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Don’t be afraid to seek specialist help

Falling victim to the Dunning-Kruger effect could cost you time and money, so don’t be afraid to seek specialist help

The expression ‘a little knowledge is a dangerous thing’ relates to people who become falsely overconfident about their expertise in a certain subject despite possessing a small amount of knowledge about it.

In a nutshell, this is called the overconfidence effect (or the Dunning–Kruger effect) – and it’s dangerous because when a person’s confidence in their ability is greater than their actual ability, mistakes happen.

The opposite of overconfidence is under confidence and, strangely enough, this can occur in people with high ability or considerable knowledge and is the other half of the Dunning–Kruger effect. The theory is that people with low ability overestimate their own ability, and that people with high ability underestimate their own ability. The theory is based on self-awareness and the ability to objectively evaluate one’s own level of competence. As theories go, I quite like it.

Unknown unknowns

People who lack the ability to proper evaluate their own competence levels are unable to pick out gaps in their own knowledge. They don’t know what they don’t know, and so assume that they’re right (one way or the other).

Just for a moment, let’s pretend that ‘they’ is actually ‘you’ – we all have a bit of ‘they’ in us. So, if you don’t know what you don’t know, and you have confidence in your own

judgment and ability, how do you know when help is required?

The simple yet completely unhelpful answer is that you don’t, or you’ll work it out after the fact (if it all goes wrong, or someone nearly dies). As neither of those are good answers, let’s take a practical approach.

Use your fear

For me, fear is key to my decision-making processes. Fear, not as in being scared (arborists do not tend to be timid), but in terms of fear of not going a good job; of not meeting high personal standards.

When it comes to landscapers working on or near trees, there are a couple of things worth being aware of. Note that I’m not saying raid – being afraid is an emotional state, while fear is useful.

Precaution when pruning

If you take it upon yourself to prune a tree, be extremely careful and never do the following:

  • Make cuts with a chainsaw when that chainsaw is above your head.

  • Make cuts with a chainsaw when standing on a ladder.

  • Or worse still, own or use one of those chainsaws on a pole (which you should never do).

Doing any of the above creates a risk that you will ruin the tree. It’s important to be aware of this because trees can be valued and the value may surprise you. I am currently involved in a legal matter where one party has served notice on another party to the tune of $600,000.00. The matter involves a number of trees – and when I say a number, the number is seven. Yes, seven trees to the tune of $600,000.00.

Additionally, I recently used a Court accepted tree evaluation method to value a self-seeded Douglas Fir tree at just under $20,000! To explain, it wasn’t for me to agree if that was what the tree was worth or not, the methodology was good and the system has been used and accepted before, in this instance it was a matter for the Court to decide.

Roadmap to roots

The other thing to consider is roots, and there are two aspects to this. While you are legally able to remove roots (and/or branches) that encroach over a boundary line (back to, but not beyond the boundary; this is called abatement), you are not allowed to create problems in doing this.

For example, you cannot undermine the stability of the tree or the ground around it. So, if you are putting in a new drive, or a sunken garden, or drainage, or power or anything else in close proximity to a tree on the other side of the boundary, you need to be sure that you don’t create a potential harm situation (ie, cause the tree to fall onto people or property). Note, it might take years to fall over, but if falls, it falls, and your actions may be questioned in a Coroners Court.

In this case, not only could you be charged with replacement costs of the tree (as noted above) or the property damaged, but, worst-case scenario, if the tree falls and kills someone.

The same causes and concerns hold true for damage to your client’s trees, so be mindful when dealing with root systems – you don’t want to damage your clients’ trees or have them falling onto them and/or their property.


Of course, insurance should cover all of those points and insurance is a must, but if your actions weren’t unforeseen (ie, if you chopped all the roots off and as a landscaper, I should know where tree roots are and what they do) then will your insurer still cover you?

So, when it comes to asking for help, be proactive. Ask before and not after. If you are asking for help after the fact, then you’re probably asking for someone to come in and fix something.

If you are claiming on your insurance or answering questions in Court, then someone probably made some bad choices. If in doubt, and there is even the remotest possibility that your actions could cause harm, damage or expense, then make it someone else’s problem.

Get help, get a specialist in. When it comes to trees, if you are using a chainsaw and the saw is above your head, if you are off the ground and/or you’re not in full control of the thing you are cutting, then get an arborist in. If you are digging near a tree and cutting structural roots, or if you are digging near a tree and you don’t know what structural roots are… then get an arborist in. It is okay to ask for help, and it is okay to use a specialist, and much better than the possible alternative.

Mark Roberts is a qualified arborist and tree risk assessor with 25 years’ experience. Mark is also former President of the International Society of Arboriculture, and a past President of the NZ Arboricultural Association. Mark now heads an arboricultural collective based in Dunedin:


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