanying flora and fauna, sites have been selected to give a wide geographical coverage. Sites are considered here which are not strictly mixed deciduous: as a structural variant in the range of variation of British woodlands, these ancient woods do not fit easily into a species-based classification.

The south-east and south of England were richly endowed with mediaeval forests and parks, many of which survive with overmature woodland composed mainly of oak, beech, holly or some combination of these. The two sites with the richest epiflora, the New Forest (W.26) and Bridge Park (W.g), are of international importance. The former contains the typical oak-beech-holly composition, but the latter is somewhat richer in tree species, notably with field maple and ash as additions. In south-east England, Ash-burnham Park (W.iy, gr. 2) is mainly oak and mixed oak-beech, birch and holly. Parham Park (W. 18) is included as an ancient oak woodland. In southern England two other sites in mediaeval royal forests are included, not so much as alternatives to the New Forest, but as sites of separate significance but less importance. Savernake Forest (W-3i) is mainly oak, with a more continental epiflora and Windsor Forest (W.23, gr. i) is mainly of oak and beech. Ebernoe Common (W.n), The Mens and The Cut (W.I3), part of Bignor Hill (W.8, gr. i) and Staff hurst Wood (W.ig) also contain a few ancient beech and oak with a rich epiflora, but they are included mainly for other characteristics.

In East Anglia, mediaeval park woods are of particular importance biogeographically, containing in the most continental part of Britain species which are normally regarded as Atlantic in distribution. Three sites have been selected: Staverton Park (W-34) has one of the richest epifloras in East Anglia and one of the best stands of holly in Europe; Sotterley Park (W-37, gr. i) is the richest East Anglian site for epiphytes, and is an excellent example of a mediaeval deer park; Benacre Park (W-46, gr. 2) is also rich in epiphytes and is complementary to Sotterley Park. Burnham Beeches (W.28, gr. 2) is a beech and mixed oak wood with numerous ancient trees and a rich epiflora for a site so close to London. Epping Forest (W-55) also includes some ancient oak-beech-hornbeam woodland, but its epiflora has been largely eliminated by pollution and it is in any case selected for other features.

In south-west England two ancient parks, Boconnoc (W.6o, gr. i*), Cornwall, and Melbury (W.59, gr. i), Dorset, have been chosen for their outstanding epiphytic lichens; the trees of Boconnoc support at least 180 species, the largest number for an area of this size in western Europe.

In the west Midlands and west Gloucestershire a further concentration of ancient woodlands occurs. Three sites are selected but further research may show that this choice is inadequate. One site, Speech House (W.73(c), gr. i), lies in the Forest of Dean: it is beech-oak- holly woodland, structurally very similar to parts of the New Forest but not as rich epiphytically. Moccas Park (W. 117, gr. i) has a rich variety of tree species and epiphyte lichens. It is similar to Brampton Bryan Park (W. 124, gr. 2) which may on further examination be the better site. However, Moccas Park is regarded as more important at this stage, because it has a greater variety of tree species and is known to be outstandingly rich faunally, while Brampton Bryan Park is virtually unexplored in this respect (see Appendix).

The epiphytic flora of the east and central Midlands is impoverished by pollution and the only known site of importance in other respects is Sherwood Forest (W.i3o). This is an oakwood, with the two species more or less equally abundant in a range of ages including saplings and very old individuals, and appears to be one of the few woods of any value in the area.

In northern England away from areas of high atmospheric pollution a number of mediaeval parklands have survived. The ancient woods are mainly oak, with ash, elm, yew or sycamore. Three sites have been chosen, all of which have the additional feature of floristically rich ravine or valley woodlands. Monk Wood (W.i64) - part of Whitfield Park, Northumberland - has the richest epiphytes. Hesleyside Park (W.I65) and Lowther Park (W.I52, gr. 2) are also rich in epiphytes and extend the geographical coverage.

In Wales and Scotland these woods are both infrequent and differ less in their epiflora from other woods of younger trees. For this reason, no sites of ancient woodland have been selected in these areas.

3.4.6 Beech

Beechwoods occur in most parts of Britain, but the status of beech as a native tree has been much confused by widespread planting. Although there are good beechwoods which regenerate naturally in some northern districts, e.g. Aber-deenshire, this species is regarded as native only in the southern half of England and in south- east Wales. It is believed that the native range of beech once extended into Cornwall, north Wales and north Norfolk, and some present day occurrences in these districts may represent relict colonies. A valuable timber tree, beech has also been widely planted within its native range, and many existing beech-woods are the product of eighteenth- and nineteenth-century planting of sheep- walk. Nevertheless, many beechwoods occupy sites which have been wooded throughout historic times, although the woodland has often been modified considerably. Many were probably managed as coppice- with-standards, from which unproductive species were eliminated, but the majority have been converted to high forest, so that beech coppice is not a rare structural type.

Management has also obscured the ecological relationships of beech with other trees, especially oak, and the relationship of beechwood to other natural climax forest types in Britain is not clear; the relationship may vary according to conditions of soil and topography. For the purposes of the Review, some compromise in the treatment of beechwoods has been necessary, and it has been decided to select sites only from those districts where the species is likely to be native, but to choose here from the full range of variation, regardless of departures from the natural condition caused by management.

Beechwoods within the native range have been divided by Tansley (1939) into five main types, according to underlying soil type. These are rendzinas of softer Chalk and Jurassic limestones; shallow soils of harder limestones; slightly alkaline to acidic loams; unpodsolised sandy soils; and podsolised silts and sands. To some extent these edaphic differences correspond with the major geographical groupings of beechwoods, those of soft calcareous rocks being represented on the Chalk of the North Downs, South Downs, and Chilterns, and the Jurassic limestones of the Cotswolds; whilst those of hard limestones are exemplified by the beechwoods of the Wye valley and Brecknockshire. The middle range of beechwoods, on basic to acidic loams, occurs on the plateau soils of the Downs and Chiltern Chalk, and examples on unpodsolised sands are well represented in the Weald and the London Basin. Beech-woods on strongly podsolised sands are especially well developed on the Tertiary deposits of the New Forest and London Basin.

