Green spaces, and subsequently trees, are mother nature’s remedy. Boosting both physical and mental wellbeing, it has been proven time and time again (especially through biophilic design) that flora is a force for good.

Alongside its wellbeing benefits, trees also assist in mitigating urban heat, removing carbon dioxide from the air and even reducing temperatures. It's these factors that formed the basis of Gallagher Studios’ Libby Gallagher’s PhD, and the creation of the Cool Streets program.

“In about 2010 felt a pull to dive deeper into climate change and how to properly address climate mitigation in our designs,” Gallagher says.

“I was particularly interested in how to retrofit what we've already got in the existing city. I left full-time practice and went and did a PhD and set about developing an integrated, climate model for streets that pulled together all the components of the street, and then tried to understand what the life cycle emissions were, the mitigation potential of each of those elements.

“What the research found was that the most effective mechanism you can use is trees because of their ability to sequester carbon, but also their ability to lower local temperatures and thereby reduce the amount of electricity.”

Gallagher’s research has been melded into her work at Gallagher Studio, under the Cool Streets moniker. The debut project was completed in collaboration with Blacktown City Council and completed in three stages.

“I'd focused on Western Sydney in the PhD just because of its susceptibility to climate change. It's also extremely vulnerable to urban heat. So I was particularly interested in Western Sydney and retrofitting those environments. That first project was really thinking about how I could get this research out from academia, away from the peer reviewed papers.”

cool streets

The first part of every Cool Streets project puts residents in the driver's seat. Gallagher and her team conjure up three potential tree combinations, varying in size and therefore output. The bigger the tree, the bigger the benefits. While it is a daunting prospect having residents make the choice, Gallagher believes it to be an empowering approach.

“People are really invested and engaged with the information. They’re very interested in what their neighbours are voting for and how the trees will feel on their street and what the difference would be with this tree planting,” she says.

“It was incredibly encouraging and affirming for me having consigned myself to climate data streams for so long. After that first stage, we go away and do a deeper dive into their perceptions and then come back with real designs for their street, two different options, with the environmental and economic benefits clearly stated in terms of how much the shade would reduce their electricity bills at maturity for those trees and how much the trees take in and reduce the amount of emissions.”

A diverse range of species and shade densities results in the best outcomes in terms of shade cover, temperature reduction and energy efficiency. The final step of the project is a planting day, where street residents are given a watering can to care for the trees, furthering the sense of ownership. Gallagher has seen first hand how that sense of ownership is felt by local residents.

“A local, unassuming resident of Glenwood made the tree choice and was so inspired that he subsequently has become the custodian of the trees on that street and still waters them. I've watched him go from being part of this first engagement, to standing under the tree that was planted in his street seven years ago, now over his head and shading his house.”

Gallagher Studio has recently worked alongside the NSW Government, looking at tree canopy targets for private land. It has found that all types of development have capacity for tree planting without compromising on development potential.

“We think it's a catalyst for not just getting trees in the ground, but for bigger conversations about the climate and how we adapt and how we care for our neighbours and how we look after our communities,” Gallagher says.

“I think local governments are doing a great job in trying to get tree planting on public lands where they can, but it's often quite fraught in the street because there's a lot of different service providers, such as garbage trucks and energy and telecommunication companies.”

Gallagher Studio’s work can be found here.