Friday, February 3, 2023

From Paris to Lisbon: why European cities need trees, but then planting them isn’t so easy

From Madrid to Berlin, Paris to Budapest, scientists and urban planning experts agree: Trees, trees and more trees could help create friendlier European cities for years to come as global warming intensifies. Few cities where you can survive.

But concrete pavements, skyscrapers, historic squares and underground car parks present an unfavorable environment for trees, and officials are finding it difficult to plant more. In fact, many cities in the European Union (EU) are less green than they were a century ago.

“It’s a big challenge,” says Christophe Najdowski, deputy mayor and responsible for regeneration and green areas at Paris City Council. “We know that, with enough trees, we can reduce city temperatures by up to eight degrees in summer. They’re basically a natural air conditioner. But it’s not always easy to plant them.”

group final report intergovernmental Climate change experts couldn’t be more clear: Trees in cities combat climate change by sequestering carbon and indirectly by cooling urban areas and reducing energy demand.

The report argues that trees provide a number of other benefits: better air quality, less heat stress, and fewer “urban heat islands” caused by roads and buildings absorbing and retaining heat, which can lead to “mental health problems”. Improving” and physics “.

2,000 Euro per tree

In short, it should be clear for municipalities to plant trees. But according to the Organization for Economic Co-operation and Development (OECD), the number of trees in many European cities has been declining since the early 1990s. Some urban areas have lost up to 10% of their green surface.

In part, experts say, that’s because the trees that were overtaken by successive generations of city planners struggling to make room for cars — in the late 19th and early 20th centuries — their Nearing the end of life.

But this is also due to technical difficulties and the cost of planting new trees. According to Ana Luisa Soares, landscape architect at the University of Lisbon, a new tree can cost the municipal administration up to 2,000 euros over five years.

“You have to buy trees,” Soares says. “You have to plant it, you have to water it… especially during the first five years, when it is most vulnerable. Life is hard for a tree in the city: the compacted earth, the air pollution… you have to maintain it. It has to be kept, it has to be cut, it has to be treated against diseases. If we talk about thousands of trees, it is a huge investment.”

The benefits for the city dwellers are clearly visible. The architect says “we need trees”. “They are important to all of us, residents and visitors. They give us more shade, better air quality, lower temperatures, their natural beauty… In short: more trees equal happier people. This much we know. And they will be even more important in the future.”

set profit margin

But while the costs are easily quantifiable, the benefits are not so great. Worse, says Soares: The environmental, social, economic, aesthetic and health benefits that trees provide “are often easily overlooked because cities are focused solely on management costs.”

In an effort to give these benefits monetizable value, Soares has adapted a US-based software, iTrees, and fed it with data from Lisbon’s approximately 41,000 trees. Their findings suggest that the services they provide are worth $8.4 million, compared to the $1.9 million per year cost for trees.

“Therefore, for every dollar a city invests in its trees, its residents reap $4.5 in benefits,” he says. Energy savings of $6.20 per tree, carbon reduction of $0.33, air pollution abatement of $5.40, and storm water runoff reduction of $47.80. It also concluded that trees add value to real estate.

Obstacles in the underground

Last year, the European Commission proposed a regulatory draft for the 27, which guaranteed that at least 10% of the surface of every city and urban area would be covered by trees in 2050 and vowed not to lose green areas. committed himself to

But cost is not the only hurdle facing urban planners. Cities often can’t plant trees where they want to, says Najdowski of Paris’ city hall, socialist and in green hands – and who has been driving one of Europe’s most ambitious tree-planting schemes for the past two years. , “The biggest problem is the underground infrastructure: metro, gas pipes, electricity and telephone cables, parking lots… Under a tree, soil needs to be at a certain depth. We would like to plant along the entire length of Rivoli Street , which runs east to west from the city center, but unfortunately the metro is right under it.”

On the other hand, guaranteeing access for emergency vehicles through narrow streets can also become a barrier, as can heritage laws, which sometimes prevent planting trees next to buildings, roads and intersections that are not designed for this. were not done. Most large squares in European cities were conceived as open spaces with commanding views.

“This is the case in Paris, for example, the Place de la Concorde or the Avenue de l’Opéra,” says Najdowski. “The city’s architects ensure that they remain as they were first designed, without trees to decorate them, and that the view of Oprah Garnier cannot be hidden or impaired. We seek to find a balanced solution.” I want to, but it’s not easy.”

However, in other major arteries such as the Avenue de Wagram, Paris is in full replantation work, where thousands of them were removed during the 20th century, when the city replaced them with grand boulevards with double rows of trees on each side. on a four-lane road with parking spaces on the sides.

“What we hope to do, fundamentally, is to drastically reduce the space reserved for cars in Paris and allocate whatever we can to plant trees: a massive redevelopment program, nature over automobiles.” rebuilding. The goal is to plant trees in large numbers and wherever possible,” says Najdowski.

against the neighbors

Since his re-election in 2020, the municipal government has planted 38,500 new trees in the capital, of which 18,000 have been planted along the retaining wall of the Ring Road peripheral12,000 in the Bois de Boulogne and de Vincennes and 8,000 in the streets and squares of the city centre.

The plan calls for a further 21,000 trees to be planted this winter, including 11,000 in the area around the Ring Road and 800 on another 80 roads in the city centre. The city also has plans for three “urban forests”, mainly in the east of the city, including 3.5 hectares of former railway tracks in the 20th arrondissement, which will host 2,000 new trees by 2024.

His overall goal, by the end of his six-year term, is 170,000 new trees, including 20,000 on inner-city streets. The traditional flat trees of Paris will dominate the majority, but some Mediterranean species such as the holm oak, which are more resistant to warmer temperatures, are also being introduced.

like Brussels, where the plan Canopy (or a plan to build a 10-year green vault) aims to preserve the city’s existing trees and plant several hundred new trees each year until 2030, the Paris City Council’s plans have sometimes sparked heated protests, especially from bikers from organizations of

“Like I said, it’s not always easy, and objections from motorists and residents are only part of the issues we face,” Najdowski says. “Some residents say to me: ‘Look, I don’t want trees outside my apartment. They will take my electricity and that will make it cost thousands of euros less.’

“I answer them: ‘How much do you think your apartment will be worth when summers in Paris start regularly reaching 40 or 50 degrees?’ If the city is basically unlivable, who loses the most?’” he says.

Nation World News Desk
Nation World News Desk
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