Tree protection

Tree protection is an important part of tree planting on many sites, and must be planned carefully from the outset. Tree protection materials are expensive, and often cost more than the trees themselves. However, without proper protection, most planting will be a waste of time and resources. Tree protection may also be needed to protect young trees which have naturally regenerated.

On urban sites, protection against stock and wild animals may be unnecessary. Proper public consultation and appropriate planting design is likely to be more effective than fencing or other protection against people, which may attract vandalism, see The Urban Handbook – People and places. Many urban woodlands have been successfully established in recent years with no tree protection at all.

Any of the following agents may cause damage to young trees. They are discussed further below. Animals cause damage by bark-stripping, which weakens the tree. Animals also ‘browse’ on trees, which means to eat the leaves and young shoots. larger animals can trample and uproot young trees.

• Wild animals. These include voles, rabbits, hares, and deer. you will need to find out which of these are present in the area, and what the level of threat is likely to be.
• Stock. These include sheep, cattle, horses and goats. Check any planned uses for grazing land for the few years after planting.Adequate protection against sheep, for example, would not be sufficient against horses. This can be difficult to plan, as changes are often made at short notice.
• People. young trees can be damaged accidentally, for example by people trampling them, or they can be vandalised. Consultation with local people is an important part of planning tree planting. A lot of damage is also  caused  by  careless  mowing, brushcutting and strimming by mowing contractors or ground maintenance staff.
• Wind. Strong winds are damaging to young trees, not only because of physical damage to tender leaves, shoots and stems, but because of the drying effect of the wind, which reduces the humidity around the tree. Treeshelters were originally designed to increase the humidity around the tree, but are also useful against some of the agents mentioned above.

There are various types of protection, some of which can protect against more than one of the agents given above. you need to select the type of protection which will be effective against the most agents, will not have unwanted side effects such as attracting vandalism, and will be cost effective. The method of weed control being planned can also affect the choice of tree protector. For example, tree shelters have the useful side effect of protecting the young tree from being damaged by herbicide spray.

Trees can either be protected individually, or as a group, or a combination of methods can be used.

A large number of different products are available, including those listed below. All the products are available in a range of heights to suit various purposes. Further details are given below.

• Vole or strimmer guards
• Spiral guards, opaque and transparent
• Wire or plastic mesh guards
• Tree shelters
• Metal surrounds
• Timber tree surrounds. normally built from standard fencing materials.

The following methods can be used to protect groups of trees. They can be used instead of, or in addition to, individual protection.

• Fencing of planted area.
• Chemical deterrents.
• Control of animals causing damage.

See below for details on the choice between individual protection or fences.

Stock and wild animals can not only damage trees, but also may hinder the development of a diverse shrub layer and ground flora. in existing woods, high numbers of deer can seriously affect the value of existing ground vegetation. On the other hand, lower grazing densities can promote diversity and keep glades open. When considering tree protection, the management of the wood in the longer term also needs to be considered.

Wild animals

In order to make a suitable choice of protection, you need to know the likelihood of damage occurring. This means finding out about which of the ‘pest’ species are in the area, and what the level of threat is likely to be. Talk to others responsible for tree planting and management in your area, to farmers, and to your local Forestry commission officer. if you are planning to rely on natural regeneration as a way of rejuvenating a woodland, protection against wild animals and stock will be essential.

Voles

The field or short-tailed vole is probably the most widespread and numerous British mammal. it is 10cm (4”) long, short-tailed, brown with grey below, and lives in hedges, rough grassland, the borders of woodlands and in gardens. In plantations of young trees the population can quickly grow to plague proportions of around 500 per acre, causing damage to stems and young shoots up to about 5cm (2”) in diameter. Populations tend to be higher following a mild winter. Normally, voles live mainly on grass, often biting off long stems at ground level.

Field voles are most likely to cause problems where there is long grass to give cover. Mulch materials such as bark or plastic sheeting can also provide cover. This in turn can lead to problems where foxes tear at the plastic mulch in order to get at the voles! Mainly in winter, the voles gnaw the bark away just above the soil level, typically leaving a bare strip on which tiny teeth marks, about 1mm wide and in pairs, can just be seen. They can also gnaw the roots be- low ground level. If you part the surrounding mat of grass, you’ll find a complex system of vole runways and par- lours, with vole droppings and small piles of grass stems cut into short lengths. Damage can also occur beneath snow.

