Willow removal near Lake Coleridge protects wetland and power supply

Large ‘wilding’ willow trees are being removed along the main road to Lake Coleridge to protect a pristine local wetland and critical power infrastructure in a partnership between councils, local landowners and power suppliers. 

What’s happening near Lake Coleridge

What: Around 40 mature ‘crack’ and ‘grey’ willow trees are being removed using a “drill and fill” method, followed by manual removal by ground crews.

When: Work is taking place throughout March 2026.

Where: Along Lake Coleridge Road in North Canterbury. The trees line about 500 metres on both sides of the road, with branches closing in on Transpower's transmission poles and residential power lines. They are also growing amongst a local wetland.

What this means for you: If you are travelling through the area over the next few weeks, temporary traffic management will be in place while work is underway.

Working together to manage risks

This work is part of an Environment Canterbury core service to control pest plants and protect and enhance biodiversity across Waitaha Canterbury.

We’re doing this mahi in partnership with Transpower, Orion, Coleridge Downs Station and the Selwyn District Council to collectively address the risks posed by these pest trees. 

A coordinated approach to long-term protection

Councillor Claire MacKay, Environmental and Protection Core Service Lead, says this project is about good governance - addressing ecological threats early and working collaboratively to deliver lasting benefits for the region. 

“This project reflects our responsibility as a regional council to manage long‑term environmental and infrastructure risks. By working with landowners, local councils and power providers, we’re protecting a rare wetland while also safeguarding critical electricity assets that communities across Canterbury rely on.” 

Why wetlands near Lake Coleridge need protection

Wetlands act as earth's ‘kidneys’ and purify water by filtering out pollutants. They:

• store carbon and help combat climate change
• act as natural buffers against floods
• provide a sanctuary and nursery for a wide array of biodiversity.

The wetland near Lake Coleridge Road contains a large diversity of native species and is a flood mitigating factor for water coming off surrounding hills. The wetland is almost untouched - as it would have been centuries ago.

Why wilding willows are a problem in Canterbury

We collectively decided to remove these willows because they are 'wilding’ willows as well as unwanted species. Previously trimmed trees are growing back aggressively.

Wilding willows

• Self-seed and grow aggressively in areas they are not wanted through seeds spread on the wind or broken bits of tree establishing new plants. 
• Considered a major ecological pest because they rapidly dominate native ecosystems, overpower native species, and disrupt the flow of water and waterways.   

‘Crack’ and ‘grey’ willows

• Crack’ and ‘grey’ willows are resilient to a range of adverse conditions - tolerating flooding, heat and cold freezing temperatures, most soils and semi-shade.  
• ‘Crack’ willows – which make up most of the trees along Lake Coleridge Road - can establish a new tree from just a small twig falling into soil. Chopping them down before they are chemically killed would allow them to spread, which is why we treat them and then remove them in a two-stage process that can take up to a month. 
• Grey willows typically spread their seeds on the wind to create hardy, fast-growing new trees.

Learn more about these species and how they are managed:

Find out how to identify crack willow, why it is a pest, and how it can be managed

Find out how to identify grey willow, why it is a pest, and how it can be managed