Hedgerow research and surveys
This part of the site covers the research and survey work that members of the Hedgelink partnership have commissioned or supported by in recent years. It also contains information on, and links to, other research and surveys related to hedgerows.
If you would like your research or survey work to be placed on this site, or signposted from it, please send us a message through the Contact and Feedback page.
A wide range of hedgerow research has been undertaken. In the early part of the last century this focussed on the agriculture impacts. Then, from the mid-1960s onwards, the focus began to shift to the wildlife value of hedgerows. In the last two decades, a substantial amount of research has been undertaken to support agri-environment schemes, such as Environmental Stewardship.
To maintain a hedge’s shape, ongoing management is required to prevent it from turning into a line of trees. This management can incorporate a wide variety of practices, such as flailing, laying and pollarding. Which technique is used and when is undertaken can have a big influence on the diversity of the hedge; for example the number of berries it produces or its suitability to provide nesting habitat for birds. Much of the recent hedgerow research has been used to fine-tune these techniques to maximise the benefits that hedgerows can offer.
The frequency and timing of when a hedge is trimmed has an influence on the berries produced. Defra research project BD2102 showed that more berries are produced on second-year growth of woody species.
BD2108 highlights extensive research that mixed species planting, rather than single species, is better for wildlife. This study also found evidence that hawthorn selected by local provenance had better survival and growth rates. BD2018 also showed the difficulty in balancing the need to suppress weed growth in the early years of hedge establishment, with that of developing ground flora for the benefits of wildlife. It was concluded that the suppression of ground flora should stop by the fourth growing season.
Research commissioned in 2008 by Defra from Forest Research on behalf of Hedgelink has shown that to stabilise the hedgerow tree population 45% of trees should be under 20cm in diameter. Currently this figure is only 19% which explains why Countryside Survey 2007 reported a significant 3.9% fall in hedgerow tree numbers in Britain between 1998 and 2007. To maintain the current population of 1.67 million trees 30,000 new trees need to be recruited to the population each year, whereas in fact only between 10,000 and 15,000 are. Urgent action is needed to address this shortfall if we are not to lose most of our hedgerow trees in the next few decades.
Here you can read the full report.
BD2108 identifies research showing that coppicing every 8 to 20 years is a low cost maintenance operation for hedgerows used throughout Europe. BD2106 showed that woody hedges should encourage the greatest number of birds on farmland in winter. Hedge laying has been found to significantly increase insect numbers (BD2108).
More information can be found in the hedgerow management section of this website.
Adjacent land use can have a big influence of the hedge and its associated species. For example, project BD2106 found that hedges next to stubbles held greater numbers of reed bunting and yellowhammers and hedges next to grass held greater numbers of thrush species.
A hedgerow’s vegetation can depend on its previous history, for example whether it was formed during the clearance of ancient woodland or deliberately planted. Hooper’s Rule suggests that planted hedgerows will become more species rich by one species every 30 yards every 30 years. There is much scepticism about whether this rule can be applied and it is generally accepted that there is at least a regional variation. Research can pick up long term trends. When a resurvey of Dorset’s hedgebanks was undertaken some 70 years later it found that they had dramatically deteriorated both floristically and structurally (BD2107). Research (BD2102) has also shown that reducing the fertiliser contamination in the bottom of a hedge can help maintain plant diversity.
The herbaceous flora that grows alongside and under the hedge itself is an important habitat but its plant species diversity has declined in the last 20 years. Project BD5301 identified six distinct types of herbaceous vegetation that will need different approaches to restoration.
All hedgerows will need to be protected from fertiliser contamination, herbicide drift and severe disturbance. Vegetation that already contains species typical of woodland or species-rich grassland can be maintained by low intensity cutting or grazing. Rank, grassy vegetation will be difficult to restore on fertile sites but on some it might be possible to increase woodland, grassland or tall herb species by extensive management over a long period.
Disturbed, species-poor pasture may require re-establishment of perennial vegetation by reseeding but only on less fertile sites and where heavy grazing and trampling can be avoided. Disturbed arable vegetation would also require reseeding, although establishing a grass margin will often be the only realistic option. Heavily shaded, sparse vegetation might require reduction of the canopy by more regular hedge management but this would need to be balanced against other environmental objectives.