Use of herbicide which leaves a bare patch around the base of the stem discourages voles by removing their cover. Otherwise, guards will be needed on grassy sites. Where populations are high, voles will cross bare ground. The worst damage occurs when populations reach ‘superabundant’ numbers, which happens on a three to five yearly cycle in suitable grassy habitats. The base of the vole guard or treeshelter (see note below Table 6d) must be buried at least 5mm into the soil. Spiral guards with ventilation holes are not effective.

Voles are food for birds of prey, with kestrels and barn owls in particular likely to hunt over areas of long grassland. Where the site lacks high trees or posts for perching, you may be able to encourage some of these birds to hunt over a newly planted woodland by providing perching positions. If you can erect them safely, a couple of ‘telegraph pole’ size posts with a ‘wire’ between may be just the job! Pole-mounted barn owl and kestrel nesting boxes require quite an investment of time and resources, but have proved very successful in encouraging these birds of prey into young tree plantations. See Dewar Shawyer (1996) for further details.

Rabbits and hares

Rabbits are common in many parts of Britain, with hares locally common in suitable habitats. Rabbits graze mainly on grass, but outside the breeding season can survive on bark and shoots of trees and bushes. Damage is most severe in winter and early spring, especially during snow when other food is scarce. Snow also gives access higher up the stems. Rabbits are likely to be absent from areas where there are high numbers of urban foxes, where myxomatosis is present, and in very wet terrain.

Rabbits require dry shelter within about 400m of grazing. They can breed anytime between January and August, and numbers can increase very rapidly in suitable habitats. To check for rabbits, look for droppings or freshly used burrows within a 400m radius of the planned tree planting area. Total exclusion of rabbits using rabbit fencing is usually too expensive for conservation planting. Extermination of rabbits is a specialist job. Rabbits thrive in cover such as thickets of bramble, elder, hedgerows, and on banks and piles of rubble, which are just the sort of habitat the conservationist usually wants to keep and increase!

Browsing damage by rabbits and hares can be distinguished from browsing by deer, because rabbits and hares make a clean, usually oblique cut and often leave the severed shoot on the ground. Deer leave a ragged cut, and eat the shoot. Bark damage by rabbits and hares is usually from ground level up to 50cm (20”), but may be higher after snow. The damaged area shows a diagonal pattern of teeth marks, with the width of each tooth mark less than 3.2mm. Smooth barked trees are preferred, with ash and cherry favourites, whilst alder may be ignored. Compared to vole damage, the damage is higher up the stem, always above the level of the grass mat, and is not so concentrated in one patch, so that areas of bark remain between the gnawed strips.

Damage by browsing and bark stripping can occur up until the trees are about eight years old, but sometimes even the thick bark at the base of semi-mature trees may be attacked.

Hares can be damaging in commercial plantations, but are unlikely to cause problems in conservation or amenity plantings. Their favoured habitat is open grassland, with one hare per two hectares a high population, but they can cause damage where they use woodlands for shelter.

Trees can be protected against rabbits and hares by various guards (see table below) or by fencing. Where populations of rabbits are high, specialist help with live trapping or gassing may be necessary.

Deer

There are seven species of deer living wild in Britain, of which two, red and roe, are native. Most areas of Britain have one or more species well established. Fallow deer are fairly common throughout lowland England, with roe deer common in southern England, and in most of Scotland. Sika, muntjac and chinese water deer have spread from various parks and are common in certain localities. There are probably more deer in Britain today than at any time in the past.

Deer cause damage to young trees by browsing on the shoots, especially between January and May, when the shoots are tender and other food may be scarce. Browsing damage can occur though at any time of year. young trees browsed by deer develop many leading shoots, or if severely browsed, form small, clipped bushes. Cherry is particularly palatable to deer, followed by ash and willow, whereas they dislike alder, birch and walnut. Taller shelters than those normally recommended against particular species of deer may be needed for the more palatable tree species.

The vulnerability to being browsed will depend on other food available, but likely targets are:

• Recently planted trees, especially if planted in clearings where deer are accustomed to graze. There is some evidence that planted trees are more palatable than natural seedlings, which may be due to the increased nitrogen content from use of fertiliser in the tree nursery.
• Young trees surrounded by thicket-stage plantings, scrub or bushes, which give cover and shelter.

