The NFI definition of woodland is a minimum area of 0.5 hectares under stands of trees with, or with the potential to achieve, tree crown cover of more than 20% of the ground
Areas of young trees, which have the potential to achieve a canopy cover of more than 20%, will also be\ninterpreted as woodland and mapped. The minimum width for woodland is 20 m, although where woodlands are connected by a narrow neck of woodland less than 20 m wide, the break may be disregarded if less than 20 m in extent.
Intervening land classes such as Roads - all 'tarmac' roads should be excluded from the woodland area, but\ninternal forest tracks, farmers tracks, rides etc. will be included as part of the woodland if < 20m wide.
Rivers - where the gap in woodland is 20m then rivers will be excluded from the woodland area.
Power lines etc. - where the gap in woodland is 20m then power lines will be excluded from the woodland area.
Railways - all normal gauge railways should be excluded from woodland.
Scrubby vegetation is included within this survey where low woody growth seems to dominate a likely woodland site.
The definition of an open area is any open area that is 20m wide and 0.5 ha in extent and is completely surrounded by woodland.
The woodland boundaries have been interpreted from colour aerial ortho-photographic imagery. For the base map, photographic images aimed to be no older than 3 years at the time of mapping (i.e. areas mapped in 2007 would be based on photographs that were ideally taken no earlier than 2004). As the map is be the basis for a longer rolling program of sample field surveys it has been necessary to develop procedures to update the map to the date of the field survey, currently 2011, for the purpose of reporting on the current phase. The map is continually updated on an annual basis. These updates will are achieved by a combination of remote sensing and updated aerial imagery analysis for changes in the woodland structure and with reference to available new planting information from grant schemes and the FE sub-compartment database. Ordnance Survey MasterMap® (OSMM) features have been used as a reference for capturing the woodland boundaries. OSMM is the most up to date large-scale digital map of GB providing a seamless database for 1:1250, 1:2500 and 1:10000 survey data.
All woodland (both urban and rural, regardless of ownership) which is 0.5ha or greater in extent, with the exception of Assumed woodland or Low density areas that can be 0.1ha or greater in extend, as been mapped Woodland that is less than 0.5ha in extent will not be described within the dataset but will be included in a separate sample survey of small woodland and tree features.
The primary objective is to create a new digital map of all woodland in Great Britain using O.S.MasterMap features as boundaries where appropriate. The map shows the extent of all woodland of 0.5 ha. Woodland categories are defined by IFT (Interpreted Forest Type) values. Detailed Woodland categories are:
Ground Prepared for New Planting
Mixed - predominantly Broadleaved
Mixed - predominantly Conifer
Coppice with Standards
Cloud or Shadow
Non woodland categories are defined by the IOA (Interpreted Open Area) values. Detailed Non woodland\ncategories are:
A full list of att6ributes can be found in the Data Lineage section.\n\n
Any maps produced using this data should contain the following Forestry Commission\nacknowledgement: "Contains, or is based on, information supplied by the Forestry Commission. \n© Crown copyright and database right [Year] Ordnance Survey ".