Urban forests increasingly central to planning in poor and rich countries alike

Forests in the heart of the city as well as the edge of town are vital not just for aesthetics but for improving residents’ health and reaping economic benefits, according to the UN FAO.

spore biophilic cities
Singapore as a compact city is considered as a world model of a biophilic city as the government invests in extensive park and green areas, elevated walkways and canopy walks. Image: Tristan Tan/ Shutterstock

Bill Stephen has a view most office dwellers would pine for. Perched on the edge of Vancouver’s iconic Stanley Park, Stephen’s window looks out on trees — lots of them. Douglas fir, western red cedar, bigleaf maple, Sitka spruce and hemlock all jockey for position in a carpet of green.

Staring out the window at a thick canopy of trees would be particularly relaxing for most. But as Vancouver’s Urban Forester, any gazing Stephen does is strictly on duty.

Not that he doesn’t admire the majesty of some of the specimens under his care. “There are some big old codgers with massive, three-metre trunks,” he told Citiscope on a misty afternoon late last year. “It feels like you’re walking through a coastal temperate rainforest. Some trees are well over 600 years old.”

Way back in 1886, civic leaders in this coastal city perched on Canada’s western edge had the foresight to set aside the 400 hectares (1,000 acres) that jut into Vancouver Harbour when they incorporated the burg. Now the booming Pacific city is reaping the benefits of that decision, not only from the half-million trees crammed into the verdant park but also via a legacy of stewardship that emphasises care for street trees even as new residential and commercial towers spring up at a rapid pace.

Vancouver is a model recently cited by the Food and Agriculture Organization’s Simone Borelli, co-author of a new set of guidelines for maintaining healthy urban forests. The FAO’s pointers range from big-picture items such as how to embed forest management into urban plans and land-use law, to precision advice on how to avoid allergy-inducing trees and create local wildlife habitats.

Throughout, the FAO emphasises how forests in the heart of the city as well as the edge of town are vital not just for aesthetics but for improving residents’ health and reaping economic benefits.

The agency explicitly lists dozens of interconnections with the new Sustainable Development Goals, which countries began to implement last year, noting that robust urban tree cover can create employment, filter drinking water, remove pollution, reduce the cost of urban infrastructure, increase mental well-being, lessen energy costs, bolster tourism prospects — even directly mitigate climate change.

Forests and trees make cities healthier for those living there by providing a wide range of goods and services.

Simone Borelli, Food and Agriculture Organization

No isolated issue

Although traditionally focused on rural agriculture, the FAO, a United Nations agency, is increasingly looking at the urban dimension of its mandate.

That consideration was spurred in part by last year’s U. N. conference on cities, Habitat III. The four-day summit resulted in a 20-year urbanisation strategy, the New Urban Agenda, that calls for more robust urban planning as the world heads toward a global population that will be 70 per cent urban by 2050.

To that end Vancouver earned Borelli’s nod, as did Melbourne’s Urban Forest Strategy, for not treating a city’s trees as an isolated issue. “A key element of success is the integration of the urban forestry aspect in the overall urban planning process,” he said.

In Vancouver’s case, that means street trees feature prominently in its Greenest City 2020 Action Plan, an ambition to make the city the world’s most environmentally friendly by the end of the decade. As a result, Stephen, who works out of the city’s Park Board, is confident that urban forestry is a priority item for Mayor Gregor Robertson  — in fact, he cut our interview short to make the cross-town trip to City Hall.

Vancouver also manages its urban forest collaboratively within the city government. For example, the Engineering Department is responsible for street trees that fall outside the purview of a city park.

And the administration takes those street trees seriously. The Greenest City plan calls for the city to continue planting at least 2,000 new street trees annually and for tracking data on all of the city’s estimated 138,000 street trees (the figure as of the plan’s publication in 2011). Ultimately, the plan hopes to boost the city’s tree cover — a combination of parks, street trees, and trees on private and public land — by 150,000 ahead of the 2020 deadline.

Luxury no longer

Seeing increased value in maintaining a healthy urban forest is a new global trend, according to the FAO. Importantly, a key part of that trend is that the issue is no longer being seen as a mere luxury for rich countries.

Borelli cites growing interest in the developing world. For instance, Kumasi, a Ghanaian city of more than 1 million people, embarked on an urban forestry project two years ago with support from international donors. Its goal is to energise schoolchildren and households to plant over a million trees by 2017.

He also pointed to China’s National Forest City programme, which combines national targets with local community involvement with the aim of inculcating a sense of environmental stewardship among residents. By last year, more than 170 cities and 12 provinces were actively involved the initiative, Borelli said. Tree cover in these urban communities had increased to 40 per cent or more, up from less than 10 per cent in 1981.

While urban growth often seems to necessitate cutting down trees to make room for subdivisions and more, Borelli argues that new approaches suggest the two aims are not incompatible. “Affordability should not be at the detriment of healthy living conditions,” he said. “Forests and trees make cities healthier for those living there by providing a wide range of goods and services.”

Reflective of this growing trend, researchers at MIT’s Senseable City Lab used Google Street View to create an online database of urban forests they call the Treepedia. The current version of the database offers up analysis of more than a dozen cities — Amsterdam, Boston, Geneva, London, Los Angeles, New York City, Paris, Sacramento, Seattle, Tel Aviv, Toronto, Turin and Vancouver.

Among these, Vancouver won out, with around a quarter of the city under a leafy canopy. And that doesn’t include the dense concentration in Stanley Park, where roads, and thus Google Street View, do not reach much of the forest.

Valuing tree cover

But the numbers that really matter are fiscal, with urban forest advocates increasingly making their case with dollars and cents by tallying up what those services are worth.

To preserve the world’s largest water system, for instance, New York City opted to invest USD 1.5 billion in watershed protection projects — including improved forest management. That was instead of building a filtration plant estimated to have cost USD 6 billion to build and a further USD 250 million per year to maintain.

“Green infrastructure is just as important as grey infrastructure,” Stephen said, alluding to cement and concrete as opposed to soil and seedlings. “In many cases, it’s more cost effective.”

London has pioneered the measurement of an urban forest’s value. Last year, its i-Tree Eco Report determined that the city derives GBP 132.7 million (USD 161.5 million) annually in quantifiable ecosystem services such as pollution removal, carbon sequestration and stormwater alleviation from its tree cover. The report further estimated that it would cost GBP 6.12 billion to replace the British capital’s nearly 8.5 million trees.

Property owners also benefit from a robust tree cover. In a 2008 study, economists at the University of Pennsylvania’s Wharton School of Business valued a single tree planted within 1,000 feet of a house as raising the building’s value by 7 to 11 per cent.

Research like this has prompted Vancouver to require a one-to-one replacement of trees, even as the city undergoes a massive development boom.

If a single-family home on a tree-lined lot is demolished to make way for a larger multi-family building that will take up a larger footprint — a fairly common sight these days in one of the world’s hottest real-estate markets — the developer must design around trees and their root systems in order to receive a building permit.

This story was published with permission from Citiscope, a nonprofit news outlet that covers innovations in cities around the world. More at Citiscope.org.

Like this content? Join our growing community.

Your support helps to strengthen independent journalism, which is critically needed to guide business and policy development for positive impact. Unlock unlimited access to our content and members-only perks.

最多人阅读

专题活动

Publish your event
leaf background pattern

改革创新,实现可持续性 加入Ecosystem →