The choice of beechwood sites has been made with the two directions of variation in mind, and with special regard to floristic diversity associated with these edaphic and geographical differences.

The beech 'hangers' at Selborne (W.27) at the western end of the South Downs, are especially good examples of scarp slope beechwoods on chalk rendzinas, and the Selborne site has plateau woodland in which beech is mixed with oak and ash over basic loam. Bignor Hill (W.8) is another Chalk scarp beechwood farther east on the South Downs and lies on a steep, north-facing slope, which gives it a damper aspect than the other beech hangers, with associated floristic differences. Perhaps because of their oceanic position, these South Down beechwoods contain a greater abundance of evergreen shrubs than other examples farther inland. Wouldham-Detling (W.y) has beechwood in a diverse woodland also noted for scrub. Old Winchester Hill (L.25) is another South Down site but with a rather small area of beechwood. On the North Downs, Crookhorn Wood (W.6, gr. i) and Box Hill (L.y) have areas of beech-wood of both the scarp and plateau types.

There are many fine and large areas of beechwood in the Chiltern Hills of Oxfordshire and Buckinghamshire, ranging from the scarp woods with thin, highly calcareous soils and a sparse ground flora of calcicolous species, through plateau beechwoods on neutral Clay- with- Flints soils to mildly acidic sands on the dip slopes. This is an area where woodland conservation should not be confined to a few sites of high scientific value, but must become part of an overall management policy for the whole region. Three sites have been selected. The Bradenham Woods (W.22) represent the neutral and acidic soil types; Windsor Hill (W.3o) is predominantly of the calcareous, scarp type. Aston Rowant Woods (W.29) cover both types, but have recently been modified by felling, thinning and replanting. Scarp beechwoods are represented well elsewhere, so only Bradenham Woods are graded as I.

The south-western half of the Cotswold hills carries beech-woods, and forms one of the major areas dominated by this species on calcareous soils. They contrast strongly with the woodlands on the north-eastern half of the Cotswolds, which have been managed as mixed coppice-with- standards for many centuries, and whose affinities are towards the eastern coppice woodlands. Many of the beechwoods are undoubtedly of a secondary nature, having been planted on unprofitable sheep-walk, but some are certainly primary. The latter appear to be the woods with the richest ground flora, but this point requires further study. The dominance of beech, often to the exclusion of other species from the canopy, is a product of management. Clearings left in these woods are often filled with dense thickets of ash, a process which occurs throughout the natural range of beech in Britain. Floristically, these woods are believed to be more closely related to continental beechwoods: in particular the species Cephalanthera rubra, Stachys alpina, Epipactis leptochila and Hordelymus europaeus are very rare or restricted in this country but characteristic of that type of woodland on the continent.

Within this extensive and fairly uniform woodland type the selection of sites depends on minor qualitative differences, mainly extent and fioristics. The Cotswold Commons and Beechwoods (W.J2, gr. i) on the Jurassic limestones in Gloucestershire form an important complex, including both scarp and plateau beechwood, and containing considerable floristic diversity, in regard to composition of tree, shrub and field layers. The Birdlip—Painswick Woods are the most diverse single group, containing a rich flora and a range of structural types. They are nearly contiguous with Sheeps-combe Wood, another excellent beechwood with a wide variety of species. This is an area which, like the New Forest, Chilterns, Western Weald and elsewhere, should be considered as a whole. The beechwoods on harder limestones are represented by the gorge woodland of Cwm Clydach (W.88, gr. i) in Brecknock, lying partly on Carboniferous Limestone. Cwm Clydach is also interesting as one of the westernmost outliers of native beechwood, while the Wye beechwoods are an important component of a diverse range of woodland characteristic of this valley, where they also occur on the sandstone at Hudnalls (W.y5).

The Weald of Sussex has beechwoods or mixed beech-oak woods on fairly base-rich clay loams and sands in plateau situations. The best of these woods located so far is on Ebernoe Common (W.n), where the beech is mixed with a good deal of oak. The Mens and The Cut in the same district is partly a mixed deciduous wood but has a good deal of beech, especially in the Bedham Escarpment area where there is a fine stand of beech on acidic strata. The best examples of the two beechwood types at the acidic end of the series, on non- podsolised (but acidic) and podsolised sands, are in the New Forest, and the London Basin. In the New Forest (W.26), Mark Ash and Denny Wood are among the many especially fine stands of beech, whilst Bramshaw Wood is an example of mixed beech-oak wood. A similar range of beechwoods occurs at Burnham Beeches (W.28), and Epping Forest (W- 55). The New Forest woods have been preferred because they form part of the largest and most important semi-natural woodland area in southern Britain and because their epiphytic flora is much richer than in the other two areas. Epping Forest has areas with loam over heavy clay where beech is mixed with both oak and hornbeam. While all three areas contain a mixture of age classes, they all have a substantial proportion of mature and overmature timber, which creates a considerable management problem.

As a counterpart to Cwm Clydach, Felbrigg Woods (W-5o) in north Norfolk is an eastern outlier at the probable native limits of beech. It has a good epiphytic lichen flora, but is so similar to the other southern beechwoods on acidic sands that it is not regarded as a grade I site.

