This digitised boundary defines the upper limit of enclosure which distinguishes Upland and Lowland habitats, adopted during the Phase 1 Survey and the Wales Field Unit (WFU) Upland vegetation survey of Wales. The original field surveys were carried out from 1979-99 as part of a national habitat survey project required to implement conservation at a local level. The boundary was verified and digitised in 2000. The lower altitudinal limit of upland vegetation shows considerable variation across Wales. This boundary line reflects the local environmental factors that influence vegetation type.

Lineage: The Field survey spanned from 1979 to 1999. Closely co-ordinated teams of surveyors carried out field recording of habitats onto 1:10,000 scale maps (rarely 1:25,000 during the upland stage). The minimum size of habitat patch recorded lies predominantly within the range 0.1 - 0.25 hectares, although smaller areas were mapped in the lowlands. The survey methods employed during the initial upland stage are given in more detail in a WFU report (Day, A. (1989) Upland Vegetation Survey 1979-1989 Background Methodology and Summary of Data Collected. NCC, Bangor). Methods for the lowland survey followed the Handbook for Phase 1 Habitat Survey with some minor modifications adopted for use in Wales (Howe E.A. and Blackstock T.H. (1991) Supplementary Notes for Phase I Survey in Wales. CCW, Bangor). All field mapping was carried out by trained and closely co-ordinated teams of surveyors. Two studies of survey reliability were conducted during the lowland phase (Kerry, Rimes, Smith, Williams. 1994. An Assessment of Errors in Phase I Habitat Survey in Wales. Bangor: Countryside Council for Wales, Report No. 94/4/1), (Stevens, Blackstock, Howe, Stevens. 2004. Repeatability of Phase 1 habitat survey. J. Environ. Manage. 73, 53-59). The electronic data have undergone a series of checks for accuracy both by the contractor and subsequently within NRW (CCW).

Attribution Statement

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.

Context for Woodland opportunity Map (WOM) 2021

This dataset shows the boundary between Upland and Lowland Wales that was adopted during the Phase 1 Survey and the Wales Field Unit Upland vegetation survey of Wales. The layer is built from the same data within the “Priority Habitat - High Sensitivity” and “Priority Habitat Mosaics - Investigation Required” datasets, found elsewhere in the WOM 21.

Historically for woodland purposes the boundary between upland and lowland has been 300masl. However, the upper limit of enclosure derived from field survey enables the upland boundary to follow local environmental conditions, which often do not follow a rigid altitude contour.

Sustainable Management of Natural Resources (SMNR) guidance sets out that certain habitats (acid grassland, marshy grassland) are section 7 and therefore protected when they are lowland, but not upland. Consequently, this boundary line provides context for all tree planting proposals. Schemes that propose planting on “Priority Habitat – High Sensitivity” areas are unlikely to be verified; these areas should be excluded from planting proposals. However, if you have reasonable grounds to believe the land has been wrongly recorded you can submit photographic evidence and ask for a review using GN009.

The “Priority Habitat Mosaics – Investigation Required” data layer indicates areas where patches of upland acid grassland and/or upland marshy grassland are thought to be present in a mosaic with section 7 priority habitats. Where these areas of upland acid grassland/upland marshy grassland are extensive they have the potential to be planted as per the Woodland Creation SMNR guidance provided this is agreed well in advance with NRW prior to verification.

It is important that other sensitivities e.g., priority species, deep peat, landscape designations are also taken into account when developing tree planting proposals, and relevant guidance sought. Further guidance on other sensitivities is contained within the ‘Sensitivities’ folder of the WOM21, and also in GN002.

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