Vegetation management

Tree contractor trimming a tree from a cherry picker

We love trees, but not near our lines.

Trees cause around a quarter of all power cuts on our electricity network each year. Many serious outages in storms are caused by trees or branches being blown into lines. Overgrown trees also make it difficult for our crews to restore power.

To help keep the power on for our customers, we run a cyclical vegetation management programme across our network.  

This proactive approach sees us manage each tree site at least once during the cycle period. 

Cycles are designed to achieve the best balance of network reliability and cost-effectiveness, and are split into three areas:

  • Tauranga, Waikato and Thames Valley – 3 yearly cycle

  • Taranaki, Whanganui and Manawatu – 4-yearly cycle

  • Wairarapa – 5-yearly cycle

In areas where our most critical assets are, we carry out annual inspections to trim or remove vegetation.

Proactive management of the vegetation around our network is important as it affects how many power outages our customers experience in the short-term, and the overall reliability of our network in the long-term.

In FY21, we’ve managed a total of 14,389 tree sites by…

  • Trimming at 3,815 sites

  • Removing at 10,185 sites

  • Spraying at 390 sites

Technology also plays an important role in our vegetation management programme.

We use LiDAR (Light Detection and Ranging) technology to see where trees and other vegetation is growing too close to our overhead lines. This allows us to proactively trim or remove it to avoid any potential outages.

We’ve also started using mechanical mulching technology, a forestry mulching machine using a rotary drum with “teeth” mounted on the front of a small all-terrain vehicle that clears sections of vegetation in bulk. We’ve also started using digger mounted tree shears to remove fall in trees around the network.

The end result is reduced risk of tree-related power outages.

While removing trees is necessary for keeping our network safe and reliable for our customers, we support planting native trees in areas away from our powerlines. That’s why we’ve partnered with Asplundh (one of our contractors) and Wild for Taranaki for Replant for Tomorrow.


Latest project update

Tuesday, May 18, 2021
We've joined forces with the Electricity Networks Association to highlight the importance of trimming trees.

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