An inner-city suburb on the Brisbane River could be home to the “greenest residential building in the world” with ambitious plans currently under review by the city’s council.
Development plans lodged last week by the Aria Property Group propose a 30-storey “vertical forest” and “a beacon for sustainability in South Brisbane”.
With Brisbane High School to the south and the Exhibition and Convention Centre a stone’s throw away, the development, aptly named The Urban Forest, would become “an exemplar”, submission documents state, “placing Brisbane at the cutting edge of the world.”
“The Urban Forest concept will be the greenest residential building in the world and will reduce the heat-island effect, improve the micro-climate, undertake localised air-cleansing, absorb pollutants, reduce noise levels and contribute to biodiversity,” the document states.
Designed by Koichi Takada Architects, the plan boasts 1003 trees and more than 20,000 plants, a predicted equivalent of taking 150 cars off the road each year. Lat27 and Arno King Landscape Architects were also involved in the design.
“Solar and thermal insulation provided by natural vegetation and sculptural cantilevered slab projections, plus high performance glazing, and ceiling fans to all bedrooms improve insulation and reduces reliance on airconditioning,” the document states.
“The planting maximises solar access in the winter, and shields from the harsh and hot western sun.
“Each unit has openings on multiple sides, creating a pressure differential and facilitating cross ventilation.
The proposal includes 529 resident car parking spaces, 32 for visitors, one for people with a disability and five electric vehicles for shared used. Space for parking bicycles has been provided for 382 residents and 96 visitors.
Mark Limb, a Queensland University of Technology lecturer in urban and regional planning, pointed out the apt location of the development, close to the city, would likely curb the use of cars, a large and growing source of carbon emissions, but questioned whether the designers had adequately encouraged sustainable transport further.
“Are private car parking spaces minimised in exchange for car sharing and high-quality bike facilities to encourage residents to use more sustainable transport options?” he said.
He also raised concerns over future maintenance of the abundance of trees and plants, saying landscaping would be a steep, ongoing cost falling on residents.
“This is many plants on a high-rise building. They are going to rely on intense cultivation and attention. There is a wonderful amount of green space, which is fantastic on one hand, but you have to wonder whether future maintenance costs will be manageable for the body corporate and the impact on the building’s green rating if it cannot be sustained.”
Dr Limb noted that sustainable development also involves social dimensions asking if “…the development provided affordable housing options and a variety of housing types to suit diverse household structures?”
Targeting a five star Green Star rating, the design includes rooftop solar panels, high efficiency airconditioning, LED lights, high performance glazing, natural ventilation and gardens irrigated by harvested rainwater.
While not quite meeting the six star “world leadership” rank, the building is projected to produce up to 45 per cent fewer greenhouse gas emissions than buildings built to industry standard, use 50 per cent less electricity and 51 per cent less water than the average Australian building, according to the plan.
In 2016, the Brisbane City Council called for more “Buildings that Breathe” to embrace the sub-tropical climate where temperatures soar to 30 degrees in summer.
The council’s New World City Design Guide: Buildings that Breathe non-binding policy document encouraged new developments to capitalise on orientation to reduce heat load from the sun and capture cooling easterly breezes in the summer.
It encourages natural ventilation, porches, tree shade and natural light to replace or minimise the use of mechanical cooling.
Senior lecturer in Urban Planning at the University of Queensland Dorina Pojani welcomed the sustainable design, saying it met the Buildings that Breathe brief, but questioned the consideration to an issue widely discussed in Brisbane: the “missing middle”.
“It is a 30-storey-high residential tower similar to ones South Brisbane residents have been complaining about for ages now because it doesn’t do much to fill the missing middle,” she said.
As urban planners and academics continue to examine issues of the missing middle, tall developments are rapidly emerging in very low residential neighbourhoods with no gradual increase, she said.
“It seems like Australia, in its effort to densify and create more compact cities, has gone straight from one or two-storey houses to 30 storeys and there is nothing in between.
“The issue is these very abrupt changes in height have been very contentious with local communities who want variety.
“On the sustainability front, there are two narratives around climate sensitivity in new residential developments. One narrative says we need more compact cities, which means a denser and taller city, because that minimises travel distances, but then the other narrative says the taller the city becomes, the more intense the urban heat island becomes.”
One would have to crunch the numbers to calculate the mitigating effect of the trees on lowering temperatures on this particular development, she said, but it should provide some cooling.
“I want to make it clear, it is not as if it is just this development that is causing issues of the missing middle… it’s an Australia-wide phenomenon,” she said, while also raising similar concerns to those held by QUT lecturer Dr Mark Limb.
“The green footprint looks very nice, but looking at the floor plans, it seems like all those plants will be in residential space and up to the buyers of those apartments to maintain that green… and what happens if they don’t?” Pojani said.
“That has been a concern in the past, where we see lots of greenery in rendering, but then the actual development happens, and it is very difficult to get private parties to do the level of maintenance these green walls require.”
The planning document confirms each unit will have a minimum of two trees and 30 low level shrubs but abates fears of upkeep with a maintenance strategy.
“The maintenance strategy includes making all gardens accessible from common areas without specialist equipment to maximise long term growth of planting and all planting to be irrigated and maintained at a comparatively lower cost by body corporate not individual owners, ensuring long term health of vegetation,” the document states.
The Fifth Estate requested interviews with the developer and architects but with no response by the time of publication.
Roxanne Fitzgerald is a Melbourne-based journalist who most recently spent two years reporting in the Northern Territory.