The project also identified a need for further research on hedgerow soils and to test restoration options.
For more information, you can download the full report (.PDF, 1MB).
Hedgerows provide important nesting habitat for birds and, as project BD2108 recognised, the degree of management undertaken influences the nesting of birds. As highlighted in the hedge management section, cutting hedges every second year will encourage a large berry crop for birds to feed on. Project BD2102 also showed that mixed species hedgerows provide a more consistent berry supply. As well as berries, birds also rely on the invertebrates that hedgerows support. Research on this area is provided in the invertebrate section below. Defra project BD2106 identified that there was a relationship between the size and structure of the hedge and which species would be most to be present.
Hedgerows have been shown to provide an important habitat for a number of species that include bats, shrews, voles, harvest mice and dormice etc. (BD2108). Focusing on dormice, BD2108 highlighted evidence that hedgerows were found to be dormice’s second most important habitat after woodland, and also that they acted as corridors for dispersal. Key management guidelines to emerge from managing hedgerows for mammals are to allow the hedge to grow as tall and wide as possible with a dense hedge bottom, and to trim in late winter to maximise autumn fruit production.
Hedgerows provide habitat for a range of invertebrates from butterflies to spiders. Defra project BD2102 found invertebrate groups response to the hedge being cut in either winter or spring was complex, with different taxa responding in different ways. It also found that hedge laying can increase provide a diverse range and high abundance of invertebrates as the hedge grows. BD2108 highlights several research conclusions for enhancing invertebrate diversity in hedgerows. One of the most important methods is to maximise floral diversity in a hedgerow. Other findings include planting and retaining hedge trees and minimising fertiliser inputs close to hedgerows.
Little research has been undertaken to look at the direct relationships between hedgerows and amphibians and reptiles. BD2108 suggests that hedgerows with dry banks and dense ground flora are likely to be most beneficial. For amphibians the hedgerow should be located within 2km of a pond.
More information about how hedgerows support wildlife can be found in the ‘wildlife and hedges’ section of this website.
Hedgerows have been widely suggested as facilitating species movement along corridors by acting as wildlife corridors. Though this is more accepted for animals and birds (CR0389), analysis of Countryside Survey data in BD2108 has shown that this assumption is questionable for plant species. Defra report BD2302 looks at the contribution hedgerow options in agri-environment schemes make to ‘capturing’ carbon and therefore mitigating the effects of climate change.
Research on attitudes to hedges by those who maintain them is important to help understand why management decisions are made. A major piece of research (BD2103) was undertaken in the late 1990s and a follow up study was completed in 2011 (BD2117). Both research projects were funded by Defra and provide information on what period of the year hedges are cut and why, and the reasons for the method, style and frequency of cutting.
BD2103 Final Report (PDF)
BD2117 FINAL REPORT - Hedgerow Management: A survey of land managers, and contractors' practices and attitudes. (PDF)
APPENDIX 1 Farmer Questionnaire (PDF)
APPENDIX 2 Contractor Questionnaire (PDF)
APPENDIX 3 Follow-up Questionnaire (PDF)
APPENDIX 4 Field Survey Form (PDF)
Socio-economic research examines the relationship between the activity of hedgerow management and the social impact, such as the employment of those who maintain and restore hedges, supply of goods and services e.g. firewood etc. Little research has been carried out in this area, but a study based in Devon, undertaken for the Countryside Agency, predicted several outputs including numbers of jobs created and local goods purchased. It showed a positive multiplier effect because both hedge contractors and materials are largely locally sourced.
The UK Biodiversity Action Plan (BAP) Steering Group will continue to examine which areas are a priority for future research. If you know of any other relevant hedgerow research, please contact us.
Hedgerow surveys, whether of individual hedges, parishes, districts or even of whole countries, are immensely valuable for the information they provide about the diversity and state of the UK’s hedges and what needs to be done to restore or maintain them.
