Unison is asking Rotorua customers to check whether trees are growing too close to power lines, as trees cause 20 per cent of power outages.

Unison commercial relationship manager Danny Gough said each year, particularly during autumn and winter, power outages which were avoidable occurred due to trees growing too close to the lines and coming into contact with the network during heavy rainfall and high winds.

Mr Gough said there were vegetation crews based in Rotorua who were dedicated to identifying issues and responding to them.

There were areas in Rotorua with a lot of trees, and around the lakes there were a lot of vegetation, he said.


It can also be a big issue in rural areas, Mr Gough said.

He said Union's annual aerial survey programme - happening in Rotorua in mid-April - helped identify potential vegetation problems on the network, but it still relied on customers to make good planting choices or contact Unison if they had concerns.

 'Growth Limit Zone', which explains how far trees must be from power lines.
'Growth Limit Zone', which explains how far trees must be from power lines.

Unison had a planting guide which it was offering to supply to garden centres to enable customers to choose species that would not grow to be a problem, he said.

"We are actively working to educate our customers on 'how close is too close', and the need to contact Unison before trimming or felling the tree, so we can ensure it is done safely.

"Electricity can travel through leaves, branches and tree trunks, transforming them into a deadly hazard. We don't want anyone's day in the garden to end in tragedy, so we ask people to play it safe, and call us before getting out the chainsaw.

"If you do have lines down after a storm, stay clear and keep family, pets or stock well away, and call us immediately."

To report trees near lines or other damage call 0800 2 UNISON (0800 2 86476).

How close is too close?

The Electricity (Hazards from Trees) Regulations 2003 details a 'Growth Limit Zone', which is the space around the power line where trees must not encroach, even in windy or storm conditions.

Further information on 'zones' is available on their website at www.unison.co.nz/growth-limit-zone.

Is there a cost to have my tree trimmed?

Unison may cover the cost to perform the first cut or trim on a tree encroaching on a power line, based on conditions outlined on their website at www.unison.co.nz/trees.

What can I plant near power lines?

Unison recommends that you do not plant trees near power lines. However, if you do decide to plant a tree anywhere near powerlines, you can find Unison's planting guide at www.unison.co.nz/tree-planting-guide.