Saving Urban Trees

Stefan Caddy-Retalic,  Environment Institute member and adjunct senior lecturer at the University of Adelaide’s Waite Arboretum, has extensive knowledge of urban ecology. His expertise in environmental science has allowed for him to comment and address the challenges that iconic trees like the Overbury Drive red gum face in rapidly urbanizing areas.

In the middle of Overbury Drive stands a giant red gum tree, estimated to be over 200 years old and more than 20 meters tall. Known as the 'Sacred Tree,' it serves as a symbol of resistance against urban expansion within a cul-de-sac in Adelaide. Stefan explained that the tree’s struggles are linked to the changing urban environment. Historically, red gums would have accessed groundwater through deep tap roots while drawing surface moisture from rainfall. However, as the city grew around it, trenching for roads, building foundations, and stormwater systems disrupted these natural water sources. The tree was left parched, its ability to draw moisture compromised by the city’s infrastructure.

When the Overbury Drive red gum showed alarming signs of decline, the residents advocated for help, as a result, the City of Unley installed water bollards to hydrate the tree’s roots and planned modifications to reduce urban stress factors.

Stefan has also expressed the importance of proactive urban planning that takes into account the preservation of mature trees. His commitment to urban biodiversity and practical solutions has brought attention to how cities can protect their natural heritage even as they grow. Stefan’s comments have featured in major media outlets, including The Guardian, Yahoo News, AOL, and MSN. 

Learn more about Stefan’s work and the red gum’s journey in the full article.