It’s the time of year when farmers’ thoughts turn to the management of their hedgerows. The winter crops have been drilled and there’s a bit of a lull in the arable farmer’s schedule before the spring field work begins.

road hedge cutting vehicle in rural countryside - hedgerows

Hedge cutting with a flail. Image credit: Bluestock/123.rf

What is a hedgerow?

The UK countryside is criss-crossed by hedgerows – long rows of bushes, sometimes containing trees, which have mainly been planted to keep livestock from straying or to mark parish boundaries. Not all have been planted though. Some are the edges of old woodland that has long-since been felled, while others may be the result of tree and shrub seedlings establishing themselves alongside a linear feature where they have been protected from grazing livestock.

For the purposes of hedgerow protection regulations, a hedgerow is defined as any boundary line of trees or shrubs over 20m long and less than 5m wide. Any bank, ditch, wall or tree within 2m of the centre of the hedge is considered to be part of the hedgerow habitat, as is the herbaceous vegetation within 2m of the centre of the hedgerow1.

The last Countryside Survey of the UK2, an ‘audit’ of the UK countryside’s natural resources, took place in 2007 and then it was estimated that there were 402,000km of managed hedgerows in the UK. This was a 6% decrease in length since the previous 1998 survey. Much of this loss was believed to be down to neglect and mismanagement leading to hedgerows becoming lines of gappy shrubs or trees, rather than the removal of hedgerows. Recent reports into our hedgerows suggest that the total length of the UK’s hedges may be increasing, with a lot of effort being put into new planting and better management, particularly under environmental stewardship schemes.

Working out the approximate age of a hedge

You can roughly work out the date of any hedge that hasn’t recently been planted by using the following formula:

  1. Choose a 30 metre length of hedge
  2. Count the number of species of trees and shrubs you find in it
  3. Multiply the number of species by 100

The answer is the approximate age of the hedge. One new species establishes itself about every 100 years, so a hedge with 3 species is about 300 years old. Bear in mind that a recent hedge may have been planted with several species but the look of the hedge should give you an idea as to whether you have an old, established hedge or a more recent one.

Why are hedgerows useful to wildlife?

Newly planted hedge on a Fair to Nature farm - hedgerows

Newly planted hedge on a Fair to Nature Farm. Image credit: B Hughes/CG

Hedgerows provide a home and a larder for many wildlife species, from butterflies such as the Brown Hairstreak and the Gatekeeper, to birds like the Cirl Bunting and the Turtle Dove, and mammals such as the Dormouse. They also provide safe corridors for wildlife to travel between other areas of habitat such as woodland. Bats are known to use hedge and tree lines as a navigation aid. A research project3 by Michael Pantling from Southampton University, which looked at bat activity and foraging along field boundaries, compared the management of boundaries and habitats on farms implementing government funded environmental stewardship schemes, Conservation Grade principles and organic principles. The common theme to come out of this research was the importance of hedgerow trees and hedgerow maintenance to avoid large gaps in the hedge line. Some bat species can be deterred by gaps of over 30m.

Different wildlife species prefer different types of hedgerow. Generally, the bigger the hedge the more wildlife it will support, but some species prefer shorter hedges and where these species are present hedge size should be taken into account. Lapwings, for example, favour open countryside so hedges should be kept shorter with less hedgerow trees for predators to hide in. Some smaller birds, such as Yellowhammer, like to nest in tighter, shorter hedges that offer protection from predator. Turtle Doves favour tall, straggly hedges to nest and shelter in.

Are there any restrictions governing hedgerow management?

Two pieces of legislation relevant to the management of the UK’s hedgerows are the Hedgerow Regulations 19974 and the Wildlife and Countryside Act 19815. Farmers and landowners also have to be aware of the cross compliance rules6 governing boundary features (called GAEC 7a)

It is important not to disturb nesting birds. The main nesting period is between 1st March and 31st August so in most circumstances farmers and landowners are not allowed to cut or trim their hedges during this period.

How do Fair to Nature farmers manage their hedgerows?

A good habitat for turtle doves - hedgerows

A nice tall hedge – good habitat for turtle doves. Image credit: S Abbott/CG

Hedgerows can only survive in the long term if they are correctly managed. Otherwise they become a line of trees. Today incorrect management and neglect is leading to more hedgerow loss than outright removal.

Fair to Nature farmers really value their hedges. Many of our Fair to Nature farmers have increased the amount of hedgerows on their farms by planting new ones and rejuvenating existing hedges.