Browsing by deer not only causes immediate damage, but delays the time by which leading shoots grow beyond their reach, so in the worst cases, the trees never ‘get away’.

The smaller deer, roe and muntjac, can cause damage by fraying the stems of young trees with their antlers. Fraying by roe deer occurs for several months before the rut, and can cause scattered damage to a developing woodland.

Trees can be protected from deer by guards (see table below), chemical repellents or perimeter fencing. Electric fencing has not been found effective for more than very short-term protection. Roe deer are virtually immune to electric shocks! For the longer term management of woodland, control of deer populations in association with a local Deer Management Group is likely to be the best method. contact your local Forestry commission office for advice.

Squirrels

Squirrels do not damage newly planted trees, but affect which species you should choose to plant as they can severely damage established smooth-barked trees, of between 8 and 30 years age, by bark stripping. It is not worth planting beech or sycamore if the local squirrel population is high. Oak and sweet chestnut may also be attacked, while ash, cherry or walnut are usually not touched. Bark stripping is thought to be caused by males with insufficient territory. Fencing and tree guards are ineffective, and control by poisoning or live trapping is the only method, preferably in association with a local Squirrel Management group. Contact your local Forestry commission Office for advice. control measures should aim for a small number of dominant males to keep out invaders, as eradication will only cause others to move in to the territory. See Chapter 7 – Aftercare.

Stock

Cattle, sheep, horses, goats and other stock do not mix with young trees. Even where there is plenty of grass to eat, stock are always curious, and will tend to nibble most things within reach. They will also trample young plants, use stakes and guards as rubbing posts and strip the bark. Stock will seek the shelter and shade of young trees, trampling them and compacting the ground around the trees, impeding drainage and causing damage to roots.

Tree guards, surrounds and fences around young woodlands must be designed to exclude stock in adjacent pastures, as detailed in the tables here. Any structure must be substantial and soundly built, as stock will lean on the surround to reach inside to browse and graze, and rub themselves against posts and rails. Goats and some sheep will also put their feet up on rails or netting in order to reach higher to browse.

When selecting the type of guard or fence, consider the general state of fencing in the area. Particularly when grazing is in short supply, animals on neighbouring land may break out through inadequate fencing and stray onto land where they have access to your trees, and cause damage in a matter of hours. It is the legal duty of the neighbour to control his/her stock, but it may be prudent to take precautions against the loss of several years’ tree growth.

People

In some situations and communities, there will be no need to protect young trees from accidental or purposeful damage. Some sites will require protection, while in other situations protection may actually draw attention to the trees, making them more vulnerable to vandalism. Elaborate tree surrounds may be seen as a challenge for people to get through, take apart or torch. Sometimes larger trees are respected more than small transplants, while in other places larger trees may get snapped off while smaller ones are ignored.

Consultation

Consultation with local people is vital at an early stage in planning any tree planting. It’s not just a matter of ‘winning people over to your point of view’, but allowing locals to take a real part in putting forward ideas, forming plans and taking a practical part in planting and management. See The Urban Handbook – People and places for further discussion.

Guards

Vole guards, spiral rabbit guards and treeshelters make trees more easily visible so they are less likely to be trampled or mown accidentally, although this visibility can also attract unwanted attention. They have no effect against accidental damage from children playing football for example, or against vandalism.

Plastic or wire mesh guards protect against trampling and mowing damage, and prevent direct damage to the stems and bark of trees. Plastic guards are easier to vandalise than wire mesh guards.

Rigid metal tree guards are expensive, but may be appropriate for trees in parks, pavements and pedestrianised areas.

Post and rail or post and netting surrounds will be respected in many communities,but in some areas may be vandalised, torched or stolen. chestnut paling is difficult to climb and awkward to take apart, but can be quite easily stolen or cut away in sections.

Other methods

The planting design and method of management in the early years will have an effect on people’s perception of the planting, and its susceptibility to vandalism. When planting areas of formerly mown grass, the simplest and most effective method for successful establishment and weed control is to plant direct into the sward, and then use a herbicide. However, this may draw unwanted attention to the young trees. Instead, it may be better to let the grass grow up long, until the area is perceived as a piece of rough ground, and then plant shrub and tree species amongst it. The conditions of shelter, shade and higher humidity may physically benefit the young trees on otherwise exposed sites, as well as hiding and protecting them from unwanted attention. On the other hand, some residents may view this type of planting as untidy and unkempt.

