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Ancient Woodland
Inventory for the Chilterns
Report and Inventory Maps July 2012
an Area of Outstanding Natural Beauty
CONSERVATION BOARD
WYCOMBE DISTRICT COUNCIL
Chiltern Woodlands Project
ChilternDistrict Council
The Chilterns Ancient Woodland Survey has been undertaken by a partnership of the following organisations:
Chilterns Conservation Board Natural England
Forestry Commission Chiltern Woodlands Project
Thames Valley Environmental Record Centre Buckinghamshire County Council
Chiltern District Council Dacorum Borough Council
Wycombe District Council Hertfordshire County Council
Buckinghamshire
Oxfordshire
Bedfordshire
Hertfordshire
Greater London
Map 1: The Chilterns AONB
County Boundaries
Administrative Boundaries
Chilterns AONB
Area outside the Chilterns AONB
N
0 5 102.5
Km
Aylesbury Vale
Wycombe
Chiltern
South BucksSouth Oxon
Dacorum
Central Beds
Three Rivers
NorthHerts
© Natural England copyright. Contains Ordnance Survey data and database right 2012.
© Ordnance Survey Licence no. 100044050 & 100022021
© Crown copyright
Foreword
After quitting Chesham I passed through a wood…. Here there are only two sorts of trees, beech and oak:…..
none of that stuff which we generally call underwood: the trees standing very thick in some places: the shade
so complete as never to permit herbage below: no bushes of any sort; and nothing to impede your steps but
little spindling trees here and there grown up from the seed.
he Chilterns is an iconic landscape, designated as an Area of Outstanding Natural Beauty (AONB), and
one of the most heavily wooded parts of the United Kingdom. The Chilterns supports the most Textensive area of native beech woodland in England and contains protected woodlands, such as those at
Bradenham and Ashridge, which are of international importance. This is part of the country, perhaps unlike any
other, has a deep rooted and ancient woodland culture.
Woodlands are valued for many reasons; wildlife, recreation, timber, heritage and carbon storage. They contain
a wealth of archaeology and many features from their own past management. Ancient woodlands are
extraordinary survivors and must be protected and managed as part of the heritage of the Chilterns and the
nation.
It is essential that we actually know where all the ancient woodlands are. It may come as a surprise to many
that until now we didn't. This new survey puts right the mistakes and omissions of the national survey
undertaken over 20 years ago. We now have an up to date and comprehensive inventory of all our precious
ancient woodland, no matter how small. The challenge now is for everyone to care for it - it is truly
irreplaceable.
Mike Fox
Chairman
Chilterns Conservation Board
Chilterns Ancient Woodland Survey Report Page 1
William Cobbett, Rural Rides 1822:
Wooded landscape - Gade Valley, Herts
Contents
1. Summary 3
2. Introduction 4
3. Methodology and Sources 11
4. Results 20
5. Outputs 23
6. Discussion 24
7. Acknowledgements 26
8. References and Bibliography 27
Appendices
Appendix 1: Ancient woodland vascular plant 'indicator species' in the 'South' 29
Appendix 2: Woodland survey features record sheet 30
Appendix 3: Management issues identified from site survey visits in the wider
Chilterns Survey area 32
Maps
Map 1: The Chilterns AONB inside front cover
Map 4: Comparison of the Ancient Woodland Inventories for the Chilterns 34
Map 5: Comparison of planted and semi natural ancient woodland 35
Map 6: The revised inventory for the Chilterns – overview and index sheet 36
Map 7: The revised Ancient Woodland Inventory – North West 37
Map 8: The revised Ancient Woodland Inventory – Mid West 38
Map 9: The revised Ancient Woodland Inventory – South West 39
Map 10: The revised Ancient Woodland Inventory – North East and outlier 40
Map 11: The revised Ancient Woodland Inventory – North 41
Map 12: The revised Ancient Woodland Inventory – Mid 42
Map 13: The revised Ancient Woodland Inventory – South 43
Map 2: The Survey Area, showing Local Authority areas covered and the Chilterns AONB 5
Map 3: The Chilterns Ancient Woodland Survey Area showing National Character Areas 31
Copies of this report can be downloaded from www.chilternsaonb.org
Chilterns Ancient Woodland Survey Report Page 2
Cover photo: Old hornbeam stubs on the boundary of an ancient wood
ncient woodland is a nationally important and threatened
habitat, and its existence over hundreds of years has enabled Airreplaceable ecological and historical features to survive.
The Chilterns Ancient Woodland Survey was set up in recognition of the
importance of ancient woodlands and the deficiencies of the existing
Ancient Woodland Inventory. The revised inventory will assist everyone
making decisions which affect any aspect of ancient woodlands and
their management.
This report summarises the methodologies and findings of a two year
project undertaken to revise the earlier inventory published in 1991. It
only included woodlands greater than two hectares and recorded a total
area of 17,581 ha of woodland covering 20.97% of the AONB, of this
9,827 were ancient woods, which is 11.72% of the area.
The new survey includes woods under two hectares and the total area of
ancient woodland now identified in the Chilterns AONB is 11,058
hectares, a net increase of 1,231 hectares, covering 13.19% of the
AONB.
Mike Render's PhD research reported in our Pilot Ancient Woodland
Survey in 2007 showed an additional 689 ha of small woods under 2ha in
the AONB, which brings the total woodland cover up to 18,277ha. This
ancient woodland inventory revision shows that ancient woods occupy
60.5% of all woods, making the Chilterns one of the most important ancient woodland landscapes in England.
1. Summary
Summary TableAncient WoodIand Inventory Results
District FC digitized AWI % Area Revised AWI % Area Change Area >2ha Cover (only woods >2ha) Ancient (incl. woods <2ha) Ancient AW ha
Before Now
AONB 83,824 17,581 20.97 9,827 11.72 11,058 13.19 1,231
Dacorum 21,247 1,997 9.4 771 3.63 963 4.53 192
Chiltern 19,635 2,905 14.8 1,792 9.13 1,953 9.95 161
S Bucks 14,127 2,833 20.05 1,022 7.23 1,190 8.43 168
Wycombe 32,457 6,091 18.77 3,674 11.32 4,037 12.44 363
Total All Woods % Woodland
Chilterns Conservation Board - Chilterns AONB Pilot Ancient Woodland Survey 20071
1
Chilterns Ancient Woodland Survey Report Page 3
Birds Nest Orchid (Neottia nidus-avis)
Results are for the Chilterns AONB and the four Districts surveyed in full.
he core of the Chilterns ancient woodland survey was the Chilterns Area of Outstanding Natural Beauty
(AONB) (see map 2). In addition to the AONB, it included the whole of Chiltern, Wycombe and South Bucks TDistricts and Dacorum Borough. Full data sets are available for these areas as separate appendices.
This survey follows on from revisions in East Sussex, Hampshire, Kent, Surrey and West Sussex. The Chilterns survey
was commissioned by the Chilterns Conservation Board, Natural England and Forestry Commission. The following local
authorities provided funding and were members of the steering group:
Buckinghamshire County Council
Hertfordshire County Council
Chiltern District Council
Dacorum Borough Council
Wycombe District Council
The Chiltern Woodlands Project, Thames Valley Environmental Record Centre and Surrey Biodiversity Information
Centre were contracted to undertake the survey itself.
This survey was commissioned because it was known that the existing national inventory did not include woodlands of
under two hectares, of which there are many in the Chilterns, and some woodland had not been correctly classified.
The surveys which had taken place in other parts of the south east suggested that the inventory covering the Chilterns
would need to be revised. A pilot survey in 2007 confirmed this view and a full re-survey was commissioned in 2010.
The result has been identification of an additional 1,231 hectares of ancient woodlands in the AONB.
Woodlands are a priority identified in the Chilterns AONB Management Plan and have been for many years. A key
document was “A Plan for the Chilterns Woodland Policy” published by Bucks County Council in 1991, which included
paper maps showing the ancient woods across the AONB for the first time and introduced a “Code of Guidance for
Woodland Management in the Chilterns”. Both national and local thinking about, and policies for, the protection and
management of all ancient woods has moved on since then.
The National Inventory of Ancient Woodlands is a government dataset managed by Natural England. It is made
available on websites including under Habitat Inventories
Also in the Forestry Commission's Land Information Search
2.1 Project aims
The primary aim of the survey was to identify all ancient woodland in order to revise and update the Ancient
Woodland Inventory. All available information was re-examined and many woods were visited to gather additional
information.
The revised survey can be used in many ways including:
To protect ancient woodland from damaging development in accordance with local, national and international
planning guidance and policy.
To develop a better understanding of the key issues and threats affecting ancient woodland.
To identify areas of opportunity for environmental enhancement, increase habitat connectivity and targeting
woodland management
To promote appropriate woodland management and support.
http://magic.defra.gov.uk/
http://www.forestry.gov.uk/forestry/infd-6dfkmn
2. Introduction
Buckinghamshire County Council (1991) A Plan for the Chilterns Woodland Policy2
2
Chilterns Ancient Woodland Survey Report Page 4
2.2 Background
Ancient woodland sites over two hectares in size are recorded in the county Ancient Woodland Inventories which were
compiled in the 1980s and 1990s by the Nature Conservancy Council (NCC). These inventories, now brought together as
the National Ancient Woodland Inventory, have become an important tool for policy makers and planners whilst also
assisting land managers to identify key areas for the restoration and planting of native woodlands and increasing
awareness of the importance of ancient woodland.
At the time, the compilation of the original inventories was an extremely valuable process, and a landmark
achievement for the conservation of British woodland. However, new information and advances in technology mean
that their inaccuracies and omissions can now be addressed. With the pressure on land increasing year on year, these
errors can cause significant problems for planning authorities. In addition, the exclusion of woodlands less than two
Chilterns Ancient Woodland Survey Report Page 5
3 Spencer & Kirby (1992)
3
Buckinghamshire
Oxfordshire
Hertfordshire
Bedfordshire
Greater London
County Boundaries
Chilterns AONB
Entire Districts
Chiltern District
Dacorum Borough
South Bucks District
Wycombe District
Partial Districts/UA (within the AONB)
Aylesbury Vale District
Central Bedfordshire UA
North Hertfordshire District
South Oxfordshire District
Three Rivers District
0 10 205
KmN
Map 2: The Survey Area, showing Local Authority areas covered and the Chilterns AONB
© Natural England copyright. Contains Ordnance Survey data and database right 2012.