3.4.7 Ash

Woodland dominated by ash represents a western and northern equivalent to beechwood, as an alternative end-point to the edaphic series beginning with pure oakwood on acidic soils and ending with a different dominant on calcareous soils. The intermediate type, mixed oak-ash wood, naturally grades imperceptibly into ashwood, and there are few ashwoods, even on the most calcareous substrata, which are without a small admixture of oak. Ashwood is a strongly oceanic forest type, better represented in Britain than in any other part of Europe, and therefore rates as an ecosystem of international importance. It is widespread but local, with a distribution determined largely by the occurrence of strongly calcareous rocks. There is considerable variation in the subsidiary elements of ashwood from south to north, but, compared with that needed for oak and mixed deciduous woods, a smaller series of sites adequately covers this range of diversity.

Climax ashwood occurs chiefly on the Carboniferous Limestone formation and has four main distribution centres, on the Mendips of Somerset; around the edges of the south Wales coalfield, in Glamorgan and Brecknock; in the Derbyshire Dales; and in the Craven and northern Pennines of Yorkshire and Westmorland.

In the Mendips (W.yi, gr. i) a group of three sites is regarded as necessary to represent variation at the southern limits of climax ashwood. Rodney Stoke is an example of the drier facies on mainly south-facing slopes, Ebbor Gorge includes the damp gorge facies, and Asham Wood represents the plateau type. These Mendip ashwoods have a well-developed, species-rich, calcicolous shrub layer containing most of the species characteristic of southern England, and there is a rich ungrazed field layer containing a number of thermophilous southern forbs. The Chalk of southern England has a number of ashwoods which may be a climax type, but here the relationships between ash and beech are not clear. Mostly these chalk ashwoods do not differ sufficiently from the limestone ashwoods, or from the oak- ash woods on Chalk, to have strong claims for inclusion in the national series, but the example at Wye and Crundale Downs (L-3) is regarded as a bonus and ashwood is well represented in the Wouldham- Detling Escarpment complex (W_7). Ashwood on Jurassic limestone is also well represented in the naturally regenerated woodland complex on the Axmouth-Lyme Regis Undercliffs (W.6y, gr. i), and there is a bonus example in the Cotswold Commons and Beechwoods. Chippenham Fen (P. 13) in Cambridgeshire also has enough ash to be regarded as a bonus site for this type of wood, and this species is locally abundant in the southern England woods of Blean, Bignor Hill, Chiddingly and Wakehurst and Fairlight Glen.

The Carboniferous Limestone in south Wales has only limited areas of ashwood and only two sites are regarded as nationally important. The small wood of Penmoelallt (W.Sg, gr. i) in south Brecknock is unique for its populations of endemic or rare Sorbus spp., while Darren Fach (W-99) on the opposite side of the same valley is a grade 2 example. However, Craig y Rhiwarth has a good area of bonus ashwood within the open water grade i * site of Ogof Ffynnon Ddu (OW.27), and the coast scrub woodland of Tor Gro on the Gower limestone is also worth including in this category (see C-42). In north Wales, Coed Tremadog (W. 105) has stands of ash at the foot of cliffs.

The Derbyshire Dales (W.H5, gr. i*) contain probably the largest stands of ashwood in Great Britain. These deep, steep-sided limestone valleys have complexes of calcicolous grassland, scrub and woodland which evidently represent serai stages leading to the climax, and have to be considered as composite ecological units. Dove Dale has probably the finest example of ashwood in the district, from the structural point of view, with an uneven aged population of the dominant ash and a well-developed shrub layer rich in species, including both southern and northern elements; the opposed slopes give west- and east-facing aspects. Lathkill Dale has especially fine field communities rich in woodland forbs which show no sign of past disturbance by grazing, and the opposed slopes here give south- and north-facing aspects. The woods of Cressbrook Dale (W. 115(6)) and Monks Dale (L.i24(i)(c?)) are on their own not as important as the two previous sites, but are each an integral part of limestone complexes regarded as having first national importance. They both show differences in representation of shrubs and herbs compared with Dove Dale and Lathkill Dale, and both have good examples of serai limestone scrub.

At least one of these sites should include plateau land with base- poor soils, on which acidophilous woodland could be re-established, to show the relationships between contrasting woodland types according to topographic and edaphic conditions. The bryophytes of ashwood are especially well represented in these Derbyshire Dales woods, but most of the less common species belong to the exposed rock habitats within the woods, though a few are corticolous. On the whole, ashwoods are, from the calcareous nature of the habitat, poor in Atlantic bryophytes, even when they lie close to the west coast. The ashwoods of the Hamps and Manifold Valleys in Staffordshire (W.I23, gr. 2) are generally similar to the Derbyshire Dale ashwoods but exhibit unusual features in the presence of abundant holly and of well-grown trees of both species of oak.

The remaining ashwoods of the Craven and northern Pennines are mostly small, and, as they are nearly all situated on the lower slopes of hills, tend to be grazed by sheep. A small group of the Craven ashwoods, each in a different

Regional diversity and selection of key sites topographic situation, has been chosen to exemplify the range of northern ashwood, with a subalpine element in the field layer of the Ribblehead Woods (W.I42, gr. i). Colt Park Wood on the lower slopes of Ingleborough, represents the best example of ashwood on limestone pavement, while the nearby Ling Gill on one of the headstreams of the Kibble, is a limestone gorge ashwood. Both lie at just over 300 m and have field communities which owe their richness and luxuriance to the protection from grazing conferred by the peculiar topographic features. In Wharfedale, part of Bastow Wood (W.I43, gr. i) is regarded as nationally important for its field communities which contain a different blend of rare species from the previous sites, and lie in a different topographic situation, namely exposed scar and scree. The wood itself requires restoration and the herbaceous field layer needs protection against the increasing sheep grazing. In Littondale, Hawkswick Wood (W.I55, gr. 2) and Scoska Wood (W.I56, gr. 2) are similar to Bastow Wood, but are regarded as less important floristically and are also subject to moderate grazing. Several other ashwoods in Wharfedale and Littondale were once of high quality but have deteriorated during the last 20 years through heavy grazing. In the same middle section of the Pennines, two other river glen ashwoods of good quality are represented at Thornton and Twisleton Glens (W.I57), Ingleton, and at Kisdon Force Woods (W.i6i) in Swaledale, but neither is considered to be sufficiently different from other ashwoods of this type to rate higher than grade 2.