Partner members of Hedgelink are very keen to promote more surveys: more information is needed for most places about how many hedgerows there are, about their composition and structure, and about their condition.
To get the most out of surveys they need to be carried out in a consistent and rigorous way across the UK. In particular the use of a standard method makes it much easier to compare results from different parts of the Britain and Ireland and to monitor progress towards the targets in both UK and local Biodiversity Action Plans (BAPs). So, Hedgelink members have produced a standard survey method, survey form and database.
We have also commissioned a Review of Surveys, to provide information on what surveys have already been done, and to help spread good practice and new ideas.
Survey information is also needed to tell us how much progress we are making towards both UK and Local Biodiversity Action Plan targets. Hedgelink members have been working closely with Countryside Survey team to provide relevant information at the country level.
Hedgerow surveys can have additional value through helping to raise awareness and interest among land managers and local communities about the great importance of hedgerows, and what they can do to help improve their condition and ensure survive well into the future.
From September, you can help scientists learn more the nation's hedges so that the condition of these important habitats can be mapped for conservation. The
A free identification guide and activity book can be downloaded from www.biodiversitysurvey.org, and by uploading your findings you can help contribute to this national scientific project. The website will display your survey results, along with those of other people from around the country, building a picture of the ecological health of our hedges.
The OPAL Biodiversity Survey is led by The Open University, in association with Hedgelink and the Peoples Trust for Endangered Species (PTES). It is funded as a part of OPAL's grant from the Big Lottery Fund of £11.75m.
In 2007, on behalf of Hedgelink, Defra published the second edition of the popular Hedgerow Survey Handbook (PDF 900 KB): A standard procedure for local surveys in the UK.
The Handbook sets out a standard way of recording hedgerows. Its focus is on the wildlife, or biodiversity, of hedgerows, but it takes account of the importance of hedgerows for farming and their contribution to the beauty of our countryside and to our history and culture.
Using the survey method presented in this handbook will give you accurate information about the state of hedgerows at a local level, about the main influences on their condition, and what needs to be done to maintain or restore them.
Hard copies of the handbook can be ordered from Natural England on 0845 600 3078 or email: firstname.lastname@example.org.
We welcome feedback on the handbook and suggestions for improvement. Please send any comments to email@example.com. Although we have no immediate plans to do so, having received much positive feedback, we know the handbook can be improved and will take any suggestions into account when we next revise it.
The hedgerow recording form for use with the standard Handbook method can be downloaded as a Word document here.
The Handbook also contains a form to summarize the key information from local surveys. Completion of this form is very helpful to allow the results from local surveys to be compared and contrasted, and in particular to help develop country-wide and UK pictures about the state of our hedgerows. Her you can download the summary report form.
A new web-based database is now available for use with the standard survey procedure given in the Hedgerow Survey Handbook (2nd edition, 2007). This hedgerow survey database allows quick entry of all information collected using the standard recording form, including optional sections. It will shortly also have full analytical capability, allowing key results to be produced simply and quickly, as well as reports to be prepared. It will also be capable of being linked to GIS and to photos, and can be exported to Microsoft Excel if necessary. Here you will find further details on the new hedgerow survey database.
This new database, funded by Defra and developed by the Food and Environment Research Agency on behalf of Hedgelink, replaces an earlier Microsoft Access database. Most users found this earlier database difficult to use and its analytical and reporting capabilities were limited. The old database was not designed to be used on-line but to be downloaded onto a PC: Microsoft Access 2000 or above was required. Although we do not recommend its continued use and will not be able to support it, here you can download the old hedgerow survey database.
Please contact firstname.lastname@example.org. For any queries relating to the new database.
On behalf of Hedgelink, in 2007 Defra commissioned Barr Ecology to complile an inventory of UK hedgerow surveys undertaken since the 1980's, regardless of the survey methodology. In all, 70 surveys were found and questioannaires completed for 51 of these. The review is intended to be a helpful resource for all those carrying out surveys. You will be able to find out what other surveys have been carried out in your locality, and learn lessons from those carried out elsewhere but in similar circumstances or with similar objectives. The inventory will be updated as further surveys come to light or are completed.
