Bird-friendly trees to replace V-cuts as power lines go underground

“V for Vector” pruning cuts made to trees lining 6.3km of St Heliers streets will gradually disappear as a result of a major undergrounding project by the lines company and its majority shareholder Entrust. 

The project will remove 14.9km of overhead electricity lines that at present run through the centre of berm (street-side) trees, which have to be severely pruned back to give the lines clearance.

Fifteen streets are involved, covering the eastern side of St Heliers Bay Road through to the waterfront, including streets bordered by Maskell Street, Sylvia Road and Glover Road (see map). 

Work has already begun in Maskell Street and Sylvia Road, and the entire project is scheduled to be completed in late 2023. More than 420 poles will also be removed.

Once the lines are removed, nature will take over and gradually fill in the V-shaped gaps in the trees. However, some trees that have had major branches removed might have to be replaced.  Entrust does not decide whether trees should stay or go — they hand over that responsibility to the trees’ owner, Auckland Council. 

David Stejskal, the council’s Regional Arboriculture and Ecology Manager Community Facilities, explained which criteria are used to decide which trees should be removed and what they will be replaced with. He said two council teams are involved: the Arboriculture team and the Urban Forest team. 

The Arboriculture team evaluates the safety and structural soundness  of the tree.  “In cases where a tree has been reduced to two widely-spread ‘arms’ with nothing in the middle, and is  about to fall apart, or is a safety hazard, a decision will be made to remove it, although this requires resource consent if the tree is more than 4m high. Sometimes all the trees in a street will be removed, which requires public consultation.”

If a tree has to go, David explained, the council’s Urban Forest team will decide on “a lovely new tree that has a better chance to survive”.  Asked whether  trees are prioritised for berm planting if they provide berries and nectar to feed native birds, David said the Urban Forest team was “on the same page” as the Songbird Project in that regard. “We try to plant the right tree in the right place,” he said. “When choosing new trees we focus on trees that are food sources for birds, whilst taking into account factors like their forecast height, parking requirements (will cars be parked on their roots?) and whether in some cases a deciduous exotic tree would be best.

Consumer trust Entrust, which owns 75.1% of Vector, has an agreement with Vector that requires an average of $10.5 million to be invested in undergrounding and other projects in the Entrust area every year.

On its website, Entrust says Vector’s process for choosing where to underground is run independently of Entrust. St Heliers was chosen based on a number of factors including the age, condition and performance history of the existing electricity lines and equipment in the area, the number of customers who will benefit, and the opportunity to link in with fibre deployment and other infrastructure projects.

All new residential developments since the late 1960s were undergrounded at the time of construction. Older areas such as St Heliers are gradually being ticked off  the “to do” list. So far more than $195 million has been invested in 230 undergrounding projects throughout Auckland since the programme began in 2001.

Residents who live just over the project’s perimeter of Riddell Road and Maskell Street — and thus outside the undergrounding zone — are looking enviously at what’s happening down the hill and wondering if they’ll be next. However that decision will not be announced until the current project has been completed.

Story and picture by Jan Power