On the limestone exposures around the head of More-cambe Bay, much of the remaining woodland is of the mixed deciduous type. Eaves Wood (W.I53) near Silverdale is much modified by management and planting, but is important floristically for its field layers. Hutton Roof Crag wood (L.i 3 5) to the east has a grazed ashwood which may be regarded as a bonus to this important pavement site. The Roudsea (W.I39) and Whitbarrow and Witherslack Woods (W.I36) are mainly oak- ash, but contain patches of ashwood alone, and in the Lake District, the Seatoller Woods (W.i33(^)) show alternation between ash-hazel and sessile oak as the rock varies between calcareous and non- calcareous beds of the Borrowdale Volcanic Series.

In the northern Pennines, above Brough, is the fine hill ashwood complex of Helbeck and Swindale Woods (W.I38, gr. i*). The Helbeck section lies on the Pennine scarp slope facing the Eden valley, while the Swindale portion occupies a deep glen with high cliffs in places. These woods have ungrazed areas and here show finely developed herbaceous field communities. In places the upper edge of the wood, which reaches 360 m, is fringed with rather open birch- hawthorn growths. Situated about 160 km north of the Derbyshire Dales ashwoods, these Brough woods are of high quality; they are particularly valuable as the best woodland component of the outstandingly important upland area which includes Upper Teesdale. A few kilometres west of Kirkby Stephen, the deep wooded glen of Smardale (W.i5i, gr. 2) provides an alternative though less varied and floristically rich ashwood site characteristic of northern England. The grassland complex of Crosby Gill (L.i4o)

near Shap also contains an interesting small fragment of herb-rich ashwood in a rocky valley. In east Yorkshire, stands of ash are represented in some of the mixed deciduous woods, e.g. Raincliffe Wood (W.I44), and extend the diversity.

In southern Scotland, mixed deciduous woods on basic soils of the Ordovician and Silurian Series of rocks often show local dominance of ash, and a good example is represented at Chanlock Foot (W.I72) on a tributary of the River Nith. Despite the extensive occurrence of mixed deciduous oak—ash wood on basic soils in Scotland, ash- dominated wood is rare and very fragmentary. Patches occur in many mixed woods in both the Southern Uplands and Highlands, but are seldom continuous over more than half a hectare. One of the best examples of Highland ashwoods occurs at the head of Loch Creran on the west coast of Argyll, not far north of Oban. This Glasdrum Wood (W.I93, gr. i*) lies on a south-east-facing slope of calcareous Dalradian schists and consists of an ash-hazel zone grading into alderwood below and oakwood above, as soil conditions change. It is lightly grazed and has well-developed field communities which show a considerable resemblance to those of more southerly regions, whereas the shrub layer lacks the species variety of that in southern ashwoods. There is a rich Atlantic flora of bryophytes and lichens, though this is more strongly represented in the upper oakwood zone. Above the village of Glencoe, on the north-facing side of the same massif, the corresponding woodland on a rather steeper calcareous schist slope has an unusual ash-alder mixture. This Carnach Wood (W.igi, gr. i) appears to owe its existence to the combination of moisture-retaining clay soils on a north aspect and an extremely heavy rainfall, which give conditions suitable for the growth of alder in an unusually steep situation.

The most northerly ashwood of any size in Britain is at Rassal (W.2o8, gr. i), at the head of Loch Kishorn in west Ross, and lies on an outcrop of the dolomitic Durness Limestone. This wood had become a rather open stand of ash, with virtually no shrubs, on an area with fragmentary exposures of limestone pavement, but covered mainly with a heavily grazed grassland. Fencing has allowed both regeneration of the ash and vigorous growth of the field layer into a tall grass-forb community in which bryophytes are much reduced. Rassal ashwood is interesting as an example of woodland near its climatic limit. Fragmentary ashwood also occurs on outcrops of Durness Limestone on Skye and the species is represented at the north end of Tokavaig Wood (W.2OI, gr. i*) and also in Coille Ardura (W.2I2), Mull.

3.4.8 Pine

Woods of truly native Scots pine are generally thought to occur only in the Scottish Highlands. It is, however, quite possible that some woods or more open growths of pine on lowland acidic mires or even heaths farther south could be fragmented remnants of a native population. Pine growths of this kind are well represented on Kirkconnell Flow (W.i68, gr. i), Kirkcudbrightshire, which is also a key mire site; Wedholme Flow (P.&2), Moorthwaite Moss (P-5o), and Cumwhitton Moss (P.57), Cumberland; Cliburn Moss (P.66), Westmorland; Chartley Moss (P-42) and Cranberry Bog (P-45), Staffordshire; Llyn (P- 33), Radnor; Cranes-moor (P.3(a)), New Forest, Hampshire; and Morden Bog (P.27), Dorset. Some of these pine areas are likely to be plantations, for this is a very widely planted tree in Britain. It regenerates well under favourable conditions and some pinewoods south of the Highlands are evidently sub-spontaneous (self-regenerated), e.g. at Orton Moss (W.I35) in Cumberland where pinewood is one component of a mixed woodland complex on former raised mire. Pine rows, clumps and hedges form a characteristic habitat in the Breckland, and are represented on many of the sites selected in that important district.

