There is no single Landscape Character Assessment (LCA) for the Chilterns AONB. The whole of the AONB is covered by a number of county and district-based LCAs that have been undertaken using similar (but not identical) specifications. A précis of these assessments gives us four broad types of landscape.
The Scarp Foothills and Vale Fringes consist of the gently undulating chalk slopes between the base of the scarp and the clay vale to the west. In the north of the Chilterns, often only a few fields of the Scarp Foothills and Vale Fringes form a narrow band at the edge of the AONB. Further south, approaching the Thames between Wallingford and Goring, the area is much wider. The Scarp Foothills and Vale Fringes also include land within the bases of the ‘amphitheatres’ at the heads of arterial valleys which break through the chalk scarp.
Most of the Scarp Foothills and Vale Fringes are in intensive agricultural use, with large, smooth, ploughed fields and distinctive mottled, flinty soils. Field patterns generally date from the 17th to 19th Centuries. This was when the medieval open fields were divided into regular parcels through the process of parliamentary enclosure.
The land is mainly in arable use with relatively few hedgerows or other semi-natural habitats. However, there are some stretches of ecologically rich clear streams and springs rising from the base of the chalk scarp, running north and west away from the scarp before entering the clay of the vale.
There is a strong visual relationship between the Scarp Foothills and Vale Fringes and the scarp, which rises immediately to the east. The nearby Scarp influences the landscape character of the Foothills. The Scarp Foothills and Vale Fringes form the visual setting to the Scarp both in views towards and from it. There is a striking contrast between the colours, textures and form of the scarp and those of the Scarp Foothills and Vale Fringes.
This area has evidence of settlement back to prehistoric times. The light soils, fresh springs and access to the Icknield Way would have made it an attractive area for early occupation. Most scarp-foot villages are nucleated in form, although some (particularly those on key transport routes) have expanded from the 19th Century onwards.
There is some variation in vegetation and land use within the Scarp Foothills and Vale Fringes, which creates subtle changes in landscape character, as described below.
Open chalk foothills
Much of the open chalk foothills consist of large arable fields with few field boundaries. It is an open and expansive landscape with a smooth texture and simple form. The nearby presence of the Scarp contributes to its sense of place and there is little settlement or woodland cover. The flinty soils have a distinctive grey colour that is particularly apparent in the winter months. Some parts of the Open chalk foothills may have been sheepwalks until they were ploughed in the mid-20th Century.
Semi-enclosed chalk foothills
These landscapes are generally found in the southern part of the Scarp Foothills and Vale Fringes, within Oxfordshire. Here, pockets of increased tree cover (often made up of linear belts of woodland) and a stronger landscape structure of hedgerows creates a more gradual transition to the scarp, particularly where the scarp is dominated by scrub and secondary woodland. These trees and hedgerows, and the associated field margins, provide a greater range of habitats. These landscapes were often less affected by parliamentary enclosure, so the surviving field patterns are older.
Around Aldbury, a relatively rare medieval landscape of lanes, woodlands, field systems and villages has survived on the edge of the clay vale. There are also pockets of historic parkland at the base of the scarp (such as Tring Park) which contain mature trees, avenues and ornamental features.
Settled chalk foothills
A string of settlements developed along the springline at the base of the scarp, particularly in the central part of the AONB. They are likely to have ancient origins but some (particularly those on transport routes) have expanded, either as linear developments along roads, or as housing estates on the edges of villages. This can create a more urbanised character. The AONB boundary has been drawn to exclude most of the larger scarp-foot settlements, such as Princes Risborough, Tring and Wendover, but some villages such as Ewelme, Great Kimble and Ellesborough are included within the AONB.
The ‘spine’ of the Chilterns is the chalk Scarp that runs roughly north-east to south-west along the western side of the AONB. A spectacular ridge rises high above the vale to the west and dominates views over a wide area. It is both a landmark and barrier for travellers; even those moving at speed on the M40 notice the approaching ‘wall’ of chalk and the change in gradient. Although the trend of the Scarp is south-west to north-east, its shape is quite convoluted, with numerous combes and headlands. Where the arterial valleys cut through the chalk, it has created ‘amphitheatres’ where the scarp turns to form the valley sides, such as at Tring and Wendover. In places, the scarp is less steep and pronounced, and towards the southern end of the AONB, the scarp blends with the rolling hills below it.
