FFrom Madrid to Berlin and from Paris to Budapest, scientists and planners agree, trees, trees and more trees can help make European cities more comfortable, even survivable, in the years to come as global warming takes hold. strengthens.

But concrete sidewalks, high-rise buildings, historic squares and underground car parks are a hostile environment for trees, making it hard for authorities to plant more. In fact, many cities in the EU are less green than they were a century ago.

“It’s a big challenge,” said Christophe Najdovski, deputy mayor for revegetation and green spaces in Paris city ​​council. “We know that with enough trees we can lower the city’s summer temperature by up to 8C. They are basically natural air conditioning. But planting them is not always easy.”

The latest report of the Intergovernmental Panel on Climate Change couldn’t be much clearer: Trees in cities combat climate change both directly, by storing carbon, and indirectly, by cooling urban areas, reducing energy demand.

They also offer city dwellers what the report calls “multiple co-benefits”: improved air quality, reduced heat stress, fewer “urban heat islands” caused by streets and buildings absorbing and retaining heat,” improving mental and physical health.

In short, for municipalities, planting more trees should be a no-brainer. Aim according to the Organization for Economic Cooperation and Developmentthe number of trees in many of Europe’s cities has been declining since the early 1990s, with some large conurbations losing up to 10% of their cover.

In part, experts say, that’s because older trees from the late 19th and early 20th centuries, those that have survived the efforts of successive generations of urban planners to make more space for cars, are beginning to fade. come to the end of their lives.

People cool off in the shade of the trees in Paris.  The city has embarked on an ambitious tree planting program.
People cool off in the shade of the trees in Paris. The city has embarked on an ambitious tree planting program. Photo: Anadolu Agency/Getty Images

But it is also due to technical difficulties and the cost of planting new trees. According to Ana Luisa Soares, a landscape architect at the University of Lisbon, a new tree can cost the city administration up to €2,000 (£1,740) over five years.

“You have to buy the tree,” Soares said. “You have to plant it, water it, especially in the first five years, when it is most vulnerable. Life is hard for a tree in a city: compacted earth, polluted air… You have to maintain it, prune it, treat it for diseases. When you’re talking about tens of thousands of trees, that’s a huge investment.”

The advantages, for city dwellers, seem clear. “We need trees,” she said. “They are important to all of us, residents and visitors. They give us more shade, better air quality, lower temperatures, natural beauty; basically, more trees mean happy people. We know this. And they will be even more vital in the future.”

But while the costs are easily quantifiable, the benefits are less so. Worse still, Soares said, the environmental, social, economic, aesthetic and health benefits that trees provide “are often simply ignored, because cities are simply looking to manage costs.”

In an effort to put a monetary value on the benefits of trees, Soares adapted an American software program, iTrees, and fed it data on some 41,000 Lisbon trees. She found that while the trees cost about $1.9 million a year, the services they provide are worth $8.4 million.

“So for every $1 a city invests in its trees, residents get about $4.5 in benefits,” he said: energy savings of about $6.20 per tree, $0.33 worth of carbon reductions, air pollution removal $5.40 and stormwater runoff reduction $47.80. Trees were also found to significantly increase property values.

The European Commission proposed last year a draft regulation that obliges the 27 member states of the bloc to guarantee that at least 10% of the surface of all cities, towns and suburbs are planted with trees by 2050, and to commit not to miss the green space

But cost isn’t the only hurdle urban planners face. Often, Najdovski said at Paris’ socialist and green city hall, which in the past two years has embarked on one of Europe’s most ambitious tree-planting programs, cities simply cannot plant trees where they would like.

“The biggest problem is the underground infrastructure. The subway, gas pipes, electricity and telephone cables, parking lots… You need a certain depth of soil under a tree. We’d love to plant along rue de Rivoli, which crosses the city center from east to west, but unfortunately the metro is just below it.”

Place de la Concorde in Paris, view during a Covid lockdown in 2020.
The city’s architects are said to be opposed to plans to introduce trees to large squares that were designed without them, such as the Place de la Concorde in Paris. Photograph: Ludovic Marin/AFP/Getty Images

Elsewhere, ensuring emergency vehicle access through narrow streets can be an obstacle, as are property laws that prevent trees from being planted in or near buildings, streets and squares that were not designed for them. Most of the great squares in European cities were designed as open spaces, with commanding views.

“That is the case in Paris with, for example, the Place de la Concorde or the Avenue de l’Opéra,” Najdovski said. “The city’s architects argue that they must remain as originally designed, without trees, and that the view of the Opéra Garnier cannot be obscured or marred. We are looking for a compromise, but it is not easy”.

Yet on other major arteries like the Avenue de Wagram, Paris is busy replanting trees that were uprooted by the tens of thousands during the 20th century when the city transformed the grand boulevards, lined on both sides by double rows of trees, into four. lane avenues with roadside parking.

“Essentially,” Najdovski said, “our goal is to significantly reduce the space reserved in Paris for cars and use as much as we can to plant trees: a massive revegetation program, the reconquest of nature over the car. The goal is to plant trees in large numbers and whenever possible.”

Since his re-election in 2020, the City Council has planted 38,500 new trees in the capital, including 18,000 on the embankments of the peripheral ring road, 12,000 in the Bois de Boulogne and de Vincennes, and 8,000 in the streets and squares of the city center.

His goal is to plant another 21,000 this winter, including 11,000 around the ring road and 800 on 80 more streets in the city center. The city is also planning three “urban forests” primarily in the east of the city, including one on 8.65 acres (3.5 hectares) of former rail sidings in the 20th arrondissement that will house 2,000 new trees by 2024.

People between trees in a park in Brussels
Brussels has presented a 10-year plan to preserve the city’s trees and plant several hundred new trees. Photo: Anadolu Agency/Getty Images

His ultimate goal, by the end of his six-year term, is 170,000 new trees, including 20,000 on downtown streets. The traditional plane trees from Paris will dominate for the most part, but some Mediterranean species are also being introduced, such as the holm oak, more resistant to warmer temperatures.

As has happened in Brussels, where a 10-year plan pavilion (or canopy plan) aims to preserve the city’s existing trees and plant several hundred new trees every year until 2030, the Paris city council’s plans have sparked heated protests, most notably from motorist organizations.

“As I said, it’s not always easy, and objections from motorists and residents are just one of many problems we face,” Najdovski said. “Some residents tell me, look, I don’t want trees outside my apartment; they will cut off the power, that will take thousands off the sale price,” he said.

“I tell them: when the summers in Paris start to regularly reach 40 or 50 °C, how much do you think your apartment will be worth then? If the city is basically uninhabitable, who loses the most?”

By sbavh

Leave a Reply

Your email address will not be published. Required fields are marked *