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Did you know? is a feature that provides information about Vector’s electricity business that we think you’ll find interesting.

Here we take a closer look at the impact of vegetation on the network.

managing trees responsibly to build resilient communities

Trees provide a number of benefits for our city both from an environmental and social perspective.  Managing trees is a community responsibility and by working together, we can help prevent power outages and keep the community safe.

In April 2018, over 200,000 homes and businesses lost power, some for up to 11 days, when trees were blown onto power lines by winds reaching up to 215km/h. At Muriwai, a falling tree narrowly missed a repair crew and destroyed the work they had just completed. 
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Outside of a storm situation however, trees falling on power lines account for one in four faults resulting in loss of power. To reduce the occurrence of these faults, Vector launched an accelerated tree trimming programme in July 2019 whereby “at risk” trees were identified and pruned for free – which will result in greater reliability of power supply. The following statistics illustrate the magnitude of the vegetation impact.
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homes/businesses affected across the network

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1 in 4

faults caused by trees in power lines

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2 for 1

2 natives* planted for every tree cut down

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trees trimmed away from power lines

Figures based on January – October 2019 Vector data.

Besides proactively trimming trees, we also use aerial conductors which are wrapped around power lines to insulate them from contact with trees.

*Vector Urban Forest is our promise to plant two native trees for every tree we cut down to protect Auckland’s powerlines.

tree trimming goes high tech


We use an internationally recognised model called Quantified Tree Risk Assessment (QTRA), to determine the annual risk of harm from tree and branch failure.

Trees that have been identified and prioritised using QTRA are then trimmed by utility arborists that we have partnered with - Treescape, Asplundh and Arborlab. We make every attempt to contact customers who are tree owners, to outline our tree management plans before any tree trimming takes place.

We are also exploring and trialling new technology and innovative practices for the future:

  1. We are trialling new technology with IBM to proactively identify vegetation trouble spots to remove the risk before it impacts the community. Read more here

  2. We are using Light Detection and Ranging (LIDAR) technology where light is used to measure the distance from a tree to a power line to identify at risk trees without the need for foot or vehicle patrols. This technology helps us to identify trees outside of the Growth Limit Zone at imminent risk of coming into contact with our overhead network.

how you can help

  1. Work with us - we will arrange a suitable time to prune at risk trees with your consent. Please do not attempt to trim these trees yourself, as this is highly dangerous work that can result in severe injury or death. You can find more information about maintaining trees around power lines here.

  2. Plant wisely - consider tree species and growth rates carefully before planting new trees or vegetation on your property. More information here.

  3. See a tree growing into network lines? Please report it by contacting us on 0508 832 867 or emailing us at,  and we will send someone out to inspect it.


Did you know?

  • Take a closer look at what happens when a vehicle collides with a power pole, tranformer or another piece of network equipment. 


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