The chalk scarp contains a concentration of prominent prehistoric monuments including burial mounds and hillforts, indicating its ritual and functional importance for millennia. The Icknield Way, which was in use as a route from prehistoric times onwards, followed the scarp, with a summer route at the base, and a drier winter route above the springline. Despite its historic importance as a route, today the scarp is relatively difficult to access by vehicle. Roads tend to run at the base of the scarp, or cross it using the deep arterial valleys. There are some deeply hollowed-out paths and lanes which climb the scarp, and which have a strong sense of history. Some may have been in use since prehistoric times, and some are ancient parish boundaries. In more modern times, both the A41 trunk road and M40 have left dramatic incisions through the scarp.
There are spectacular panoramic views along and from the scarp, particularly looking west across Aylesbury Vale. As already mentioned, the scarp dominates views from within the vale. Figures cut in the chalk (such as the cross at Whiteleaf Hill and the lion at Whipsnade Zoo) and structures on the summit (e.g. the communications tower near the Coombe Hill monument) are particularly prominent landmarks. There is little settlement on the scarp itself but it is a popular recreational resource. It is exhilarating to stand on the crest of the scarp, enjoying the views and listening to the skylarks overhead. The Ridgeway National Trail follows the scarp and there are many popular viewpoints. These include Ivinghoe Beacon, Dunstable Downs and Coombe Hill.
The scarp contains a mosaic of land cover and habitats, including chalk grassland, woodland, scrub and parkland. These variations give the landscape a different feel in different parts of the scarp, as described below.
Open scarp slopes
The open scarp slopes include some of the most well-known features of the Chilterns, such as Ivinghoe Beacon and Coombe Hill. The smooth turf of the open scarp slopes allows the dramatic landform, and the earthworks of prehistoric monuments, to be fully appreciated. There are extensive areas of chalk grassland SSSIs containing a range of herbs and grasses, including rare orchids, which support many different insects, butterflies and birds. Some grasslands are managed as nature reserves. Open scarp slopes may be found throughout the full length of the scarp. In some areas, there are extensive areas of grassland, whilst in others it may be pockets within woodland. Traditionally, much of the scarp would have been unimproved chalk grassland grazed by sheep, cattle, horses and donkeys, supporting a rich sward of herbs and grasses. However, the extent of the open scarp slopes has declined markedly since the mid-20th Century because of reduced grazing and consequent invasion of scrub. A very small proportion of the scarp has been ploughed and is now in arable cultivation. This has tended to occur in the north and south of the AONB where the scarp is shallower.
Wooded scarp slopes
Woodland cloaks the scarp over much of its length, creating a backdrop of seasonally-changing colours. Much of the woodland is deciduous but there are also quite extensive areas (such as Wendover Woods) where coniferous trees have been planted on the scarp. Some of these scarp plantations are popular for recreation. There are numerous paths, trails, viewpoints, nature reserves, car parks, and a visitor centre (e.g. Ashridge). The scarp also contains nationallysignificant populations of species such as yew, juniper and box.
Semi-enclosed scarp slopes
These areas include historic parkland (such as at Tring Park) where the scarp has been incorporated into the designed landscape. Here, specimen parkland trees including copper beech and chestnut are prominent on the steep slope, along with dramatic lime avenues. Other areas of semi-enclosed scarp occur where chalk grassland is gradually being lost to scrub, which will eventually become secondary woodland if left unmanaged.
Plateau and Dip-slope
The Plateau and Dip-slope covers a large proportion of the AONB. It consists of the land east of the top of the scarp, which gradually falls away towards the east and Greater London. It is less visible and striking than the scarp itself but forms a key part of the classic Chilterns landscape. The topography is complex, with areas of plateau dissected by long, narrow valleys (often dry). Between the valleys, the higher plateau areas feel more open but their high proportion of woodland means that views are often limited.
Much of the Plateau and Dip-slope landscape remains largely unchanged since medieval times in terms of its landscape structure of fields, lanes, paths, woodlands, commons and villages. Therefore, in many areas it feels timeless and tranquil, with a sense of detachment from the modern world. It also has relatively dark night skies, particularly in areas away from settlements; and where the landform creates high horizons.
Settlements on higher ground are often found at the edge of commons. These linear villages developed from medieval times onwards, as dwellings were constructed quickly and informally on the edges of common land. Associated open common may survive as village greens or scrubby woodland. In valleys, settlement tends to be clustered around water sources, or forms rows strung out along valley roads. Scattered farmsteads, many with medieval origins, can be found throughout the area.
