We found this article while reading through a recent issue of one of our trade magazines and wanted to share it with our readers. We are sharing it as a demonstration of how a well thought out landscape design and specific placements of trees can improve quality of life, as well as positively impact your neighborhood and the local community. We hope you enjoy!
A Cooler Canopy: An excerpt from Landscape Architecture Magazine, June 2018
Byline: Gweneth Leigh, ASLA
In Suburban Sydney, A Landscape Architect Quantifies the Variable Effects of Street Trees.
Libby Gallagher spent two years collecting data as a PhD student at the University of Sydney on how the different forms, species, and age ranges of street trees affect their ability to lower temperatures, sequester carbon, and reduce household energy costs. “It was an onerous process, to be honest,” says Gallagher, a landscape architect and the director of Gallagher Studio in Surry Hills, New South Wales.
Now, however, that hard-earned data is the backbone of Cool Streets, an initiative Gallagher created with community planners Cred Consulting. Gallagher’s modeling revealed that nontraditional street planting designs —such as using asymmetrical layouts and a mixture of species—helped keep neighborhoods cooler. However, maximizing benefits relied on trees’ reaching maturity, and survival can be tough for juvenile tree stock. Cool Streets wants to improve their chances by helping residents become better tree stewards.
The program measures the potential impacts of different street planting strategies. For instance, a young, 16-foot-high tree can save up to AU$100 on a household’s annual electricity bill. Within a few decades, the annual savings can grow to AU$400. The Cool Streets team uses this information in neighborhood workshops as a way to help residents determine planting designs for their streets.
For example, Boonderoo Avenue in suburban Glenwood, New South Wales, is just under a decade old; street trees had never been incorporated. The Cool Streets team shared multiple canopy options with street residents, each accompanied by data quantifying impacts of CO2 emissions and household power bills. Desiring the appearance of neatness and order, residents opted for a symmetrical design using small, compact trees. The option delivered few benefits in terms of cooling. So the Cool Streets team devised ways of maintaining a “neat” appearance using bigger trees that were four times more effective at cooling temperatures and reducing energy bills. The majority of residents were swayed by the data and decided to implement the alternative design.
Cool Streets has caught the attention not only of local city councils but also of residents who are keen to implement similar street planting strategies in their neighborhoods. A methodology is being developed in hopes of replicating it across the country. “Climate change can feel so overwhelming,” Gallagher says. “Being able to empower people to do something from their street and in their neighborhood opens up a dialogue to new possibilities.”