How to transform cities into urban forests
As rural areas become less productive due to climate change, cities will have to become more productive. Trees will play a large role. They are central to the cooling, regulating and cleaning of city air and water flows as well as keeping urban soils healthy.
T
he 21st century is the urban century. It has been forecast that urban areas across the world will have expanded by more than 2.5 billion people by 2050.
The scale and speed of urbanisation has created significant environmental and health problems for urban dwellers. These problems are often made worse by a lack of contact with the natural world.
With research group the Tree Urbanistas, I have been considering and debating how to solve these problems. By 2119, it is only through re-establishing contact with the natural world, particularly trees, that cities will be able to function, be viable and able to support their populations.
Urban forests of the future
The creation of urban forests will make cities worth living in, able to function and support their populations: Treetopias.
This re-design will include the planting of many more urban trees and other vegetation – and making use of new, more creative methods. Although we didn’t fully realise it at the time, the 1986 Hundertwasserhaus in Vienna, a building that incorporated 200 trees in its design, was the start of more creative urban forestry thinking.
This has been carried on in Stefano Boeri’s Bosco Verticale apartments in downtown Milan, which incorporates over 800 trees as part of the building. Similar structures are being developed around the world, such as in Nanjing in China and Utrecht in The Netherlands.
The urban forest needs to be designed as a first principle, part of the critical infrastructure of the whole city, not just as a cosmetic afterthought. We know for example that in 2015, urban forest in the UK saved the NHS over £1 billion by helping to reduce the impact of air pollutants. In 2119, we may well look back on this present time as the equivalent of the Victorian slum.
Trees can create places which can greatly improve our health and well-being. Our urban forest can give us the spaces and places to help manage our mental health and improve our physical health. Research has indicated for example that increasing the canopy cover of a neighbourhood by 10% and creating safe, walkable places can reduce obesity by as much as 18%.
The Hundertwasserhaus in Vienna incorporated 200 trees in its design. Photo by Marco Verch/ Flickr (CC BY 2.0)
Building on trees
As rural areas become less productive as a result of climate change, cities – which previously consumed goods and services from a large hinterland – will have to become internally productive. Trees will be at the centre of that, contributing to the city energy balance through cooling, regulating and cleaning our air and water flows, and ensuring that our previously neglected urban soils function healthily.
Urban forests could also provide timber for building. We have a history of productive woodlands in the UK, yet alternative construction materials and a growth in an urban population with less knowledge of forest management means that the urban forest is rarely viewed as productive. We are now recognising the potential productivity of the urban forest, as campaigns to stimulate homegrown timber markets and achieve more efficient management efficiencies are proving to be successful.
Furthermore, economic growth is still deemed to be the prime symbol of the effectiveness of a city, but we need to be equally aware of other invisible values. This will open up new approaches to governance. Governance needs to embrace all forms of value in a balanced way and facilitate a new vision, considering how trees can help create liveable cities.
Stefano Boeri’s Bosco Verticale apartments in downtown Milan have over 800 trees as part of the building. Photo by Fred Romero/Flickr
Who will guard the urban forests?
As the urban population rises, we need to get better at understanding the breadth and diversity of the values held about our urban forest. Individual people can hold several distinct values at once, as urban forests may contribute to their wellbeing in different ways.
The current guardians of our urban forest, mainly local authority tree officers, spend much of their time managing risks rather than maximising the opportunities of trees. They often receive complaints about trees and tree management, and it can sometimes be difficult to remember that people do care about trees. We need to develop viable partnerships between tree managers, community members and businesses to support trees in our cities.
Although the canopy cover of cities worldwide is currently falling, this is not the case in Europe, where it is increasing. Many European countries are acknowledging the fact that we have over-designed our towns and cities to accommodate the car, and now it is time to reclaim the public realm for our people – either pedestrians on foot or on bicycles.
Creative developments like the Hundertwasserhaus are not the only answer to creating Treetopia. We are and will continue to plant more street trees, urban groves and informal clusters of trees in our parks and green spaces. Treetopia has begun.
The ideas presented in this article aim to inspire adaptation action – they are the views of the author and do not necessarily reflect those of the Global Center on Adaptation.
