Australian cities must work harder to preserve their large, old trees if we want to keep our native animals. Across Australia – and the world – the future of large old trees is bleak and yet large trees support many species such as birds and small mammals says CEED researcher Darren Le Roux.
“Studies based in Canberra – the ‘Bush Capital’ – show that Australia could lose 87% of its hollow-bearing trees in the urban landscape over the next 300 years,” says Le Roux. “Under the worst case scenario, we could lose all large hollow-bearing trees within the next 115 years.”
Le Roux explains that the loss of old trees, as well as other critical habitat structures, in urban landscapes is largely due to ‘tidy-up’ practices that are driven by negative public attitudes.
“Large old trees, dead trees and branches, woody debris and shrubs that support native wildlife are often removed because of fears that branches might injure people or damage property, or because structures appear untidy or pose a bushfire risk,” he says. “We are far too quick to remove habitat like large trees without first considering alternative ways to retain these structures that won’t risk people’s lives and property.”
To reverse the decline of large old trees, native trees need to remain standing for much longer than currently tolerated in urban areas, and more young trees need to be planted now for the future says Le Roux. Instead of cutting down large old trees or removing logs, landscaping techniques can be used to separate people and public facilities like footpaths, playgrounds and benches, from these so-called ‘riskier’ structures and ensure the safe retention of vital wildlife habitat. Surrounding dead trees with rocks, logs, litter and native shrubs can create effective safety barriers and keep maintenance costs associated with weeding and mowing down.
“We also need to change public perceptions about big old trees,” says Le Roux. “Signs displaying the biodiversity values of large old trees and other key resources in public spaces will go a long way to encourage tolerance, dispel misconceptions and create an awareness and appreciation of the importance of these habitat elements.”
Le Roux DS, K Ikin, DB Lindenmayer, W Blanchard, AD Manning & P Gibbons (2014). Reduced availability of habitat structures in urban landscapes: Implications for policy and practice. Landscape and Urban Planning.125: 57-64. http://bit.ly/1ICSQbo
Le Roux DS, Ikin K, DB Lindenmayer, AD Manning & P Gibbons (2014). The future of large old trees in urban landscapes. PLoS ONE. http://bit.ly/139OZCq