Of all the many and varied services that tree surgeons and arborists offer, crown reductions are among the most drastic and potentially damaging to the health of a tree. Unlike other kinds of tree pruning used to merely thin or shape growth, the aim of crown reduction is to reduce the overall size and spread of a tree with extensive cutting and pruning. As you can imagine, such invasive surgery can severely damage and weaken a tree, particularly if the tree's species does not tolerate pruning well, so it's important not to reduce a tree's crown without good reason.
What is crown reduction?
In simple terms, crown reduction aims to significantly reduce the area and volume that a tree's branches occupy, while still keeping the leaf canopy and shape of the tree intact. This involves trimming many branches to length across a large proportion of the tree's spread. If a tree needs to be significantly reduced in size, crown reduction is generally preferred to topping, as it weakens the tree less and leaves less internal wood exposed to infection and decay. However, the sheer number of smaller cuts that reduction involves can still place great strain on a tree's health.
When and why does a crown reduction become necessary?
There are a number of circumstances in while a simple, localised pruning or branch thinning is not a sufficient solution and reduction becomes necessary:
- If a tree has suffered damage in a load-bearing part of its structure, such as a large branch or within the roots, crown reduction can significantly reduce the load on the damaged wood, making the tree less likely to shed branches or topple over.
- A tree with dense foliage that is casting too much shade on your property (or that of an angry neighbour) can have its crown reduced as an alternative to felling.
- Trees that have started to interfere with overhead power or telegraph lines should be reduced as soon as is feasible -- your local council authorities may mandate a crown reduction in these cases.
- If a tree has suffered extensive branch damage on one side of the crown, for instance during a bad storm or gale, it may become imbalanced and threaten to topple over -- having the less damaged parts of the branches reduced can counter this.
As counter-intuitive as it sounds, the extensive damage that crown reduction causes to a tree can actually be advantageous. After a crown reduction, a tree is forced to slow its growth dramatically to replace the resources it has lost during pruning, and is more likely to limit its growth to lower, unaffected parts of the crown -- as such, a crown reduction generally only needs to be conducted once or twice over the lifetime of a tree.
How should I go about reducing a tree's crown?
Crown reductions are difficult, lengthy procedures that generally involve a lot of dangerous tools working at dangerous heights, so it almost goes without saying that you should call in professional tree surgeons for this one. However, you should always have the surgeons inspect the tree before they start work -- a reputable tree surgeon will be able to assess the tree's overall health and determine the best places to cut back growth without causing unnecessary damage. If a large proportion of a tree needs to be removed, you may prefer to have the job completed in halves, spaced out over several months. This will spread the damage over a longer time period and give the tree much more time in which to recover.
For more information and assistance in a crown reduction, talk with local tree service companies, like Waratah Tree Services.