© Ordnance Survey Licence no. 100044050 & 100022021
© Crown copyright
hectares has undermined the protection afforded to these sites through the planning process. This is particularly the
case in heavily wooded counties, where small woodlands are a central part of the fabric of the countryside and make
a significant contribution to the overall woodland resource. This inventory revision includes these small woodlands for
the first time.
The original Ancient Woodland Inventory (AWI) for the Chilterns was produced on a county by county basis between
1987 and 1995, by the NCC. Originally, the county inventories were only available on printed maps, but between 1998
and 2000 they were digitally mapped (digitized) by the Forestry Commission and English Nature. This first digitization
is the electronic version that most resembles the original printed inventories, which have a published methodology,
although it includes some changes made since the paper versions were produced. This digital dataset was
subsequently updated on a case-by-case basis by English Nature (now part of Natural England), the successor to the
NCC, and is now administered by Natural England.
For this report, comparisons have been made to the county level inventories produced for the Chilterns, the 1998-
2000 digitized version of it and the 2003 digitized version created by the Forestry Commission (from which more
detailed statistics at the district and borough level can be derived than from the paper reports). Hereafter, the 1987-
1995 inventories are referred to as the 'original AWI', the 1998-2000 digitized inventory as the 'first digitized AWI' and
the 2003 digitized inventory as the 'FC digitized AWI'.
The Forestry Commission's English Woodland Grant Scheme can offer higher rates of grant for appropriate woodland
management operations in ancient woods and for the restoration of plantations on ancient woodland sites to more
natural conditions.
2.3 The Chilterns Ancient Woodland Inventory revision
The Chilterns AONB is densely wooded. In total, there are 17,581 ha of woodlands over 2ha. Proportionately, woodland
covers 20.9% of the AONB. As a result of this revision 11,058 ha are now classed as ancient woodland; this is 13.2% of
the area of the AONB.
The extent of woodland in the Chilterns, the exclusion of small woodlands from the original Ancient Woodland
Inventory, the desire to complete the revision for the entirety of the South East region and large scale developmental
pressures were all important factors in deciding to undertake this revision of the inventory
2.4 The policy context
Local authorities have a key role to play in the protection of this unique resource through the planning process. The
publication of the National Planning Policy Framework (NPPF) builds on the principals set out in Planning Policy
Statement 9, which required local authorities to identify areas of ancient woodland without statutory protection.
NPPF states that 'to minimise impacts on biodiversity and geodiversity' planning policies should 'identify and map
components of the local ecological networks.' Furthermore, 'Keepers of Time: A Statement of Policy for England's
Ancient & Native Woodland,' set out the Government's vision that 'Ancient woodlands, veteran trees and other native
woodlands are adequately protected, sustainably managed in a wider landscape context, and are providing a wide
range of social, environmental and economic benefits to society.'
This was confirmed in “A revision of the ancient woodland Standing Advice” issued by Natural England 30 May 2012
The Natural Environment White Paper (June 2011) includes an ambition for a major increase in the area of woodland
in England, better management of existing woodlands and a renewed commitment to conserving and restoring ancient
woodlands.
4 Robinson (1987), Robinson (1988), Reid & Wilson (1995), Wilson & Reid (1995)5
National Archives, Series Reference FT 43. 6Based on statistics taken from the Forestry Commission National Inventory of Woods and Trees (2002).
http://www.nationalarchives.gov.uk
7Department of Communities and Local Government (2012)
8 Office of the Deputy Prime Minister (2005)9
DEFRA and the Forestry Commission (2005)10
Natural England (May 2012) A revision of the ancient woodland Standing Advice
Chilterns Ancient Woodland Survey Report Page 6
4
5
6
7
8
9
10
The woodlands of England have a significant value; primarily as areas of high biodiversity, settings for recreational
activity, components of high quality landscapes and repositories of carbon (National Ecosystem Assessment (2011)
Chapter 8: Woodlands) It says that England now has 1,238,000 ha of woodland, or 9.5% of the country. It states that
many woodland species have declined in number due to lack of management, deer grazing, fragmentation and,
increasingly, climate change. Woodlands possibly deliver the greatest number of ecosystem services including carbon
storage, recreation, timber and a contribution to water regulation.
Semi-natural woodland (ASNW) in the UK
The UK Forestry Standard says that the UK has no truly natural forest, but has about 650 000 hectares of semi-natural
woodland, of which about 326 000 hectares (~1.2% of land area), are identified by the nature conservation agencies as
ancient semi-natural They are especially significant for biodiversity, landscape and cultural heritage, and reflect
centuries of interactions between human activities and the environment. ASNWs have a unique character and they
support a high proportion of rare and threatened species. To be described on the ASNW inventory, there must be
indications that the woodland has continuously existed. The indicative date of 1600AD in England is used, but
evidence depends on mapped records and these are sometimes uncertain.
The Chilterns Conservation Board has a statutory duty to produce a management plan for the Chilterns AONB, as a
nationally protected landscape. The woodlands are one of the special qualities of this landscape. The updating of the
1990 ancient woodland inventory to include woods under 2ha was one of the key actions identified in the 2008-13
AONB Management Plan.
2.5 Historical and
ecological overview
of the Chilterns
The Chilterns AONB is rich
in woodland; in extent,
historical and ecological
diversity. Sites such as
Bradenham Woods, a Site
of Scientific Interest
(SSSI) and Special Area of
Conservation (SAC), are
of international
importance in terms of
their biodiversity.
Many woods in the area are designated as SSSIs, National Nature Reserves (NNRs), Local Nature Reserves (LNRs) or
other local wildlife sites. Furthermore, there are hundreds of small woods which have received relatively little study
or attention.
The woodland types include beech hangers (a wood on the side of a hill), wooded commons, historic and designed
parklands, hornbeam coppice, yew and box woods to name but a few. The basis of this variety that shapes the
character and distribution of woodland in the Chilterns are climate, geology, topography and soils. These factors,
along with the historical management, determine the development and composition of vegetation.
The first sign of woodland clearance comes from the Neolithic period, and was centred on the Icknield Way, an
ancient road, thought to be the oldest in Britain, linking East Anglia and the Salisbury Plain. Earthworks from the Iron
Age, such as Grim's Ditch and hill forts, are still in evidence and often survive best in woods. During this period,
increasingly greater quantities of wood were required for the smelting of ores and this resulted in an increase in
woodland management and the creation of woodbanks to enclose against grazing livestock. The Romans were
responsible for further clearance as they made inroads along the valleys.
Forestry Commission (2011) The UK Forestry Standard The UK governments' approach to sustainable forest management11
12 Chilterns Conservation Board - Chilterns AONB Management Plan 2008-1313
Ratcliffe (1977)
Chilterns Ancient Woodland Survey Report Page 7
11
12
13 The bluebells end at a boundary bank that defines the edge of an ancient woodland, near Tring.
Woodland clearance declined in the 13th century following the Black Death. But the fuel provided by coppicing and
thinning was in high demand. Ports along the River Thames, such as Marlow and Henley, delivered beech, oak and
hornbeam to London. This led to the management and maintenance of existing woodland stocks.
By the 18th century, the demand for wood fuel declined as it was replaced by coal as the preferred fuel source. Many
of the woods of the Chilterns were converted to produce stands of tall, beech trees, which were particularly prized by
the furniture and chair making industry centred in and around High Wycombe.
2.6 Chilterns National Character Areas
The vast majority of the Chilterns Ancient Woodland Survey area and the Chilterns AONB fall within the National
Character Area known as the Chilterns. The Chilterns is largely formed from a ridge of Cretaceous chalk. On the scarp
slope can be found some of the richest and most interesting woodlands. They develop on the nutrient poor, calcareous
rendzina soils and support many rare orchid species.
Most of the ancient woods are to be found on the clay with flint soils which cap the chalk hilltops. Much of the
plateau is overlain by Tertiary clays and sand deposits, which result in acidic habitats and the formation of oak-beech
woodlands on the heavier soils and bluebell carpets. Dry valleys carved during the periglacial period create a varied
topography.
At the base of the Chilterns dip slope, in South Bucks District, the soil has developed from the ancient alluvial sand
and gravel deposits of the River Thames. Here the chalk is overlain by poor acid sands, clays and gravels and is now
heavily wooded
Only a very small portion of the Chilterns Ancient Woodland Survey area corresponds with the Bedfordshire and
Cambridgeshire Claylands, and Upper Thames Clay Vales National Character areas and therefore they have not been
discussed in greater detail.
2.7 Ancient woodland definitions
Woodlands in Britain are routinely grouped into the two categories of 'ancient woodland' and 'recent woodland'
according to their history. This follows the pioneering research on the subject by George Peterken, Oliver Rackham
and others in the 1970s. The distinction is now well established as a useful one and the concept of 'ancient woodland'
is embedded in national forestry and nature conservation policy.
2.7.1 Recent woodland
Secondary or recent woodland (less than 400 years old), is where a wood has either been planted or where trees have
developed naturally through regeneration. Recent woodland can show similarities to ancient woodland depending on
their age, proximity to ancient woods and the diversity of microhabitats within the site. However, generally their
biological diversity is not as great as that of ancient woodland. They are therefore excluded from the inventory.
2.7.2 Ancient woodland
The definition of ancient woodland by English Nature (now part of Natural England), as included in their guidance
documents for local authorities is shown below:
'Ancient woodland in England is defined as an area that has been wooded continuously since at least 1600 AD. Ancient
woodland is divided into ancient semi-natural woodland and plantations on ancient woodland sites. Both types of
stand are classed as ancient woods.'
Thames Valley Character Area
Chilterns Ancient Woodland Survey Report Page 8
14 For more information on these National Character Areas see the publication section of 15
For example, Peterken (1977), Rackham (2003)16
Bannister (2007)17
Kirby & Goldberg (2006) and A revision of the ancient woodland Standing Advice issued by Natural England 30 May 2012
http://www.naturalengland.org.uk/
14
15
16
17
The trees and shrubs in ancient woodlands may have been felled or cut for coppice at various times since 1600, but as
long as the area has remained as woodland, i.e. the coppice stools have regrown or the stand has been replanted soon
after felling, then it remains ancient woodland. Because it may have been cut over many times in the past, ancient
woodland does not necessarily contain old trees.
The date used to define ancient woodland for England, 1600 AD, was chosen by Peterken, because it reflected the
point at which good maps started to become more common and was prior to the impetus for new woodland planting
from the publication of Evelyn's influential book 'Sylva.' Other dates could be argued for: 1650 was used by Peterken
and Harding to distinguish post-medieval woods in Rockingham Forest, as a detailed map for that area was produced
at that time, while Rackham uses 1700. In practice 1600 has been adopted for policy and practical purposes in
England.