The pinewoods of the Highlands represent a southern and western outlier of the boreal coniferous forest of northern Europe, and in this region Scots pine replaces oak to a large extent. The most extensive pine forests are in the more central parts of the Highlands, where they occupy the poorer, more base-deficient soils. On the north side of the Cairngorms, draining to the Spey Valley, pine forest covers the lower slopes and flats of granitic drift soils at 210-610 m in a discontinuous belt extending from Glen Feshie to Nethy Bridge in Inverness-shire. The main segments are the Invereshie, Inshriach and Rothiemurchus Forest (W.i87(tf)) and Abernethy Forest (W.i87(e)). That within the Glen Feshie sector of the Cairngorms NNR is best regarded as a bonus. The woods of Invereshie and Inshriach consist mainly of hanging pinewoods on steep slopes, and include the important example, at 640 m on Creag Fhiach- lach, of the natural upper limit to woodland which now hardly occurs elsewhere in Britain. Much of the Rothiemurchus area lies on gently sloping ground, and here the trees attain a larger size in places. Abernethy Forest is the largest continuous block of pinewood on Speyside, and lies mainly on level or gently sloping ground, and so has a good deal of peatland, including an interesting complex of valley and basin mires.

On Deeside in Aberdeenshire there are pinewoods in the glens on the south side of the Cairngorms, such as Glens Quoich, Lui and Derry (W.i87(c)) but the more important forests lie south of the Dee. There are two main areas, the Ballochbuie Forest (W.i$j(a)) near Braemar and Glen Tanar (W. 187(6)) near Aboyne. Crathie Wood (W.iSi, gr. i) on the north side of the Dee is a mixed wood of pine, birch and juniper on richer soils than most pinewoods.

These Speyside and Deeside pinewoods (W.i87, gr. i*) are all of high conservation value, principally because of their large size, for they are the largest continuous areas of semi-natural woodland remaining in Britain. Each differs from the others in some respects, such as age class distribution and form of the trees, but all show a general similarity in field communities and flora. There are a few faunal differences, such as the abundance of the crested tit in some of the Speyside woods and their absence from Deeside. On the whole, however, it is difficult to choose between these woods and they are all regarded as grade i in quality. Some of these woods, notably Abernethy, Ballochbuie and Glen Tanar, are so large that their management for commercial timber production need not necessarily detract in any appreciable way from their value as conservation areas -provided that cutting is on a rotational basis, that the total area under trees is maintained, and the native Scots pine is kept as the dominant tree. It would be desirable to preserve some of the remaining stands of really old trees, such as those in Glen Quoich, but for the rest there is every reason from a conservation viewpoint to have a wide distribution of age classes within a forest.

Although there are woods of Scots pine at Crannach (W.2I5, gr. 2) overlooking Rannoch Moor in Argyll, and at Cononish, near Tyndrum in Perthshire, the only large and important pinewood in the southern part of the Highlands is the Black Wood of Rannoch (W.i86), overlooking Loch Rannoch, Perthshire, from the south side. The Black Wood also has areas of birch and there is oak on the opposite side of the lake, so that climatically this locality may be close to the natural limits of Scots pine. The large extent, southern position and entomological interest justify grade i status for the site.

North of the Great Glen, on the sides of the glens which feed the Beauly River in eastern Inverness-shire, is the second area of extensive pinewoods in the Highlands: Glens Guisachan, Affric (W.2O4, gr. i), Cannich and Strathfarrar (W.2O3, gr. i). These woods are mostly on slopes of moderate steepness and lie in an area of rather more oceanic climate than the forests of the Spey-Dee Valleys. A negative feature here is the general absence of natural regeneration of pine, perhaps due to heavy grazing by red deer. Much of this pine woodland has been affected recently by felling, and the best remaining area is that of Glen Strathfarrar, which is therefore proposed as the representative grade i site for this district, but also has a good deal of birchwood.

On the eastern side of the northern Highlands, the most northerly pinewood of relatively natural appearance is that at Amat Wood (W.224, gr. 2) in Strath Carron, east Ross, though there are more obviously planted pinewoods around Bonar Bridge and Rosehall in east Sutherland, such as the Migdale Woods (W.228, gr. 2) at Spinningdale. Much of the Amat pinewood has been felled and birchwood is now the more extensive type there. Farther south, in the Black Isle, the grade i peatland site of Monadh Mor has bonus pinewoods. In west Ross there are important western outliers of pinewood at Loch Maree (W.2o6) both on its larger islands and on the southern shore, on the lower slopes of Beinn Eighe. These Loch Maree pinewoods occur in a region of strongly oceanic climate, with a very heavy rainfall, and the associated communities, especially of bryophytes, have a strongly hygrophilous character. Natural regeneration is limited in these woods, evidently by a combination of deer-grazing and unfavourable soil conditions related to the humid climate. The Loch Maree woods are regarded as the best example of north-western pinewood. There are less extensive pinewoods in Coulin Forest and Shieldaig (see Appendix) (W.222, gr. 2) south of Loch Maree, and the

Regional diversity and selection of key sites most northerly example on the west side of the country is at Rhidorroch to the east of Ullapool. The mixed woods on the islands of Loch Morar (W.zoo, gr. i) contain small stands of pine.

Some of the western pinewoods show interesting relationships with other woodland types. At Loch Maree, south-facing slopes around Letterewe are occupied mainly by oakwood, except on the shallow soil of precipitous slopes, and pine occurs on north-east aspects or more level ground where there is a layer of peat. In the Beinn Eighe wood, pine gives way to birch on an area of richer soil receiving drainage from calcareous mudstones. A zonation of birch above pine may be a natural altitudinal sequence in Crannach Wood, but the reverse order obtains at Rhidorroch, where it is evidently related to the change in soil conditions according to slope and altitude.

