129 - Thames Basin Heaths : Analysis: Landscape Attributes & Opportunities

Analysis supporting Statements of Environmental Opportunity

The following analysis section focuses on the landscape attributes and opportunities for this NCA.

Further analysis on ecosytem services for this NCA is contained in the Analysis: Ecosytem Services section.

Landscape attributes

Plateaux of Tertiary sands and gravels in the London Basin. The largest plateau dominates the eastern end and drops into the London Basin to incorporate the Thames flood plain.

Justification for selection:

• The Tertiary sediments were variously deposited by rivers and seas, giving rise to a complex layering of silts, sands, gravels and clays. The area gave its name to the Bagshot Beds.
• Sands and gravels give rise to acidic, free-draining soils that favour heathland plants and trees such as birch and oak. These soils make for poor cultivation and rough grazing is the frequent land use in terms of agriculture. In many cases, landowners planted the heathlands with conifers to maximise the productive possibilities of these soils as per early 20th-century forestry theory. Conifers are self-seeding and encroaching onto open heathland.
• The entire NCA drops in altitude eastwards into the London Basin which is at its lowest near London in the east where the Thames meets the Wey and Mole and the low-lying area around Chobham is drained by numerous small watercourses.

Chalk edges into the area in the far west, including the escarpment of the Hampshire Downs. There are several chalk watercourses including the River Lambourn.

Justification for selection:

• Walbury Hill is the highest chalk hill in the country at 297 m.
• The escarpment of the Hampshire Downs is characterised by species-rich chalk grassland, hanging woodlands, parklands and springline villages.
• The base of the Berkshire Downs dipslope and the Hampshire Downs escarpment lie around Newbury. This area is recognised as being a nationally important landscape by inclusion in the North Wessex Downs Area of Outstanding Natural Beauty (AONB).
• The Pang, Lambourn and Kennet have eroded down to the Chalk. The national importance of their ecology is recognised by SSSI designation and, in the case of the River Lambourn, European importance as an SAC.

River valleys floored by London Clay surround the plateaux. Watercourses arise from outside the NCA but also drain the plateaux.

Justification for selection:

• Watercourses have eroded through the overlying Tertiary deposits to reach the London Clay and shape broad valleys intervening the upstanding plateaux and lay down deposits. Minor watercourses drain down the slopes of the plateaux in steep ‘gulleys’ that create a rippled profile along the plateaux slopes.
• The Loddon catchment lies in a broad belt of London Clay in the centre of the NCA while the Kennet catchment has created sinuous valleys between several small plateaux. There are numerous minor watercourses off the plateaux and in the flood plains.
• The Blackwater is one of the more heavily engineered watercourses since it is surrounded by extensive settlement. It also suffers from phosphate pollution. Other rivers exhibit unmodified sections and good water quality, including the Lambourn (chalk river) and parts of the Loddon (eutrophic).
• Canals passing through this NCA are the Basingstoke, Wey Navigation and Kennet and Avon Canal. The River Wey Navigation exhibits engineered sections dating back to the 17th century.
• Wetlands include ditches, wet pasture, historic meadow, reed beds, mires, ponds and fens. Wetlands are strung along river corridors with rare neutral meadow on London Clay being present as isolated fragments. Watercourses and wetlands vary in acidity with watercourses flowing off the plateaux, such as the Blackwater, being influenced by acid geology and the watercourses on the London Clay being eutrophic.
• Important wetland habitats include wet pasture, flood plain meadow, reed beds, mires, ponds and fens. The most extensive semi-natural wetlands are in the Kennet Valley, including the largest reedbed in southern England at Thatcham and a complex of wet woodland designated the Kennet Valley Alderwoods SAC.
• The Kennet and Lambourn Floodplain SAC protects numerous areas of habitat of the Desmoulin’s whorl snail.
• Pollarded willows and poplar avenues are found in the flood plains on the London Clay.
• Alluvium soils permit localised areas of arable while pasture, meadow fragments and wetlands are found in wetter areas.

Gravel and sand extraction along the Kennet and Blackwater where chains of numerous old pits have been restored to open water lakes and reedbed.

Justification for selection:

• Water-filled sand and gravel pits are prominent in the Kennet and Blackwater valleys.
• Open water is often managed for angling and watersports. Planning authorities have sought public access in many cases. There is considerable bird and invertebrate interest associated with individual pits and also complexes.

Large plantations and secondary woodland across former heathland including commons. Small ancient semi-natural woodlands are densely dispersed across the west, including wet woodlands.