Ancient woodland is divided into ancient semi-natural woodland and plantations on ancient woodland sites.
Ancient semi-natural stands are composed predominantly of trees and shrubs native to the site that do not obviously
originate from planting. They include stands that may have been managed by coppicing or pollarding in the past, as
well as those where the tree and shrub layer has grown up by natural regeneration.
Plantations on ancient woodland sites (also known as ancient replanted woodland)
are areas of ancient woodland where the original native tree cover has been felled and replaced by planted stock
most commonly of a species not native to the site, for example conifers such as Norway spruce (Picea abies) or
Corsican pine (Pinus nigra var. maritima), but also broadleaves such as sycamore (Acer pseudoplatanus).
The division between semi-natural stands and plantations is not always easy to define, because there are
intermediates, for example small clearings within woods, old plantations of native species, semi-natural structured
stands of introduced species, planted conifer stands that now contain a proportion of self-sown native broadleaves, or
semi-natural tree layers with no native understory or improved ground floras. Therefore, a judgement may be
necessary as to the balance between the planted/introduced elements versus the native/naturally regenerating
elements.
Areas with continuous woodland cover.
Areas managed or periodically cleared for timber or underwood production.
Areas regenerating following woodland management.
Open grazed areas within the woodland (at least 20% canopy over 80% of the site).
Temporary clearings that may have been created within the woodland complex but which have regenerated,
or are regenerating, back to woodland.
2.7.3 Ancient wood pasture
Wood pasture describes woods derived from ancient pasture woodland managed for both trees and livestock or deer.
These woodlands are usually associated with ancient deer parks, Royal Forests or wooded common land. They
frequently occur in a mosaic with other habitats and the boundaries are often poorly defined. Wood pasture was
previously included on the original Inventories as ASNW where recognisable stands of trees evident on old maps remain
unchanged. Parkland sites with wide-spaced trees were omitted. However, the map sources used for the original
Inventories were often inconsistent with only a partial coverage.
Ancient semi-natural woodland (ASNW)
Plantations on ancient woodland sites (PAWS)
Chilterns Ancient Woodland Survey Report Page 9
19
Evelyn (1664)20
Peterken & Harding (1974)21
Rackham (2003)22
Harding & Rose (1986)
18Peterken (1977)
23Spencer & Kirby (1992)
18
19
20
21
22
For the purposes of this survey, the following definitions have also been used to help define areas of ancient woodland:
23
The revision of the Ancient Woodland Inventory in Wealden District (East Sussex) highlighted the problems of
classifying woodland sites in historically more open areas such as the Ashdown Forest and other former commons and
hunting forests. Some of these woodlands had been classified on the original inventory as ancient whilst others had
been omitted. However, re-examination of the historic map and other evidence does not always appear to support
these decisions. Study of the historical extent of these sites can reveal a complex management history with a mixed
pattern of woodland, grazing and shifting agricultural use. Similarly, Berkhamsted Frith part of the National Trust's
Ashridge Estate, has been difficult to classify. Split between several different parishes, this large area of land
contained a mixture of enclosed coppices, wood pasture and common land and presents a complex history.
Within the revision of the Ancient Woodland Inventory for the Chilterns, some sites were classed as a subcategory of
ancient woodland, wood pasture, whilst keeping the ASNW/ PAWS split.
The following criteria were used to define the subcategory:
Wooded today (at least 20% tree cover over 80% of the site).
Woodland shown on the Ordnance Survey First Edition County Series maps (produced for the Chilterns between
1865-85), with the cartography indicating at least 20% tree cover over 80% of the site.
Former enclosed Forest or common land as identified on the Ordnance Survey Drawings (1804-1815).
(See section 3.2.2 for a fuller description of these map sources).
Pasture woodland is defined as a semi-natural habitat that has retained a wooded nature throughout recent history as
documented by the above map sources. The revised inventory includes these areas and they can be readily extracted
from the dataset.
25
Greenaway et al (2004)
24Westaway (2005)
Chilterns Ancient Woodland Survey Report Page 10
24
25
Shady mature beech wood, with banks, South Oxfordshire.
Chilterns Ancient Woodland Survey Report Page 11
3. Methodology and Sources
he guiding principles followed in the Chilterns Ancient Woodland Survey are those used to compile the
original inventory. The work, combining desk-based analysis, field surveys and archive research, utilised Tmethods piloted in the Wealden district of East Sussex inventory revision and developed in subsequent
revisions to the inventories in Kent, East and West Sussex and Surrey.
The revision represents a complete and systematic rebuilding of the Ancient Woodland Inventory dataset for the
Chilterns. It draws heavily on the established intelligence contained in the original inventory (and its subsequent
amendments) but also reappraises this information in the light of a range of, often hitherto unavailable, evidence
sources.
The availability of high precision digital mapping tools and large-scale historical map sources in digital format meant
that, for the first time, small ancient woods (less than two hectares in size) could routinely be included in the
inventory revision for the Chilterns.
Whilst the methodology aims to be systematic and robust, because of the scope of this research, the methods are, by
necessity, relatively simple and quick, with more detailed historical and field surveys confined to a priority set of
sites. The inventory is therefore inclusive, meaning that the default for borderline sites, or those for which data is
lacking, is that they are retained on the inventory, thus ensuring they can be considered in future surveys.
3.1 Software
The mapping of woodland in this project and much of the map research underpinning the final dataset was done in a
Geographic Information System (GIS). This allows the relatively rapid comparison and combination of a variety of
spatial data sources. Importantly, it also allows the editing of the dataset to a standard of spatial precision which
would have been impossible to achieve within the space of time available without such technology. The GIS software
used was ESRI ArcMap® 9.3.1. The resulting GIS database can be linked to external databases which hold more
detailed site survey and archive data.
Data accrued from on-the-ground woodland surveys was held in a Recorder 6 database by the Thames Valley
Environmental Record Centre, from which a report for each site outlining the main survey findings could be generated.
Recorder 6 is specifically designed for biological recording. It allows species observations and habitat data to be
captured in an electronic format that is compatible with the National Biodiversity Network. This enables the methods
of data storage to be easily reproduced and also allows easy exchange of data.
3.2 Inventory revision
The approach to mapping ancient woodland is deductive. A relatively large set of woods is first captured from highly
accurate and reliable but relatively recent map evidence. This 'indicative ancient woodland dataset' is then
sequentially refined and filtered by interpretation of further sources of historical, ecological and archaeological
evidence. The procedure for revising the Ancient Woodland Inventory has three interlinked elements:
1. Desk-based mapping – capture of the dataset
2. Research on historical maps and documents – refinement of the dataset
3. Field survey work – refinement of the dataset
27
26
28
29
30
26 Westaway (2005)27
Westaway, et al (2007a); Westaway et al (2007b); Sansum et al (2009); Hume et al (2010); Davies et al (2011)28
Spencer & Kirby (1992)29
ESRI Inc (2009)30
JNCC (2007)
3.2.1 Desk-based mapping - capture of the dataset
The initial stage identified, with a high degree of spatial accuracy, that subset of the present-day woodland resource
which could clearly be demonstrated to be long-established woodland. Woods of late 19th century and 20th century
origin were thereby eliminated from the search.
This capture of potentially ancient woodland sites employed two key mapping elements:
The current Ordnance Survey MasterMap® Topographic Layer displayed over recent high-resolution aerial
photographs covering the Chilterns (supplied May 2010).
Ordnance Survey First Edition County Series 25 inch to 1 mile map: Bedfordshire 1876-82, Buckinghamshire
1867-81, Hertfordshire 1865-85 and Oxfordshire 1872-80 (also referred to in this report as Epoch 1 - a term
used by historians).
The first of these is the modern vector dataset from which other current OS map products are derived. It is the
'industry standard' baseline for the creation of maps and geographic datasets in the UK. The second is the earliest very
large scale mapping to give a complete and systematic national coverage. It is sufficiently accurate that, following its
recent digitization and georectification by a partnership between the Ordnance Survey and Landmark Solutions, it can
be routinely used in a GIS environment alongside modern datasets (see Figure 1). Both maps were surveyed at
comparable scales of 1:2500 or greater and are arguably the most detailed and precise maps ever produced as a
national coverage. As such, the comparison and integration of these sources provides an ideal method for the accurate
capture of historic woodland boundaries – including small woods – as a first stage in revising the Ancient Woodland
Inventory.
Working systematically through a grid of 500m x 500m cells covering the survey area, all MasterMap® polygons visibly
containing woodland on the aerial photograph were compared with the Epoch 1 maps in order to identify those areas
of woodland common to both. Each woodland MasterMap® polygon (or part of) was coded according to its presence or
absence on the Epoch 1 map. This approach is flexible. If available for a given region, more layers of map evidence
can be worked into the procedure.
31
31 Dates from the British Library: http://www.bl.uk/reshelp/findhelprestype/maps/index.html
Chilterns Ancient Woodland Survey Report Page 12
Bluebell wood in Wycombe District.
For the purposes of this mapping, woodland was defined as land with at least 20% canopy over 80% of the site. Any
continuous blocks of woodland were regarded as discrete sites with historical or ownership boundaries disregarded;
ponds and other open areas within the wood less than one hectare in size were included. Man-made linear features
passing through wooded areas such as surfaced roads have generally been edited out of the polygon whereas
unsurfaced tracks and natural and semi-natural linear features such as watercourses less than 10m wide have been
included as part of the woodland polygon.
Woods which were depicted on the Epoch 1 map but are no longer visible (lost woods) and woods which appear in
MasterMap® and recent photographs but which are not shown on the Epoch 1 map (woods apparently of recent origin)
are systematically identified in this way. The absence of a wood on the highly accurate Epoch 1 maps was generally
considered sufficient evidence to eliminate it from the search for ancient woodland where it only appeared on later
maps or aerial photographs. An important tenet of the methodological approach adopted was that no other
elimination of woods depicted on the Epoch 1 maps was carried out based on judgement or interpretation of the map
at this capture stage. Many woods shown on these maps have a modern, planted or planned appearance but may
prove upon further examination (3.2.2) to have deeper historical origins. Premature removal of sites from the dataset
would prevent any such examination being carried out.
The resulting dataset comprises a map of a particular subset of the woodland resource – the surviving portion of the
woods which appeared on the Victorian Epoch 1 maps – in which woodland boundaries are both historically accurate
and conform wherever possible to OS MasterMap®. Theoretically speaking, the woods included in this dataset contain
all the ancient woods in the area of interest in addition to some woods with origins in the 17th, 18th & 19th centuries
(see ancient woodland definitions - 2.2).