3.4.9 Birch

Birch is represented in a large number of woodland key sites scattered widely over Britain, and as a bonus within sites chosen for other formations. Acidic heathland in the lowlands is often subseral to birchwood and some sites show a marked tendency to change from the one to the other; sites selected for their heathland, but containing colonising birch in quantity, include Thursley and Hankley Commons, Surrey; New Forest, Hampshire; Tuddenham and Caven-ham Heaths and Dunwich Heaths and Marshes, Suffolk; Skipwith Common, Yorkshire; and the Moor of Dinnet, Aberdeenshire. Birch, mainly Betulapubescens, also colonises lowland acidic mires, where the peat is drying around the edges, as on Dersingham Bog, Norfolk; Rhos Goch, Radnor; Glasson Moss, Bowness Common, and Wedholme Flow, Cumberland; and Kirkconnell Flow, Kirkcudbrightshire. In Orton Moss (W.I35), Cumberland, a former peat mire is almost entirely covered by woodland in which birch-wood is an important component in its own right; while at Holme Fen (W./p), Huntingdon, a raised mire developed over fen is covered by an almost pure wood of tall birch of both species regarded as grade I. The mixed dune woods at Earlshall Muir (W.i88, gr. 2) in Fife contain a good deal of both birch and alder. The ancient oakwoods of Sherwood Forest (W. 130), Nottinghamshire, also contain some birch. In the above localities, birch is itself probably a serai type which would in theory eventually be replaced by oak, or perhaps Scots pine in a few localities. In practice, however, further change would be unlikely until the birchwood began to die out from old age and, in some sites, parent oak is so scarce in the immediate area that it is not easy to envisage its spread onto the birchwood site. In some situations, poorly drained ground supports birch, but remains too wet to carry oak, e.g. in Johnny's Wood (W.i33(/)), Cumberland. Besides these there are woodlands in which birch has become locally dominant, evidently as a serai stage, following thinning or more general removal of the dominant oak. This would seem to account for the abundance or local dominance of birch in Coed Camlyn-Ceunant Llennyrch and Coed y Rhygen (W.io7(a)), Merioneth; Lodore-Troutdale

Woods (W.i33(</)) and Scales Wood (W.I46), Cumberland; Naddle Low Forest (W.I49), Westmorland; Inverneil Burn (W.iQS), Mealdarroch Point-Skipness (W.igy) and Glen Nant Woods (W.I94, gr. i) in Argyll. On Birk Fell (W.I37, gr. i), Westmorland, birch may have replaced oak, but much of the hillside is now covered with juniper and the relationships between these three species in the original woodland of the site are not clear. Co-dominance of birch and oak is also found in places, e.g. Roeburndale Woods (W.i4i), Lancashire, and here too relationships between these trees are sometimes obscure. There are in addition a large number of woods in which birch occurs as an abundant component tree, with a fairly stable (or at least 'steady state') role in the woodland ecosystem, but without ever becoming dominant. This is particularly true of mixed deciduous woods in northern and western Britain. Birchwood is sometimes a distinctive subsidiary component in hill ashwoods, such as the Helbeck and Swindale Woods (W.I38), Westmorland. There are in fact few key woodlands from which birch is entirely absent.

In southern Scotland, birchwood is represented in the oakwoods of Wood of Cree (W.ijj) and the gorge woodland of Avondale (W.iyo).

Most of the key sites chosen as examples of birchwood lie in those parts of the Scottish Highlands where this type is likely to be a climax woodland. The selection is made to represent the main directions of variation in climate and soil type found within these largely upland (subalpine) birchwoods. The most southerly example of subalpine birchwood, possibly the remnant of a once more extensive climax forest of the same type, is the small wood at High Force in the Upper Teesdale upland grade i* site in Yorkshire and Durham. This fragment is notable for its tall herb communities containing several northern species. Probably the finest example of subalpine birchwood in Britain is that on Morrone (W.i82, gr. i), Braemar, at 380—610 m, where a rather small juniper forms both an understorey beneath the birch and areas of treeless scrub. The site has calcareous soils and there is a range of subalpine grassland, marsh and flushes; the whole complex has strong Scandinavian affinities.

Also on Deeside, Crathie Wood (W.iSi) is a mixed birch, pine and juniper wood, again on rich soils, but the altitude is lower (270- 400 m) and both birch and juniper are of larger growth form than in Morrone Wood. This wood has a diverse composition and age structure, whereas the rather similarly situated Craigellachie Wood part of the Aviemore birchwood complex (W.i83, gr. i) in the Spey Valley, is a mature, fairly even-aged birchwood, evidently representing the climax forest type on the more fertile soils in this district. Craigellachie is especially interesting for its rich insect fauna. The Torr Alvie birch woodlands of Kinrara contain areas of Scots pine and of oak (planted) with juniper occurring extensively as an understorey. The field layer is generally acidophilous but with a more pronounced basiphilous element on the north and east slopes. The fairly central area of the Highlands around Laggan and Loch Ness has a good deal of birchwood at still lower levels. The deep valley of Glen Tarff (W.i84) draining from the Monadhliath to Fort Augustus is an example of a centrally situated birchwood but also contains a good deal of oak, ash and hazel, and is perhaps better regarded as a mixed deciduous woodland on fairly rich soils. Observations at this site would throw light on serai and climatic relationships of different woodland types in this area. There are also extensive pinewoods in the Beauly-Garve area, for example at Strathfarrar (W.2O3).

