When it comes to “green” cities – those graced with leafy parks and tree-lined streets – the rest of Australia could take a leaf out of Hobart’s book.
A mix of deciduous trees originally introduced from Europe and our own native eucalypts and wattles not only provide shelter from rain and sunshine, but give shape to the seasons.
There is no greater sight than Tasmanian blue gums in white flower in Sandy Bay in spring, or the maidenhair tree, ginkgo biloba from China, in scarlet leaf along the streets of South Hobart in autumn.
The importance of trees in our cities had been brought into focus in recent years with research revealing that green spaces are actually good for city dweller’s physical and mental health. However, the seeds of this new understanding of the value of city trees appears to have fallen on barren ground in Australia’s second largest city, Melbourne, where tree cover has been found to be declining at an alarming rate.
The Age newspaper reported last month that the city had lost thousands of hectares of tree cover in the past five years.
Evidence from nearly 40 years of research in the United States and Europe confirms that nature found in cities – mainly in parks and gardens – improves human health. Green open spaces can promote exercise and wellbeing which in turn can help prevent chronic diseases like diabetes, heart disease and respiratory problems.
Open spaces not only encourage people to get fit by walking or running, trees are also important for mental health. Trees help to blunt the harsh environment of glass, brick and concrete that surrounds city dwellers, particularly the way the city-scape magnifies noise
Trees are not just important for humans. Tree cover also increases the abundance of birds like boobook owls and, if areas are large enough, can attract mammals. These in turn can encourage a calming, smoothing inter-action with people sharing the same urban environment.
In Melbourne, green space is being eaten up in the suburbs as backyards are cleared for new higher-density housing.
The Age reported that the amount of urban forest removed over the past five years was equivalent in size with Melbourne’s largest suburb by area, Reservoir. The eastern suburbs, long celebrated for their leafiness, experienced the greatest loss of greenery, accounting for more than two-thirds of Melbourne’s total tree canopy loss, researchers at RMIT University found.
In all, Melbourne’s tree cover has shrunk from 50,964 hectares in 2014 to 46,393 hectares in 2018.
Lead author Associate Professor Joe Hurley, of RMIT’s Centre for Urban Research, said the findings were troubling because they impacted on both people and nature. He also pointed out that trees helped keep cities cool at the height of summer.
Some Melbourne residents are so concerned about the loss of trees that they have decided to take action by mounting volunteer tree-planting missions on public land. One group developing a tree-rich landscape along a railway corridor in Melbourne’s north-west term themselves tree-planting “guerrillas”.