C40 Expert Voices: Cr Cathy Oke, Councillor at City of Melbourne

By: Cr Cathy Oke, Councillor at City of Melbourne

World leading research on Melbourne’s trees

Melbourne is famous for its trees. Our tree-lined boulevards, parks and gardens are internationally renowned.

That’s why the City of Melbourne commissioned ground-breaking research into the impact of climate change on our trees.

Principal researcher at the University of Melbourne, Dr Dave Kendal, examined tree inventories from 200 international cities and global biodiversity information against projected climate scenarios for Melbourne.

We believe the application of this research, ‘Trees for Melbourne’s Future Climate,’ will lead the world in urban forest planning.

The research ranked tree species by colour to show their temperature vulnerability under the following climate scenarios, which are considered conservative by climate scientists:

  • 2040 - 0.8 °C further increase in temperature
  • 2090 - 3 °C increase in temperature.

The research showed that climate change is likely to have a significant impact on many of the 375 tree species currently planted across the city.

877 moreton bay fig tree avenue princes park melbourne   small .originalSome species will perform better, while some will perform worse.

Around 19 per cent of species currently growing in the City of Melbourne are already temperature vulnerable; while 35 per cent of trees will be vulnerable by 2040 and 62 per cent by 2090.

The most vulnerable species will be deciduous trees from colder climates such as the Dutch Elm (Ulmus x hollandica), along with some species of indigenous Eucalypts. These trees are unlikely to survive in Melbourne in 100 years’ time, let alone thrive.

This means we need to plant new Australian and international species that will be suited to warmer temperatures.

The research includes a list of 1729 new species that will be suitable for Melbourne’s future climate realities.

This includes the sub-tropical South American Jacaranda (Jacaranda mimosifolia), the Australian native evergreen Brush Box (Lophostemon confertus) and the indigenous Coast Banksia (Banksia integrifolia).

We are using the research to guide the selection and trialling of new tree species in the city.

In the past year we have planted a diverse mix of 180 individual tree species, of which 85 are Australian native species and 95 are exotic tree species. Of the Australian native trees, 16 species are indigenous to the Melbourne area. The list also includes 17 new species for Melbourne, which are being trialled in a range of locations.

I look forward to sharing this research when I attend the CBD COP 13, the 13th meeting of the Conference of the Parties to the Convention on Biological Diversity in Cancun, Mexico.

The full report is available at: http://www.nespurban.edu.au/publications-resources/research-reports/CAULRR02_CoMFutureUrbanForest_Nov2016.pdf