202020 Vision calls on planners to create more shade to tackle urban heat island effect

A LACK of trees and shade is contributing to the urban heat island effect, making it harder for many areas to keep cool in hot weather.

Cr Arron Wood of City of Melbourne on shady swans ton Street. The council is planning to increase tree canopy coverage and green spaces in the city. Picture: Andrew Henshaw

MELBOURNE  suburbs need to increase their tree coverage to combat rising temperatures, a recent study says.

A lack of trees and shade is contributing to the urban heat island (UHI) effect, making it harder for many areas to keep cool in hot weather.

The effect occurs when built-up areas with surfaces such as roads, concrete and buildings absorb heat on hot days, increasing the temperature and retaining heat into the night.

Victorian research shows inner-urban areas can be up to 5C warmer than surrounding rural areas, and it is forecast warming due to the UHI effect will continue to rise by approximately 1C each decade.

To tackle this, the national 202020 Vision campaign aims to increase, by 20 per cent, the level of urban green spaces throughout Australia. The campaign is led by industry bodies, some councils, sustainable businesses and academics.

Simon Divecha, from the University of Adelaide’s Environment Institute, said there needed to be an urgent culture shift to counter the UHI effect.

“We need businesses, communities and government to act on this,” Dr Divecha said.

“There needs to be a paradigm shift, it needs to reflect in the building codes and urban planning to encourage sustainable design.”

Simple things such as planting trees to shade buildings and pavements could reduce urban temperatures by 1-2C, he said.

“Lower retained heat also means you shouldn’t need to use the airconditioner as much, thereby reducing your energy usage and greenhouse gases emitted,” Dr Divecha said.

The Institute for Sustainable Futures analysed land cover in 30 metropolitan Melbourne council areas and three regional municipalities to quantify tree canopy coverage, hard surfaces and grassed or bare land.

Yarra Ranges had the highest percentage of tree coverage at 77 per cent, ahead of Nillumbik (49.1 per cent) and Manningham (40.1 per cent).

Wyndham, Brimbank, Melton, Maribyrnong, Hobsons Bay, Hume and Greater Dandenong had less than 10 per cent tree canopy coverage, the least of the Victorian areas surveyed.

But they were also among areas with the greatest potential to improve their tree coverage due to their high hard space to tree ratios.

Wyndham Council chief executive Kerry Thompson said the council played an active­ part in the Greening the West initiative and conducted regular thermal imagery assessments to better understand which areas were prone to heat stress and the UHI effect.

“(We have) planted 34,222 indigenous plants in the 2013-14 financial year on council-owned or managed reserves,” Ms Thompson said.

Brimbank Council planted 25,600 trees in 2013-14, while Maribyrnong Mayor Nam Quach said the council allocated about $1 million in the past two financial years for extra tree planting and enhancing green spaces.

Hobsons Bay Mayor Colleen Gates said the council was in the unique position of having large areas of both industrial areas and native grasslands, neither of which provided a lot of tree cover.

Cr Gates said the council planted more than 10,000 young plants throughout their conservation reserves and was reviewing its Open Space Strategy.

Increased tree coverage did not only counter the UHI effect, but also improved air quality, biodiversity along with public health and wellbeing, Dr Divecha said.

Between July 2011 and June 2014, 814 Victorians were admitted to hospital for heat-related illness — more than half of them in the 2013-14 period.

The spike during this time was attributed to four straight days of extremely high temperatures in January 2014.

Victorian Injury Surveillance Unit figures showed Whitehorse (38), Moreland (37) and Monash (36) had the highest number of residents admitted.

MELBOURNE SET TO DOUBLE CANOPY COVERAGE

THE City of Melbourne plans to double its tree canopy by 2040, with hopes to lower temperatures by 4C.

Councillor Arron Wood said it had a target of 3000 new trees a year, which he hoped would significantly increase the canopy over the Melbourne Council area.

“The City of Melbourne has long been regarded as Australia’s ‘garden city’, but 13 years of drought in tandem with severe water restrictions left the city’s urban forest in a state of unprecedented decline,” Cr Wood said.

“By 2009, 40 per cent of our significant trees were declining or dying.”

Having developed an Urban Forest Strategy in 2011, the council has since spent $40 million on making landscapes more resilient.

During those four years, it planted 12,000 new trees. It was estimated it needed another 30,000 to reach its target for the year 2040.

“We have an annual, ongoing budget of $1.5 million to achieve this,” Cr Wood said.

Melbourne, Banyule, Moonee Valley and Moreland councils are official supporters of the 202020 Vision campaign.

PLANS AFOOT TO REDUCE URBAN HEAT

MELBOURNE’S open space and its benefits — including improved health, reduced urban heat and regulation of air and water quality — is being explored by the State Government’s Metropolitan Planning Authority (MPA).

Planning for this strategy is still in the early stages but will build on previous work done by the Government and councils.

It will create a metropolitan open space network map, identify opportunities for new open space and new connections, clarify government roles and responsibilities, set out principles for good network design, canvas funding options for open space and explore ways of making better use of open space.

The MPA will run a series of community engagement activities­ later this year to inform preparation of the strategy.

For more information, go to mpa.vic.gov.au/openspace

Associate Professor Tonia Gray.

GREEN SPACES ARE CHILD'S PLAY

IF TONIA Gray had her way all schools would have more trees in asphalt play areas and pupils would spend more time outside in ‘green’ classrooms.

The associate professor from the University of Western Sydney is an advocate of the 202020 Vision campaign and has researched the relationship between people and nature, and how this effects childhood development.

“Nature has a calming effect, it recalibrates your body,” Assoc Prof Gray said.

“Australian kids spend an average of 52 hours a week in front of a screen but an average of 40 minutes outside.”

“It’s not unusual for some people to have no contact with nature.”

Assoc Prof Gray said research showed neighbourhoods with more green spaces were much healthier and socially cohesive.

“It’s basically an ‘everything old is new again’ approach, in going back to what they did 120 years ago when we weren’t so reliant on technology for entertainment and education.”