Raising The Bark: Why, When, And How You Should Have A Tree's Crown Raised
A large, strong tree can be a fine addition to any garden or plot of land, but leaving your trees to grow unchecked can cause more problems than benefits. One common way in which unwanted tree growth can cause issues is with low branch growth -- fortunately, there is an effective method for removing unwanted low branches while minimising injury and long-term damage to your tree. This method is known as crown raising.
Why should I have a tree's crown raised?
When a tree's limbs grow or hang too close too the ground, they can cause a number of problems:
- Obstructing pedestrian access and road traffic
- Obscuring important signs and traffic signals
- Damaging nearby buildings and structures, particularly in high winds
- Blocking out sunlight and starving plants beneath the tree of much-needed ultraviolet light
Trees growing in urban areas are particularly likely to require crown raising, as public access bylaws can be quite strict on trees allowed to grow unchecked into public spaces. In these cases, you may be required to have your tree's crown raised by order of your local authorities.
What does crown raising involve?
The 'crown' of a tree is the name given to the mass of branches and leaves that spreads out from the central trunk. When the crown of a tree is raised, the lower section of the crown is pruned, leaving the tree with most of its crown intact while creating a larger area of bare trunk. This method of tree pruning effectively clears useful space underneath a tree while minimising branch removal as much as possible. Only removing the lower, shaded limbs of a tree also means that its ability to collect sunlight through its leaves is minimally affected, helping the tree to recover more quickly from the pruning.
How should I have my tree's crown raised?
If your offending tree is a small ornamental variety, such as a lilac, you may wish to undertake crown raising yourself. However, raising the crown of a large tree is a complex and dangerous task, and you should always call in professional tree surgeons to tackle jobs involving working at heights and removing larger branches.
How the crown of your tree is raised will depend largely on the shape and species of the tree, but a good crown raising should have the following qualities:
- Large branches should be left intact wherever possible to minimise damage and infection risks.
- Branches should be removed evenly from the entire circumference of the lower trunk, without focusing damage on any one area.
- Only a few branches should be removed at a time -- ideally a crown reduction will take place in increments over the course of several months to allow the tree ample time to recover from each surgery.
- Less than half of the tree should be bare trunk, even directly after a crown raising. Excessive low pruning can cause a tree to become top-heavy and overbalanced, leaving it vulnerable to high winds and more likely to shed branches.