Volunteers plant mini-forests in Paris to slow climate change and fight heat waves
French volunteers are using a pioneering Japanese method of planting trees to create pocket forests in Paris in hopes of slowing climate change, creating biodiversity hotspots and combating the growing number of heat waves in the capital.
On a damp Saturday afternoon in the southern suburbs of Paris, a 9-year-old boy wields a shovel to plant a sapling on a deserted strip of land.
It is not much bigger than the sapling it plants. The afternoon rain turned the ground beneath him to mud. He throws his shovel aside and cleans the clay soil with his hands.
Together with his proud grandmother and fellow volunteers, he is busy planting a mini-forest, also known as pocket forest, next to a busy highway in the Chevilly-Larue district, 9.3 kilometers south of the center of Paris.
The French non-profit organization Boomforest organized a tree planting initiative and attracted a dozen volunteers of all ages dressed in hats and boots as they braved the cold and rain.
Grazia Valla, 79, a former journalist, said she “seized the opportunity with both hands to do something real” about climate change and showed her grandson how to plant trees.
“He likes going to the community vegetable garden,” she said, giving him an affectionate look. “When I take care of him, he always begs to go.”
“Not all children have the opportunity to see and taste vegetables growing,” she said, applauding the initiative. “We are very interested in everything that has to do with nature.
Maxim Timothée, 31, was happy to be outside and was motivated by the simple and symbolic gesture of planting a tree.
“It’s very special to plant a tree,” he said, pausing before cutting into the wet clay. “It’s not just any object. I feel connected to the life of this tree. I want to protect him. I planted it.
Despite the gloomy weather, Timothée said it feels good to take action, rather than sitting at home worrying about climate change and the sharp decline in biodiversity.
The Miyawaki Method
Mini forests were first developed in the 1970s by Japanese botanist Akira Miyawaki, who studied remnants of ancient forests around sacred temples and shrines.
Miyawaki found that they not only thrived without human intervention, but were also richer and more resilient than more recently planted forests.
In his study of old-growth forests, Miyawaki claimed that densely planted native species, grown in carefully prepared soil at four different elevations to provide multiple layers of cover, grew up to 10 times faster and sequestered more carbon than native species. standard managed forests.
Miyawaki then tracked the planting of more than 1,500 forests around the world and said that a forest of just 100 square meters can harbor exceptional biodiversity.
Miyawaki forest advocates have adapted his methods and used them around the world as cities try to curb the effects of climate change, restore degraded lands, create biodiversity hotspots and sequester greater amounts of carbon.
Forests the size of tennis courts have been planted in Beirut, in cities across Asia, across India and increasingly across Europe.
Paris planted its first mini-forest on the northern edge of the city’s ring road at Porte de Montreuil in March 2018 with the Boomforest grant from the French capital’s participatory budget.
“Ninety-five percent of the trees planted there survived,” said Guillaume Dozier, 33, a regular Treeforest volunteer, as he hauled compost into a wheelbarrow to mulch the soil around the newly formed saplings. planted.
“The trees have now reached a height of almost four to five meters,” he happily reports, adding that the biodiversity of the mini-forest is now thriving.
“Every time we go there, we see more and more insects and birds that weren’t there before,” says Dozier, explaining that they were setting up a program to monitor the species that were there before. meet.
Motorways are “an extremely hostile environment” for birds and insects, Dozier says over the roar of traffic, explaining that the Val de Marne authorities had given them the roadside land to plant the new forest. .
By mimicking the same richness and density of a wild forest, the new trees will be home to hundreds of small mammals, insects and birds, Dozier continues.
Unlike artificial forests planted for timber production, where trees are arranged in neat rows and planted 10 meters apart, trees in Miyawaki forests are planted close together.
As many as three trees per square meter were planted haphazardly along the highway, with the slender young shoots close together.
Planting a single tree has been shown to have the same cooling effect as 10 air conditioners. But trees are social and do much better when planted in the company of other trees, says Dozier.
“They shade each other and can exchange water, nutrients and information. If one of them is attacked, they can warn the others. For example, they will bitter their leaves to make them less edible for the attacker,” he says.
All young trees are local French species. Locally, the City of Paris defines native French plants as those of the region before A.D. 1500, Hannah Lewis explains in her book “Mini-Forest Revolution: Using the Miyawaki Method to Rewild the World.” But the Treeforest team conducted additional research to ensure their trees and shrubs were the best locally adapted species and would coexist well.
Oak, ash, beech and willow are planted in the center, while shrubs such as hazel, holly and charcoal are planted around the edges. Only 15 different plant species were planted this weekend, but no less than 31 local trees and shrubs were planted in the other Boomforest projects.
Pocket forests in Paris
Proponents of pocket forests also hope they can make a city as close as Paris more livable in the heat.
In the summer of 2022, Paris was overwhelmed by three consecutive heat waves for a total of 33 days, and temperatures in the French capital reached near-record highs of 40 degrees Celsius.
The lack of trees and the shade and tranquility they provide – Paris has about 9% tree cover – became apparent as the city became an oven.
Parisians languished on the city’s cobbled streets as the asphalt, concrete and metal of the buildings absorbed and passed on the scorching heat.
Paris City Hall has pledged to plant 170,000 trees in the French capital by 2026. But 76 ancient plane trees in April last yearto make way for green spaces has drawn the wrath of environmentalists, among others Burger trees and the GNSA, anti-tree cutting groups.
Green activists also say that newly planted saplings are no competition for the cover of a decades-old treeand that young trees are particularly vulnerable to drought.
Critics of Miyawaki-style forests add that mini-forests are expensive to plant and the science behind planting them in Europe is not strong enough. A 2010 study of a mini-forest in Sardinia, one of the few studies of mini-forests in Europe, estimated the tree mortality rate after 12 years to be between 61 and 84%.
Despite the Parisian authorities’ apparent enthusiasm for planting trees, Dozier admitted that it was difficult to find space for them in the city center.
“Paris is a bit of a museum,” he said wryly, adding that mini-groves have only been planted at the city gates, Porte Maillot and Porte des Lilas. .
He hopes that one day they will have the opportunity to plant a mini-forest in the heart of Paris, adding that they are adapting their tree-planting methods and are constantly learning. He also hopes that others will decide to plant their own pocket forests and that those concerned about climate change will be encouraged to take action. Downloadable step-by-step forest planting instructions are described at J’agis je Plante (I act, I plant), on the website of Boomforest and other mini forestry groups in France such as MiniBigForest and Toulouse and Transition.
Towards the end of the afternoon the rain had increased. But the enthusiasm of the volunteers does not weaken. Nearly half of the 250 square meters they planned to reforest over the weekend had been dug up and planted with saplings. If Boomforest’s budget allows, they hope to return to plant more of the total 800 square meters they are allotted.
Over the next few months, in the spring and then in the fall, permanent Boomforest volunteers will return to the newly planted forest to remove weeds that may compete with saplings and monitor their progress.
In just three years, the new forest will be self-sufficient. Boombos hopes that in 10 years it will look like an ancient natural forest.
Valla hopes her grandson will return to the forest in the spring and for many years to come.
“I hope he comes walking around here and says, ‘Hey, I really did something here’.”
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