The Plateau and Dip-slope supports a mosaic of land uses and habitats, including woodland, common, arable farmland, pastoral farmland and parkland. Combined with changes in topography, these create variations in the character of the landscape, as described below.
These landscapes are found in the ridges and dry valleys so typical of the Chilterns. The shallower slopes and flatter areas are in arable cultivation, and steeper slopes are used for pasture. The farmland contains a range of important habitats, including grassland, hedgerows, trees and small woodlands. This is an ancient farming area with its first field systems and linear boundaries being set out at the start of the second millennium BC. The field systems are regular, almost grid-like, in their layout, described as ‘coaxial’ field systems. Many remain to this day. This landscape also contains most of the Chilterns’ surviving pre-18th Century field patterns, as well as a network of ancient lanes. Often dark and sunken below steep banks, these ‘holloways’ form part wider transit netwrorks connecting historic villages and farms.
Woodland-dominated landscapes are generally found in the areas that are most difficult to plough such as the heavy, sticky clay soils on the plateau and ridge tops, and the steepest slopes. Woodland often appears to drape over the landscape, extending down to cover the steepest slopes at the tops of the valley sides. A quarter of the AONB is wooded and much is ancient woodland. However, the tree species within the woods have changed over time in response to practical and commercial needs. For centuries woodland was managed to produce different sizes, shapes and species of timber needed for different purposes, and many still contain an archaeological legacy of this management. The extent of the famous Chilterns beech woods is relatively recent, many being planted in the 18th Century to provide materials for the furniture-making industry.
The Chilterns contain a relatively high proportion of land within country estates, with some of the largest found in the central part of the AONB such as around Ashridge. Estate landscapes may include parkland, farmland, woodland, wood pasture (where animals graze under trees), lakes, country houses, villages, focal points (such as follies and obelisks) and estate buildings. Some have origins as medieval deerparks, whilst others were laid out in subsequent centuries. There are examples of work by well-known landscape designers including Capability Brown (e.g. Ashridge and Gaddesden Hoo) and Humphrey Repton (e.g. Bulstrode Park and Shardloes).
Commons and heaths
Small pockets of once extensive areas of common and heath are found throughout the Plateau and Dip-slope, often on higher ground or areas of more acidic soils. These areas could not be profitably managed as farms or woodlands so were left to help the subsistence life style of commoners (Commons are areas where a specific group of people hold beneficial rights to use land that they do not own). Although not as extensive as in previous centuries, they nevertheless add to the distinctive character of the area. Vegetation is often more acidic or heathy in character, including heather, bracken and gorse which provide habitats for a range of insects, birds and animals. It also gives a different texture and colour to the landscape. Associated settlements often occur around village greens or along common edges, with names such as ‘end’ or ‘heath’. Some commons are still grazed but others are less well managed. These may be succeeding to woodland.
Rolling plateau farmlands
These distinctive landscapes are generally found in the northern part of the AONB, particularly in the outlier north-east of Luton. They comprise open, rolling expanses of large arable fields on light chalk soils (which may have been sheepwalks until the mid-20th Century). Although they are located above the scarp, these landscapes are very similar in character to the open chalk foothills found below it.
The Chilterns contains a series of larger river valleys that cut through the scarp and dip-slope. They can be dramatic, particularly where the rivers have cut through the chalk escarpment to create wind gaps, such as at Tring and Wendover. The topography of the valleys is gentler in the valley floors, becoming steeper higher up the sides. Some valley sides contain spurs and coombes, whilst others are smoother in profile. The valleys of the dip-slope are often asymmetrical in shape and can be hidden until approached. They often have an enclosed and secretive quality, especially away from major roads. The larger arterial river valleys also run north-west to south-east through the dip-slope.
Chalk streams meander along the base of valleys. They are often inconspicuous, sometimes only being visible as lines of pollarded willows. Chalk streams are fed by groundwater. Some sections, known as winterbournes, only flow when the water table is high after the winter rains.
Valley floors often contain a smaller and more irregular pattern of fields. Fields generally become larger and more regular in shape on the valley sides and may be in pastoral or arable use. There are some surviving pockets of unimproved chalk grassland, particularly on steep slopes. The steepest gradients usually occur at the tops of valley sides, where they are often covered by woodland. Some valleys are strongly influenced by the presence of estates and parkland. This is particularly where large houses are perched high on the valley side to achieve a commanding prospect over the valley.
