2.3.1 Open Chalk Escarpment

Key characteristic features

• Predominantly open grassland; patches of scrub and woodland form distinctive patterns.
• Variations in relief are fully exposed so that contrasts of light and shade have strong visual influence.
• Relatively minor elements in the landscape, such as pylons and quarry scars, are highly visible.

Landform and context

The open chalk escarpment landscape predominates along the chalk escarpment to the east of the Arun valley and is therefore most commonly associated with the open east chalk uplands. However, the few small sections of the western escarpment which remain substantially free of woodland, such as Treyford Hill, are also included within this landscape type.

The open chalk escarpment follows a rather meandering east-west alignment before turning southwards at Polegate to meet the coast at the dramatic white cliffs of Beachy Head. It is deeply indented by steep, rounded coombes and in places forms a series of headlands jutting out into the lowland landscape to the north. Wind gaps occur wherever the principal chalk valleys have broken through the escarpment; at such points the ridge is seen in profile and the defined landscape type broadens to include the valley sides of the escarpment summit. Visually, these eroded gaps are particularly dramatic and significant as they provide opportunities to appreciate the massive bulk of the tilted chalk plateau. Principal communication routes follow these valleys, so in many respects the escarpment summits can be seen as gateways to the South Downs.

Occasionally two branches of the principal valleys have eroded either side of an escarpment summit to form an outlier, such as Mount Caburn at Lewes and Wolstonbury Hill to the north of the Pyecombe Valley.

The relatively open character of this escarpment landscape makes the landform of the ridge impressive because its strong, smoothly undulating profile is uncamouflaged by trees. The escarpment is a series of smooth, rounded summits and ridges, which generally reach an elevation of 200m, but have high points of 238m and 248m at Chanctonbury Hill and Ditchling Beacon respectively. To the east of Lewes the ridge is marginally lower, averaging a maximum height of 180m.

The highest, steepest summits are historic as well as topographical landmarks, as many are Iron Age hill forts sited in key defensive positions with commanding views.

In geological terms, the escarpment consists of Upper and Middle Chalk, with Lower Chalk outcropping on the lower slopes. The familiar geological sequence of Upper Greensand, Lower Greensand and Gault tends to occur further to the north.

The northern slopes are consistently steep, and in places precipitous, with abrupt breaks of slope. The numerous indented coombes give the slopes a dynamic, rhythmic quality, particularly when a low sun casts long shadows emphasising the landform. There is no visual evidence of landslips and the slope profiles remain consistent along the entire escarpment.

From the escarpment summits there are panoramic views over the lowland farmland landscape to the north and also across the chalk dip slopes to the south. The dry valley systems often end in steep, dramatic coombes, on the dip slope side of the escarpment. Examples are Well Bottom, to the south of Chanctonbury Hill, Hogtrough Bottom, to the south of Ditchling Beacon and the Devil's Dyke valley.

Land use and landscape pattern

The arable fields of the lowlands to the north often extend some way up the lower slopes of the escarpment and emphasise the line marking the break of slope between the rough textured steep slopes of the ridge and the managed, relatively small-scale farmland patchwork below.

The steep escarpment slopes are an irregular, patchy mosaic of scrub, chalk grassland, rough grazing and occasionally broadleaved woodland. Hedgerows are infrequent; the field network usually breaks down abruptly as the slopes steepen. On the steeper slopes, wire fencing is typically used. Fences aligned at straight angles across or up and down the slopes can detract from the visual unity of the slopes, particularly where they separate areas with different management regimes.

Mature woodlands with a diverse range of species form irregular strips and patches along the lower escarpment slopes. Stands of beech are found in sheltered locations and oak wherever there are pockets of clay. Other species are ash, field maple, wild cherry and, more importantly, large-leaved lime - an indicator that some of the woodlands are of semi-natural ecological status. Such woodlands help to ‘anchor’ the slopes visually and sometimes have distinctive outlines.

The skyline of the open chalk escarpment is generally open and vegetation cover usually decreases with elevation. However, there are some partially wooded sections, and irregular patches of scrub often extend up to the ridgeline.

Open grassland areas are a muted grey-green colour and are interspersed with patches of scrub, giving the slopes a rough texture and a wild, natural character. Soil creep often causes a hummocky surface and the steepest slopes are wrinkled into tiny terracettes, with rough sheep tracks and footpaths zig zagging along the contours.

The South Downs Way is an important visual element of the escarpment landscape, particularly where it is seen as an exposed, chalky-white track ascending an open grassland summit. The track generally follows the skyline and gives additional visual emphasis to the landform along the crest of the ridge.

The escarpment itself is a landmark, but there are also many particularly distinctive features, with both a positive and negative visual influence. Ancient earthworks, such as Chanctonbury Ring and the hill fort at Devil's Dyke are evocative landmarks but there are also modern, less attractive elements, such as the Devil's Dyke pub and the profusion of masts and buildings on Truleigh Hill. The white scars from abandoned chalk pits are a recurring prominent feature and some are sufficiently large to disrupt the slope profile of the escarpment.

At a smaller scale, individual trees, patches of scrub and bostals may be highly distinctive in local views. Sometimes such landmarks are a distracting negative visual influence; for instance the small, rounded blocks of scrub on the upper slopes of Beddingham Hill are out of scale with the landform.

Settlements

With the exception of a few isolated buildings associated with the golf course and pub at Devil's Dyke and occasional residential properties on the lower slopes, there are no settlements within the open chalk escarpment landscape.

The springline settlements which occur at the foot of the escarpment are generally outside the area defined as the escarpment landscape and are found within the scarp footslopes to the north.

Subjective response

This is a landscape of dramatic, evocative contrasts. The windswept, exposed ridgetop is juxtaposed with the hidden, secretive landscape of the deep coombes on the chalk plateau to the south and spectacular panoramic views across the patchwork maze of the farmland to the north.

