Ancient Woodland Inventory

This dataset comprises of the boundaries of Ancient Woodland sites in Wales. Each site is categorised as either Ancient Semi Natural Woodland (ASNW), Restored Ancient Woodland Site (RAWS), Plantation on Ancient Woodland Site (PAWS) or Ancient Woodland Site of Unknown Category (AWSU).

Initially all woods greater than 2 ha shown on the Ordnance Survey (OS) 1:25 000 1st Series maps surveyed between 1880 and 1960 were considered. Evidence as to which of these were ancient was provided by presence on the earlier 19th century OS 1st Edition Maps (surveyed 1805 - 1873; scale 1:63 360). The general presumption was that woodland on 1800s maps was ancient, unless there was other evidence that the wood originated between 1600AD and 1800. Supportive indications of ancient status included the wood's name, its situation in the landscape, and the nature of both the surrounding pattern of enclosure and the pattern of boundaries within the wood. Where available, field survey data such as the presence of indicator species, or other historical maps and documents were also used. In mountainous areas such as Wales the first edition Ordnance Survey 1 inch maps were hard to interpret because the heavy hatching used to indicate steep slopes tended to obscure tree symbols. The 2021 update to the ancient woodland inventory includes changes to the 2011 version resulting from the provision of additional evidence presented to NRW through public enquiries. This includes private estate maps, tithe maps, management records and photographs. The evidence has been considered by a panel of NRW experts and the inventory amended if the evidence indicates that a site has had another land use for a significant period, i.e. woodland is absent from the site in two consecutive epochs of OS historic maps, or there has been significant ground disturbance to the site, e.g. quarrying, mining or development. Amendments include removal of sites from the inventory, adjustments to boundaries or changes to the ancient woodland category of sites.

The 2011 version remained static until it was replaced by the 2021 version. The 2021 version is being updated at least annually as new evidence becomes available. An older 2004 version of the dataset also exists - please see metadata for dataset number NRW_DS125363 - Ancient Woodland Inventory for Wales 2004 (AWI2004) https://metadata.naturalresources.wales/geonetwork/srv/api/records/NRW_DS125363?language=eng

Identifier: NRW_DS116442

Alternative Title

Ancient_woodland_inventory 2011.LYR
Ancient Woodland Inventory 2021.lyr
AWI 2011

Metadata Language: English

Lineage: The areas of ancient woodland with non-native trees planted on them, termed Plantations on Ancient Woodland Sites (PAWS), and those areas of ancient semi-natural woodland (ASNW) were identified and delimited by using the latest Ordnance Survey maps and field survey records. The area of each was measured using a dot grid overlay on flat projections of the 1:25 000 1st series map. The results were presented as a series of reports and maps by administrative regions (counties). As new information has been received from surveys and ad hoc informants, the initial county inventories have been revised by adding or deleting sites, or by changing the classification of the growing stock.

The Ancient Woodland Inventory (AWI) identifies woodlands that have had a continuous woodland cover for centuries. Studies show that these woodlands are typically of higher nature conservation value than those that have developed recently. In the 1980s the former Nature Conservancy Council instigated the AWI, which attempted to list all ancient woodlands in Britain. A baseline date of 1600 AD was adopted because reasonable maps were available from this time (in England, at least). 1600 AD however, was an arbitrary date, and there was no clear ecological cut-off.

The AWI was always considered to be provisional and subject to refinement, and never a definitive listing of the ancient, or the 'best' woods. Between 2010 and 2011 Forestry Commission Wales (FCW) and Countryside Council for Wales (CCW) commissioned a revision of the AWI in Wales comparing the existing AWI and National Forest Inventory with the Epoch 1: 1st County Series Ordnance Survey maps in terms of identification of ancient woodland. Epoch 1 County Series maps provide a more reliable and comprehensive baseline than the AWI. Moreover, the Epoch 1 maps incorporate numerous practical advantages over the AWI in terms of their ease of use, accuracy and level of detail.

Additional Information: The maps combined with new methodology have provided a more accurate inventory which has resulted in an additional 33,000 hectares being identified as Ancient Woodland of which 5,000 is on the WGWE. Categories of Ancient Woodland identified on the AWI map: Ancient Semi-Natural Woodland (ASNW) – broadleaf woodlands comprising of mainly native tree and shrub species which have been in existence for over 400 years.

Dataset Reference Date (Publication): 2026-07-27

Owner

Natural Resources Wales (NRW) -

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Originator

Natural Resources Wales (NRW) -

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Originator

Forestry Commission Wales -

Forestry Commission Wales, 6 Victoria Terrace, Aberystwyth, SY23 2DQ

http://www.forestry.gov.uk/wales

Originator

Countryside Council for Wales (CCW) -

Countryside Council for Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW

http://naturalresourceswales.gov.uk/splash?orig=/

Extent

Geographic Extent: Wales (WLS)

Distribution

Format Type and Description

Geographic Information System ( )

Specification

ESRI Feature Class

Resource Locator: Web Mapping Service ( OGC:WMS )

Resource Locator: Download Data and Web Services ( WWW:LINK-1.0-http--link )

Data quality

Quality Scope: Dataset

Conformity: Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services
Explanation: This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
Degree: false

Lineage: The areas of ancient woodland with non-native trees planted on them, termed Plantations on Ancient Woodland Sites (PAWS), and those areas of ancient semi-natural woodland (ASNW) were identified and delimited by using the latest Ordnance Survey maps and field survey records. The area of each was measured using a dot grid overlay on flat projections of the 1:25 000 1st series map. The results were presented as a series of reports and maps by administrative regions (counties). As new information has been received from surveys and ad hoc informants, the initial county inventories have been revised by adding or deleting sites, or by changing the classification of the growing stock.

