“With climate change upon us, and local water supplies running low, we will need to closely monitor current conditions and be better prepared in the future and to plant the most resilient trees to local conditions,” says Environmental Science and Hydrology Professor Huade Guan, from the National Centre for Groundwater Research and Training at Flinders University.
“Knowledge of which trees, where, and why, do not cope with droughts in Adelaide would be useful for informed urban forest management to keep our city greener and cooler.
“The drought over the past summer, with only one-third of average rainfall, provided an opportunity to obtain such knowledge,” says Professor Guan, from the College of Science and Engineering.
Information collected will be shared and validated with local councils.
“One possible solution is to integrate urban tree and stormwater management together, as many councils in Adelaide are already doing. For known vulnerable trees and locations, stormwater harvesting devices can be installed to provide more water for the trees.
As well as species selection, ground conditions (whether the surface is concreted or permeable, flat or sloping), solar exposure (whether the tree is fully exposed to the sun or under shade from the surrounding building or trees), any green infrastructure nearby, the soil, and conditions of the nearby trees will also be considered.
During extreme heat, tree canopy and shade make the ground up o 30C cooler and outdoor conditions more amenable. “Also by retaining more stormwater using what we call ‘water sensitive urban design’ structures, our research has shown that the canopy temperature is 1.5C degrees cooler on a hot summer afternoon,” Professor Huade says.
Speaking to a recent Tree Fund webinar for aborists and other garden professionals, Professor Huade says: “In summer, urban trees work like evaporative air-conditioners using free solar energy.
“If we can retain more stormwater in urban soils, we will have cooler summers.”
Flinders University is also leading another project in collaboration with the Hort Innovation Green Cities Program, to explore the potential of using private property roofs and gardens for harvesting stormwater to enhance tree health and summer cooling.
The project involves partners at the local councils of Marion, Mitcham, Unley, Onkaparinga, Port Adelaide Enfield, with experts from UniSA, Water Sensitive SA, TREENET, Resilience South and Space Down Under.
Metropolitan Adelaide’s Urban Greening Strategy was launched in March, with one of the headline targets for the five-year strategy is moving metropolitan tree canopy cover from 17% (current) to 30%.
At Flinders University, we are dedicated to finding solutions to complex challenges with research that matters. In a groundbreaking initiative, we asked 30,000 Australians from across the nation to voice the problems that matter to them the most in their local communities, resulting in The Flinders Wicked Problems Report. Read more here.
