REPS has created awareness, discussion and some confusion about this management. Confusion has arisen because the purpose of hedgerow management and how the hedge reacts to it are not clearly understood.

The first issue to clarify is the purpose of hedgerow management. Is it in the interest of wildlife, stock control, shelter or the visual appearance? Hedgerow features important for each of these are not necessarily similar.

Size
The larger the hedgerow volume, the better it is for birds. It must be at least 4'6" (1.4m) tall and 4' (1.2m) wide for birds to breed successfully. Most songbirds that nest in a hedgegrow prefer to site their nests at least 4' (1.2m) from the ground to avoid ground predators. They also need overhead cover to avoid detection by magpies. Obviously the bulkier a hedgerow, the more food and concealment it provides.

Structure
The detailed structure of a hedgerow determines its use as nest sites, song posts, feeding sites, cover from predators, roosting sites or corridors for movement.

Birds such as dunnocks, robins and wrens prefer a hedgerow which is thick at the bottom, which provides cover when scratching for insects particularly in winter when the open ground may be frozen. The bottom of the hedgerow with its carpet of dead leaves will remain unfrozen and thus provide a rich source of food.

Tall shrubs provide the higher vantage points and nest sites preferred by birds such as wood pigeon. Small trees and saplings only a metre or so above the body of the hedgerow are used regularly as song posts by the blackbird and songthrush amongst others.

Laid hedgerows offer more nest sites for birds and concealed hibernating places for invertebrates.

Trees
Tall trees within hedgerows are used by birds as song posts, nest sites and vantage points. Some birds place their nests in ivy on trees. Owls nest and roost in tree holes.

Dead wood and trees with holes and rotten timber riddled with insects and fungi, provide nest sites and a food source. Beetles feed in decaying wood.

Species Composition
The more species of trees, shrubs and ground flora in a hedgerow, the more wildlife it will contain. Some trees or shrubs support a wide variety of wildlife. Hawthorn supports over 200 insect species. Of the hedgerow trees, willow and oak are particularly valuable, each capable of supporting over 400 different insect and mite species, while the field maple, sycamore and horse chestnut support less than 50 species.

Some trees or shrubs supporting less variety of wildlife may be valuable as the main or only food source of a particular species. For example, the brimestone butterfly depends primarily on the occurance of buckthorn.

A varied composition provides continuity of food supply for birds and small mammals, with seeds, fruits and berries ripening at different times.

Hedgebanks
Wild flowers such as primrose and bluebell grow on banks. Stony banks support ferns and lichens. Banks provide hibernation sites and warm basking places for lizzards.

Drains
Hedgerows with a drain alongside provide better feeding sites, with more insects available.

Field Margins
The opportunities for wildlife are substantially enhanced where the margin between the hedgerow and the field is left for natural grasses and flowering plants to grow. Field margins provide nesting cover for partridge, skylark and other birds. They are important as hunting ground for the kestrel and barn owl.

Connectivity
Continuity of hedgerows enables wildlife to move along. Many butterfly species use them rather than crossing open fields. Songbirds move along hedgerows using them to feed. Barn owls require over a mile of grassy margins alongside hedgerows as a flight path in order to seek out their prey.

Continuity is adversely affected by gaps in a hedgerow. When gaps only occupy a small proportion (up to about 10%) of the total length they are probably relatively unimportant to the numbers and diversity of birds present. However more gaps result in fewer birds.

Hedgerows near or adjoining woodlands contain more birds and small mammals. Similarly more birds are found around intersections of hedgegrows and in those on either side of a road.

Variety and Diversity required for Wildlife
Overall, variety and diversity in hedgerows are essential for wildlife. The larger the hedgerow in both height and width the better, with a variety of species and a varied structure including trees, tall shrubs, banks, drains and field margins.

Thorny species of hedgerow shrub are essential to retain stock. A dense base with no gaps is also required. Trees such as sycamore, beech and chestnut appear to shade the hedgerow resulting in gaps. The height required is not necessarily any higher than that required to retain the stock.

A good shelter belt will provide some protection into the field for up to 30 times its height, so obviously the taller the hedgerow the better. The best shelter is provided by hedgerows with a slightly open and flexible structure and a rather uneven and bushy top. The orientation of a hedgerow has implications for the shelter it provides. While the prevailing winds here are from the south-west, the objectionable wind in a particular location may come from any direction.

