Guarding trees against danger

Trees are vulnerable to a number of threats. Here's a look at the latest products designed to protect them.

At one time it was simply enough to order a tree and plant it. Now aftercare is mandatory, along with a consciousness of the environmental impact of the use and, ultimately, disposal of supporting and protection products used in conjunction with the trees.
Although there has been a significant fall-off of tree grants for forestry, both local authorities and the private sector still spend a great deal of money on trees (there has been huge investment in them at Heathrow’s T5, and there are good portents for the forthcoming Olympics villages in east London).
The last thing we need, therefore, is for the millions being spent on trees to be wasted because they fail to establish once they are planted.
The main reason for failure of newly planted trees is dryness, which is largely determined by the climate, and is remedied by choosing more drought-tolerant species in the first place, and/or appropriate irrigation systems subsequent to planting.
But, assuming ground preparation is good and the health of the trees at planting time not in question, there are other factors that determine whether they will survive or fail. And most of these factors can be reduced, or minimised, with the use of materials such as tree guards, shelters, or protectors, as well as suitable stakes and ties (where appropriate).
Exposure A position exposed to the full force of the elements can dry out and even dessicate a tree. Suitable guards, which may or may not be solid-sided, can reduce the wind-drying effect. Guards made of fine mesh are known to provide wind shelter. They also permit good ventilation around the tree stems, which helps to prevent fungal disease. On top of this they are kinder to wildlife that gets trapped and perishes in smooth-sided guards.
Animal pests Deer, followed by rabbits, hares, voles and mice are the worst culprits in rural and, increasingly, semi-rural situations. They will destroy the bark of young trees. Leading supplier Tubex est-imates that tens of thousands of trees are killed by voles and mice, which is why the company’s Vole Guard shelter, made from UV-stabilised polypropylene, is so succ-essful. The height of the guard is just 20cm, whereas the standard tree shelters, which are effective against bigger rodents and deer, are 60cm, 75cm and 120cm high.
Vandalism A known urban problem but, these days, even a newly planted tree in a rural location can be susceptible.
Unintentional damage This is caused by such things as bicycles and other larger vehicles knocking in to trees, or the careless use of a strimmer.

Eco-friendly solution to waste
Landscaping budgets for tree guards and shelters should include collecting them in when they have been out-grown. This is a labour-intensive process and with larger schemes represents a significant cost. Director Simon Towler of Norfolk-based Acorn Planting Products has been undertaking manufacturing trials of bio-degradable Shelterguards and Treeguards.
“The aim is to produce a product with a lifespan equal to that of our existing guards, so that browsing protection is not compromised, but to formulate the guard so that once it has split and fallen off the tree it will then start to biodegrade, gradually being buried under leaf litter and ultimately completely breaking down,” Towler explains. “This is a process ideally suited to our Shelterguard material as, being a mesh rather than a solid tube, there is a much lower volume of plastic to break down.”
Acorn is hoping to launch the guards later this spring, and at prices only 10 to 15 per cent higher than the standard range of products. “Hopefully this will make a financially viable, and much more environmentally friendly, alternative,” says Towler.
Shropshire-based Farm Forestry is also conducting trials on biodegradable products. Director Francis Plowden says: “We are not ready to go public yet with this but it is something the industry is crying out for.”
But, as most in the forestry supply sector would agree, times are tough. “We are getting increasing business from the landscape sector,” continues Plowden, “which is useful as forestry grants, where traditionally our market was, are practically non-existent.”
Landscapers, he explains, are providing him with a strong demand for the brown and green 50mm spiral shelters.
“We also have a new business line — extra strong Mega-Mesh shelters for putting around cricket bat willows (Salix alba var. caerulea),” he says. “There are a tremendous number of these trees being grown across the UK, as the worldwide market for cricket bats seems to be for British-grown willow.
“Unfortunately, red deer have worked out that if they stand on their hind legs and bring the weight of their forelegs down on to tree shelters they can get to the saplings underneath, so we’ve been asked for shelters with extra linear strength to stop the deer from bending them down. The Mega-Mesh shelters, made from high-density polyethylene, are also suitable for maiden orchard trees.”
Despite the decline in tree grants, several suppliers of traditional landscaping and tree-care remain positive, with one or two pockets of real investment. In the past year, York-based supplier Green-Tech has seen significant growth, investment both in product, real estate and people, and has been winning awards. It is the biggest supplier and distributor of market-leading Tubex guards and shelters.
Sales director Mark Whiting, who joined the firm a year ago in a newly created role, says: “We have been delighted at our own start to this season. We finished our financial year at the end of September and were seven per cent ahead.” He confirms that Green-Tech has had a record autumn and has a healthy order book for the new year.
“We have invested in an Irish sales manager, who has been instrumental in our significant growth in that market, including our first attendance at the Kildare County Show. We have also commenced a trial plot in Ireland, at Navan Racecourse, to illustrate the benefits of planting with shelters to the Irish market. This has allowed managing director Richard Kay to spend more time on new product development.”
Stakes Traditional staking is still preferred by many specifiers and landscapers. Square sawn tree stakes are the most common, and these are used in the main part for semi-mature trees. Any stake used should be pointed and tannalised to BS 8417:2003.
A 20-25mm square stake is adequate for most tree-planting schemes, but in exposed, soft or stony areas a 32mm square stake should be used. Many other sizes, including machine-rounded stakes (with a chamfered top) are available.
Due to the higher strength of hardwood, and an inherent lack of knots, narrower stakes can give the same strength as a much wider softwood equivalent.
The stake should be driven firmly into the ground prior to planting, so as to avoid damaging the roots. It should preferably be on the northern side of the plant so that it does not cast shade, however, if the site is exposed it may be better to place it on the side of the prevailing wind. Use a small club hammer and knock in the stake far enough to leave about 50mm above the tie.  

