The aim of the Native Woodland Survey of Scotland (NWSS) was to undertake a baseline survey of all native woodlands, nearly native woodlands and PAWS sites in Scotland in order to create a woodland map linked to a dataset showing type, extent and condition of those woods.
The objectives were to:
1. Identify the location, type, extent and condition of all native and nearly native woodlands and Plantations on Ancient Woodland Sites (PAWS - as identified from the Ancient Woodland Inventory) in Scotland.
2. Produce a baseline survey map of all native woodland, nearly native woodland and PAWS in Scotland.
3. Collect baseline information to enable future monitoring of the extent and condition of the total Scottish native woodland resource.
4. Provide information to support policy development and the delivery of social, environmental and development forestry.
The following datasets are available on the Scottish Forestry Open Data website:
- Native Woodland Survey of Scotland (base map and polygon level attributes)
- NWSS Canopy Structures
- NWSS Habitat Components
- NWSS Herbivore Impact
- NWSS Invasives
- NWSS Other Traits
- NWSS Species Structures
The following describes the layers available from Scottish Forestry and also gives an indication of the nature of the spatial data and the related component non-spatial data. (N.B. Every table contains a SCPTDATA_I field. This is a unique field which is used to link all other component tables). If you wish to carry out complex analysis, particularly involving elements of the components tables, e.g. species selection, you should do so using GIS software.
NWSS Map:
This is a straightforward view of the data which describes the type of NWSS polygon based on the following categories:
Native woodland: >50% native species in the canopy
Nearly-native woodland: >=40% and <=50% native species in the canopy
Open land habitat: <20% canopy cover, usually 100% surrounded by woodland and adjoining a native woodland
PAWS: A woodland area wholly or partially identified in the Ancient Semi-natural Woodland Inventory as ancient semi-natural but currently not semi-natural.
NWSS Nativeness:
Displays the percentage share of native species in the total canopy. This ranges from 0% to 100% in 5% classes.
NWSS Habitat:
This view of the data shows the priority woodland type and National Vegetation Classification (NVC) woodland community. Open land habitat is defined by UK Biodiversity Action Plan (BAP) type.
A dominant habitat is recorded for each polygon, however some polygons have habitats of equal dominance. In this case only one of the habitats is recorded in the top level spatial data. To identify all of the habitats in a particular polygon please refer to the FCSNWSSHABITATCOMPONENTS table or use the map browser identify tool on the NWSS Habitats layer.
Plantations on Ancient Woodland Sites (PAWS) may not display in the Habitat layer if a surveyor has not recorded a native priority habitat type for the site. This will happen when a site is non-native.
NWSS Canopy Cover:
Displays as a percentage, an assessment of the area covered by trees/shrubs. Values range from 0% to 100% in 10% classes. A minimum of 20% canopy cover is required to define woodland, so the 10% and 20% bands are skewed to allow for this.
NWSS Canopy Structures:
This displays the number of different structures recorded in a polygon (ranging from 0 to 6). The types of recorded structures are veteran, mature, pole immature, shrub, established regeneration or visible regeneration.
A dominant structure is recorded for each polygon, however some polygons have structures of equal dominance. In this case only one of the structures is recorded in the top level spatial data. To identify all of the structures in a particular polygon please refer to the FCSNWSSCANOPYSTRUCTURES table or use the map browser identify tool on the NWSS Canopy Structures layer.
Information on the species identified in each polygon is also in the NWSS Canopy Structures layer and table.
- indicates a species which is classed as native for the purpose of the survey.
- indicates a species is a shrub not a tree.
NWSS Semi-naturalness:
This view of the data shows the percentage of the polygon that is semi-natural. Values range from 0% to 100% in 10% bands.
NWSS Maturity:
This indicates the approximate stage of woodland development as either: mature, young, regenerating, mixed or shrub. The value is based on the dominance of the structures recorded; a mixed maturity means that none of the others values are dominant.
NWSS Other Traits:
This layer records whether or not there are any other attributes which have been recorded in the polygon. The details of any other traits that have been found can be accessed by viewing the related information attached to a polygon.
NWSS Herbivore Impact:
This view of the data shows the overall impact that herbivores have had on a polygon.
NWSS Invasives:
This is a separate spatial dataset on the Forestry Commission Spatial Data Repository. It contains a subset of the overall NWSS Map dataset which includes only those polygons were there is some presence of an invasive species. The layer is symbolised on the percentage of invasive species with the polygons, show in 25% bands. The data itself contains more detailed information which is broken down into 5% bands.
Summary of Attributes
SCPTDATAI Polygon ID (Unique identifier)
PAWSSURVY Surveyed as PAWS
TYPE Type
CANOPYPCT Canopy cover percentage
NATIVEPCT Native species percentage
DOMHABITA Dominant habitat type
DOMHBPCT Dominant habitat type percentage
SEMINTPCT Semi-natural percentage
STRUCTNUM Number of structures
MATURITY Maturity
DOMSTRUCT Dominant structure
HERBIVORE Herbivore impact
ERNATPCT Percentage of establish regeneration of native species
INVASVPCT Invasive species percentage
INVASVNUM Number of invasive species
OTHR_TRAIT Other traits recorded
HECTARES Area in hectares