This indicative ancient woodland dataset was then incorporated and compared with the digital version of the 2003
Forestry Commission Ancient Woodland Inventory within GIS. This allowed:
Currently designated ancient woodland sites to be attributed to the corresponding polygons in the new
Ordnance Survey MasterMap® derived dataset subject to further confirmation of status.
Identification and enumeration of the sites identified by the process described above as potentially new
(hitherto unrecorded) ancient woodland sites.
Potential discrepancies between the two datasets to be marked for further investigation (for example where
a piece of woodland recorded on the original inventory does not appear to be shown as woodland on either
the Epoch 1 map or on current aerial photographs).
A general principle has been to retain areas of previously designated ancient woodland in the revised inventory where
the evidence of Epoch 1 supports this (but with boundaries now mapped to MasterMap® standard) and place the thrust
of the research effort on assigning the correct status to the additional potential sites identified by the process
described above. If incontrovertible evidence subsequently emerged in further archival and field research (see below)
against an original ancient woodland designation then appropriate boundary revisions to those areas have been made.
3.2.2 Refining the dataset using historical maps
The capture stage described above yielded an indicative ancient woodland dataset comprising MasterMap® derived
polygons. This consisted of:
previously designated ancient woodland in the project area
potentially additional ancient woodland (wooded areas in existence since at least the 1870s).
previously designated ancient woodlands, which were not shown as wooded in the 1870s.
The next stage in the methodology consisted of checking this indicative dataset against the evidence of a range of
historical map sources held both in traditional archives and in digital form which could be analysed in a GIS as an
extension of the desk-based mapping stage (above). Not all the evidence sources consulted can be detailed in this
report but the key ones are described (next page) in reverse chronological order.
Chilterns Ancient Woodland Survey Report Page 13
32 Dates from the British Library: http://www.bl.uk/reshelp/findhelprestype/maps/index.html
33
Ellesborough Tithe Map (1847). Reproduced with acknowledgement to Buckinghamshire Record Office34
http://www.bl.uk/onlinegallery/onlineex/ordsurvdraw/
The Ordnance Survey First Edition
County Series 25 inch to 1 mile maps
(produced for the Chilterns 1865-85)
The tithe maps for the Chilterns
(produced from 1837-1872)
These are the digital geo-referenced Epoch 1
images used in the capture process described
above (3.2.1). These maps are superbly
detailed and contain a wealth of information
about the woods under review beyond that of
simple presence or absence (Figure 1). The
engravers used symbols to depict different
types of woodland and scrub vegetation
including, simple coppice, coppice-with-
standards, high forest, plantations - mixed and
coniferous, osiers, pasture woodland,
parkland, etc. It is also possible to discern
from these maps which woods were enclosed
and which were not, as well as to see features
within woods such as buildings and
compartments. In fact, the nuances in the
vegetation and the varying character within
and among woods shown in these maps far
surpasses that of modern maps and reflects
the importance of woods and woodland
produce to the rural and wider economy at the
time of their production.
From the perspective of this research –
attempting to identify woods which have been
in existence since at least 1600 AD – the main
disadvantage of Epoch 1 maps is their
relatively recent date. Because of the high
level of accuracy of this source, absence of a
wood on these maps is considered highly
significant. On the other hand, whilst more
recent woods can sometimes be identified as
regularly shaped enclosures or having map
symbols that indicate a previous non-woodland
use or recent planting, the map does not, of
itself, necessarily give grounds for elimination
of such sites.
Tithe Maps were produced under the direction
of a parliamentary commission following the
Tithe Commutation Act of 1836 when tithes in
kind to the parish were replaced by payments
in rental value. For this Act to be workable, a
prerequisite was a consensus on ownership
boundaries and the extents of properties.
32Figure 1. Example of the Ordnance Survey First Edition County Series 25 inch to 1 mile map for Buckinghamshire (1867-81) showing the woods to the north-east of Princes Risborough
Figure 2. Example of a Tithe Map (1847). Drawn at a scale of 8 chains to 1 inch. This figure shows the same area as Figure 1. Land parcels are inscribed with unique numbers, which relate to a book of apportionments listing the owner, extent, state of cultivation and payment.
Figure 3. Example of the Ordnance Survey Drawing for High Wycombe (produced in the field at 2 inches to 1 mile in 1812). This employs a more generalized set of symbols to indicate trees but the sophistication of the surveying is clear with attention to the depiction of relief through shading and the inclusion of small wooded enclosures
Chilterns Ancient Woodland Survey Report Page 14
33
34
Furthermore, the land use of every parcel of land needed to be recorded as this determined the charges due.
These maps provide an invaluable record of the land-use and economy of mid 19th century England at the local level
in the way that the Domesday Book does for the 11th century but with the important advantage of spatial precision.
Maps were usually created on a parish by parish basis. The tithe maps show compartments of land together with a
code, which is indexed and listed in a bound apportionment volume detailing the owner(s) and/or occupier(s), the
name of each parcel of land, a description of its 'state of cultivation' and the associated rent charge calculation. The
maps vary in quality and accuracy from parish to parish. The original intention of the commission was to produce all
the maps to a uniformly high standard but the cost implications of this meant that there was much local variability in
the results achieved and not all of the maps were ultimately given the commissioners' seal. Those which did became
known as 'first class' maps and the rest as 'second class'.
The majority of the maps were created between the mid 1830s to the late 1840s, with some maps created as late as
the 1850s. Further information relating to the tithe maps and gaps in coverage can be found in Kain et al (1995).
Neither the tithe maps, nor the apportionment data were available in digital format. Research on the tithes of
Bedfordshire was conducted using the resources at the National Archives. Very few of the maps in this county were
considered 'first class' and the enclosure maps were likely used as a basis for many of the tithe maps.
The maps relating to the parishes of Buckinghamshire were photographed by Icam Archive Systems Ltd (see Figure 2).
These images were then georectified so they could be compared to other mapping sources using a GIS.
Apportionment data was not available electronically. Therefore, the microfiche at the National Archives were
consulted to provide the apportionment data.
Neither the tithe maps, nor the apportionment data were available in digital format. As with the tithe maps for
Bedfordshire, research was therefore conducted using the resources at the National Archives.
A large proportion of the tithe maps for South Oxfordshire had already been examined and compared to the
apportionment data by Mary Webb, who carried out research on woodland history and management using the tithe
resource for her doctorate thesis. She generously provided her data for this study. The information collated by Webb
was stored in a GIS format and therefore could be easily compared to the indicative layer. For those areas not covered
by Webb's dataset, further research was conducted at the National Archives.
The whole of the indicative ancient woodland dataset, for which there was tithe coverage, was compared to the tithe
maps and apportionments. This provided a second filter to the potential revisions as well as further verification and
evidence to support ancient woodland status.
Comparisons to the tithes could be made for 88% of the area. The remainder fell in areas where there was no tithe
coverage, parts of the map in question were unreadable, missing or damaged or the corresponding number in the
apportionment volume was missing or illegible.
These maps possess certain advantages to the Epoch 1 maps – often a greater level of accuracy and high information
content. However, they lack the antiquity needed to demonstrate that a wood is truly ancient. The tithe maps were
largely produced only a few decades before Epoch 1. Nonetheless, they remain a useful evidence source. The tithe
Bedfordshire (1837-1872)
Buckinghamshire (1838-1859)
Hertfordshire (1837-1851)
Oxfordshire (1837-1858)
35
35 Dates from the British Library: http://www.bl.uk/reshelp/findhelprestype/maps/index.html
36Kain et al (1995)
37 Webb (2010)
36
37
Chilterns Ancient Woodland Survey Report Page 15
maps come at an opportune moment in the history of the Chilterns, being produced at the beginning of the Victorian
period during which woodland produce would reach unprecedented heights in its economic value (prior to a decline of
equal proportions at the end of the 19th century). The first half of Queen Victoria's reign was a time of considerable
change for wood resources both in the style and efficiency of management and the proportion of the land given over to
managed woodland.
Examination of the Epoch 1 and MasterMap® derived polygons in the light of tithe map evidence often resulted in
further edits to the polygons being made, for example where part of a wood was shown to have been a field or
plantation in the 1830s. Following a complete check of the polygons from the capture stage, part of the indicative
layer was recorded as having a non-woodland land-use – generally pasture, arable or meadow with a further segment
shown as parkland or commons. About three quarters of the area was recorded as partially or wholly wooded.
Analysis of the tithe layer, in collaboration with other sources, provided a means to eliminate secondary woodland and
make many additional alterations. The Tithe Maps represent a very valuable tool for refining the inventory.
The Ordnance Survey Drawings and drafts (see Figure 3 for an example) are the manuscript maps upon which the first
fully triangulated large scale published maps of England were based. The published maps, referred to as the 'Old
Series,' were published in 1813. This endeavour was a military response by the English government to the Napoleonic
threat of invasion from across the English Channel. It was undertaken by the Board of Ordnance (a body something akin
to the modern Ministry of Defence) from which the Ordnance Survey takes its name.
The most detailed drawings were made at a scale of six inches to the mile in areas of military importance. Particular
attention was paid to rivers, roads, woods that could provide cover or obstruction and the contours of hills. In the
Chilterns, the maps were drawn at a smaller scale - two inches to the mile.
The data from these drawings was then reduced and standardised in order to produce the published 'Old Series' maps.
These maps were drawn at a scale of one inch to the mile. The printed maps therefore had an attendant loss of
information and simplification in the depiction of features, for instance, the straightening of woodland boundaries, the
truncation of linear woodland shapes and the removal of smaller woods.
The original drawings are held by the British Library, and geo-referenced scans of these data were used to supply
coverage of the Chilterns. The images were examined along with the tithe and Epoch 1 data using GIS software. Most
of the relevant information is contained on nine overlapping sheets of varying size. Where maps overlap, woods may
be served by two or more drawings whilst some small areas have no surviving coverage. Individual sheets were often
produced by different surveyors and map styles and dates vary accordingly. The level of accuracy also varies greatly,
with the finest sheets depicting, very precisely, woods as small as an acre (or 0.4 ha) in size but with some sheets
coarse and distorted with little information on small woods.
