街に木を植えると良い５つの効果 WORLD ECONOMIC FORUM
1. Reduce pollution and keep us cool
2.Make us happy
3.Protect urban wildlife
4. save money
5. Keep us physically health
Cities are planting more trees to fight climate change and improve healthy living
From Athens to Melbourne and Seoul to New York, big cities are increasingly turning to trees to help protect them from heatwaves and floods, and to boost people's physical and mental health, urban officials and environmental experts say.
South Korea's capital Seoul recently planted more than 2,000 groves and gardens, and Melbourne in Australia plans to nearly double its canopy cover to 40 percent by 2040.
Athens is looking at planting more trees to lower temperatures and protect the Greek capital from sudden downpours.
"We have real problems with urban heat islands and flash floods. We know we have to take trees very seriously, and we haven't up to now," said Eleni Myrivili, deputy mayor of urban nature and Athens' chief resilience officer.
Athens is still recovering from the 2008 economic crisis and lacks the staff to maintain its trees, which include bitter orange, japonica and Judas trees, she told the World Urban Forestry Forum, taking place in the northern Italian city of Mantua this week.
Milan, which plans to plant 3 million trees and expand its green spaces by 2030, has experienced a 2-degree Celsius temperature rise and increasing heat-related deaths in the past 20 years, as well as worsening floods, said the city's chief resilience officer, Piero Pelizzaro.
More trees should "reduce air pollution, improve the quality of the urban space ... and reduce the impact of climate change", he told the Thomson Reuters Foundation.
"Nowadays there's no difference between the city's energy consumption in the winter and summer" because of the rising demand for air-conditioning, he added.
Cities in Niger and Senegal in Africa are planting trees to create jobs and provide fruit for families to eat, as well as provide much-needed shade.
Trees and green spaces lower stress levels and encourage people to exercise and socialise more, experts at the forum said.
But with urban populations projected to increase by 2.5 billion people by 2050, demand for more housing and transport is putting pressure on green spaces, they said.
And a lack of expertise, data or the ability to attract funds means cities tend to opt for "grey" infrastructure projects over "green" ones to fulfill the same job, according to a report by New York-based 100 Resilient Cities network, published on Wednesday.
That could mean building a concrete wall to protect a coastal city from flooding instead of planting mangroves, which are effective, less costly, more visually pleasing and improve air quality, said 100 Resilient Cities, which produced the report.
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