Q. Why is it necessary to stake trees?
A. Stability must be given to a newly planted tree in order to keep the roots underground, which then extend to anchor the tree in an upright position while it adapts to its new home. This can be achieved by staking, bracing, guying or underground guying.
Q. Is it necessary to stake all tree stock?
A. No. A lot of research has been undertaken - some of it dating back 25 years or more - into both the need to stake and the most appropriate way to stake newly planted trees. Much of the work focused on the size and condition of the stock being planted, along with site conditions, but other factors such as planting and maintenance practices and site function should also be considered when deciding whether to stake and how to stake trees.
Q. How does size affect the need to stake?
A. Very small or low-value stock is generally planted without a stake. For one thing, the economics of providing a stake and tie simply don't stack up, but it has also been argued that small trees will be less likely to move in the wind and even that some buffeting by the wind can encourage root growth. Of course, this only applies where the stock is small, such as whips, and is unlikely to be blown out of the ground.
Larger stock, tall trees, those with spreading crowns, container-grown trees and those with limited root growth will need to be stabilised.
Q. What site conditions are likely to make it a requirement to stake?
A. Windy sites are the ones most likely to cause problems to the establishing tree, especially where the wind is funnelled between buildings. Staking should also be considered on sloping sites and where the soil is shallow or particularly sandy. Remember, the aim of staking is to keep the roots steady in the ground. It may also be necessary to consider the function of the site and the impact people, including grounds maintenance crews with mowers, and traffic might have on newly planted trees.
Q. What length of stake is required to stabilise a tree?
A. Again, this has been a topic of much research. The evidence of trees snapped off level with the top tie on tall stakes suggests that a weak point may develop below the crown. It is certainly the case that the tall stake and high tie provide a point of "leverage" where it is easy for the wind - and vandals - to snap the trunk. With this in mind many trees are planted with short stakes, the aim being to keep the roots stable in the ground while freeing the top of the tree to sway in the breeze. Some research has suggested this gives a stronger tree in the long run. Underground guying of rootballed trees also achieves this and has the advantage that there are no stakes or above-ground guys in the way of people or maintenance machinery - but it is more costly and is usually reserved for high-value plantings.
Q. There are many types of tree tie. Which is best?
A. There is a wide choice of tree ties, and a wide range of pricing. They all serve the same purpose but it is important to ensure that the materials used will last for the length of time required - the same goes for the choice of stake - and that it is designed to fit, and especially adjust, easily. Selection may be simply a matter of cost but remember that a cheap tie will not save you money if it is fiddly to fit and adjust.
Above all, remember that stakes and ties will need checking on a regular basis. Make sure the tie is not too tight around the stem and that the stake is not rubbing against the tree. Stakes should only be used until the rootball has achieved a firm anchor - probably two to three years.