Absence of a wood from these maps cannot be taken as proof of woodland not existing at this time. The experience of
the research in the Chilterns and elsewhere seems to suggest that while enclosed woods containing significant timber
would generally be accurately depicted, simple coppices (without standards), brushwood and shaws (thin strips of
woodland) are often omitted. Similarly, where steep ground is occupied by woodland or scrub, such as the hangers, the
surveyors have often placed priority on conveying the physical relief of the land above depiction of the vegetation
cover, obscuring with dense shading other features.
The suggestion has been made that woods which had recently been cut were simply overlooked by the surveyors or
that they mistook recent woodland harvesting for conversion to agriculture (an error which sometimes occurs in
modern map making). Large woods managed by coppicing would tend to be divided into a series of compartments
harvested on a cyclic rotation. Such woods would perpetually contain some conspicuous growth and be visible as
Ordnance Survey Drawings, 2 inches to 1 mile (produced for the Chilterns 1804-1815), prepared for the First
Edition Ordnance Survey maps
38 Dates sourced from the British Library website: http://www.bl.uk/onlinegallery/onlineex/ordsurvdraw/
39
Hodson and Campbell (1989)
38
39
Chilterns Ancient Woodland Survey Report Page 16
woodland. Small woods however, were sometimes harvested in their entirety, with a dispersed group of copses across a
farm or larger estate each acting as a felling compartment within the coppice rotation. At the time of the first
Ordnance Survey most, if not all, woods would have been actively managed. At any one time then, a relatively large
proportion of small woods may have been at a low and inconspicuous state of growth.
We should not expect to see every small wood depicted on these maps. However, where woodland is recorded these
maps are considered to be reliable and give a strong indication of possible ancient woodland status when this is
supported by the context of the site and the evidence from other sources. Following the approach of the original AWI,
which utilised the smaller scale printed version of this source (see below), a presumption in favour of retaining those
woods shown on these maps (as provisionally ancient woodland sites) has been made.
As with the tithe maps, the indicative ancient woodland dataset was systematically cross-referenced with the
Ordnance Survey Drawings. Nearly half of polygons were shown wholly or partially wooded. In terms of total area, a
much larger proportion, was shown as wholly or partially wooded. Many sites were not depicted as wooded at the time
the maps were drawn. But in terms of area about a tenth of the indicative layer showed no sign of being wooded. This
illustrates the skew towards the depiction of larger woodlands in the drawings. The remainder of sites could not be
analysed due to map damage or lack of coverage.
Thomas Jefferys produced a series of early, large-scale maps for various counties including Bedfordshire (1765),
Buckinghamshire (1770), and Oxfordshire (1767). Similarly, Andrew Bryant also produced a series of large-scale maps,
at a later date than Jefferys' maps: Buckinghamshire (1825), Hertfordshire (1820-21) and Oxfordshire (1824). Jeffrey's
and Bryant's maps were generally produced at a lower scale than the aforementioned maps but were consulted on an
ad-hoc basis and proved useful for larger sites or sites where evidence was unclear or contradictory.
3.2.3 Other evidence sources
This revision of the Ancient Woodland Inventory was primarily a mapping exercise supported by research on historical
maps and field survey (see below), and evidence from these sources was given the greatest weight. However, there are
important additional factors which are brought into interpretations of woodland status during the decision making
process. These include:
The attraction of historic place names is the link they speak of to features in a past landscape for which we have no
description. Unfortunately there can be disagreement over the true meaning of a name, with some assigning quite
different topographic associations to the same term. They can however, with caution, be used as a guide to help
reconstruct the landscape. For example 'wood', 'copse' and 'coppice' usually indicate woodland features, whereas 'leah'
or 'ley' may refer to open ground or a clearing. 'Hyrst' or 'hurst' suggests a wood or a grove, especially one on a hill.
'Holt' indicates a small wood or plantation, often dominated by a single tree species and 'frith' may refer to a forest or
overgrown scrubland at the edge of a forest. The disadvantage is that many topographic place names probably relate
to features which were atypical, and therefore distinctive, rather than describing the general situation. Hence, when
the term 'hurst', originally applied to a small and distinctive hilltop grove, is later transferred to the general area of
the hill, it does not necessarily support ancient woodland status for sites in the vicinity.
Names can also help to identify secondary woodlands. 'The plantation' for example, may indicate more recently
planted woodland particularly where the site is associated with a large house and/or on cultivable land. The word
'pightle' suggests a small, enclosed field often left over after the fencing off of larger, adjacent fields. However, a
large degree of caution should be exercised because names change over time and 'The Plantation' might well occupy
the site of a pre-existing wood.
Jefferys and Bryant maps
Place names
40
40
Robinson (1987), Robinson (1988), Reid & Wilson (1995), Wilson & Reid (1995)
41
ibid., and Rackham (2003)
41
Chilterns Ancient Woodland Survey Report Page 17
Woodland shape and situation in the landscape
Wood banks
Ancient woodland indicator species
Larger ancient woodland sites often survive on parish boundaries or steep inaccessible topography such as the steeper
chalk slopes. The boundaries of intact older woodlands are rarely straight and often follow natural features and
topography. Surviving fragments of historically larger woods, however, often do have straight margins where their
modern boundaries have been chased back to the limits of viable cultivation by successive agricultural improvements.
This process, known as assarting, or clearance for agriculture, was common from the medieval period onwards and
evidence of this can be seen around the edges of many of the larger woodlands and sometimes within the woods
themselves.
3.2.4. Refining the dataset through field survey
On completion of the capture stage (see 3.2.1) and in tandem with historical research (see 3.2.2), a priority set of
woodlands was identified for ground survey. These sites were selected in consultation with the relevant local
authorities and were generally situated in areas of potential growth and development or where other activities
potentially impinged on woodland. Survey site selection was further informed by the emerging historical evidence for
woodland status and sites were prioritised where this evidence was weak or ambiguous.
A further aim was to survey a representative selection of sites over the entire survey area. The field surveys were
carried out from late July to September in 2010, April to October in 2011 and late March and April 2012.
The survey aim was to make a quick assessment of each site recording the key information needed to aid in the
identification of ancient woodland. The methodology was broadly in keeping with the 'walk-about' survey
recommended by the Nature Conservancy Council for the original inventory work. Where possible, site boundaries
were walked and the interior of the wood was traversed. Potential sources of variation were investigated. Emphasis
was placed on recording the following:
A list of vascular plant species.
Living evidence relating to the past management of a wood, for example, coppice structure, veteran trees or
pollards.
Archaeological evidence relating to the past management of the site such as saw pits, charcoal hearths, old
banks, mineral diggings, etc.
Physical features indicating a previous agricultural land use, such as ridge and furrow plough markings and
lynchets.
Historical boundary features, such as wood banks, stubbed trees or outgrown laid hedges, delineating the
wood.
Current uses or factors causing disturbance or damage to the wood.
Structural and habitat diversity, presence of dead wood and the presence of streams and ponds following
natural courses and depressions.
These features can all provide evidence of past land use and so help determine ancient woodland status. For example:
Distinct wood banks are characteristic indicator features of lowland ancient woodlands. A wood bank consists of an
earth bank, often with an associated ditch, constructed at the boundary of a woodland or bordering internal
compartments. These banks were constructed to keep out both grazing animals and human intruders and to demark
ownership. They would in most cases have been topped by a hedge or fence.
The presence of these vascular plant indicator species can aid in the identification of ancient woodland, and ancient
woodland sites tend to be richer in terms of their species composition. However, care is required as other factors
Chilterns Ancient Woodland Survey Report Page 18
42
43
44
42 Kirby (1988)
43
Rackham (2003)44
Hornby & Rose (1986), Rose (1999) and Rackham (2006)
affect the presence and abundance of these species. These factors include the area of the wood, the time of year of
the survey, the diversity of habitats within the wood, soil type, and the position of the woodland relative to other
wooded areas. For example, some species, such as early dog-violet (Viola reichenbachiana), can not be identified
later in the season, once they have flowered. Current uses, including disturbance, damage or invasive species may
also influence species diversity and the time spent surveying will affect the number and abundance of species
recorded as well as the likelihood of other features being recorded.
Lists of vascular plant species strongly associated with ancient woodland sites known as 'indicators' have been
compiled for different geographical areas of the British Isles. These lists are based on the occurrence of species in
known ancient woodland sites. The 'South' list was used predominantly for this revision and is shown in Appendix 1.
3.2.5 Semi-natural or replanted ancient woodland status
The Forestry Commission's National Inventory of Woodland and Trees (NIWT) was used as the core dataset to redefine
the boundaries of PAWS and ASNW. This dataset classifies woodlands into categories such as broadleaved, coniferous,
mixed, and coppice. For ancient woodland less than two hectares, a judgement on ASNW or ancient replanted status
was based on an interpretation of aerial photographs. Boundaries were then further refined using aerial photography,
the existing AWI boundaries, Ordnance Survey MasterMap® boundaries and the results from field survey work.
The reliance on aerial photography for identifying PAWS means that there were inevitably some inaccuracies in the
classification, for example, in distinguishing between mature broadleaved plantations and stands of semi-natural
woodland. Ancient Semi-Natural Woodland was used as the default classification where it was not possible to
determine the woodland type.
It should also be noted that there has been a considerable amount of PAWS restoration since the NIWT was published in
2002, not least as a result of the Defra/ Forestry Commission 'Keepers of Time' policy in 2005. This encouraged the re-
establishment of broadleaved tree cover on ancient woodland sites, particularly on the Forestry Commission estate. It
has not been possible, within the resource constraints of this survey, to identify all areas of PAWS restoration that have
occurred since the last inventories were published. The area of PAWS shown in the results of this survey may therefore
be an overestimate of the actual remaining resource.
3.2.6 Minimum size of a wood to be included in the inventory revision
0.25 ha was generally the lowest size of woodland polygon considered for inclusion in the revised inventory, making it
directly comparable with the Forestry Commission's NIWT. However, each wood is considered separately and factors
such as the location and historical extent of the woodland mean that some woods under 0.25 ha may be included. This
allows these woods to be considered when looking at the whole habitat matrix. Querying the GIS dataset's attribute
table will allow a size restriction to be imposed, if required.
3.2.7 Ancient woodland status
It is recognised that a largely desk-based exercise will always be flawed and ideally ground survey work would be
undertaken in every wood. Due to time and financial constraints it was only possible to ground survey a proportion of
the woodlands, so the decisions for the majority of the sites were based on map and archive research data. Whilst
every effort has been made to make this revision as accurate as possible, the inventory is still regarded as provisional,
as new evidence may come to light in the future that challenges the ancient woodland status of a site.