The River Valleys have long been a focus for settlement. Many of the settlements within the AONB are located within the river valleys. Most are historic nucleated villages but there are some areas of more recent linear development. However, many of the largest valley floor settlements (such as High Wycombe, Henley on Thames and Berkhamstead) are outside the AONB boundary.
The River Valleys offer the easiest routes through the landscape. Therefore, they have a long history of use for transport, whether by river, canal, road or railway. Such infrastructure may impact visually on the River Valleys. This can also affect their sense of tranquillity. A network of smaller lanes and tracks wend over the valley sides to connect villages and farms.
The River Valleys generally feel enclosed, with views across and/or along the valleys. There are three distinct types of River Valleys within the Chilterns, as described below.
Arterial river valleys
These parallel valleys run north-west to south-east through the Chilterns, with dramatic ‘wind gaps’ where they cut through the scarp. They contain the Wye, Misbourne, Bulbourne, Gade and Ver rivers. The arterial river valleys have been used as transport corridors for millennia. They carry Roman roads, the Grand Union Canal, turnpike roads and railway lines through the Chilterns. Their ease of access and reliable water supplies mean that the valley floors are well-settled in parts and this – combined with the transport infrastructure – can give them a more developed feel in some areas. These arterial river valley landscapes are relatively simple in form and large in scale compared to the more intricate, complex landscapes of the surrounding Plateau and Dip-slope.
The Thames river valley
Located at the southern edge of the AONB, this area comprises the sides and broad valley floor of the Thames Valley. The River Thames dominates views from the valley sides. When the climate warmed after the ice age, glacial melt-water breached the scarp and the River Thames changed its course, eroding the chalk to create the significant landmark feature of the Goring Gap. The North Wessex Downs AONB continues to the west beyond Goring. The larger Thames-side towns of Henley-on-Thames, Caversham and Marlow are outside the AONB boundary, so the majority of the Thames river valley area within the AONB has a rural feel. The valley sides contain a significant amount of woodland, with some areas of grassland, agricultural land and parkland. The settlements of Goring, Whitchurch-on-Thames and Mapledurham developed at crossing-points (bridges or ferry landings) over the Thames. Between Wargrave and Maidenhead, a quirk of post glacial flow pushed the Thames northwards and isolated a section of ‘Chilterns’ landscape between these settlements.
Non-arterial river valley
The non-arterial Chess Valley has a very distinctive character compared to the Arterial River Valleys, and to the dry valleys of the Dip-slope. The clear chalk stream of the River Chess meanders through species-rich water meadows. The surrounding network of hedgerows, interlocking woodlands and small parklands add to the valley’s well-treed and pastoral character. It is an enclosed and harmonious landscape with a secretive feel. The lack of transport infrastructure gives it a more tranquil ambience than the Arterial river valleys. The small, picturesque villages of Latimer and Chenies add to the character of the ever popular Chess Valley.
The Chilterns landscape has been shaped by geological forces, nature and by people. The skeleton of the Chilterns Hills is made up of layers of chalk. This is a soft, white limestone laid down in the Cretaceous Period, approximately 80-100 million years ago. The same movements of the earth’s crust that formed the Alps caused the chalk layers to buckle into a series of folds. Subsequent erosion by wind and water led to the formation of the steep chalk scarp and shallower dip-slope.
Flint was formed during this period. Organisms, such as sponges, use silica from sea water to manufacture their skeletons. When the organisms die this silica is scattered on the sea bed and becomes incorporated in the accumulating sediment. The chalk sea bed was deeply burrowed by many different organisms, such as shell and worms. These burrows filled with the sediment after the organism had died. The silica was initially in the form of crystalline opal but gradually transformed into quartz (flint) during later burial and with time. Flint formed within these old burrows often has a nodular shape.
During glacial and interglacial periods, material was deposited in layers over the chalk by glaciers, melt waters and wind. This material was mostly clay but there are also patches of sand and gravel. For several thousand years during and immediately after the ice ages, the Chilterns experienced peri-glacial conditions. The chalk was frozen and therefore impermeable to water, meaning that surface water could erode the rock and create valleys.
