University of South Australia environmental researchers have called for new national planning policies to mandate the inclusion of trees in developments and housing design.
Housing subdivisions, smaller yards and a dependence on air-conditioning have led to a 30 percent decline in residential trees in Australia in the past decade.
The results are hotter neighbourhoods and increased energy costs.
Many current residential policies rely too much on public and communal open spaces to compensate for the lack of trees in private yards, yet this does not provide energy savings. “Local government focuses on public parks and urban forests, but it’s the residential trees that make a significant difference to home energy costs,” says architect and UniSA PhD candidate Mina Rouhollahi.
Rouhollahi and her colleagues devised an optimal tree strategy for different housing configurations, nominating specific tree types, volumes and placement to achieve maximum benefit.
The researchers studied 90 Australian residential suburbs to prepare the strategy paper ‘Potential residential tree arrangement to optimise dwelling energy efficiency’ in Energy and Buildings.
“We need a more cohesive urban planning approach to compensate for residential tree loss in recent decades and regulate heat as well as curb energy costs,” says Professor John Boland, the project’s supervisor.
Our access to and reliance upon air-conditioning poses a challenge. A shift in Australians’ attitudes, to a focus on home energy efficiency through tree planting, double-glazing and better house design, has become necessary.
“Australians have the power to influence the design process,” says Rouhollahi, “requesting tree allocation when building or buying their home, in the same way they insisted on a double garage in the 1990s.
“Redesigning our homes with trees in mind will better serve residents, cities and the environment. Trees have numerous benefits: they shield us from the sun, provide wind protection, reduce stormwater run-off [and provide] passive cooling and natural ventilation. The net result is a more energy-efficient home, lower energy costs, reduced air-conditioning and carbon dioxide emissions, and less polluted air.”