Justification for selection:

• Decline in grazing pressure has allowed succession of open heathland to secondary woodland of birch, oak and also conifers where plantations are nearby.
• Around 6 per cent of the NCA comprises conifer woodland and another 7 per cent is mixed. There are large plantations on former heathland on the eastern plateau, including Bracknell Forest for example. Heathlands were planted up in order to make productive use of the land since agriculture was marginal on these acid, leached soils.
• Nearly 5 per cent of the NCA is ancient woodland and this is predominantly in the west. These ancient woods may date back to the historic ‘hunting forests’ of Norman and perhaps Saxon times and today they lie in a small-to-medium-scale patchwork with fields and hedgerows. The largest semi-natural ancient woodland is Pamber Forest. Around 2 per cent of ancient woodland sites are planted with conifers.
• Wet woodlands are found in the steep ‘gulley’ valleys draining off the plateaux as well as in the flood plains, but largely in the west. Kennet Valley Alderwoods SAC covers 54 ha.
• Neglected and overgrown former nurseries in the east have led to unusual woodlands which provide new and varied habitats. Rhododendron is characteristic of designed landscapes such as Virginia Water and of eastern suburbs and roadsides.

Trees enclose settlements and roads in the east but boundaries are absent across huge blocks of woodland and heathland which include commons. In the valleys, there is a small to medium scale patchwork of fields and woods defined by irregular, hedge boundaries and winding lanes.

Justification for selection:

• In the past, heathlands were often managed as unenclosed common. Today there is a lack of boundaries but secondary woodland and plantations have created barriers that enclose roads and settlements and frame views.
• Assarting, dating back to medieval times, produced small fields with irregular hedged boundaries. Ancient field systems have rarely survived and there was re-organisation of field boundaries including some enclosure largely by agreement. Historic field patterns and hedgerows can be found across the west in the valleys. Heathland on the plateaux was enclosed by large estates in the 19th century for farmland as well as planted with conifers.
• More recently, horse paddocks have given rise to non-traditional boundaries and field patterns comprising fenced compartments. Rhododendron and laurel defines boundaries in suburban areas.

Localised areas of transitional habitats and diverse mosaics with varied ecology and land use history.

Justification for selection:

• Diverse habitats and transitional habitats are found in the valleys and across heathlands as a result of varying soil acidity, water regimes, topography and different land management across the area. Dependent fauna is consequently varied and includes rare species with unusual niches, many of them requiring open habitats.
• On the eastern plateau, mosaics are particularly diverse and extensive due to the large expanses of semi natural habitat. The small-scale, historic patchwork of fields and woods in the west creates a diverse mosaic of farmland with semi-natural habitats that supports wildlife of the wider countryside as well as more unusual species linked to long-established semi-natural habitats.

Three large SSSI in the east comprise heaths and woods that are extensive within the context of south-east England.

Justification for selection:

• Mosaics of acid grassland, dry heath, wet heath, valley bogs, ponds and scrub support a diversity of flora and fauna including rare dragonflies and birds such as woodlark, nightjar and Dartford warbler.
• Up until the 18th century, this area constituted the largest and most continuous area of lowland heathland in England and was managed as common. Plantations, urban development and enclosure for farmland reduced the heathland extent although it remains today as a significant area.
• Three largest heathland and woodland areas are on the eastern plateau: Broadmoor to Bagshot Woods and Heaths SSSI, Ash to Brookwood Heaths SSSI, and Colony Bog and Bagshot Heath SSSI. The latter two are designated as part of Thursley, Ash, Pribright and Chobham SAC in recognition of their European importance in addition to Chobham Common SSSI.
• Other areas of heathland are recognised as nationally and locally important by SSSI and Local Wildlife Site designation.
• Heathlands and woodlands are dissected by roads. The M3 passes through Chobham Common SSSI which is part of the Thursley, Ash, Pirbright and Chobham SAC.
• Undulating topography and watercourses give rise to varied water regimes and aspect. This produces transitional habitats and mosaics that include bogs, ponds, streams, scrub, secondary woodland and wet and dry heaths and grasslands.
• The Thames Basin Heaths SPA protects habitat of woodlark, nightjar and Dartford warbler.
• Rare dragonflies can be found at many sites with wet features including Broadmoor to Bagshot Woods and Heaths SSSI where brilliant emerald and ruddy darter have been observed.

Autumn is vibrant with colour; purples of heather alongside reds, yellows and browns of broadleaves. Churring nightjars and dragonflies are popularly associated with the heathlands.

Justification for selection:

• There is widespread colour of heathers, trees and rhododendron in green spaces and surrounding settlement and roads.
• Birds and dragonflies are relatively easily seen on the heathlands. Conservation organisations hold events to engage people in such wildlife, with evening nightjar walks being particularly renowned.

