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As the world's cities grow in size and number, urban forests are becoming increasingly important
They are also under threat, despite the many benefits they provide
What do an avenue of grand oaks, a community park and a rooftop vegetable patch have in common? They can all form part of a city’s “urban forest”, which numerous studies over the past decade have concluded make people happier.
And that’s not their only job: urban forests protect our cities from extreme weather, climate change and water scarcity.
But with more than 70% of people expected to have squeezed into cities by 2050, this green infrastructure is under threat, according to the UN’s Food and Agriculture Organization (FAO).
“The cities of the future are going to have major problems in making sure that people live a decent life,” Simone Borelli, an urban forestry expert and co-author of a recent FAO report on global urban forestry guidelines, tells CNN.
“If you don’t maintain those forests there’s no clean water, and then there’s no food security. It’s a pretty simple equation but not many people think about it.”
Are we about to lose our urban forests?
A broad canopy
You may not associate big cities like Singapore, New York or Paris with forestry but look closely: each has its own green canopy to varying degrees.
This “urban forest” is defined by the FAO as “the networks or systems comprising all woodlands, groups of trees, and individual trees located in urban and peri-urban areas” – it encompasses everything from grand parks down to a single tree.
And while there are no guidelines on exactly how much forestry a city needs, experts are very clear on its benefits.
“People think trees are dispensable and they’re not,” Stephen Sheppard, a professor in urban forestry at the University of British Columbia (UBC) in Vancouver, Canada, tells CNN. “Green space is critical infrastructure.”
He lists their advantages: urban forests can protect a city’s land and water supply, acting as natural infrastructure that protects soil and absorbs rainwater, thereby reducing runoff which causes erosion of soil and sedimentation in local water supplies.