Such information, when provided to Natural England, will be considered and a decision taken on whether a site should
be removed or added to the inventory. Nevertheless, although the revised inventory is described as provisional, the
survey's thorough methodology, with the use of both desk-based and field work, and the use of digital mapping
technology, mean that the Chilterns Ancient Woodland Survey represents the most complete and detailed update of
the inventory yet undertaken.
45
46
48
45 Kirby & Goldberg (2006)46
Smith (2000)47
ibid48
Defra and the Forestry Commission (2005).
Chilterns Ancient Woodland Survey Report Page 19
he results of the Ancient Woodland Inventory revision are primarily stored in digital format. The revised
map boundaries are shown at the end of this report. Survey data will be held by Natural England, Chilterns TConservation Board and the relevant county Biodiversity Record Centres.
The total amount of all woodland (ancient and recent) within the Chilterns AONB area, as recorded in the Forestry
Commission's National Inventory of Woodland and Trees (2000), is 17,588 ha plus 689 ha of small woods under 2ha
identified in our 2007 report. Making total woodland area in AONB 18,277 hectares or 21.8% and as such is well above
the England average of 8.4%.
4.1 Extent of ancient woodland
A sizeable woodland area was removed from the FC
digitized AWI. This loss was due to a combination of
inaccuracies in the initial mapping process,
misattribution of some woods or parts of woods in
the original inventory, and conversion of ancient
woodland to other land-uses since the original
inventory was compiled. These areas were removed
following re-alignment of boundaries with OS
MasterMap® and Epoch 1 maps and re-examination
of the historic map evidence.
The additions to the area of ancient woodland were
greater in aggregate than the areas removed. In
Table 1, comparisons have not been made to the original, 1987-1995 inventories. This is because these inventories
covered whole counties and therefore are not directly comparable with the extent of the Chilterns Ancient Woodland
Survey. More detailed comparisons were made to the FC digitized AWI available in 2003. As it is a digital dataset it can
be analysed to produce a range of woodland statistics not possible with the paper-based 1987-1995 inventories.
Some of these are genuine additions, but many have been formed by the breaking up of larger woods into smaller
units, as a result of the more precise mapping of neighbouring but non-contiguous woodland parcels that use of
MasterMap® has brought to the inventory.
Plantations on Ancient Woodland Sites
In the revised inventory, 64% of the ancient
woodland area is recorded as ancient semi-natural,
with an area of 7116ha (Table 2). However, the area
of replanted ancient woodland, or PAWS, may be an
overestimate, given the difficulty of identifying all
ancient woodland sites which may have been
restored to native broadleaved cover in recent
years.
49 Smith (2000), National Inventory of Woodland & Trees
Table 1: Summary results, areas in hectares -
each District showed an increase in ancient woodland
cover within the AONB following this revision.
Shows area of AONB in each District, new total of
ancient woodland in AONB and extent of increase
in hectares
TotalLand Area
ha
Revised AWI (including
woods <2ha)
ChangeAncient Woods
ha
Chilterns AONB
Central Beds
Dacorum
North Herts
Three Rivers
Aylesbury Vale
Chiltern
South Bucks
Wycombe
South Oxon
83,824
6,329
9,050
2,316
546
4,679
13,972
403
23,157
23,331
11,058
170.0
781.7
57.0
70.0
549.0
1,728.0
133.7
3,734.8
3,839.0
1,231
44.0
154.3
17.0
6.5
129.0
95.7
0.4
323.1
464.0
4. Results
49
Ancient woodland type (hectares) woodland area
Area % of ancient
Table 2: Ancient woodland types in the Chilterns AONB (areas in hectares).
Revised AWI - ASNW 7,116 64
Revised AWI - PAWS 3,943 36
Total: 11,059 100
Chilterns Ancient Woodland Survey Report Page 20
Woodland surveyed (ha)
Number of sites
Aylesbury Vale District
Central Bedsfordshire UA
Chiltern District
Dacorum Borough
North Hertfordshire District
South Bucks District
South Oxfordshire District
Three Rivers District
Wycombe District
Total:
92
43
221
118
7
246
203
10
211
1,142
16
11
99
64
3
100
49
5
87
432
Chilterns Ancient Woodland Survey Report Page 21
4.2 The woodland survey
Field surveys were a central part of the project. They
allowed the investigation of potential additions to the
inventory, confirmation of ancient status for pre-
established sites and the elimination of those with recent
origins. It must be stressed that the woods surveyed do not
constitute an unbiased sample of woodland and therefore
are not necessarily representative of the wider resource.
235 sites were visited in the AONB, which amounted to 705
ha of about 3.8% of the Chilterns AONB total woodland.
434 sites were visited in total covering 1142ha, (see table
5, right), about 53% were accepted as provisional ancient
woodland on the basis of the field survey data interpreted
alongside the other historical information available. 558 ha
were judged to be of recent secondary origin or else too
degraded to be defined as ancient woodland and thus
eliminated from the inventory. A further 142 sites or 164 ha
of woodland were briefly visited but either access was not
possible or the site was no longer wooded or too degraded
to carry out a full survey.
The survey methodology produced a woodland plant list for each site, along with a record of a series of features that
helped decide on the status of a site. These included site damage, management, habitat features, and archaeological
and boundary features. See Appendix 2.
Table 3: shows the breakdown of the revised inventory into ASNW and PAWS by District area within the Chilterns AONB, all areas are in hectares
RevisedASNW
ha
3,943
89.4
291.0
14.0
6.0
298.0
848.6
89.3
1,228.3
1,079.0
TOTAL Revised Ancient Woods
(including woods <2ha)
RevisedPAWS
ha
Chilterns AONB
Central Beds
Dacorum
North Herts
Three Rivers
Aylesbury Vale
Chiltern
South Bucks
Wycombe
South Oxon
Table 4: showing % cover of woodland in the Chilterns AONBShows % of woodland cover for all woods and for ancient woods. Includes previous inventory for woods over 2ha for comparison and situation with smaller woods and revisions
% areaancientbefore
11.72
1.99
6.93
1.73
11.54
8.98
11.68
33.08
14.73
14.74
13.19
2.69
8.64
2.47
12.73
11.74
12.37
33.18
16.13
16.46
% allwoodland
cover
% areaancient
now
Chilterns AONB
Central Beds
Dacorum
North Herts
Three Rivers
Aylesbury Vale
Chiltern
South Bucks
Wycombe
South Oxon
7,116
80.9
490.7
43.0
63.0
251.0
879.4
44.4
2,506.5
2,760.0
11,058
170.0
57.0
70.0
549.0
1,728.0
133.7
3,734.8
3,839.0
781.7
20.97
9.24
17.43
11.83
18.32
22.91
17.51
37.20
23.96
24.96
Table 5: Summary of surveying effort for each local authority (NB - includes areas outside the AONB for Chiltern, Dacorum, South Bucks and Wycombe)
Chilterns Ancient Woodland Survey Report Page 22
In total, 73 out of the 100 vascular plant indicator
species thought to be indicative of ancient
woodland in the 'south' region were recorded at
least once. See Appendix 1 for the list of ancient
woodland indicator species.
4.3 Archaeological and boundary features
Woods are part of our cultural heritage and
contain a wealth of archaeological features. These
are associated not only with the former
management of the woods themselves but also
with preceding historic and prehistoric land-uses.
Woodland archaeology is an under-recorded
resource. The survey did not have the time or
resources to record the features present in great
detail. However, where possible, features were
roughly mapped and measurements estimated.
50 Bannister (2007)
51
Morris
50
Orange tip butterfly resting on Coral-root
(Cardamine bulbifera)
AllWoods>2ha
17,581
585.0
1,577.4
274.0
100.0
1,072.0
2,447.0
149.9
5,547.3
5,823.0
20.97
2.69
8.64
2.47
12.73
11.74
12.37
33.18
16.13
16.46
Total Areaha
%woodland
cover
Chilterns AONB
Central Beds
Dacorum
North Herts
Three Rivers
Aylesbury Vale
Chiltern
South Bucks
Wycombe
South Oxon
83,824
6,329
9,050
2,316
546
4,679
13,972
403
23,157
23,331
Table 6: Gives the full results for Chilterns AONB showing both areas in hectares and % woodland cover. Also shows a breakdown by District for areas within the Chilterns AONB
% areaancientbefore
FC AWIonly woods
>2ha
Revised AWIincl. woods
<2ha
11.72
1.99
6.93
1.73
11.54
8.98
11.68
33.08
14.73
14.74
9,827
126.0
627.4
40.0
63.0
420.0
1,632.3
133.3
3,411.7
3,375.0
1,231
44.0
154.3
17.0
6.5
129.0
95.7
0.4
323.1
464.0
13.19
2.69
8.64
2.47
12.73
11.74
12.37
33.18
16.13
16,46
% areaancient
now
ChangaAncient
Woods ha
51
11,058
170.0
781.7
57.0
70.0
549.0
1,728.0
133.7
3,734.8
3,839.0
Chilterns Ancient Woodland Survey Report Page 23
aps five to eleven at the end of this report show the revised Ancient Woodland Inventory on an Ordnance
Survey 1:50,000 scale base map. Due to the map scale and the volume of small woods added to the Minventory this map should be treated as indicative only. These maps represent a snapshot in time and will not
show any subsequent revisions.
Natural England will incorporate the final dataset for the Chilterns into the national Ancient Woodland Inventory.
These digital boundaries will be available to download online either directly through Natural England's website but
also through www.magic.gov.uk . Any changes to the inventory made on a case-by-case in the future by Natural
England will be incorporated into the national dataset over time.
The data recorded during the field surveys is held by Thames Valley Environmental Records Centre and will be passed
on to the relevant Biological Record Centres for incorporation into their county databases. All data and information
relating to the project will also be held by the Chilterns Conservation Board
This inventory revision provides an important information base for informing local authorities' planning policies, and
will enable planning decisions relating to wooded areas in the Chilterns to be made in the light of a greatly improved
evidence base. The increased number of ancient woodland parcels identified in the Chilterns not only affords these
woodlands a higher degree of protection, but also emphasises the need for a review of the inventory in other well
wooded areas.
These results show that there were many small sites, under 2 ha, which we have been able to include on the revised
inventory. It now provides a more complete picture of the location of ancient woods within a habitat network and will
help to identify areas of opportunity for environmental enhancement. It also has the potential to inform the more
strategic distribution of funding for woodland management programmes, such as the English Woodland Grant Scheme
(EWGS).