As long as the hedge isn’t overhanging a highway or obstructing a right of way, they plan their hedge cutting regime so that the farm contains hedges at different stages of growth, maximising their benefit to wildlife. Many tree and shrub species produce flowers on one year old twigs so by cutting the hedge annually this year-old growth is removed meaning no flowers for pollinators, and no fruit or nuts for birds and mammals. Only climbing plants such as roses, clematis and brambles produce good flower and fruit crops in hedgerows that are cut every year. Another good reason for not removing the new growth every autumn or winter is that the some invertebrate species, such as the Brown Hairstreak butterfly, only lay eggs on this new growth and annual cutting will destroy those eggs. So, where possible, Fair to Nature farmers cut one side of the hedge at a time, leaving the other side to grow for another year or so, meaning that there will always be flowers and fruit and nuts available. They also leave hedges to grow for 2 to 3 years between cuts. It has been estimated that for every year a hedge is left uncut it will gain two species of breeding bird!

On some Fair to Nature farms, the farmers are trying to encourage certain bird species such as Turtle Doves. Turtle Doves are quite specific in their choice of nesting and feeding habitat. They favour tall straggly hedges, like the one pictured left, to nest in leading into scrub adjacent to arable land for feeding. Plus they need a nearby water source to enable them to produce the crop milk that they feed their chicks on.

A managed hedge on a Fair to Nature farm - hedgerows

A managed hedge on the Game & Wildlife Conservation Trust’s Leicestershire farm. Image credit: S Abbott/CG

Some hedge management can look drastic to the untrained eye, such as coppicing where the hedge is cut right back, and laying, where the hedge is thinned out and the strong stems are chopped close to the ground so that just a section of bark and sap wood connects the stem to the stump. These are called ‘pleachers’. The stems are then laid along the hedge line, with smaller stems twined in between. Strength and stability is provided by upright stakes placed at intervals along the laid hedge. Often the laid hedge is finished using hazel whips woven through the tops of the stakes. Different parts of the UK have developed their own hedge laying methods over the years, often according to the type of livestock that the hedge is required to contain.

New hedge rejuvenation methods

Traditional hedge laying is a time consuming task, so new quicker methods have been developed, using chainsaws and farm machinery. Researchers at the Oxfordshire based Centre of Ecology and Hydrology7 have compared traditional hedge laying, conservation hedging (where the base of the hedge is cut as with traditional hedge laying and the stems are laid over but the remaining stems and branches are laid along the hedge line rather than to one side and fewer branches are removed), and wildlife hedging (where the base of the hedge is cut with a chainsaw, the vegetation is pushed over with a digger bucket, and no branches are removed) with reshaping of the hedge with a circular saw, and coppicing. They looked at regrowth from the base of the hedge and the canopy, hedgerow structure, berry provision for overwintering wildlife, and cost. The research showed that conservation hedging and wildlife hedging cost much less than traditional hedge laying and any differences in regrowth and berry provision had disappeared by year 3.   

These more drastic management methods are only undertaken where a hedge needs rejuvenating and/or brought back into use as a barrier. A coppiced or laid hedge will regrow and can then be managed as any other hedge.

Some good websites for more information about hedges and hedge management are:

Hedgelink

The Wildlife Trusts

Natural England

References:

1UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008

2Countryside Survey 2007 –

http://www.countrysidesurvey.org.uk/sites/www.countrysidesurvey.org.uk/files/CS-UK-Results2007-Chapter05.pdf

3Pantling, M. 2014. Bat activity and foraging along agricultural field boundaries: The impact of agri-environment schemes. University of Southampton

4The Hedgerows Regulations – your questions answered, Defra, 1997 –

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/438650/hedgerow_your_questions_answered.pdf

5Wildlife and Countryside Act 1981 – http://jncc.defra.gov.uk/page-1377

6Guide to Cross Compliance in England: 2016 – https://www.gov.uk/guidance/guide-to-cross-compliance-in-england-2016/gaec-7a-boundaries

7Staley, J., Amy, S., Adams, N., Chapman, R., Peyton, J., Pywell, R. 2015. Re-structuring hedges: Rejuvenation management can improve the long term quality of hedgerow habitats for wildlife in the UK. Biological Conservation, 186, pp. 187-196. http://www.sciencedirect.com/science/article/pii/S0006320715001068

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