Summary
1. The Hedgerows Regulations 1997 were introduced to protect important hedgerows in England and Wales. In May 1997, a review of these regulations was announced, the objective being to make recommendations on how this new system of hedgerow protection might be strengthened. The Review Group reported in June 1998 and it proposed revised criteria (Appendix 1) for determining whether a hedgerow would be judged 'important' under the regulations (Anon., 1998a).
2. An assessment was required to determine the proportion of hedgerows likely to satisfy the proposed criteria for defining 'important' hedgerows, and the degree to which hedgerows might meet more than one of the criteria. In addition, an assessment was needed of the extent to which hedgerows that were considered to be of landscape value were covered by the proposed criteria.
3. The aim of this project, commissioned by the Department of the Environment, Transport and the Regions (DETR), was to provide these assessments. The results will inform further consideration of the suitability of the proposed criteria as definitions of hedgerow 'importance'. The DETR established a Steering Group to guide the project.
4. As part of the Hedgerow Evaluation System project (Churchward et al., 1996 ) ADAS had already recorded various ecological and historical characteristics of the hedgerows in 50 sample squares of 1 km x 1 km, in England and Wales. However, the criteria now proposed included new elements which required additional information, and the objective of the current project was to add to the original data, by both field survey and reference to records. The assessments required fell under three headings: historic, ecology and landscape.
5. Historic records held at Local Authority Records Offices, the National Library of Wales and the Sites and Monuments Records were researched to assess whether each hedgerow:
- incorporated or was associated with an archaeological feature or site;
- marked the boundary of a historical administrative boundary (such as a parish or township boundary, hundred, wapentake or maerdref), a pre-1600 estate or manor, or the outer limits of field systems, parks, woods or common land;
- was an integral part of a field system dating from before 1800/1845 or, in the case of an enclosure field system, from before 1870, and that system was substantially complete.
6. The field survey gathered information on:
- the number of listed woody species in each hedgerow;
- the number of woody species in specified 30 metre stretches - this was recorded in the previous survey and re-survey was carried out only where any of four additions to the woody species list occurred; the sections had to be extended to compensate for gaps in the woody cover; or where the length of hedgerow had changed;
- the number, location and type of connections between each hedgerow and other hedgerows, woods, ponds, rivers, streams or other semi-natural habitat;
- evidence of any Biodiversity Action Plan priority species within the hedgerow (local biological record offices were also consulted);
- whether the hedgerow marked the boundary of a public road.
7. The aim of the landscape survey was to assess the value of the hedgerows in terms of their visual importance. The survey followed an established methodology, which was agreed on site with representatives of the Countryside Commission and the Countryside Council for Wales. The process involved two stages: firstly an identification of areas of distinct landscape character, within each of which all hedgerows were given the same landscape value; and secondly an assessment of each individual hedgerow to establish whether its value should be upgraded compared with the others in that character area because of its particular attributes. Each hedgerow was assessed as 'important' or 'less important'; the 'important' category was further subdivided into 'very important' and 'important'.
8. In total, 1,597 hedgerows with a total length of 247 km were surveyed in the 50 sample squares. Of these, 261 (16%) totalling 39 km were located in the seven sample squares in Wales. The information collected was added to the existing database, and the data were analysed in relation to the proposed criteria for defining 'important' hedgerows. Where the detail had not been fully specified in the criteria (e.g. the number of woody species numbers), a range of options was examined.
9. Some 94% of hedgerows surveyed met one or more of the seven criteria proposed by the Review Group. If the two criteria that were not fully supported by the Review Group (relating to field systems and hedgerow connections) were omitted, then some 59% of hedgerows met one or more of the remaining five criteria.
10. Some 77% of hedgerows met the proposed connections criterion, whilst 57% would qualify as an integral part of a substantially complete field system dating from before 1845, or in the case of an Enclosure Act system, 1870. Almost a third of hedgerows were found to be alongside a public highway, and the proportions of hedgerows which met the various potential versions of the woody species criterion were generally within the range 25-40%.
11. In the landscape assessment, 89% of hedgerows were assessed as being important or very important. Analysis of the data appeared to indicate that species-rich hedgerows and hedgerows adjacent to public highways were particularly likely to have been judged as having landscape importance, as were hedgerows with connections to two or more other features.
12. A wide range of further combinations of criteria was examined. These included: a simplified approach, requiring a hedgerow to meet one of only three criteria; a hedgerow having to meet at least two or three criteria; and a hedgerow having to meet one of certain 'primary' criteria or at least two of the 'secondary' criteria. The proportions of hedgerows meeting these various options are presented in this report, to enable further consideration of the proposed criteria as definitions of hedgerow 'importance'.
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Published 29 November 1999 / updated 16 August 2000
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