The earliest record of human occupation in the Chilterns found to date is flint fragments from the Caddington clay pits, which date from the Palaeolithic period (before the last Ice Age). The landscape was cleared during the Neolithic and Bronze Ages (approximately 4,000 – 1,000 BC). During this time, people gradually became more settled, farming crops and domesticated animals. The chalk scarp, with its access to light, easily-tilled soils and springs of clean water would have been a focal point of settlement. Some of the most striking prehistoric monuments in the Chilterns are a series of hillforts dating from the Iron Age (650 BC to 40 AD), sited in strategic locations along the scarp or overlooking river valleys. Around this time, a route way developed along the chalk ridge, the Icknield Way (now part of The Ridgeway). Stretching from Wessex to East Anglia, the Icknield Way is claimed to be Britain’s oldest road. People, including drovers, traders and invaders, have walked or ridden The Ridgeway. It was once a part of a prehistoric track stretching over 400 Km from the Dorset coast to the Wash on the Norfolk coast. It provided a route over the high ground for travellers that was less wooded and drier than routes through the spring-line villages below.
Evidence of Roman occupation has mainly been found on the dip-slope to the east of the scarp. The nearby town of Verulamium (now St Albans) was a major Roman settlement, with roads radiating out from it. The Roman road of Watling Street headed north-west along the Ver Valley (now the route of the A5). Akeman Street headed west following the Bulbourne Valley (now the route of the A41 and A4251).
Not much is known about what happened in the area when the Romans left. The first written reference to the Chilterns is found in a 7th Century document (the Tribal Hideage) that refers to the ‘people of Chiltern’. It appears that the Saxon estates were gradually divided into smaller parishes, a pattern still recognisable today.
The Domesday Book of 1086 shows the Chilterns to be less densely-populated than the surrounding vales. However, there is a clear pattern of farmland and woodland; and the settlement pattern of villages is familiar. Much of the Chilterns landscape as we know it was in place by the end of the Medieval period.
During medieval times a clear landscape distinction developed between villages at the scarp-foot, which had an ‘open field’ system, and the villages of the dip-slope, where the land was already parcelled-up into ‘closes’ which were controlled by individual landowners or tenants. Strip parishes formed including areas at the base of the scarp and running up to the dip-slope. [NJ2] A few centuries later, the differences were enhanced by the process of parliamentary enclosure. In the open field areas, the land was divided up into regularly-shaped fields, many of which are still visible today. However, in the dip-slope areas, parliamentary enclosure was limited to some division of common land and the older co-axial field patterns remained intact.
Improved transport routes in the 18th and 19th Centuries had a major impact on the Chilterns landscapes, both directly as landscape features, but also through opening up new markets and land uses. These routes followed the easiest passages through the hills – the arterial valleys.
Several of the main roads through the Chilterns have their origins as turnpikes. These toll roads were constructed from around 1750 onwards in response to the increased volume of wheeled traffic. They enabled more goods to be moved between rural areas and towns. The Old Toll House can still be seen when heading north out of Great Missenden.
The Grand Union Canal was constructed in the 1790s through the Bulbourne Valley and connected London and Birmingham. The canal enabled the supply of bulky goods such as firewood and hay from the Chilterns to London. Gradually, however, the efficiency of national water transport meant that coal became the main fuel in London, rather than wood. This in turn led to a decline in traditional woodland management, which had included coppice for wood-fuel. At the same time, growth in the Chilterns chair-making industry led to the plantation of beech trees. This has resulted in one of the Chilterns’ most distinctive landscape features - the extensive beechwoods. Today, the Chilterns remains one of the most wooded parts of the UK.
Another consequence of the improved road network was the growth of country estates in the Chilterns. Some already existed as landed estates and deer parks (Stonor for example) but others were created by people who wanted a country estate at a convenient distance from London. This tradition continues to the present day, with the Prime Minister’s estate at Chequers. The well-treed landscape, and naturally undulating ground, leant themselves particularly well to the naturalistic style of parkland design made famous by ‘Capability’ Brown and Humphrey Repton. The parks still make a significant contribution to the landscape. Some estates remain in private ownership whilst others are owned by the National Trust and other organisations.
The building of a network of railways through the Chilterns between 1839 and 1906 transformed the local economy and led to rapid and extensive expansion of towns and villages. The 20th Century also saw construction of new communications and infrastructure including the M40, pylons and transmission masts. There are a number of 20th Century military establishments and an increasing proportion of land in recreational use, particularly as golf courses.
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