Fences or guards?

The cost of individual tree protection increases directly with the number of trees protected, whereas the cost of fencing relates to the size and shape of the land enclosed, regardless of the number of trees enclosed. On average, as the size of the tree planting area increases above 1 hectare (2.47 acres), fencing becomes proportionally less expensive than individual protection. For areas below 1 hectare (2.47 acres), individual protection is normally cheaper. However, choice should always be made by making separate costings and comparing them. Fencing costs are affected by the shape of the enclosed area, the number of strainers needed and other factors. Individual protection depends on the total number of trees and for any given area, varies according to the spacing of the trees.

Perimeter fencing against deer or rabbits should be considered for:

• Areas over 1 hectare (2.47 acres).
• Areas with trees planted at 2.1m spacing (2250 per hectare).
• Plantings which include conifers, as these are particularly vulnerable to deer damage.
• Areas which have valuable woodland flora and high deer populations. Deer, and especially muntjac, can cause severe browsing damage to bluebells, primroses, orchids, dog’s mercury and other species.

Perimeter fencing can be a disadvantage in blocking routes for wildlife or restricting the passage of game birds. Badgers can be catered for by constructing a badger gate. Fences should also not be built across deer ‘runs’, as deer will continue to try and use the run, damaging themselves and the fence.

Fences restrict public access to woodland. This restriction may be useful in the establishment phase, but may be less appropriate as the woodland matures and its recreational potential increases. In the long term, light grazing of woodland by stock or wild animals can promote diversity. It may be appropriate to remove the fencing once the woodland is established.

In large woodlands it may be possible to fence areas in rotation to use grazing, browsing and trampling as agents to manage natural regeneration and other aspects of woodland development.

For full details of stock, rabbit and deer fencing, and badger gates, see Fencing – Fencing – special uses. Note that electric line fences against rabbits and deer are only suitable for temporary protection. For long term protection, fences of rabbit netting or deer netting to a suitable specification must be used.

Products, materials and techniques

General points:

• There is a huge range of products available, with new ones being added each year. Well-tried and tested products are usually the best choice.
• Choose environmentally-sound products, for example those which do not contain pvc. Some products are made from recycled plastic.
• However well protected, weed control is still vital for at least the first three years. Make sure that weeds do not get established inside the guard or shelter, and keep at least a 1m diameter weed-free circle around the tree.
• Check at least annually, to make sure the shelter is not restricting tree growth. Many shelters are now made with perforated lines which split as the tree grows.

Table 6c is a guide to the heights required against different species. There is no point in using a guard that is taller than necessary, as this will involve extra expense, although taller guards may be necessary on steeply sloping ground. Nearly all manufacturers of tree protection products use these heights as standard. Note that treeshelters and plastic mesh tree guards are not sturdy enough to withstand cattle or horses.

Table 6c: Heights of treeshelters and guards

Table 6d (below) gives a guide to some of the products available, and their uses. Most are available in a range of heights and diameters. The choice depends on the size and bushiness of the stock being planted, as well as the animals to protect against. The products are described further below.

Treeshelters

Treeshelters were originally developed as ‘mini-greenhouses’, to increase survival and growth rates on newly planted trees, by lessening the stresses caused by transplanting. growth can be from two to five times the normal rate in the first few years. Treeshelters are also useful to:

• Reduce the losses caused by mammals, including browsing, bark stripping and fraying.
• Reduce damage by strimmers, brushcutters and mowers. Care still needs to be taken that the machine does not damage the shelter.
• Make trees easy to spot amongst tall vegetation, so speeding maintenance.
• Reduce the cost of herbicide application, by making it quicker and easier to spray or apply granules around the tree without damaging it.

Table 6d: Tree protection products

There are also disadvantages to treeshelters:

• They are conspicuous, and can attract vandalism.
• On windy, exposed sites, the leading shoots are often badly damaged once they grow above the top of the shelter. Roadside plantings can suffer similar damage from the slipstream of passing lorries.
• Treeshelters accelerate early height growth, but stem diameter and root growth do not increase proportionally. If shelters are removed too early, the young tree will not be able to support itself.
• Treeshelters are not recommended for protecting beech, as this can be severely damaged by the beech woolly aphid, which thrives in the humid conditions inside the shelter.
• As the base of the stem thickens it can fill the shelter. if the shelter doesn’t split, rainwater can get trapped and kill a ring of bark, so killing the tree.
• Weed growth inside the shelter will be enhanced, which may choke the young tree.
• Treeshelters must not be seen as the panacea of tree planting. A treeshelter will not make up for poor quality plants, careless planting or inattention to weeding.