If you know of any surveys that are missing from the inventory, or can fill in any of the missing detail please contact us.
Here you can download the full hedgerow survey review (Excel document 155 KB).
Defra invite applications for grant-aid for hedgerow surveys at the beginning of each calendar year and hope to be able to continue to do so. Individual grants have a maximum value of £5,000, and are only available for surveys in England. If you are interested in receiving notification of the next round, please contact email@example.com. Other sources of possible funding for surveys are given in Appendix 3 to the Hedgerow Survey Handbook.
Defra has grant-aided five or more local hedgerow surveys most years since 2003, nearly all in England. A list of these surveys by year can be seen below.b
In 2009 a review was carried out of all those of Defra-sponsored surveys carried out in 2006, 2007 and 2008 using the standard procedure. This is accompanied by a spreadsheet that shows the key results for each survey grant-aided by Defra between 2006 and 2010 (please note: this spreadsheet contains mainly tabular data and is not designed for printing).
The review finds that the quality of survey reports and information provided has been high. A total of 4,207 hedgerows were sampled, covering 787 km. The combined area surveyed was 7,360km2, 5.5% of the area of England. The 20 surveys were distributed across all Government Office regions. The review concludes that local surveys are effective in helping to deliver local hedgerow BAP targets, leading to direct conservation action. They stimulate provision of management advice to farmers and other landowners, and influence policy and resource allocation. Local surveys are also effective at raising awareness and understanding of hedgerows among local communities, and at increasing public participation in their conservation. They also have a valuable role to play in improving understanding about the state of hedgerows across the nation, and about countrywide priorities for action. Local surveys support, challenge and complement the information provided by Countryside Survey.
Key HAP priorities to emerge from the review are:
- Promotion of management, especially laying, coppicing and planting, to prevent and fill gaps and to increase the size of over-short or thin hedgerows;
- The restoration of plant communities affected by nutrient enrichment, and
- The recruitment of young hedgerow trees.
Recommendations are made about future targeting of surveys and about improvements to reporting. Sponsorship of surveys in Wales, Scotland and Northern Ireland by appropriate authorities is highly desirable.
- Bedfordshire County Council - Studham & Whipsnade Hedgerow Study
- Calderdale Council - The Calderdale Hedge Hunt
- Campaign to Protect Rural England - Warwickshire
- Chilterns Conservation Board - Survey of stock and condition of hedgerows in the Chilterns AONB
- Derbyshire Wildlife Trust - Chesterfield hedgerows survey
- Durham Biodiversity Partnership - Durham hedgerow Survey
- Kent & Medway Biological Records Centre - Pilot assessment of biological and historical features in Kent
- Rotherham Metropolitan Borough Council - Rotherham ancient and species-rich hedgerow survey
- Bedfordshire County Council - Maulden Parish hedgerow study
- Dorset Environmental Records Centre - Dorset hedgerow surveys
- Farming and Wildlife Advisory Group - Devon hedgerow project
- Chilterns Conservation Board - Survey of the stock and condition of hedgerows in the Chilterns AONB
- Sussex Wildlife Trust- Sussex hedgerow inventory
- South Gloucestershire Council - South Gloucestershire field boundaries survey of Development Pressure Area
- Cumbria Biodiversity Partnership - Cumbria hedgerows project
- BTCV — Species-rich and ancient hedgerows in the Canterbury area
- Cumbria Biodiversity Partnership — Cumbria hedge survey
- Bromley Borough — Darwin’s hedgerows
- Cheshire FWAG — Shocklach ancient hedge survey
- Devon FWAG — Devon hedgerow survey project
- Exmoor National Park — Celebrating Exmoor’s hedges
- Bedfordshire County Council — Chalk Hills hedgerow study
- Three Valleys — Hedgerows of the Moss Valley
- Severn Vale hedgerow survey: Parishes of Longney, Frampton, Elmore, Slimbridge and Frocester.
- Malvern Hills AONB hedgerow survey: Malvern Hills AONB, including parts of Worcestershire, Herefordshire and Gloucestershire.