Both the southern-central Black Wood of Rannoch (W.i86), and the north-western Loch Maree Woods (W.2o6) have been selected chiefly because of their pine-woods, but contain also areas of dominant birch on better soils. There is an even larger stand of birch at Shieldaig (W.222), also in west Ross, and at Amat Wood (W.224), east Ross, birchwood is now more extensive than pinewood. The birchwood components of woodlands selected on other grounds have a high bonus value and are interesting additions to the series of Highland climax birchwoods. In Taynish Wood (W.I96), Knapdale, birchwood occupies the upper slopes and ridge tops instead of the oak and mixed deciduous wood prevailing below, and may here represent an edaphic climax. In the western Highlands, a final series has been chosen from south to north to represent the Atlantic facies of birchwood. North of Ullapool in west Ross, this is, in fact the only type of wood represented, discounting hazel and willow scrub, and it represents the closest approximation in Britain to the 'taiga' of the Arctic.

On the south side of Loch Sunart the steep, rocky and gully seamed hillsides around Laudalehave birchwoods and are especially rich in oceanic bryophytes and lichens; this is the shade facies of this flora which is mentioned under the south-facing Salen-Strontian and Ariundle woods as being of great international importance (see W. 190(0), (b), gr. i*).

In the south-west, patches of birchwood on granite block scree on the lower slopes of Meall nan Gobhar (W. 195, gr. i), Argyll, may represent another kind of edaphic climax, in which the ground is too rocky and the soils too immature to support oak. These woods have extremely luxuriant growths of Atlantic bryophytes and ferns. Eighty km north-northwest, on the southern Sleat peninsula of Skye, Tokavaig Wood (W.2oi) represents another mixed wood mainly of birch, but also with some oak, which is evidently close to its climatic limits. This site is partly on limestone, and there is some ash, but perhaps the most notable feature is the rich Atlantic bryophyte flora, which contains several very rare species and rivals Coed Ganllwyd in Merioneth in this respect. The woods of Loch na Dal (W.22O, gr. 2), also in Sleat, are similar to Tokavaig Wood, but rather less rich floristically and certainly a second choice. The rocky birch-woods at Kinuachdrach (W.2i8), Jura, are chosen mainly for their wealth of Atlantic bryophytes and ferns, and represent an alternative site to the oak-birch woods of Mealdarroch Point- Skipness.

On the Inverpolly NNR in west Ross close to the Sutherland border, the area of Lewisian Gneiss and Torri-don Sandstone chosen mainly for its upland ecosystem complex, has several birchvaods, which can be regarded collectively as a grade i woodland site (W.2O7). They occur on a range of aspects and soil types and represent the typical climax birchwoods of the far north-west Highlands. Inverpolly includes the island birchwoods of Loch Sionas-caig. Ardvar Woodlands (W.229), Sutherland, are included as a grade 2 alternative site. Other examples of mixed scrub woodland with birch (and also rowan) in the north-west are on the Fionn Loch Islands (W.223, gr. 2) in west Ross, and Eilean na Gartaig (W.225, gr. 2) near Elphin, Sutherland. There are other good areas of birchwood farther north; at Loch a' Mhuillin (W.226, gr. 2) near Scourie, on Ben Hope, Ben Loyal, the Kyle of Tongue, above Loch Naver, and south of Bettyhill. The most unusual of these is a wood in which rowan is co-dominant with birch on steep block scree in Strathbeag (W.2H, gr. i*) at the head of Loch Eriboll. The aspect is north-west so that the bryophyte flora is rich and luxuriant, and the wood has a generally undisturbed appearance.

Birchwoods occur widely in east Sutherland, but none is considered sufficiently important or different from the western examples to warrant national status. Compared with western birchwoods there are fewer Atlantic bryophytes, but no parallel gain in other plants.

3.4.10 Alder

Although alder itself is extremely widespread and represented in a great many key sites all over the country, woodland dominated by this species over a large area is rather rare, and the majority of alder stands are small or contain a mixture of other tree species. The best and most extensive alderwoods in Britain are probably the hydroseral carr woodlands developed from fen vegetation in the Norfolk Broads. The Bure Marshes (W.38, gr. i) contain good and representative examples of alder-willow carr with well-developed field communities rich in hydrophilous species, and showing transitions to sedge swamp and open water. Chippenham Fen (P.I3), Cambridgeshire, and Cothill Fen (P-4), Berkshire, have examples of similar alderwood as bonus elements in complexes important primarily for their mires, and the species is well-represented in carr associated with the richer lowland mires scattered widely over Britain. The estuarine transition from salt marsh to alderwood occurs on the Fal Estuary (W.6i) in Cornwall, but by far the largest estuarine alderwood (with willows) yet found is on former tidal lands behind an artificial sea embankment at the Mound (W.2IO, gr. i), on the east coast of Sutherland. Alderwood is represented in many places as the basal part of catenas on hill slopes with other woodland types, but often forms a fairly narrow strip. The best examples of this kind are Coed y Cerrig (W.<)2), Monmouthshire; Carn Gafallt (W-97), Brecknockshire; Coedydd Aber (W.IO4), Caernarvonshire; Lodore-Troutdale, Great Wood and The Ings (see W.I33) and Lyne Woods (W.I47), Cumberland; Naddle Low Forest (W.I49), Westmorland; Wood of Cree (W.I77) and Ravenshall Woods (W.I79), Kirkcudbrightshire; and Glasdrum Wood (W.I93), Argyll. Alderwood on springlines is represented in Colyers Hanger (W.2o), Surrey, and in various parts of the New Forest, and examples in waterlogged hollows occur in Roudsea Wood (W.I39), Lancashire, and at Earlshall Muir (W.i88), Fifeshire.

