Arboricultural Practices

Topping is a historical malpractice pruning technique which is generally no longer used by qualified arborists. It is not considered an acceptable practice with the possible exception of hedge reduction.

Topping involves the indiscriminate cutting back of all branches at the top of a tree to an arbitrary height leaving stubs. It is a common misconception that topping a large tree will make it safer. The truth is that topping will make a tree much more hazardous. While there are viable methods of height reduction, “topping” is not one of them.

Because topping generally removes large amounts of foliage, sometimes up to 100% of the leaf-bearing crown of a tree, it puts a huge strain on the tree’s health by temporarily starving it. At this point the tree will either die or start producing vigorous, fast growing epicormic growth from the stubs and trunk that is left. The large wounds left by topping will also allow ingress of insects and disease into the tree’s heartwood putting further stress on the tree.

Topping will also make your trees ugly. Once topped the natural form and beauty of a tree is lost forever and can never be recovered. Instead you are left with an eyesore with the dense unnatural growth often resembling upside-down witches brooms.

New growth brings with it further problems. Firstly, it grows much faster than normal branches, sometimes up to several metres per year. The tree will often outgrow the original size it was before topping in just a year or two. The second problem is that these new limbs are only attached to the outside of the trunk or stub rather than the centre like a normal branch. This make the attachment of these new limbs very weak and they often break off in the wind once the reach a certain size.

There are also a number of hidden costs involved with topping. The original price to have the work done may be cheaper and people often feel they are getting a better deal because they are getting more of the tree cut off for less money. However, don’t be fooled. The tree will need to be re-topped next year and every year following as it now grows many time faster than it had previously.

If the tree dies it will need to be removed and the mere presence of a topped or disfigured tree can devalue your property. The risk of property damage through limb failure and the associated costs are also increased.

Thinning is the reduction of crown density by removal of selected limbs. Most trees are thinned by a maximum of 30%. Weak, damaged, crossing and out-of-place branches are removed to greatly improve the health, safety and appearance of a tree.

The beautifully structured perfect trees you see in city parks have all been carefully thinned by arborists. All Tree King arborists are well trained in thinning and other forms of tree surgery. All work is carried out in accordance to the latest arboricultural practices.

Some objectives for thinning might include:
Safety – a thinned tree is far less likely to blow over or have branches break.
Aesthetics – a properly thinning tree looks much nicer.
Health – thinning allows greater air flow throughout a trees crown.
Improve balance – some trees develop unevenly. Thinning can help balance them.
Light – thinning can allow more light to pass through the canopy to the ground below.
View restoration – trees can be thinned allowing views between branches.
Fruit production – thinning can aid fruit production.

A crown reduction is the reduction of the overall size of a tree. It is the only acceptable method for reducing tree size and should be used instead of topping. 

The objective is to make multiple small cuts shortening the trees branches to appropriate laterals leaving the outer edge of the new smaller canopy intact. When done properly the finished tree should look natural and the pruning cuts should not be too obvious when viewed at a distance.
Generally, the maximum that any tree can be reduced in a crown reduction is 30%. Most trees cannot be reduced by this much and some species are not appropriate for any crown reduction work. We will assess what can be done to your tree at the time of quoting.

An important question to ask is why you want to reduce your trees’ size. Many people will mistakenly opt for crown reduction because they are worried the tree might blow on to their house or because they want more light. In these situations general thinning is often much more appropriate. We are happy to work with you to figure out the best way to achieve your desired results.

Crown lifting is the removal of the trees lower branches up to a set height. It is usually used to provide greater access for people, buildings or vehicles under a tree. As a general rule a trees crown can be lifted a maximum of approximately 25% of the trees total height depending on the species.
Crown lifting can often work really well to improve the light for a property. For large trees it can be a lot more effective than height reduction as it will allow the sun to shine through from underneath. Sometimes a crown lifting can be combined with other forms of pruning to achieve your desired results. We’re happy to assess your trees free of charge to help decide what will be appropriate.

Pollarding is where the upper branches of a tree are removed leaving a smaller stubby-looking tree which will then produce a dense top of new growth.

New growth is usually removed each growth season producing the unique look shown in the image on the right. Pollarding is not that common a practice in New Zealand. It originated in Britain during medieval times. It is mainly used on street trees such as in Takapuna and Auckland CBD. Only certain species are suitable for this procedure. If the wrong species are used they will not survive.

Due to the large percentage of the trees foliage that must be removed for pollarding you may require resource consent to do it on large trees. Find out more in Tree Protection Laws.