Urban trees enhance Avon...

Avon Precinct

Urban trees enhance Avon River Precinct in Christchurch, NZ

The Avon River Precinct (ARP) is a new city promenade and waterfront enhancement along the Ōtākaro/Avon River in Christchurch, New Zealand. The project marks an important milestone in the city’s recovery from the earthquake that devastated Christchurch in 2011.

Extending 2 kilometres through the heart of the city from Christchurch Hospital to the Margaret Mahy Family Playground, the ARP promenade has been designed as a series of seamlessly connected usable spaces. These include a ‘shared space’ for walking, cycling, driving and tram riding, and a ‘flexible space’ for outdoor dining, parking bikes/scooters and social interaction. The ARP also includes an extensive rain garden for stormwater management and landscape amenity.


Project goals

Prior to the promenade development, there were very few trees within Oxford Terrace adjacent to the river, as this was primarily designed for cars. A major goal of the project was to transform this into a shared space and beautify the area with large, healthy trees. By adding trees, the ARP would become both more inviting and more functional.

As Fraser Miller of Rough and Milne Landscape Architects explained, “Large trees in urban environments are a great investment in the future, providing the city with shade, seasonal colour, clean air and character.”

“For this project, we wanted to avoid small, lollipop trees in paved areas in favour of bigger trees. We needed trees that would thrive in the restricted tree pit situations and provide a lasting legacy for the city. Particularly as these trees would be the signature Red Maples, which would create continuity along the length of the promenade.”


Project challenges and solutions

Due to the complexity and magnitude of this project, many factors were considered to determine the best approach.

“From the outset, we needed to prepare a robust installation methodology, work around underground services, and develop a specialised tree pit mix for the soil cells”, said Fraser Miller of Rough and Milne.

While structural soil was considered as an alternative solution, Citygreen’s Stratavault was ultimately chosen for its superior soil volume, durability and proven track record.

“Although more expensive than structural soil, Citygreen’s Stratavault delivers better results over the long term”, Fraser said.

“Stratavault provides 90% topsoil compared to just 10% in structural soil. This high soil volume allows trees to develop extensive root systems and, in turn, large canopies, which provide shade and visual relief in the city”, he added.

Stratavault’s flexibility and ease of installation was also a key factor in the selection process. The requirement to work around existing new services and the proximity of city tram lines posed significant challenges for the project. However, as Stratavault units snap together quickly and easily to form an integrated matrix, installation was smooth and efficient.


Project outcomes

Since opening in November 2018, the ARP promenade has become a popular shared space connecting people to the river. It is a favourite place for locals and tourists visiting the city.

In a recent article, Ōtākaro Limited Chief Executive, John Bridgman described the project as “transformational”, adding that the new design has helped people to “embrace the river like never before”.

While it’s early days for the 20+ new trees that were planted in Stratavault cells along the promenade, Fraser Miller from Rough and Milne confirms the trees are establishing.

“The trees appear to be growing well and keeping up with the other trees planted in the fertile river banks”, he said.

Fraser also praised the Citygreen/Metrogreen team and Stratavault system, saying: “The benefits of working with Citygreen included good support from the team, detailed documentation to show clients and contractors, and a great proven product that’s easy to install around a mine field of underground services”.



Click here to watch a video by Otakaro Limited about the exciting new development, and the impact on the locals.


More about Metrogreen

This project was completed by Metrogreen – Citygreen’s trusted local partner/distributer in New Zealand. For more about Metrogreen, visit www.metrogreen.co.nz or phone +64 800 892 726.


Media credits to Otakaro Media team.

“Great customer service, quick response times and a very in depth QA system with constant support.”

- Laura Wiesenekker, Project Engineer, Densford Civil -

“Citygreen is a very professional  business, and I found everything was great in terms of deliveries, product supply and information. It was all forthcoming and helped us to complete the project.”

- Keith Burns, Architect/Designer, Keith Burns Architect -

“Citygreen offered training and invaluable technical assistance during the works.”

- James Callan, Estimating Manager, Complex Co Pty Ltd -

“Our experience, in working with a Citygreen Design Studio was second to none. We found responses from the design studio to be very timely, and technically thorough. We went backwards and forwards a number of times, looking at different iterations of the design and, nothing was too much trouble to examine and explore different possibilities. I would highly recommend the Citygreen Design Studio to any future client considering using your services.”

- Sandra Smith, Principal Landscape Architect, City Of Monash -

“We are big on compliance on all projects, and the fact that their SmartCertify cloud platform covers all bases, and supports their 20 year warranties, is critical – especially that these pits are being installed under roadways and footpaths.”

- Johny Purkaystha, Civil Program Engineer, Central Coast Council -

"I reviewed all the previous projects that we have installed in the past couple years using your product and I can happily report back that we have 0% mortality in the soil cells, which is incredible!"

- Brendan Wilton, CEO, Trim Landscaping, Bedford, Canada -