Alder is also locally abundant in damper places in various situations within a variety of oak and mixed deciduous woodlands, spread widely over Britain, e.g. Scords Wood (W-4), Chiddingly Wood (W.I2) and Wormley Wood-Hoddesdon Park Wood (W.i5) in south-eastern England; Swanton Novers (W-39), Felshamhall and Monks Park (W-35) and Foxley Wood (W-47) in East Anglia; the Bovey Valley Woods (W.63) in Devon; Cwm Sere (see U-4) in Brecknock; Cannock Chase (W.I22) in Staffordshire; Raincliffe (W.I44) and Ashberry and Reins Woods (W.I58) in east Yorkshire; and Claggain-Ardmore (W.2I4) on Islay.

Alderwood occurs in many places as a fringing growth along river and lake banks, but a more extensive stand occurs on the alluvium of a river delta at Urquhart Bay (W.igg, gr. i), Loch Ness. An extensive stand on flushed silty material occurs at Dobbins Wood, part of the Gowbarrow Park (W.I48) site. On the uplands of the north, wet clayey soils and river alluvium often have patches or fringes of alderwood, but these are usually grazed heavily and show little or no regeneration. This hill alderwood is especially characteristic of the Borders of England and Scotland, and one of the most extensive examples is at Billsmoor Park (W.i66, gr. 2) in Northumberland; there is a smaller example within the Harbottle Moors upland site (11.30). Two unusual mixed alderwoods, of high value in themselves, are Coed Gorswen (W. 103(6)), Caernarvonshire, an oak-alder wood on rather wet drift soils; and Carnach Wood (W.iQi), Glencoe, Argyll, a hanging ash- alder wood on steep slopes of calcareous schist in a heavy rainfall district. A fairly high-level example of alderwood occurs in part of Coed Dolgarrog (W.iO3(a)) in Caernarvonshire.

This short series of selected alderwood sites is considered adequate in the light of present knowledge, but as this woodland type is so widespread yet local, it is possible that future survey may reveal still better examples which should take precedence over known sites.

Other types of wood

Under this heading are considered an assortment of woods which do not fall neatly into any of the preceding categories. They consist of woods with unusual tree dominants and those whose distinctive features result from unusual physiographic settings.

3.4.11 Holly

As an undershrub, holly is a widespread species occurring in abundance in many key woodland sites, but is unusual as a dominant in its own right. Staverton Park (W-34), Suffolk, contains one of the finest stands of holly in Europe, with trees of remarkable stature, but probably the best areas of holly wood in Britain are in the New Forest. Another interesting area with abundance of this species and actually known as The Hollies may be regarded as a bonus within the acidic heathland site of the Stiperstones (L.I23) in Shropshire. An open growth of holly on shingle at Dunge-ness (C-3) is also regarded as a bonus, though it is arguable whether this can properly be termed a wood. A very different kind of holly scrub is represented on the Fionn Loch Islands (W.223) in west Ross.

3.4.12 Yew

Yew has two main centres of distribution as a native tree in Britain: on the Chalk of southern England and both Carboniferous Limestone and relatively non-calcareous rocks (both igneous and sedimentary) in northern England. In southern England, patches of yew wood are represented on various Chalk sites such as Old Winchester Hill (L.25), but the finest yew wood in this region is the famous example at Kingley Vale (W.io, gr. i*). In northern England, yew is well- represented in the ash and mixed deciduous woods on limestone, such as Roudsea Wood and the Whitbarrow and Witherslack Woods, and is abundant in patchy mixed scrub on the limestone pavements of Gait Barrows and Hutton Roof Crag (L.I35). In Scotland, native stands of yew are scarce, but there is a long established example on Inchlonaig, one of the Loch Lomond islands (W.i6g(f)).

3.4.13 Juniper

Juniper has a distribution showing some parallel to that of yew in Britain. It is widespread on the Chalk of southern England and the Carboniferous Limestone of northern England, but in the uplands of north Wales, northern England and Scotland it is widespread on a wide variety of rocks which give acidic soils. The chalk juniper is often a constituent of mixed scrubs and, as a convenience, this type has been described in Chapter 6, section C, while the northern types are dealt with here.

Juniper is represented again in several northern key sites. It occurs in the patchy scrub on the pavements of Gait Barrows, and Hutton Roof Crag, but by far the most extensive and luxuriant juniper scrubs in the north are on relatively base poor soils. The Lake District has many good examples, but the most extensive is on Birk Fell (W.I37, gr. i) above Ullswater, where it grades below into birch-wood. Another fine stand is situated around High Force in Upper Teesdale and there contains an abundance of the rare shrub Potentilla fruticosa and is in part on fairly basic alluvial soils. Tynron Wood (W.i6y) is a very striking but completely isolated juniper wood in southern Scotland and, though probably planted, is of considerable interest and rated grade i.

Juniper is widespread in the eastern Highlands and a characteristic though patchy shrub layer species of many pinewoods. Special mention may be made of Crathie Wood (W.iSi) on Deeside, where juniper is locally dominant in a mixed wood with birch and pine; and Morrone (W.i82), higher up the Dee, at Braemar, where a more montane birchwood has a dense shrub layer of a smaller juniper. The Morrone Wood is especially interesting for its rich flora (on calcareous schist), and as a type intermediate between lowland juniper scrub and the true montane type of the north-west Highlands dominated by ssp. nana.

3.4.14 Box

There are a very few woods in southern England with local dominance of box as a native species. Three examples have been rated as key sites. The finest is at Ellesborough Warren, others are at Box Hill, where the box forms a scrub with holly and yew under a canopy of beech or beech—oak on Chalk, and Boxwell in Gloucestershire where there is a dense box scrub with only open woodland on Oolitic limestone. These sites are described in Chapter 6.

3.4.15 Rare species

Included under this heading is the ravine wood of Glen Diomhan (W.iyi), Arran, Bute, rated as grade i for its two endemic Sorbus spp., S. arranensis and S.pseudofennica, which form an open tree growth along the sides of this granite and schistose glen, and are associated also with rowan, birch, holly and aspen.

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