Prehistoric barrows and hill forts, and historic features associated with rivers and canals. Well-known designed landscapes and also parkland, ancient woods and veteran trees are the relicts of historic ‘hunting forests’.

Justification for selection:

• The Thames and its tributaries were a focus area for prehistoric man. As a result, there are numerous prehistoric earthworks resulting from their activities including barrows and hill forts. The area offers vantage points on the slopes of the plateaux and on the Hampshire Downs that are ideal for monuments and defence structures.
• The royal hunting forests from Norman, if not Saxon, times include Eversley, Bagshot, Pamber and Windsor.
• The Thames Valley has long attracted the wealthy wanting to enjoy rural scenery within close proximity to London. This has given rise to numerous parklands in the NCA. Well known designed landscapes include Virginia Waters and Highclere Castle. Registered Parks and Gardens include Stratfield Saye, The Vyne and Dogmersfield which are a continuance of parts of the royal hunting forests.
• Ancient woodlands and veteran trees are present, many of which are associated with the remnants of royal hunting forests and ancient field boundaries.
• Mills and water meadows are found along the Wey, Loddon, Pang and Kennet. The River Wey Navigation was the first canal in the country and therefore contains historically significant engineering features.
• The Roman civitas capital Calleva stands as remains under grassland near Silchester. Remnants of Roman roads and Grimm’s Ditch extend from this area. Roman farmsteads and villas are found across this NCA.

Historic farmsteads and villages are densely dispersed in the west, with Newbury the only major settlement.

Justification for selection:

• Numerous settlements have Saxon origins. Medieval farmsteads and settlements (for example Newbury, Odiham and Kingsclere) are found in the west. Some farmsteads are moated and there are historic timber-framed buildings dating back to 14th to 17th centuries.
• Saxon charters show that farmsteads were established on the clay of north Hampshire before the early 10th century.
• Military use of the heathlands in the east stimulated the development of Aldershot and Farnborough. Development in this area was significant in the later 20th century giving rise to a major change in settlement pattern whereby major conurbations are strung along the Blackwater Valley and there is a network of interconnected A roads and the M3. This development has dissected the heathlands and woodlands into blocks.
• Military use of the heathland in the west of the NCA gave rise to bases at Greenham and Aldermaston.
• In the east, just beyond the London greenbelt in which historic villages such as Chobham lie, modern conurbations such as Camberley sprawl along the Blackwater valley and M3 with numerous interconnecting A roads.

Locally made brick and tile are traditional construction materials. National concentration of timber-framed aisled barns.

Justification:

• Local sands and clays have allowed a local brick and tile industry. Tile making began as far back as the Roman period in Hampshire.
• Timber-framed buildings dominated before brick became widely available. There is a national concentration of historic timber-framed aisled barns in the downland areas.

Commons and country parks near to settlements and rights of way provide access to farmland, rivers and canals including River Wey Navigation.

Justification for selection:

• Commons are associated with historic settlements in the valleys as well as with some of the heathlands on the plateaux. The commons in the valleys can be very small whilst the plateaux heathlands can be extensive sites offering far-reaching views across undulating low hills of heath and wood.
• Large areas of heath and wood are owned by the Ministry of Defence as military training areas and, as a result, any public access is permissive and can be temporarily removed or not clearly understood. Visitors may be discouraged by military warning signs and lack of visitor facilities.
• The heaths and woods in the east near large conurbations and London and also in the west near Newbury provide opportunity for recreation to large local populations and represent relatively tranquil spaces.
• Roads dissect heaths and woods, impacting upon tranquillity in some cases. For example, the M3 passes through Chobham Common NNR.
• Local communities and local government manage commons since commoners rarely practice their rights which might help maintain commons. Commons are rarely grazed so secondary woodland is a feature at many.
• With a large urban population nearby, public green spaces are in demand and can be easily accessed by the major road network. There is provision for informal recreation at some commons with car parks and signage. Country parks and large estates also provide for visitors.
• The Kennet and Avon Canal, River Wey Navigation and Basingstoke Canal are managed as recreation corridors with rich natural and cultural heritage.

