As Adelaide aims to be the world’s first carbon neutral city, Stephen Forbes considers the value of greenspace in urban landscapes and what more can be done in South Australia.
I was delighted to see the Rio Olympics draw the connection between the value of trees and our future in the opening ceremony. The message on climate was a sombre one.
However, the symbolism of athletes planting the seeds of 230 different tree species illustrated one path for making a difference here. Almost as much carbon remains in the world’s forests as in the atmosphere – tree planting and forest conservation provide a real opportunity to make a real difference to climate change.
This opportunity is important to Adelaide, a city aiming to be the world’s first carbon neutral city.
Rua de Goncalo de Carvalho in Brazil’s Porto Alegre is renowned for its coverage
Because Adelaide has the Park Lands there’s often a perception that Adelaide’s a green city. However, if we consider where most Adelaideans live, that’s not really the case. Adelaide’s metropolitan areas are marked by relatively low levels of tree canopy when compared to other Australian capitals.
Indeed, outside the Adelaide Hills, Adelaide’s the wooden-spooner for tree canopy. However, in defence of local government, street tree (largely nature strip) plantings are competitive with leafy Melbourne – tree canopies in private gardens and in public greenspace are less impressive.
Tree-canopy cover across local government areas ranges from 44 percent in the Adelaide Hills to 20 percent in Adelaide and 12 percent in Port Adelaide Enfield. There is evidence, from air photos, showing an increase in tree planting in capital cities over the past 50 years and consequently increasing tree cover.
That’s a good thing – and we’re still going forwards. However, increasing house sizes on decreasing block sizes in urban subdivisions, together with increasing urban consolidation closer to the city, sees less opportunity for tree planting. This trajectory isn’t inevitable – Singapore has more greenspace per person now than at independence in 1965.
Lee Kuan Yew’s passion for a city in a garden has made Singapore an attractive place to live and to do business. As former Prime Minister Goh Chok Tong once joked, “Singapore’s cabinet must be the only one in the world that reads the meeting minutes of a Garden City Action Committee”.
LKY took his role as Chief Gardener seriously. Singapore’s neighbours are also now beginning to consider the benefits of urban greening. There are clear benefits for increasing tree cover – including facilitating walking and physical activity, promoting social inclusion and cohesion, contributing to mental health and wellbeing, reducing urban ‘heat island’ effect, reducing requirements for air conditioning, extending asset life through shading and sequestering carbon.
Nevertheless, trees are too often seen as a risk and a cost to the community, rather than as an opportunity and benefit for the community.
Stirling’s streets are full of leafy coverage
Parks and garden directors have perhaps been subsumed into asset management and accorded rather less influence further down the local and state government hierarchies. Greenspaces, and particularly trees, are no less critical to communities than buildings, roads, paving, pipes and wires.
There doesn’t seem to be much going on in state government in this space. What is the vision for Greater Adelaide’s greenspace and tree cover and what are the targets? How does the state government’s planning framework and local government’s tree policies inform each other and facilitate improvements in greenspace and tree cover?
The state’s 2010 30-Year-Plan for Greater Adelaide doesn’t suggest any clear strategy. While Lee Kuan Yew required urban development planning, transport, essential services and parks agencies to be jointly responsible for delivering strategic targets for greenspace, our legislation and policy settings focus on and facilitate tree elimination (such as along major roads), diminution (such as the selection of ever smaller trees to reduce perceived risk) and disfigurement (such as the lopping of roots and crowns by service providers).
Are Adelaide’s suburbs in need of greater greening?
Perhaps the draft update of the 30-Year-Plan proposed for release for public consultation in August 2016 may see innovation re ecting the green infrastructure project and the 2020 Vision driven respectively by Adelaide’s botanic gardens and the Nursery and Garden Industry Association through Horticulture Innovation Australia.
Such innovation requires a clear vision, effective governance and capacity to drive real change in Adelaide’s living environment and livability. Overwhelmingly residents plant trees for beauty. However, the roles of local and state government in tying a street, a suburb and a city together with coherent tree planting schemes is rather grander in defining the character of the place where we live.
Even after 180 years we still don’t seem to have agreement on what might be the Adelaide Plains’ signature trees. Certainly this depends on where you live, and what the opportunities are for tree planting.
Environmental and social factors see differing values and expectations for neighbourhood tree planting and management.
The Adelaide Botanic Gardens are testament to the value of greenspaces
Nevertheless, it’s worth focusing on a short list of signature trees for the Adelaide Plains. Older suburbs are characterised by plane trees, desert and claret ash, white cedar, jacaranda, and red flowering gum as roadside and street trees.
River red gums, Norfolk Island pines and Moreton Bay figs dominate parkland plantings. Playford era and more recent developments have seen a proliferation of species, especially in the northern suburbs.
Contemporary developments are rather cautious in their tree selection, releecting concerns of risk and cost both by developers and local councils, although locally indigenous trees have made a mark. With a high level of engagement between tree specialists, designers, service providers, developers, planners and project and landscape managers – good results are possible.
There are, of course, good examples. There’s a lot still to be done in understanding the value and application of urban trees. If you want to find out more try exploring TreeNet’s outstanding endeavour and excellent resources.
Or, go for a walk in Adelaide Botanic Gardens (watered) and Waite Arboretum (unwatered) and make your own choices! I’ll even go out on a limb and suggest 20 signature trees for Adelaide at the Royal Adelaide Show this year and endeavour to balance the selection across natural and cultural heritage values and utility and beauty.
Images: Shutterstock and courtesy of Friends of Gonçalo de Carvalho Street Movement