5. Outputs
Example of a saw pit
Chilterns Ancient Woodland Survey Report Page 24
he importance of ancient woodland is widely acknowledged. This resource is threatened by development
pressures and lack of appropriate management. It is hoped that the work outlined here will make a useful Tcontribution towards the long-term protection and appropriate management of this irreplaceable resource
An important benefit of the revision to the Ancient Woodland Inventory for the Chilterns is the georectification of the
relevant tithe maps within Buckinghamshire. The tithe maps are now in a format that can be easily compared to
modern maps and will be held by Chilterns Conservation Board and Buckinghamshire County Council. Over 74% of
woodlands in the indicative layer were shown as either wholly or partially wooded. The tithe maps added a further
layer of verification onto the decision making process and helped to build a clearer picture of management history.
This fascinating resource should prove invaluable for future projects seeking to investigate land-use history in
Buckinghamshire.
The boundaries to the original inventory were significantly refined. Some woods were removed from the FC digitized
version of the AWI. The changes to the Ancient Woodland Inventory were due to a combination of three factors; lack of
(or contradictory) historical evidence, improved mapping techniques and focused surveying effort. In some cases,
changes in land use have necessitated revisions to the original inventory.
The surveyors visited 434 sites covering 1,142 hectares of woodland. As well as improving the evidence base for the
revised inventory this provided an opportunity to increase our knowledge and understanding of the Chilterns' current
woodland resource, its ecology, history and management. Not only did the surveys contribute valuable biological data
concerning the distribution and abundance of species
throughout the project area, but it also provided a snapshot of
those woodlands and their archaeology.
The predominantly semi-natural condition of the small ancient
woodland resource coupled with its widespread distribution of
sites has many positive implications for nature conservation.
The accurate mapping of this resource provides important
opportunities for understanding and improving connectivity of
semi-natural habitats and biodiversity at the landscape scale
and can be used to inform and enhance initiatives such as the
Biodiversity Opportunity Areas and Conservation Target Areas.
The standards of mapping used mean that the revised Ancient
Woodland Inventory dataset will be readily synthesised with a
range of other compatible spatial datasets and inventories by
researchers, conservationists, planners and policy makers
addressing the complex landscape scale issues of the 21st
century.
6. Discussion
52
52 English Nature (2002), Defra and the Forestry Commission (2005), Ellis (2004)
Violet helleborine (Epipactis purpurea)
Chilterns Ancient Woodland Survey Report Page 25
Limitations of the survey
The Chilterns Ancient Woodland Survey built on the methods trialled in Wealden and Mid Sussex, and in the subsequent
revisions to East Sussex, Hampshire, Kent, West Sussex and Surrey. These surveys influenced the procedure for
mapping and identifying ancient woodland used in the Chilterns. There will always be limitations with the types of
evidence used in assessing ancient woodland status and these need to be considered by all users of the dataset.
The limitations and inaccuracies associated with early map sources were discussed in the relevant section of
this document.
No decision based on historical map evidence relating to woodland can be completely infallible.
Botanical evidence varies in its value as a guide to the antiquity of a wood.
The use of botanical data is more problematic in heavily disturbed woods and PAWS sites where vascular plant
floras are often poor.
Ancient semi-natural woods managed traditionally as coppice over centuries can become less conspicuously
diverse when the coppice structure becomes derelict and the ground flora enters a prolonged shade phase
with suppression of some of the diagnostic elements of an ancient semi-natural ground flora.
Beech high forest casts a dense shade which limits the ground flora and evergreen shrubs such as holly can
become dominant.
Forestry work, such as thinning, can lead to dramatic changes in the ground flora. Plants such as foxglove or
wood spurge, whose seeds can remain dormant for many years, may flourish in such conditions.
Sudden changes in management or disturbances can bring strong secondary elements to ancient woodland
vegetation locally which can mask the presence of diagnostic specialist species. In large woods such an effect
is more easily identified and understood but in small woods with high ratios of edge to area the effect of
disturbance, where the whole site may be affected, can be to confuse the decision making process
significantly.
Time constraints meant that only a single visit was made to each of the surveyed sites. Species such as
coralroot (Cardamine bulbifera), which is only visible for a few months in late spring, may therefore be under
recorded.
Woodland archaeological features, of considerable diagnostic value in interpreting the history of a site, are
most conspicuous in the winter and early spring, but ground flora recording dictates that the bulk of field
surveying is done in spring or early summer.
Ancient woods are an important habitat for a wide range of species, not just the flowering plants. Other
groups such as mosses, lichens, fungi and insects may require woodland conditions to thrive. However, it was
not within the scope of this project to record such species.
53 Westaway (2005), Westaway, et al (2007a); Westaway et al (2007b); Sansum et al (2009)
53
Chilterns Ancient Woodland Survey Report Page 26
We would like to thank everyone who contributed to this survey and especially those who served on the Steering
Committee.
Victoria Benstead-Hume Project Co-ordinator
Patrick Mckernan Natural England/Forestry Commission
Steve Rodrick Chilterns Conservation Board
Gavin Bird Thames Valley Environmental Records Centre
Emma Goldberg Natural England
Keith Musgrave Chiltern District Council
John Morris Chiltern Woodlands Project
Niki Huijer Wycombe District Council
Mai Neilson Buckinghamshire County Council
Andy McVeigh Buckinghamshire County Council
Laura Wood Dacorum Borough Council
Mary Webb Research
Rachel Sanderson Surveyor
Alison Woods Surveyor
Photograph credits
Photographs contributed by John Morris.
Mapping
The Ordnance Survey map data included within this publication is provided by the Chilterns Conservation Board under
licence from the Ordnance Survey. Persons viewing this mapping should contact Ordnance Survey Copyright for advice
where they wish to license Ordnance Survey map data for their own use.
7. Acknowledgements
Low Scrubs near Wendover
Chilterns Ancient Woodland Survey Report Page 27
Bannister, N. R. (2007). The Cultural Heritage of
Woodlands in the South East. SE AONBs Woodlands
Programme. High Weald AONB, Flimwell.
Buckinghamshire County Council (1991) A Plan for the
Chilterns Woodland Policy
Chilterns Conservation Board - Chilterns AONB
Management Plan 2008-13
Chilterns Conservation Board - Chilterns AONB Pilot
Ancient Woodland Survey 2007
Davies, R., Benstead-Hume, V., Grose, M., Westaway, S.
& McKernan, P. (2011). A Revision of the Ancient
Woodland Inventory for Surrey. Surrey Biodiversity
Information Centre, Surrey.
Defra and the Forestry Commission (2005). Keepers of
time: A statement of policy for England's ancient and
native woodland. DEFRA and the Forestry Commission,
England.
Department of Communities and Local Government
(2012). National Planning Policy Framework. London.
Ellis, J. (2004). Seeing the wood for the trees: a forestry
and woodlands framework for South East England.
Forestry and Woodlands Framework Steering Group,
Alice Holt, Farnham.
English Nature (2002). Position statement:
Environmentally sustainable forestry and woodland
management. English Nature, Peterborough.
ESRI (2009). ArcMap 9.3.1. Environmental Systems
Research Institute, Inc. Redlands, California.
Evelyn, J. (1664). Sylva, or a discourse on forest trees
and the propagation of timber in his majesties
dominions. Modern edition published by Boydell &
Brewer, Woodbridge, Suffolk.
Forestry Commission (2011) The UK Forestry Standard
The UK governments' approach to sustainable forest
management
Harding, P. T. & Rose, F. (1986). Pasture-Woodlands in
lowland Britain. Institute for Terrestrial Ecology,
Huntingdon.
8. References and Bibliography
Hornby, R. J. & Rose, F. (1986). The use of vascular
plants in evaluation of ancient woodlands for nature
conservation in southern England. Internal report.
Nature Conservancy Council.
Hume, V., Grose, M., Sansum, P., Westaway, S. &
McKernan, P. (2010). A Revision of the Ancient Woodland
Inventory for West Sussex. Sussex Biodiversity Record
Centre, Henfield, West Sussex.
JNCC (2007). Recorder 6. Joint Nature Conservancy
Committee, Peterborough.
Kain, R.J.P, Oliver, R.R., Fry, R.E.J. & Wilmot, S.A.H.
(1995). The Tithe Maps of England and Wales: a
cartographic analysis and county-by-county catalogue.
Cambridge University Press. Cambridge.
Kain, R. and Prince, H. (1985). The tithe surveys of
England and Wales. Cambridge University Press,
Cambridge.
Kirby, K. J. (1988). A woodland survey handbook. Report
No 11. NCC, Peterborough.
Kirby, K. & Goldberg, E. (2006). Ancient woodland:
guidance material for local authorities. English Nature,
Peterborough.
Morris, J.K. (2009). The Cultural Heritage of Chiltern
Woods. Chiltern Woodlands Project.
Natural England (May 2012) A revision of the ancient
woodland Standing Advice
Office of the Deputy Prime Minister (2005). Planning
Policy Statement 9: Biodiversity and Geological
Conservation. The Stationery Office, London.
Peterken, G. F. & Harding, P. T. (1974). Recent changes
in the conservation value of woodlands in Rockingham
Forest. Forestry 47: 109-128.
Peterken, G. F. (1977). Habitat conservation priorities
in British and European woodlands. Biological
Conservation 11: 223-236.
Rackham, O. (2003). Ancient Woodland: Its history,
vegetation and uses in England. New Edition.
Castlepoint Press.
Chilterns Ancient Woodland Survey Report Page 28
Rackham, O. (2006). Woodlands. New Naturalist Library.
Collins, London.
Ratcliffe, D. A. (ed.) (1977). A Nature Conservation
Review. Cambridge University Press.
Reid, C.M. & Wilson, C.L. (1995). Buckinghamshire
Inventory of Ancient Woodlands (Provisional). English
Nature, Peterborough.
Robinson, D.P. (1987). Bedfordshire Inventory of Ancient
Woodlands. Nature Conservancy Council, Peterborough.
Robinson, D.P. (1988). Hertfordshire Inventory of
Ancient Woodlands. Nature Conservancy Council,
Peterborough.
Rose, F. (1999). Indicators of Ancient Woodland – the use
of vascular plants in evaluating ancient woodland for
nature conservation. British Wildlife 10(4): 241-251.
Rose, F. & O'Reilly, C. (2006). The Wild Flower Key.
Frederick Warne, London.
Sansum, P., McKernan, P., Westaway, S. & Grose, M.
(2009). A revision of the Ancient Woodland Inventory for
Ashford Borough, Kent. High Weald AONB Unit, Flimwell,
East Sussex.