The attractiveness of hedgerows in the countryside is subjective. Some people may like low, neat, tidy treeless box-shape hedgerows. Others prefer the tall bushy hedgerows which are one of the most distinctive semi-natural features of the Irish landscape, and feature predominantly in all tourism promotions of the countryside.

The objective of REPS in relation to hedgerows is to maintain them in the interest of stock control, wildlife and scenic appearance. This requires long term planning and will take time to achieve the objective.

Management practices such as laying, and particularly coppicing, dramatically alter the visual appearance, wildlife and shelter value of the hedgerow in the short term, but benefit all in the long term. For these reasons and from a practical work point of view, such management practices should only be carried out in small lengths and in rotation around the farm.

While it may take a long time to stockproof all hedgerows, or allow very low hedgerows to grow up, it is far more important that harm is not done by inappropriate management, in the meantime.

The second consideration to understand is how a hedgegrow reacts to management.

A hedgerow is a line of shrubs and trees, which are designed by nature to progress to maturity at heights of 10' for blackthorn and spindle; 20' for whitethorn and hazel; 50' for holly and rowan; and 90' for ash and beech. If not managed, each shrub would eventually become a mature tree, grow old and die.

When a tree or shrub is cut or damaged, it reacts in two ways. Firstly dormant buds, located just below where the cut or damage occurs, sprout. Secondly the tree or shrub grows vigorously in an effort to get over the attack. It is important to understand these two facts when deciding on management options.

There is no advantage in cutting a stemmy hedgerow at a height of 2'-3' as it will just produce bushy growth at this level.

The vigorous growth that occurs explains why hedgerows appear to survive and even thrive, having been crushed by excavators. However they are likely to die back after a number of years because their root system has been disturbed and damaged in the process.

This is suitable for shaping older hedgerows which are thick at the base. It is important not to exhaust the hedgerow, which should have a green appearance after it has been cut. After a few years growth, newly planted or laid hedgerows can be trimmed.

This involves cutting stems near ground level almost but not quite through to the bark, laying them over and securing them. This results in an instant stock-proof barrier. New growth comes from the cut stumps, eventually taking over as a rejuvenated hedgerow, from the laid stems which also keep growing for many years.

The rejuvenated hedgerow may be left to grow tall for 15-20 years and relaid as it becomes gappy. Alternatively, it can be regularly trimmed and may remain stock proof for up to 50 years.

Hedgerows to be laid must be growing vigorously . Laying should only be done in the winter months.

In the U.K. hedgelaying is valued particularly for stockproofing hedgerows. Hedgelaying contractors offer this service for £5-£10 per metre.

Within the U.K. there are many styles of hedgelaying. These have developed from the type and style of bushes available, local extremes of snow or wind, altitude and type of stock, if present.

In Single Brush hedgerows, the twiggy ends of the laid stem are left to the back or animal side of the hedgerow. The stake side faces the road or ploughed land.

In Double Brush hedgerows the twiggy ends of the laid stems are left both sides, protecting the re-growth from animals on both sides.

All growth is cut down close to ground level . New growth comes from the cut stumps, which must be protected from stock by fencing. Gaps can be re-planted. The rejuvenated hedgerow can be regularly trimmed.

As with laying, hedgerows to be copppiced must be in good condition and without disease. Beech will not coppice. Coppicing should be done in late winter or very early spring before buds break.

Nicking involves a cut through the bark cover on lower stems to induce new shoots. Gaps can be planted with shade tolerant species - beech, blackthorn or holly.

Well-rotted dung should be dug in when planting, to improve soil. The new plants must be kept weed free and protected from stock. Fencing off allows re-growth especially when combined with nicking and gapping up.

In Ireland hedgecutters work to the left-hand side with the tractor travelling with the traffic. An amber beacon and warning signs should be used to warn traffic. Keep public roads clear of debris and hedgecuttings.

Farmers should refrain from stapling wire onto hedgerow trees. The action of the machine can turn sticks and "balls of wire" into missiles. The front hood and the flaps on flailheads should never be removed. This is very dangerous and leads to damage to trees you want to retain. Wire mesh should be used on vulnerable cab windows. Use 25-mm square mesh placed 75-100 mm from the cab windows.

Providing a wiper/washer unit on side windows means visibility can be maintained in wet conditions. Earmuffs may or may not be necessary depending on the cab specification. To work safely with hedgecutters flail heads and saw blades need to be maintained to a high standard and be properly balanced.