Where there is no threat to the trees from animals, the extra expense of treeshelters may not be justified in terms of improved growth and survival alone.

Treeshelters encourage faster growth by increasing the humidity around the leaves, and reducing transpiration and passive water loss from the ground inside the shelter. This is especially significant in the first spring after planting, when roots have not regrown after transplanting and are less able to absorb water. If there is a drought, losses of newly planted trees not in shelters can be high. However, temperatures are significantly higher in the shelter than outside, and this can be stressful to the young plant in mid-summer if new roots have not grown. It’s therefore important that where shelters are used, trees are planted and shelters fitted in late autumn or very early spring, so that the roots have time to grow before high summer temperatures are experienced. Shelters must not be used to extend the tree planting season into late spring.

There is a wide range of satisfactory products on the market, in unobtrusive browns and greens. All have rounded or splayed tops to reduce chafing when the leading shoot emerges. The ties are fastened to the shelter in such a way that they cannot encircle the tree. Stakes are required to support and secure the shelter (quills excepted). The stakes must not protrude above the top of the shelter, otherwise the leading shoots will chafe against the top of the stake. Suitable stakes are available from suppliers of treeshelters, normally either 20 x 20mm hardwood, or 25 x 25mm treated softwood, in lengths to suit the particular shelter. Hardwood is denser and stronger than softwood, so thinner stakes can be used.

Treeshelters are designed to break down under ultra-violet light after about five years, although in practice this does not always happen. In very shady or overgrown situations the shelters may not get sufficient light to cause disintegration, so they eventually restrict the growth of the trunk. Trees should be checked at least annually, and as necessary, shelters can be slit downwards with a knife, and then left in position for a couple more years to protect the bark against mammal damage. Some shelters have a perforated line so that the stem can break through as it expands.

Treeshelters will normally protect against voles, provided the shelter is pushed well down into the soil, so there is no gap at the base. Occasionally voles may nibble through the base of the shelter where populations are high. Treeshelters are not sturdy enough to protect against cattle or horses, as the treeshelter itself is likely to get damaged.

Shrubshelters are a similar product with a wider diameter, suitable for protecting multi-stemmed shrubs and trees. Compared to a treeshelter, the humidity difference inside the shelter is not so marked, due to the wider diameter of the tube, so growth enhancement is not so significant. quills are self-supporting shelters, 60cm high, with a pointed base for easy insertion in the ground. They are suitable for hedging and other low-cost planting, and protect against voles and rabbits.

The procedure for planting and fitting shelters varies with the situation, product and personal preference, but the result should be a shelter which is upright, firmly attached, and with the base just below ground level. In theory one should knock in the stake first and then plant the tree, in order to ensure that the stake does not damage the roots. In practice, this can be quite awkward to do, as the stake is very close to the tree, leaving little room for making a notch. If you dig a pit, you must knock the stake in afterwards or you will dislodge it. When planting, position the main roots away from the windward point, where the stake will be knocked in.

1. If notch planting, remove the turf at the planting position so that weed growth is not encouraged inside the shelter. Alternatively, apply herbicide immediately after planting, and before fitting the shelter.
2. Plant the tree as described above.
3. Knock the stake in firmly on the windward side of the notch, at the correct distance from the tree to suit the particular shelter. Try and knock it in so that a flat side of the stake, not a corner, is against the shelter, so that the tie will not work loose. Alternatively put the shelter over first to aid positioning of the stake, and then one person holds the top of the shelter out of the way while another knocks in the stake. Another variation is to slide the tree root first into the shelter before planting, and then plant tree and shelter together! This can be the easier method if the tree is branching, or if the shelter has an internal stake loop, which tends to snag.
4. The top of the stake should finish about 5cm (2”) above the upper tie on the shelter. It must not protrude above the top of the shelter, or the leading shoots will chafe against it when they emerge from the top of the shelter.
5. Fit the shelter over the tree, pushing the base into the ground. This prevent voles burrowing underneath, and for designs with only one tie, is important for holding it firm. Fasten the ties tightly.

