Tree trimming
To keep you safe and protect your electricity supply, our expert arborists can keep your trees clear of powerlines.
Trees too close to powerlines are dangerous
In high winds and storms, falling trees and branches can break lines causing power cuts, potential fire risk, electrocution and even death. Repairs can be costly.
If trees aren't regularly maintained, then they can grow into powerlines. Inconvenient power outages then need to be scheduled to trim the trees.
Trees close to powerlines can also be a major hazard to children climbing them.
Who's responsible for keeping trees clear of powerlines?
If you own the land that the tree is growing on, then it's generally your responsibility for keeping the trees trimmed and away from powerlines.
We regularly carry out tree surveys and inspect our lines and do our best to let you know if your tree is getting too close to the lines. However, we also need you to keep an eye out.
In some cases, it may be too dangerous for you to do the work yourself and you’ll need to arrange for Northpower or an approved contractor to do the work.
The Growth Limit Zone (GLZ)
The Growth Limit Zone (GLZ) is the legal minimum space surrounding any powerlines, that must be kept clear of trees. It can vary depending on the voltage of the powerlines, however no person or piece of equipment is permitted within four metres of our lines.
For safety reasons, trees and vegetation in the GLZ can only be trimmed by Northpower or an approved contractor.
The first tree trimming is provided free of charge but subsequent trimming will incur a charge.
It's important you don't trim the trees in the GLZ yourself due to risk of electrocution.
The Notice Zone (NOTZ)
The Notice Zone (NOTZ) extends one metre out from the GLZ.
You can trim any trees in the NOTZ provided we've given you written authorisation. Please contact us and let us know of the tree location and when the work will be done - at least three working days before you want to carry out the work.
If your tree is growing in the NOTZ, we may send you a Hazard Warning Notice advising that the tree needs trimming.
Table showing GLZ and NOTZ by voltage
Growth Limit and Notice Zones vary according to the line voltages.
| Voltage | Growth Limit Zone | Notice Zone |
|---|---|---|
| 400/230V | 0.5m | 1.5m |
| 11kV | 1.6m | 2.6m |
| 33kV | 2.5m | 3.5m |
| 50 to 66kV | 3m | 4m |
| 66kV or greater | 4m | 5m |
If you no longer want to maintain a tree
It's your decision whether you want to continue to maintain a tree or have it removed. If you don't want to organise and pay for regular maintenance, you can declare 'No Interest' in the tree if:
- The tree was naturally sown or
- The tree was planted and at the time of planting the tree owner believed the tree, when fully grown, wouldn't interfere with powerlines.
You need to fill out the No Interest Tree Form (below) and we will advise whether we will remove the tree or what trimming we will do.
Please note that if you choose this option, the trees may be trimmed to a level deemed suitable by us or removed.
You need to read, understand and complete the No Interest Tree Notice if you no longer want to organise regular maintenance for specific trees.
↓ Download PDF (0.21MB)Tree trimming FAQs
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What happens if I don’t keep my trees trimmed?
Because of the danger that trees in powerlines cause, there are penalties if you don’t comply with the Tree Regulations 2003.
Tree owners who receive a Cut or Trim notification from us must ensure the tree is trimmed to outside the Notice Zone (NOTZ) within the timeframe in the notification.
If you fail to do this, you could be fined up to $10,000 plus up to $500 per day for continuing offences. You could also be liable for costs if our lines or equipment are damaged by the tree.
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Which trees are best to plant around powerlines?
Ideally you shouldn’t plant trees that will grow large close to powerlines - low shrubs and small trees are best. You can view a list of our recommended trees here.
When planting trees, you should always check for powerlines and underground cables before you dig.
If you are purchasing a property, you may also like to check to see if mature trees are growing near powerlines as there can be large maintenance costs involved in keeping them trimmed.
Contact us to find out more
If you've got any queries or would like us to take care of maintaining any trees growing near powerlines, please contact us.
Contact us