Smith, S. (2000). The National Inventory of Woodland
and Trees – England. Forestry Commission, Edinburgh.
Spencer, J. & Kirby, K. (1992). An inventory of ancient
woodland for England and Wales. Biological
Conservation 62: 77-93.
Webb, M. (2010). Woodland History and Management in
the Oxfordshire Chilterns: Implications for the future.
Oxford Brooks University, Oxford.
Westaway, S. (2005). Weald Ancient Woodland Survey: A
revision of the Ancient Woodland Inventory for Wealden
District.
Westaway, S., Grose, M., & McKernan, P. (2007a). A
revision of the Ancient Woodland Inventory for Mid
Sussex District, West Sussex. High Weald AONB Unit,
Flimwell, East Sussex.
Westaway, S., Grose, M., & McKernan, P. (2007b). A
revision of the Ancient Woodland Inventory for
Tunbridge Wells Borough, Kent. High Weald AONB Unit,
Flimwell, East Sussex.
Wilson, C. & Reid, C. (1995). Oxfordshire Inventory of
Ancient Woodlands (Provisional) English Nature,
Peterborough.
Pigotts Wood near High Wycombe
Chilterns Ancient Woodland Survey Report Page 29
Ancient woodland vascular plant 'indicator species' in the South
The 100 species in NCC's South East Region that are most strongly associated with ancient woodland and are
typical components of botanically rich ancient woodland communities.
Grasses, sedges, rushes and ferns
Bearded couch
Common polypody
Creeping soft grass
Giant fescue
Great wood rush
Hairy brome
Hairy wood rush
Hard fern
Hard shield fern
Hart's tongue
Lemon scented fern
Narrow buckler fern
Pale sedge
Pendulous sedge
Remote sedge
Scaly male fern
Smooth stalked sedge
Soft shield fern
Southern wood rush
Thin spike wood-sedge
Wood barley
Wood club rush
Wood horsetail
Wood meadow grass
Wood melick
Wood millet
Wood sedge
Wood small reed
Flowering plants
Barren strawberry
Betony
Bilberry
Bird's nest orchid
Bitter vetch
Black bryony
Black currant
Bluebell
Broad leaved helleborine
Bush vetch
Climbing corydalis
Columbine
Common cow wheat
Daffodil
Early dog violet
Early purple orchid
Goldenrod
Goldilocks buttercup
Greater butterfly orchid
Green hellebore
Herb Paris
Large bitter cress
Lily of the valley
Marsh violet
Meadow saffron
Moschatel
Narrow leaved everlasting pea
Narrow lipped helleborine
Narrow-leaved lungwort
Nettle leaved bellflower
Opposite leaved golden saxifrage
Orpine
Pignut
Primrose
Ramsons
Red currant
Sanicle
Saw-wort
Slender St Johns Wort
Small teasel
Solomon's seal
Spurge laurel
Stinking iris
Sword leaved helleborine
Three nerved sandwort
Toothwort
Tutsan
Violet helleborine
Water avens
Wood anemone
Wood sorrel
Wood speedwell
Wood spurge
Wood vetch
Woodruff
Yellow archangel
Yellow pimpernel
Trees and Shrubs
Alder buckthorn
Aspen
Butcher's broom
Crab apple
Field rose
Guelder rose
Holly
Hornbeam
Maple
Midland hawthorn
Sessile oak
Small leaved lime
Wild cherry
Wild service tree
Wych elm
54 NCC's South region comprised Hampshire, Wiltshire, Buckinghamshire, Berkshire and Oxfordshire.
See Hornby & Rose (1986), Rose (1999) and Rose & O'Reilly (2006)
Appendix 1
54
Feature type
Appendix 2
Woodland survey features record sheet
Damage
Significant presence of invasive species
Rubbish
Gardenization
Other localised damage
Garden Waste
Browsing
Garden planting
Grazing
Heavy recreation
Physical boundary features
Bank without ditch at boundary
Bank & ditch at boundary
Track at boundary
Ditch at boundary
Other feature at boundary (stream, walls, fences, houses etc)
Physical internal features
Pits
Track running through wood
Saw pits
Internal bank
Internal bank & ditch
Built structures
Internal ditch
Mounds
Charcoal hearths
Living features
Other notable trees
Veteran coppice stools
Old outgrown hedges
Boundary stubs
Pollards
Current management activities
None
Felling
Planting in wood
Woodland Structure
High forest
Conifer plantation
Broadleaf plantation
Mixed plantation
Coppice with standards
Coppice
Chilterns Ancient Woodland Survey Report Page 30
Upper Thames Clay Vales
Chilterns AONB
Area of Chilterns Character Area excluded from survey
National Character Areas in survey
Bedfordshire and Cambridgeshire Claylands
Chilterns
Thames Valley
Map 3: The Chilterns Ancient Woodland Survey Area Showing National Character Areas
N
0 5 102.5
Km
Chilterns Ancient Woodland Survey Report Page 31
© Natural England copyright. Contains Ordnance Survey data and database right 2012.
© Ordnance Survey Licence no. 100044050 & 100022021
© Crown copyright
Chilterns Ancient Woodland Survey Report Page 32
Appendix 3
Management issues identified from site survey visits in the wider Chilterns Survey area
Please note the survey was a biased sample of woods selected because of doubts from the mapping evidence that
required the wood to be visited, so these results are not necessarily typical of all woods in the area. They reflect the
total area surveyed including many woods outside the AONB boundary.
Site damage was taken to mean both direct physical damage, such as fly tipping or loss of woodland through garden
extension, to biological factors including invasive species and over-grazing. 68% of the surveyed woodlands showed
some sign of damage, with invasive species (24% of sites), rubbish dumping (23% of sites) and gardenization (14% of
sites) being by far the most frequently encountered.
Grazing
Overgrazing is taken to mean action either through lack of sufficient livestock control or through the action of wildlife
such as rabbit or deer. 5% of the woods were judged to suffer from grazing, browsing or poaching - deer being the
prime cause.
Rubbish dumping
Close to urban centres, woodlands often served as dumping grounds for a variety of rubbish including cars, sofas and
fridges. In total 24% of sites showed some form of dumping varying from casual rubbish to the use of woods as regular
waste disposal sites.
Garden encroachment
Of the sites surveyed, 14% had lost some of their area to the expansion of gardens. In some cases native trees were
retained but the natural woodland vegetation had been lost to be replanted with turf, for example. In other instances
even the trees had been removed and replanted with non-native species. Grass clippings, compost and other garden
waste would often be disposed of in woodlands, thus introducing non-native species and causing localised nutrient
enrichment. This type of activity was recorded in 10% of sites.
Invasive species
24% of the woods surveyed had invasive species recorded on them. This ranged from the almost complete dominance
of the vegetation by rhododendron (Rhododendron ponticum) or cherry laurel (Prunus laurocerasus), to localised
patches of Himalayan balsam (Impatiens glandulifera).
Sycamore (Acer pseudoplatanus) was the most frequently recorded non-native species, occurring on 55% of sites.
Cherry laurel (Prunus laurocerasus) and rhododendron were found on 27% and 15% of sites, respectively. Indian balsam
(Impatiens glandulifera) and Japanese knotweed (Fallopia japonica) were found at 2% and 1% of sites, respectively.
Woodland management
Beech high forest dominated the Chilterns with variations reflecting local soil conditions. 67% of sites were recorded
as high forest. In places there has been a clear fell and replant approach, with conifers or mixtures being planted in
the 20th century (16% of sites were recorded as conifer plantation, 9% as broadleaf plantation and 3% as mixed).
Ancient woodland indicator species
434 sites were surveyed for the revision, totalling 1,142 ha, with an average size of 2.64 ha. Of these, 30% had at least
10 ancient woodland indicator species recorded, with 4% of sites having 20 or more. 44% of sites had five or fewer
indicator species recorded, with the average number of indicators per site overall being 7.4 (minimum 0, maximum
34).
Holly (Ilex aquifolium), wild cherry (Prunus avium), Bluebell (Hyacinthoides non-scripta), field maple (Acer
campestre) and hornbeam (Carpinus betulus) were the most frequent indicators, all being present in 42% or more of
the sites. Coral-root (Cardamine bulbifera) is a rare and distinctive species of the Chilterns. Rose (1999) considered it
too rare to be included on the list of regional indicator species. However, surveyors recorded coral-root at nine sites
(or just over 2% of the sites surveyed).
Chilterns Ancient Woodland Survey Report Page 33
Woodland features
By far the most common features recorded were boundary banks (recorded in 32% of sites) and banks with ditches
along site boundaries (recorded in 26% of sites). Older trees, stubs and outgrown hedges were sometimes found
associated with these features. Simple boundary ditches were found along at least part of 4% of the sites surveyed.
Other linear features such as streams and walls were found in 2% of the sites.
Internal banks and banks with ditches were found in 8% and 7% of sites respectively. These features could be indicative
of administrative boundaries, ownership or management areas or may have been associated with sunken tracks.
26% of sites contained chalk or clay extraction pits or unexplained depressions. Archaeological features contribute to
the wealth and diversity of woodland vegetation, and pits, ponds, streams, banks and ditches create variation in
topography and environmental conditions. Ancient land use techniques can provide pockets of diversity in what might
otherwise be species-poor sites.
Ancient wood near Chalfont St Giles
Chilterns Ancient Woodland Survey Report Page 34
Map 4: Comparison of the Ancient Woodland Inventories for the Chilterns
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Chilte
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Chilterns Ancient Woodland Survey Report Page 36
Map 6: The revised inventory for the Chilterns – overview and index sheet
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Map 7: The revised Ancient Woodland Inventory – North West
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Chilterns Ancient Woodland Survey Report Page 37
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Map 8: The revised Ancient Woodland Inventory – Mid West
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Map 9: The revised Ancient Woodland Inventory – South West
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Chilterns Ancient Woodland Survey Report Page 39
Map 10: The revised Ancient Woodland Inventory – North East and outlier
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County
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Map 11: The revised Ancient Woodland Inventory – North
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Chilterns Ancient Woodland Survey Report Page 41
Map 12: The revised Ancient Woodland Inventory – Mid
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Chilterns Ancient Woodland Survey Report Page 43
an Area of Outstanding Natural Beauty
Victoria Benstead-Hume and John Morris
Chilterns Ancient Woodland Survey
May 2010 to June 2012
Report published July 2012
The Chilterns Conservation BoardThe Lodge
90 Station RoadChinnor OX39 4HATel: 01844 355500
www.chilternsaonb.org
ISBN No. 978-1-908277-01-5
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