Quills

The quill is a slim-diameter shelter with a pointed base, designed to be used without a stake. In friable soil, the base of the quill can be pushed about 15cm (6”) into the ground without damage, which is sufficient to hold it securely in position. quills are mainly used on hedging and other low- cost single-stemmed stock.

Gro-Cones

These treeshelters are slightly conical in shape, so they can be nested together for storage and transport. They are made of a net-reinforced transparent plastic, with a weld-line that splits as the stem fills the shelter. They should be fitted with the wider end uppermost, and can be supported by stakes, canes or steel rods.

Shrubshelters

These are strong, wide-diameter shelters for shrubs and other multi-stemmed plants. They need to be well anchored with stakes, as they offer greater resistance to the wind than do narrower shelters. Acane pushed into the ground on the opposite side to the stake will help prevent the shelter spinning round in the wind.

Shelterguards

These are a cross between a shelter and a guard, and are made of plastic mesh laminated with polythene film. The film degrades after two to three years, leaving the mesh to give longer term protection to the stem. Various sizes are available for trees and shrubs.

Plastic spiral guards

These prevent rabbits and voles stripping the bark from young trees, and are suitable for protecting the lower stem of large transplants which are at least 15cm (6”) taller than the guard. Small transplants hidden within an opaque guard will not grow properly. Spiral guards can also be fitted to young established trees with a stem diameter of about 38mm (1.5”), to protect the bark after a treeshelter has been removed or disintegrated. Spiral guards can be re-used.

Spiral guards are available in brown, green, white and clear, and are supplied nested together for ease of transport. Depending on the size and type of planting stock, canes are normally needed to support the guard, otherwise the stem bends over under the weight of the guard. Spiral guards are not suitable for feathered trees, multi-stemmed shrubs or conifers, as they are only suitable for protecting a single, clear stem. Spiral guards are often used in addition to further protection, such as a perimeter fence to keep people and domestic stock at bay.

To fit, it’s usually easier to fit the guard around the stem first, and then push the cane down through the guard and into the ground. Push the base of the guard a little way into the soil, to prevent it being dislodged by the wind or by animals. Once the stem has grown larger than about 5cm (2”) diameter, gaps are created in the spiral and the guard no longer gives complete protection. Some guards disintegrate after a few years, whereas in more sheltered positions they can last almost indefinitely. remove them once they become ineffective. Check particularly that the base of the guard is completely removed, and is not entangled at the base of the stem.

Vole and strimmer guards

These are short plastic guards which can be wrapped around the base of established young trees in areas where long grass can lead to explosions of vole populations. In most situations, treeshelters or spiral guards will give similar protection from the time of planting, but vole guards can be useful after shelters have been removed. Strimmer guards are used in mown areas to protect the stems of young trees, of over 6cm (2.5”) stem diameter, from damage by strimmers and mowers. Some companies market the same product against voles and strimmers, others have separate products.

Plastic mesh guards

These are available in different sizes, heights and weights to protect against the full range of domestic and wild animals. They also protect against mower damage and inadvertent trampling, but are not vandal-proof. They give limited protection from wind damage. Mesh guards are recommended in preference to treeshelters for beech, as the humid atmosphere in treeshelters encourages the beech woolly aphid. Mesh guards need supporting by one or two stakes. On established trees, they can be used without stakes to prevent bark-stripping.

Various mesh sizes, colours and heights are available, either in rolls, or pre-cut and supplied as split tubes. Ring guns are available from tree guard suppliers, for quick fastening of rings to join mesh. Alternatively use tree shelter ties, or thread a bamboo cane through to join the ends of the mesh together.

Steel mesh guards

These are not generally used when planting transplants or other young trees, but are more suited to protecting the trunks of standard trees against vandalism, mowing or bark-stripping. They are more durable than plastic mesh, but are also more expensive. On some sites it may be worth substituting treeshelters or plastic mesh guards with steel mesh guards once the new trees are established, to give long term protection.

Mild steel guards and grilles

These may be needed to protect trees planted in pedestrian precincts, car-parks and other vulnerable sites. The grille prevents the tree being dug up, and protects the roots from surface damage.

Timber guards

Custom-built timber guards are suitable for long-term protection of individual trees in pastures and parkland. These can be designed to protect against domestic stock, as well as preventing mower damage and discouraging vandalism. They should be carefully designed and built, and constructed of preserved timber for durability. They are only worth doing well. A poorly constructed guard or one  of  weak  timber  will  soon  be damaged by stock.

