What protection is needed?
Consider the planting location and look at the threats to the tree. In urban areas the greatest threats may be human.
Wilful damage by bored youths may occur in urban areas while on roadside verges the effects of traffic and road or roadside treatment with salt and herbicides should be taken into account.
In gardens, and on verges, one of the biggest threats is from the mower.
In rural situations it is essential to recognise the dangers posed by wild and farmed animals. They may browse on leaves, chew buds and break off branches, while bark stripping is also a serious problem. Look for signs of rabbits, hares and deer; consider what livestock may use the site in the future, either for grazing or as a means of accessing other land.
What are the options?
There is a wide choice of guards and shelters for use on single trees, small planting projects, roadside verges and where trees are spaced far apart, such as in avenues. Where a lot of trees are planted close together on one site, fencing is an option, but it is important to remember that the cost will be determined by the shape of the site to be fenced. Square sites are the most economic, while erecting fencing around a long, thin site will dramatically increase the cost of protection per tree.
Tree shelters have the additional benefit of promoting growth by acting like a mini-greenhouse — reducing draughts and increasing the temperature slightly. There is also a lower risk of herbicide damage and, being more easily visible, of being hit by machinery.
How long is protection required?
The risk from threats tends to diminish as the tree grows, but the length of time protection is needed will vary depending on the threat and on the tree species.
Protection can be short or long term. Some of the plastic tree guards and shelters are light-responsive and disintegrate after a few years. Others may require collection, disposal or recycling — increasingly common demands in tree-planting contracts.
Protection from deer and livestock is likely to be a long-term requirement, so in pastures and parkland it is an advantage to use timber guards. Where protection is long term, it is important to consider the growth rate of the tree, as guards left unmonitored may cause growth restriction and damage.
Access should also be considered, as it may be necessary to water the tree, weed and loosen the ties around it.
How do I work out what size of guard or shelter is required?
The size of guard needed to protect a tree will depend on the size of the tree when planted and, equally if not more importantly, the threat to the tree. It is essential to understand the threat and know which parts of the tree are likely to be damaged. Rabbits are notorious for nibbling away at the bark but, even standing on their hind legs, will be unable to reach higher than 85cm.
In some instances, the distance from guard to tree also has a bearing on best choice. Red deer can reach a little over 2m high when standing next to the tree, but if the guard extends a metres from the tree, the height can be reduced to 1.2m. As a rule, the closer the guard to the tree, the taller it needs to be.
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