The Ancient Woodland Inventory (AWI) identifies woodlands that have had a continuous woodland cover for centuries. Studies show that these woodlands are typically of higher nature conservation value than those that have developed recently. In the 1980s the former Nature Conservancy Council instigated the AWI, which attempted to list all ancient woodlands in Britain. A baseline date of 1600 AD was adopted because reasonable maps were available from this time (in England, at least). 1600 AD however, was an arbitrary date, and there was no clear ecological cut-off.

The AWI was always considered to be provisional and subject to refinement, and never a definitive listing of the ancient, or the 'best' woods. Between 2010 and 2011 Forestry Commission Wales (FCW) and Countryside Council for Wales (CCW) commissioned a revision of the AWI in Wales comparing the existing AWI and National Forest Inventory with the Epoch 1: 1st County Series Ordnance Survey maps in terms of identification of ancient woodland. Epoch 1 County Series maps provide a more reliable and comprehensive baseline than the AWI. Moreover, the Epoch 1 maps incorporate numerous practical advantages over the AWI in terms of their ease of use, accuracy and level of detail.

Keywords

GEMET - INSPIRE themes, version 1.0

Land use

Type: Theme

Citation

Date (Publication): 2008-06-01

Code: geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Keywords

NRW Thesaurus

woodland (woodlands)
private woodlands
native woodland
broadleaves (broadleaved woodland)
woodland ecology
deciduous woodland
FORESTRY/WOODLANDS
semi-natural woodland
small woodland
ancient woodland (ancient trees) (veteran trees)

Type: Theme

Citation

Date (Publication): 2026-07-24

Code: geonetwork.thesaurus.local.theme.converted_nrw-keywords

Keywords

NRW SMNR Keywords

Energy (SMNR)
Woodlands (SMNR)
Natural Resources (Incl. Features and Processes) (SMNR)
Management Areas (SMNR)
Sustainable Management of Natural Resources (SMNR)
Ecosystem Services (SMNR)
Animals, Plants and Other Organisms (SMNR)
Ecosystem (SMNR)
Supporting Services (SMNR)
Provisioning Services (SMNR)

Type: Theme

Citation

Date (Publication): 2024-06-26

Code: geonetwork.thesaurus.local.theme.converted_nrw-smnr-keywords

Code: British National Grid (EPSG::27700)

Content Information

NRW Profile

Custom Elements

NRW Related Title: Amendments to the Ancient Woodland Inventory for England 4 February 1997 - 13 February 1998

NRW Related Title: Amendments to the Ancient woodland inventory for England 29 February 1996 - 4 February 1997

NRW Related Title: Amendment to the Ancient woodland inventory for England July 1994 - February 1996

NRW Related Title: The ancient woodland inventory database and digital boundary project: an update of recent developments

NRW Related Title: Ancient Woodland inventory (provisional) England : amendments to county reports up to June 1994

NRW Related Title: Ancient woodland inventory : database documentation

NRW Related Title: Identifying ancient woodland in Wales - the role of the Ancient Woodland Inventory, historical maps and indicator species

Constraints

Limitations on Public Access and Use

Restriction type: Other restrictions

Access Constraints Directive

Limitations: no limitations

Access Constraints Text

Other constraints: There are no access restrictions on this data. NRW may release, publish or disseminate it freely.

Use Constraints

Use constraints type: Other restrictions

Other constraints: © CNC/NRW. Data may be re-used under the terms of the Open Government Licence providing it is done so, acknowledging both the source and NRW's copyright. It is the recipient's responsibility to ensure the data is fit for the intended purpose.

Attribution Statement

Other constraints: Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved. Contains Ordnance Survey Data. Ordnance Survey Licence number AC0000849444. Crown Copyright and Database Right.

Licence

Other constraints: Open Government Licence

Metadata

File Identifier: 4f4c4942-4343-5764-6473-313136343432 XML

Metadata Language: English

Resource type: Dataset

Metadata Date: 2026-07-28T08:46:35.593Z

Metadata Standard Name: NRW

Metadata Standard Version: 1.0

pointOfContact

Natural Resources Wales (NRW) -

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Publishing Body

Access the portal

Full access to the portal and metadata.

Ancient Woodland Inventory

Identification

Extent

Extent

Distribution

Distribution

Quality

Data quality

Keywords

Keywords

Citation

Keywords

Citation

Keywords

Citation

Spatial Reference System

Content

Content Information

NRW Profile

Custom Elements

Constraints

Constraints

Limitations on Public Access and Use

Access Constraints Directive

Access Constraints Text

Use Constraints

Attribution Statement

Licence

Metadata

Metadata

Publishing Body