At close quarters, the ridge is commanding and dominant; from a distance it is a distinctive landmark. The massive, smooth rounded summits have a primitive, monolithic quality and there is an overwhelming sense of the power of natural forces.

Sensitivity to change

The north-facing slopes of the open chalk escarpment are prominent in views across the Weald and ensure that the Sussex Downs are a landmark for miles around. This landscape is therefore extremely sensitive to change. Any built development is likely to be visually intrusive and to have a particularly widespread influence.

The elements of the escarpment landscape which are most vulnerable to change are the skyline of the escarpment ridge and the headlands at the wind gaps where the principal chalk valleys have broken through the escarpment. It is important that skylines are uninterrupted by elements such as buildings, telecommunication masts and power lines and that their predominantly open character is retained. Elsewhere, modern farm buildings, pylons and badly-sited fence lines can all detract from the natural qualities of this landscape. Changing patterns of land use on the chalk escarpment should aim to minimise intensive arable farming and its associated hard edges, and to encourage large-scale, unified swathes of chalk grassland.

The open chalk escarpment is probably one of the most visited of the landscape types within the AONB and also the most sensitive to visual intrusion. It is particularly important to ensure that any facilities associated with recreation are kept to a minimum.

Key issues for landscape management

Farmland mosaic

• Maintain predominantly open skyline along crest of escarpment ridge; strategic scrub clearance or thinning and appropriate grazing regimes as necessary.
• Conserve and manage chalk grassland habitats; extend and link adjacent sites wherever possible to create unified swathes of open grazed grassland. Archaeological sites should be a priority for grassland restoration schemes.
• The primary objective is to retain the essential open character of the scarp landscape so all areas of scrub should be cleared or managed to ensure that they are limited in extent, closely related to landform and irregular in pattern. The scale of the landscape mosaic varies but is typically finely-grained, irregular and patchy in character, particularly in the more open parts of the escarpment. This level of detail should be preserved and landform should always remain the predominant visual influence.
• Wherever established scrub is to be retained for wildlife or visual purposes, it should be managed by a combination of coppicing and removal to provide scrub of mixed age and species structure. Scrub clearance or thinning should be carried out in irregularly shaped patches to avoid hard edges and to maintain the visual character of the random, patchy scrub/grassland mosaic on prominent slopes. Areas of relatively stable, uninvasive scrub such as gorse, should be retained for its visual and nature conservation value, subject to archaeological considerations.
• The visual structure of the escarpment landscapes should be assessed from the surrounding lowlands to ensure that the relationships between the escarpment and its adjacent landscapes are well balanced.
• Identify any distracting, oddly-shaped landscape elements and remove them, or seek to improve their form and visual impact.
• Carry out detailed visual assessments to improve the landscape setting and appearance of visually intrusive development at Truleigh Hill and Devil's Dyke.
• Encourage the reversion of arable land to grazing pastures as a priority on escarpment summits and on the steep slopes at the ‘entrance’ to principal chalk valleys to improve the visual continuity and unity of the rounded chalkland relief. Such reversion should also be encouraged where arable fields sweep high up onto escarpment slopes at key, visually sensitive locations, such as the north-east escarpment slopes of the Adur valley.
• Encourage the development of chalk grassland on the south-facing dip slope side of escarpment ridges to enhance their ecological value and also to reduce the visual impact of harsh edged, geometric arable fields on the rounded slope profiles of the escarpment ridge.
• Wherever possible, avoid the use of fencing which is aligned straight up and down or across the grain of the steep escarpment slopes, particularly where they separate contrasting land uses.
• Historically important hedgerows should be conserved, along with any historic, irregular field patterns on the lower escarpment slopes. Scrubby, secondary hedges should be removed.

Trees and woodlands

• Conserve species diversity and age structure of escarpment woodlands: thinning, coppicing and replanting as necessary. Give priority to areas of semi-natural ancient woodland. Some replanting of beech and other important chalk trees may be required in areas where such species are not being replaced by natural regeneration and where sycamore and ash may otherwise predominate.
• Avoid straight, hard edges, particularly up and down or across the grain of the slopes. Woodlands should have irregular, patchy forms with long, sinuous linear protrusions and indentations which follow the landform and emphasise minor variations in relief. Encourage scattered, fragmented edges with a gradual breakdown to the typical, small-scale landscape mosaic of scrub and open grassland.
• New woodland planting should only take place on a small-scale and following careful visual and ecological assessments to ensure that the visual continuity of the open escarpment is maintained and that ecologically important chalk grassland sites are not jeopardised. Use only appropriate native broadleaved species. Carefully designed woodland planting could help to screen and integrate visually intrusive features.
• Special management programmes are necessary to retain important woodland stands such as beech hangers.

Tracks

• Conserve chalkland tracks and manage their associated verges, banks and hedgerows to avoid erosion and encourage wildflower interest.
• Avoid fenced-in tracks wherever possible.

Quarries

• Specialist studies, which take full account of geological, nature conservation and aesthetic issues are required to determine the best approach to quarry restoration. In some cases restoration might include the chamfering and stepping back of sheer faces; elsewhere it might be preferable to retain quarry faces intact to preserve their geological or nature conservation interest and to limit the extent of any further changes to the landform. The shaping of the quarry face should be designed to improve its visual impact and ecological value.

Priorities for action

• Grassland/scrub management to maintain a predominantly open skyline
• Encourage unified swathes of grassland on open, rounded escarpment summits
• Identify and improve small, visually intrusive landscape elements.
• Conserve and enhance strong contrasts in scale and character of landscape mosaic while always ensuring that landform remains the predominant visual influence.
• Promote complementary management between different landowners

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