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Canberra
Wednesday, December 2, 2020

Native, heat-tolerant trees best for beating urban heat

Yellow box and kurrajongs were some of the top ranked trees to beat the heat in a report which assessed 211 tree species used in Canberra’s urban spaces that was released earlier this month.

The Urban Tree Species report, commissioned by the ACT Government and undertaken by the ANU Fenner School of Research, identified the best tree species to improve Canberra’s urban tree canopy and adapt to rising temperatures.

“Growing trees in urban environments is about more than just species selection,” the report stated.

“In an increasingly challenging urban landscape, planning and infrastructure must support these carefully selected trees species to ensure they have the adequate resources (water and soil) and hospitable growing conditions.”

The report showed a warming climate will intensify the urban heat island effect and have a significant effect on the health and resilience of trees in the urban forest of Canberra.

“Climate change projections for Canberra, such as NARCliM and CSIRO Analogue, suggest temperatures could increase between 2°C and 4°C by 2090,” it stated.

“It is clear that both introduced and native species, especially eucalyptus, are suitable for Canberra’s climate change future.”

The report assessed and ranked tree species on a range of climate factors including drought tolerance, frost tolerance, extreme heat tolerance, weed potential and allergen potential.

It found the overall list of species used in Canberra’s urban spaces is currently suitable, but recommended trialling other native trees such as lemon-scented gum, spotted gum, wilga and silky oak.

It also recommended that oriental plane trees be used more sparingly due to allergenic pollen.

Canberra’s Living Infrastructure Plan, released last month, outlines best practice in regard to keeping Canberra cool in a warming climate, and sets out how we most effectively go about increasing our urban tree canopy cover from 21% to 30%.

ACT Minister for Climate Change and Sustainability, Shane Rattenbury, said it’s critical that we design our city to deliver a more sustainable and liveable Canberra for the future.

“Improving our urban tree coverage will not only help to reduce urban heat but will enable more green spaces and increase our natural biodiversity,” the Minister said.

“Growing trees in an urban area requires careful consideration of location, quality of soil, how it will be supported by water, and its heights and characteristic must be considered to ensure longevity.”

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