Federal Street sprouts 3,500 plants in green wall first

Federal Street, in central Auckland, has been home to the Southern Hemisphere’s first ever circular green walls since 23 May. A key part of the street’s transformation into an attractive shared space by Auckland Council, Auckland Transport and SKYCITY, the circular green walls encase seven pillars, rising to meet a 48m long living wall above.

Conceived by New Zealand’s living wall experts, GreenAir, and their Australian partner Fytogreen, in collaboration with project landscape architects Boffa Miskell, the green wall has a total area of 130 square metres, containing 3,500 plants, and is thought to be the largest yet built in New Zealand.

Auckland Council Design Champion Ludo Campbell-Reid says, “When we developed the City Centre Masterplan in 2012 we saw opportunities to transform the central city’s laneways from traffic thoroughfares into vibrant, enticing spaces for people to walk, relax and spend time and also to connect our magnificent city parks with a series of ‘green streets’. We knew from public consultation that Aucklanders wanted to see more greenery on Federal Street and we also worked with local iwi to consider ways to bring native plants back into the city centre. The green walls on Federal Street realises all of these insights and goes a step further; they give city workers and visitors something unique – the experience of our native forests where you’d least expect them – right in the heart of the city centre.”

Designed by GreenAir to introduce greenery, bio-diversity and improved air quality into this challenging city-centre location, the green pillars required a creative engineering and planting approach. Working closely with Boffa Miskell on the project since late 2012, GreenAir designed and constructed circular Fytowalls to wrap around the columns and support the plants. The selection of plants provided its own challenges, and a lengthy research and development phase preceded the final selection and arrangement of plant species, over 80% of which are New Zealand natives.

“Parts of the green wall are exposed to the Southerly wind at one end and have limited direct sunlight,” said GreenAir CEO, Simon Chamberlain. “We needed to be sure the plants would thrive in the location and that hardier species would protect more vulnerable ones.”

The pillar planting was inspired by the under-canopy of the Waitakere Ranges where Chamberlain grew up. “We’ve been able to combine NZ natives, like climbing rata (Metrosideros perforate), Asplenium Obtusatum, Microsorum Scandens and astelias so the seven columns, right in the city, remind people of the plants that grow up tree trunks in the bush,” Chamberlain says.

SKYCITY Auckland General Manager John Mortensen says the green wall will make a fantastic addition to Federal Street, which is used by more than 5,000 pedestrians each day.

“The streetscape will complement SKYCITY’s world-class offering in New Zealand’s largest city which includes the Sky Tower and casino, two award-winning hotels, a convention centre and a theatre. Our support of this project really marks our commitment to the city,” says Mr Mortensen.

The columns don’t just look like tree trunks; they’ve been designed to work like them from an ecological perspective. The top of the columns will be colonised by larger growing species that cover the column tops, and extend to the horizontal green wall above. Once established, these species will work like a tree canopy, with the plantings below reflecting natural epiphytic ecologies, with top, middle and lower canopy species, all arranged to suit light and wind exposure and the thickness, angle and length of the plants around them.

GreenAir, responsible for design, build, installation and maintenance of the green wall, used the leading international Fytowall system by Fytogreen, to ensure the living wall is supported by the best possible technology.

Auckland Council estimates the social cost from air pollution in the city to be $1.07 billion1 while studies show2 that in city streets bounded by buildings, careful placement of plants can reduce concentrations of nitrogen dioxide by up to 40 percent and of microscopic particulate matter by up to 60 percent.

Campbell-Reid says, “Council’s vision is to create the world’s most liveable city and one of the ways we’ll get there is through developing green infrastructure networks which incorporate ecological and biodiversity principles and enhance the city’s environmental sustainability. The green walls do exactly that.”

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