To trim or not to trim

By Stacy Colyer, spokesperson for Stop the Chop, member of the New Zealand Arboricultural Association and director of arboricultural consultancy Greenscene Ltd, Auckland.

As the new protection rules relating to tree trimming take effect on Thursday, October 1, many New Zealanders will be asking themselves if protected trees on their property should be pruned. Perhaps “how to trim or how not to trim?” is a more relevant question.

With Environment Minister Dr Nick Smith bringing in a last-minute change to the Resource Management Act and revision of blanket tree protection rules, councils throughout New Zealand who have this district plan provision have had to scramble to provide residents with a definition of what constitutes a non-consentable level of trimming.

In an act that is a positive sign of things to come (read “Supercity”), most of the Auckland councils have had a meeting of minds. In consultation with experienced council arborists and external companies like Greenscene, they have agreed on a definition for the permitted level of protected tree trimming. Consent will still be required for pruning scheduled, listed or notable trees.

As of Thursday, if you have a protected tree growing on your property, your local council may say that consent is not required if your trimming work is limited to no more than 20% live growth removal within a year. Auckland City Council allows for the removal of up to 30% live growth if done by a qualified arborist. Pruning should also be done in accordance with correct arboricultural practice, ensuring that the natural form and branch habit of the species is maintained.

Sound easy? It is when you know how. So what does 20%, or even 30%, of live growth look like once it’s on the ground? What are “correct arboricultural practices” – and equally important, what are not? How can you ensure the natural form and branch habit of the species is maintained when you might not even know what kind of tree it is? And what, you might ask, constitutes a “qualified” arborist and how does he or she prune?

Well, 20/30, 30/20… even for a professional arborist, it is sometimes difficult to be sure of the percentage of foliage that has been removed. I would recommend applying the “less-is-best” adage, just to be on the safe side. After all, there’s always next year’s trim if you need to take out more.

The tree industry is often asked what constitutes “correct arboricultural practices”. The closest we have to a New Zealand-compiled, best-practice document is the New Zealand Arboricultural Association’s Amenity Tree Pruning Specifications. I recommend you visit the NZAA’s website www.nzarbor.org.nz for more information about correct pruning practices.

When it comes to understanding the natural form and branch habit of the species you want pruned, a quick visit to the appropriate section of your local library (perhaps online) or the NZAA’s website could point you in the right direction.

Take a look around your neighbourhood and parks – these can also give you a visual indication of a quality “post- prune” look.

For the weekend tree warrior, pruning can be easy if done from ground level, potentially dodgy when undertaken from a ladder and downright dumb if branch walking is required. Believe me, there are well-founded reasons why the arborist’s climbing rope is referred to as “the umbilical” or “the lifeline”. Depending on the pruning required, it may be a wise investment – for the quality and longevity of both you and the tree – to bring in the professionals.

As in any industry, there are good and bad operators in arboriculture. Some are in it for the care of our environment, some for the cash. Some may be in it for both. Using an experienced and qualified arborist – and ensuring they will be actually doing the pruning – will hedge your bets against poor pruning practices. It is important to remember the results of poor pruning can sometimes take years to rectify.

The arborists you get should be able to demonstrate they use current quality arboricultural pruning practices and to provide local referees to vouch for the quality of recent pruning work. Qualifications like a minimum Level 4 Certificate in Arboriculture (or international equivalent) and membership of the NZAA will go some way to proving they are serious about their profession. Having a professional arborist prune your trees should result in a quality job that stands the test of time.

There is an old Greek proverb that says: “A society grows great when old men plant trees whose shade they know they shall never sit in.” With that in mind, prune well and with care for both the tree and yourself.

Stacy Colyer is the director of Greenscene Ltd, New Zealand’s largest arboricultural consultancy (www.greenscene.net.nz), a spokesperson for Stop the Chop and a member of the New Zealand Arboricultural Association.
ENDS

© Scoop Media