- Cornwall hedgerow survey project: St Dennis and Tregony Parishes.
- Chalk Hills Hedgerow Survey II: Area east of Barton Hills SSSI including Deacon Hill SSSI and the farmland to the north around Knocking Hoe SSSI on the border of Bedfordshire and Hertfordshire.
- Historic Parklands and Estates Hedgerow Survey, West Yorkshire: Harewood, Lotherton Hall and Temple Newsham estates in Leeds District, West Yorkshire.
- Devon Hedgerow Survey 3: Parish of Spreyton.
- West Worcester Tree and Hedgerow Survey: North-west of Worcester City, between St John’s, Hallow and the villages of Lower Broadheath and Upper Broadheath.
- Dorset Hedgerow Surveys: Parishes of Hammoon, Manston and Hinton St Mary, together with small areas of Marnhull, Sturminster Newton and Okeford Fitzpaine, in North Dorset.
- Kingsclere Parish Hedgerow Survey: Kingsclere Parish, NW Hants (half of parish is in N Wessex Downs AONB).
- Hartlepool Hedgerow Survey: The Borough of Hartlepool.
- Severn Vale hedgerow survey (Phase 2): Severn Vale parishes/parts of Arlingham, Cam, Coaley, Eastington, Elmore, Frampton on Severn, Frocester, Fretherne with Saul, Longney, Slimbridge and Whitminster.
- Hedgerows for Hazeleigh Woods Project: Hazeleigh Woods Living Landscape area, Maldon district, Essex. The area stretches from the parish of Woodham Mortimer eastwards to the Blackwater estuary.
- Moreton, Fyfield and The Lavers Hedgerow Survey: Parishes of Moreton, Fyfield and The Lavers in Epping Forest District, Essex.
Some excellent examples of hedgerow surveys can be found on the website of the Hedge Laying Association of Ireland
Since 1999 the Suffolk Coastal Greenprint Forum has been organising voluntary hedgerow surveys, initially within the Suffolk Coastal area, but soon expanding to cover the whole of Suffolk. By October 2010 a hundred and seventy six parishes had completed their surveys of 22,800 hedgerows.
The Suffolk Biological Records Centre is already relating the hedgerow data, to data it holds on the incidence of various species and habitats, and clear correlations are already emerging between landscape and species rich hedgerows to the favourable status of those species and habitats.
For more information, visit the Suffolk Hedgerow Survey website.
Countryside Survey (CS) is a sample based comprehensive audit of the natural resources of the UK's countryside.
The Survey has been carried out at regular intervals since 1978. The countryside is sampled and studied using rigorous scientific methods, allowing even gradual and subtle changes in the UK's countryside to be detected. The latest survey took place in 2007 and the results are now available on the Countryside Survey website.
Countryside Survey is the principle tool used to assess progress with most of the targets in the UK Hedgerow Biodiversity Action Plan. In England, Scotland and Wales it is carried out by the Centre for Ecology and Hydrology (a Natural Environment Research Council institute). CEH is a member organisation of Hedgelink. A linked survey was carried out in Northern Ireland by the University of Ulster.
The main findings from the 2007 survey relating to hedgerows are available in the Boundary and Linears Broad Habitat Chapters of the various country level reports available in the ‘Output’s section of the CS website. It is also possible to access data on the findings from the survey for a range of plot types associated with hedgerows at regional levels by simply registering as a user on the site in the ‘Data Access’ section of the website.
The latest National Statistics on agri-environment and business practices on farms from the
Defra Farm Practices Survey (FPS) were released on August 2008.
Four main topics are covered by the report; administration, business practices, livestock and environmental impacts which includes a section on hedgerow management (section 6) and the survey aims to investigate the impact of farming on the environment. A more descriptive report is due to be published towards the end of 2008.Also look out for an article which will compare the hedgerow management results from the latest survey with those of past surveys.
Here you can view the results from past surveys.
A survey of contractors in Devon has shown that the amount of hedge laying and planting had fallen in recent years, and links this to the decline in grant aid available under schemes like Environmental Stewardship over recent years. Read the full report here (pdf - 95KB)