We’ve produced a guide to tree surgery practices below.
A crown reduction involves shortening the branches of the canopy to reduce the height and/or spread. This may be done to reduce the sail area and the stress on the tree or to create more light and/or space around the tree. The tree should retain its original shape but a bit smaller. This technique is not suitable for all species of tree.
Crown lifting or raising involves removing or pruning the lowest branches of the tree to allow more light below the tree or to improve access, for vehicles for example. No more than 15% of the crown height should be removed leaving the crown to make up at least two thirds of the tree’s total height.
Crown thinning involves removing smaller branches to produce a less dense crown. This may be done to create more light around the tree or to create less weight or wind resistance. This technique should not alter the size or shape of the tree and no more than 30% of the density should be removed. This technique is really only used on broadleaved trees.
Dead-wooding is the removal of any non-living branches and stems from the tree to avoid any risk of danger should it fall. This is particularly important in areas where people may walk, play or drive underneath.
This is fairly self-explanatory; the tree is felled, either in one whole mass if there is space and this is a suitable procedure, or dismantled in sections and lowered down to the ground. A stump will be left afterwards. In some cases you may want to grind the stump to below ground level – see here on when this would be appropriate.
Pollarding or high coppicing is a technique used to manage the size and shape of a tree. A frame-work is created when a tree is young by removing the top of a tree to encourage multi-stem branches at that point. This is carried out every year or two from then on. This is only suitable for certain tree species.⠀
NOTE: not to be confused with topping – an unacceptable and outdated tree surgery practice!⠀
Epicormic and basal growth is when dormant buds in the bark of a tree are stimulated to grow, usually as a result of stress on the tree (perhaps from environmental changes, heavy pruning, changes to the surrounding soils etc) causing smaller branches to grow directly from the base (basal) or the main stem (epicormic) of the tree.
This is very typical with certain species such as Lime, Oak, Willow and Poplar. This growth can be a nuisance in garden and urban environments and can be maintained regularly with pruning to keep the stem and surrounding area clear.
Sometimes trees may grow in a way that means they cannot sustain their own weight. In order to reduce the risk of limb failure and extend the life of the tree two or more limbs can be braced together to spread the weight load and stabilise the tree.
Modern bracing does not contain steel rods as in yesteryear and is now made of a soft mesh braiding which is non-invasive and won’t damage the tree. It is also very flexible and allows for dynamic movement.
Bracing ought to be replaced roughly every 12 years.