Landscape opportunities

• Conserve the unenclosed, historic commons, including the downlands and heathlands, for their biodiversity, archaeology and amenity value. Seek to secure grazing and scrub management to maintain open habitats in good condition. Manage and create corridors linking heathlands into a network that is resilient to climate change and wider environmental pressures, particularly taking into account the risks of fire. As a minimum, conserve the current size and contiguous distribution of the heathlands and the undeveloped attributes of these areas.
• Where possible, restore historic extents of open heathland through clearance of encroaching scrub and felling of failing or redundant plantations and secondary woodland upon former heathland. Target scrub and tree clearance upon former heathland where this will most improve the habitat mosaic, where historic extent of common land has been lost, and where historic monuments have been overcome.
• Maintain semi-natural habitats across the range of soil types and topography in the area and, where possible, extend, restore and create new areas of habitat including woodland, heathland, grassland, wetland, downland and farmland. This will maximise biodiversity interest and secure resilience to climate change, so conserving rare species and locally significant species such as nightjar.
• Strengthen fragments of historic meadow by expanding species-rich grassland, ditches, watercourses and hedgerows nearby.
• Where there are fertile soils in the valleys and there has been a long history of cultivation, maintain these arable fields so that there is a visually diverse landscape and a mosaic of farmed habitats with historic interest.
• Maintain the wooded character of the area, recognising that conifers as well as native species can positively contribute to landscape character in some places. Conserve historic hedgerows and protect veteran trees in any location in order to maintain the biodiversity and landscape value of these features. Plan for successors to veterans, particularly within the historic boundaries of the royal hunting forests and parklands.
• Manage woodlands to maximise timber quality, biodiversity value and recreation provision. Manage and create rides as links in the ecological and public access network. Encourage recreational use of conifer plantations where it will divert visitor pressure away from ecologically fragile places.
• Restore conifer plantations on ancient woodland sites to semi-natural native woodland by natural regeneration or, where appropriate, re-planting, taking care not to damage archaeology. Focus this particularly in the historic boundaries of the royal hunting forests.
• Conserve ancient semi-natural woodlands and, where possible, restore historic features such as coppice for biodiversity, landscape and historic environment interests. In the historic boundaries of the royal hunting forests, create new woodlands to improve the habitat mosaic and restore historic wooded areas.
• Manage wet habitats such as valley bogs, reedbeds, wet woodland, chalk streams and clay-based watercourses to maintain their diversity of habitat and landscape features. Increase the resilience of these habitats to climate change through managing water levels and extending or adapting habitats where necessary.
• Where relevant, reconnect watercourses with their flood plains where possible. Restore or adapt culverted and other modified sections of watercourses to improve their ecological and aesthetic value and to allow fish to migrate upstream.
• Maintain and conserve geological exposures, particularly key reference sites for Bagshot Beds, Reading Beds and the Quaternary environment.
• Plan to restore pits worked for aggregates in ways which enhance the network of habitats, conserve geodiversity and provide public access opportunities.
• Bury powerlines where they have a negative impact upon views. Ensure the associated impacts upon soils, archaeology and hydrology are acceptable. Target those areas and views most popular with visitors and undeveloped landscapes, such as open heathland commons.
• Adapt existing roads and plan new roads to minimise negative visual and noise impacts and accommodate for species movements and public access links. Avoid further fragmentation and destruction of habitats and historic landscapes. In relation to roads and also the urban edge, adapt existing and design new woods and tree belts to provide good sound and visual barriers, while also catering for public access into the wider countryside.
• Adapt horse paddocks so that they better reflect historic boundary patterns and boundary types. This will bring benefits to the landscape, ecology and historic environment.
• Encourage traditional building styles and materials, particularly where there has been a loss of distinctiveness of local character in the built environment. Target the restoration of key historic buildings within settlements and maintain historic settlement patterns.
• Restore and sensitively adapt historic built structures, such as those associated with canals, watercourses and farmsteads. Ensure historic timber-framed aisled barns are maintained as they are distinctive of this area. Provide interpretation as appropriate.
• Protect the full range of archaeological features including prehistoric henges, long and round barrows, iron-age hill forts, Roman settlements, medieval moated sites, traces of ancient field systems and evidence of lynchets. Manage scrub and woodland cover, particularly where it is encroaching upon little disturbed sites such as on heathland, and manage visitors to avoid erosion and other damage. Provide interpretation of key features where there is public access.
• Restore degraded parklands, including those not on the Register of Parks and Gardens, in order to maximise biodiversity, landscape and historic value.
• As a minimum, conserve current levels of tranquillity in those places where it is enjoyed. Ensure tranquil places are easily accessible to the public, particularly in relation to the large conurbations in the east and near to London.
• Sensitively improve visitor facilities to support enjoyment of commons, country parks and rights of way, particularly near to settlements and major road networks. Manage visitor pressure to avoid damage to features.
• Enhance public access routes and associated visitor facilities near to settlements lacking adequate greenspaces and to key landscape features such as Calleva.
• Create and restore views through clearance of tree and scrub cover, particularly in relation to key landforms such as the Hampshire Downs escarpment, key viewpoints in popular green spaces, popular public access routeways and historic monuments on vantage points.
• Provide interpretation and visitor information about the military history and current use of areas owned by the Ministry of Defence that are publicly accessible. Clarify the identity of these areas.