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Monday, November 18, 2019, 15:04
Growing green cities
By Karl Wilson in Sydney
Monday, November 18, 2019, 15:04 By Karl Wilson in Sydney

Urban areas covered in plants, trees and shrubs will benefit the environment, people’s health

A “vertical forest” features in the design of a residential community in Chengdu, Sichuan province. (ZHANG LANG / CHINA NEWS SERVICE)

Wthe spread of urbanization worldwide, many people are asking: What will cities of the future look like?

Urban planners and architects have been grappling with this issue for decades. But one thing is becoming abundantly clear — these cities will be clean and green.

They will be living, breathing spaces, not only free of pollution but also generating fresh air for residents.

Signs of this are already starting to emerge in China and also Singapore, Sydney, Australia, and Milan, Italy.

Bharat Dahiya, one of the world’s leading experts on sustainable urbanization, said the cities of the future will feature 20- or 30-story buildings that will be “green, use clean energy sources and be covered in trees and shrubs”.

Dahiya is director of the Research Center for Integrated Sustainable Development at Thammasat University College of Interdisciplinary Studies in Bangkok, Thailand, and also a distinguished professor at the Urban Youth Academy in Seoul, South Korea.

“Trees provide shade; trees cool areas such as streets, roads and open spaces that are exposed to the sun, and in turn lower average temperatures in cities and human settlements,” he said. “Trees clean the air, reduce urban pollution and provide much-needed oxygen.”

During the UN Climate Summit in New York in September, several international organizations, including China’s Urban Forest Research Center, met to lay the foundations for a project that will have a profound impact on cities and how we live.

Although still in its early stages, the project will involve planting forests in 90 cities in countries across Africa and Asia, including China, which already has several urban forest projects either at the planning or planting stages.

For example, in Nanjing, capital of Jiangsu province, two residential high-rises designed by Italian architect Stefano Boeri are being built.

When completed, the buildings will house 1,100 trees from 23 local species and 2,500 cascading plants and shrubs, which will absorb 25 metric tons of carbon dioxide each year and produce about 60 kilograms of oxygen a day, according to the architects.

To put that in perspective, removing 25 tons of carbon dioxide would be equivalent to taking five cars off the road for a year. Chinese cities are among those with the most polluted air in the world.

In addition to the Urban Forest Research Center and Boeri’s company Stefano Boeri Architetti, other participants at the meeting in New York included: the UN Food and Agriculture Organization; UN Habitat; the C40 Cities Climate Leadership Group (which represents 94 cities or 8.3 percent of the world’s population); and the Arbor Day Foundation (a US nonprofit conservation and education organization).

“We are still at the very beginning of this program and will be working over the coming months on ways to make it concrete,” said Simone Borelli, an FAO expert on urban forestry.

Borelli said several cities had already been contacted “either directly or through our partners” to see if they want to take part in the project, but “no selection has yet been made”.

“The overall idea is to establish a multi-donor global mechanism that would provide matching funds for national or local projects, such as those collected through environmental fees and/or public-private partnerships in which users of urban forests contribute to their establishment or preservation,” he said.

Borelli said the program aims to establish forests within cities and restore those already existing in surrounding areas.

“Our goal is to plant 500,000 hectares of new forests and restore another 300,000 by 2030,” he said.

The program will promote locally adapted native species, which will reduce the need for irrigation. In some instances, recycled wastewater, or even desalinated water, may be used.

For some time, urban planners have realized the enormous benefits of green cities on the environment as well as on people’s heath. 

According to the World Health Organization, green spaces in cities, such as parks and sports fields, as well as woods and natural meadows, wetlands and other ecosystems, are a fundamental component of any urban ecosystem.

It said green urban areas facilitate physical activity and relaxation and provide a refuge from noise. Trees produce oxygen, and help filter harmful air pollution, including airborne particulate matter. Bodies of water, from lakes to rivers and fountains, moderate temperatures.

Green spaces are also important for mental health.

The WHO said access to such spaces can reduce “health inequalities”, improve well-being and help in the treatment of mental illness. Some analysis suggests that physical activity in a natural environment can help counter mild depression and also reduce stress.

Dahiya, the urbanization expert, said: “Trees help combat climate change by absorbing carbon dioxide, removing it from the air. They help prevent soil erosion, especially in cities located on hilly terrain, as they slow the surface water runoff.” 

In turn, preventing soil erosion also helps prevent natural disasters, such as landslides and floods.

“Tree cover helps enhance urban biodiversity by providing habitat for all sorts of animals, reptiles, birds, insects and so on,” he added.

Borelli, from the FAO, said China already has a number of “vertical forest projects”.

“In my view, China has a vast amount of know-how that could be used to support countries in other parts of the world when this project gets off the ground,” he said.

According to Boeri, the Italian architect, the future of urban living lies in plants, trees and shrubs.

His company’s approach is simple: avoiding the unrestrained use of cement; blocking the expansion of cities by enclosing them with forests; safeguarding forests and biodiversity within cities to reduce pollution; and making nature an essential component of architecture.

“Cities produce nearly 70 percent of carbon dioxide emissions, the cause of phenomena such as the greenhouse effect, the melting of ice caps and rising sea levels, while forests and oceans are the main enemies of carbon dioxide, absorbing approximately 35 percent of the amount emitted,” Boeri said.

“Bringing forests within cities, or creating forest cities, means fighting the enemy on its turf, and transforming carbon dioxide into a fertilizer to feed plants.”

In the next 10 years, China is expected to be home to almost half of the world’s new construction.

As the country finds fresh ways to bolster its robust economy with an emphasis on sustainability, significant investment opportunities are emerging in Chinese markets, such as construction, architecture and urban design.

Many current construction projects in Chinese cities adhere to strict environmental regulations, and the government now requires 50 percent of new urban buildings to be certified sustainable.

One ambitious Forest City project is being planned in Shijiazhuang, a northern industrial hub and capital of Hebei province. The initiative is hoped to curb the city’s high rate of air pollution.

Artists’ impressions from Stefano Boeri Architetti depict the Forest City as a sustainable utopia in which every building is covered in plants — nearly 1 million of them. These “green citizens” are expected to absorb thousands of tons of carbon dioxide and pollutants produced by 100,000 residents.

China’s willingness to innovate in the architectural arena presents myriad possibilities for investors. The country’s ambitious plans to support increasing urbanization — coupled with its determination to go green — will create abundant sustainable investment opportunities in groundbreaking architectural design.

Dahiya, the urbanization expert, said the initiative discussed in New York is a “welcome step toward addressing and tackling some of the perennial urban ecological and environmental issues we face today”.

These issues include: alarming levels of biodiversity loss; growing average temperature levels; air and noise pollution; lower groundwater tables; land degradation; and related natural hazards like heat waves, droughts, gales, landslides and floods.

“We should encourage such concerted efforts toward greening of cities and expanding urban forests,” Dahiya said.

However, expanding tree and forest cover, especially in larger cities, will not be easy, because of two interrelated factors, he said.

“First, the ever-growing demand for developed land for commercial, residential, institutional and industrial uses. Second, high land values that often prevent urban planners and policymakers from reserving land for tree cover, green spaces and urban forests — as opposed to allocating it for uses that contribute to urban and national economic growth.

“To tackle this difficult issue, on one hand, city governments will have to put a premium on green spaces and urban forests, and on the other, urban residents will have to demand a better quality of life, that is, improved urban livability if we really want to have green cities now and in the future,” Dahiya said.


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