Ties and restraints Alpha Contracts of Preston, Lancashire, supplies a tree restraint that provides a protective enclosure to allow the tree to swing slightly. Director Ken Linford says: “A rubber tube protects the bark, but you have to be careful about the shape of the tube. Round tubes can damage the bark when the trunk expands, so we use a flattened, elliptical rubber tube that doesn’t cause abrasion.”
The problem of trees being strangled by unloosened ties is still all too common. This led Big Cushion Tree Ties, based in Denbigh, North Wales, to develop “maintenance-free” ties, designed to give way under the pressure of expanding trunks. The spacer is made of high-density foam, which compresses to allow expansion, and the stitching on the buckle gives way in three to five years. Big Cushion Ties are available in four different sizes, with corresponding spacer widths.
Blocks come slotted to enable strapping to pass through freely. The rubber blocks are made of a durable, high-quality rubber and include nail holes for ease of fitting.

Guards and shelters Tree shelters provide improved growing conditions (a micro-climate) inside the shelter, and they also give protection against small animals and spray drift. When used correctly, shelters will considerably reduce the amount of time spent on site inspecting trees.
Although they are a relatively high investment, avoiding the need for fencing can make savings. There is a high labour input with plastic tree shelters because they should be removed after five to eight years, when most trees and shrubs are established, then disposed of at great effort.
Tubes can cause problems. Birds get caught in them, and as the tubes are smooth-sided, they are unable to get out. And, because tube sides are enclosed, there is a greater propensity for some pests and diseases to take hold. Moisture builds up inside solid-sided tubes and this can encourage disease and rotting, often resulting in deformed specimens. Many solid tubes have a vertical perforated “laser-line” that is designed to come apart as the tree grows.
Mesh guards offer less wind resistance than the solid ones, but unless the mesh is very fine they can also increase water loss from the tree (particularly damaging during the establishment period).

Tree protectors On many urban and rural sites, newly planted trees need protection from vandalism, machinery and animals, and in many situations guards are not sufficient to protect the tree.
Tree protectors, such as those available from Rainbow Professionals, Arbortech (City Guard range) and even the polypropylene Netlon shelters that are available from Derby-based Growing Technologies, will protect semi-mature trees, particularly the most vulnerable area — the trunk — from harmful damage.
They are generally made from mild steel and often with a polymer coating (galvanised finishes are also available).
Supplied in two parts, they allow installation to take place after the tree has been planted. Once the tree has reached maturity and the protector is no longer needed it can be removed and re-used.
If well designed, once in position a protector will continue to allow water and nutrients to be applied. It can be used without grills where the ground is soft and no hard surface is present, but decorative grills or grids placed over the ground and around the tree can help in preventing soil compaction.

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