Within the timber surround, the young tree can be protected from voles, rabbits and hares by a treeshelter or spiral guard.

Tables 6e and 6f give information on suitable dimensions of fencing or timber guards to protect trees against different types of wild and domestic animals.

Table 6e: Spacing of verticals and horizontals

Table 6f: Height of guard required (in metres)

Note the following:

• Make sure that all likely damaging animals are taken into account, as it is difficult to subsequently upgrade the protection.
• Unless vandalism is a problem, a section of climbable fence is useful for tending the tree.
• As with all young trees, keep a weed-free circle of at least 1m radius around the tree, by using a mulch or herbicide. If the entire enclosed area can be kept weed- free, this has the added benefit of removing the inducement for animals to lean over or push through to graze.
• It is not possible to build a tree guard simply of three or four posts with strained wire or netting, as sufficient strain to keep the wires taut will pull the posts inwards. Horizontal rails, preferably rebated, must be included (see below).
• Where netting is fitted to a surround, it’s not usually a good idea to slant the posts outward to increase the distance of the top rail from the tree, as it’s then difficult to fit the netting neatly.
• Barbed wire should not be automatically added, as this won’t stop stock leaning over the barrier, but will make it difficult to climb in to tend the tree.
• The vulnerability to browsing or bark damage depends partly on the availability of other food, and the palatability of the planted trees. Where grass is plentiful, trees may be ignored, although beech in particular tends to be targeted. It’s vital to protect the leading shoot from any damage. Once this is out of reach, light browsing by cattle may not be a problem, and may merely encourage upward growth by ‘side pruning’. Horses can be very destructive, particularly when they are bored, and can destroy a tree by bark-stripping.

The designs shown can be adapted using tables 6e and 6f. Unless using home-produced posts and rails, it’s easier to design the surround using standard sizes of fencing materials. For example, standard 3.6m rails, cut into lengths as necessary, are used in the designs below.

The first design is proof against sheep, and against cattle in most situations.

The tall surround with rabbit netting around the lower section is proof against all likely damaging animals, except voles and squirrels. Attach one end of the upper netting by twisting the wires, without stapling. This allows the section of netting to be rolled back to give access for tending the tree. A heavy-duty mulch mat which covers the enclosed ground area is recommended for weed control inside netting surrounds, as accurate herbicide application may be difficult. This type of surround, which excludes browsing animals by height, rather than by reach, tends to be the most economical design. Its cage-like appearance can look rather unattractive.

This type of fencing surround against horses and cattle is expensive in materials, but may be preferred because of its appearance. Sheep netting can be added, and individual rabbit guards used as necessary.

Planting a single tree in a surround is not necessarily the best way of creating a future specimen tree. The young tree will have a hostile microclimate with little shelter and low humidity, and even an expensive surround will not guarantee its survival. Where space is available, it may be better to plant a group of trees and shrubs, and then thin at a fairly early stage to leave the desired number of individual trees. Don’t leave the thinning too late, or the trees will not have put out sufficient bracing roots, nor have the desired spreading shape for ‘parkland’ trees.

Other methods of protecting trees

Thickets

Thickets of bramble, blackthorn and other prickly shrubs can be useful for hiding young trees from vandals, deer, and other unwanted attention. A shrub border will also give shelter from the wind and greatly increase the wildlife value of the planting. However, shrubs can also provide cover for vandals and deer, and need to be impenetrable to be totally effective. Brambles and blackthorn are very invasive, so regular management is needed to make sure they don’t overtake the young trees.

Chemical repellents

Chemical repellents against deer have been tried in the past. These have included specially developed products, as well as wood preservatives and lion dung.

Chemical repellents may be useful for short term protection, for example if pest populations increase unexpectedly. Proprietary products, for example ‘Aaprotect’ are applied by spraying or painting vulnerable parts of the young tree, and are mainly used for commercial conifer plantations. ‘Aaprotect’ can also be effective against rabbits. For further information see Pepper, Neil and Hemmings (1996).

Rags dipped in creosote have been used to deter deer. Tie the rags at deer head height at hedge gaps or points where deer enter the planting area. Brightly coloured plastic strips, old CDs and other waste materials have also been tried, but will only have short term effect, if any. The Forestry Commission tested the use of lion dung, but reported no measurable effect!