Plane trees felled on a boulevard to prevent the spread of a fungus

The plane trees have been falling one after the other, since the beginning of the week, on Boulevard Henri-IV, in Montpellier (Hérault). The town was forced to cut down about twenty, because of the detection of the colored canker, on one of them. “This is not good news, but it is mandatory,” laments Stéphane Jouault (EELV), the deputy mayor in charge of biodiversity.

This disease, which causes the irreparable decline of plane trees, spreads very quickly from tree to tree, and no antidote exists. On the Canal du Midi, it had resulted in the felling of more than half of the plane trees. To avoid its proliferation, there is only one solution: cut down the trees, within a radius of 35 to 50 meters from the affected subject. Otherwise, the risk is that the colored canker, which is transmitted, in particular, by the roots, does not spread at high speed on the city. “The root system of these trees is actually one and the same system,” explains Rodolphe Majurel, the ecologist appointed for this project. When the roots cross, they come together. “

Preserving bats

To replace these plane trees, new trees will be planted. “New species, because we cannot plant plane trees for ten years, once there has been a case of colored canker,” continues Stéphane Jouault. The idea is to diversify the species, to have a more resilient alignment, in the event of illness. The felled plane trees will be replaced by Korean elms and cork oaks.

But the felling of trees is particularly delicate: in particular, it is necessary to ensure its impact on the fauna. Because these trees, several tens of meters high, are home to several species of bats. “On this site, six may possibly be in cavities,” explains Rodolphe Majurel. We put sock sleeves, pieces of fabric, on the cavities, which allow the bats to come out, but not to come in. And every piece of a felled tree is visually checked, to make sure there aren’t any small animals inside. “In case of suspicion, the piece is left aside, in peace, for 48 hours, so that the animals can leave”, explains Pauline Lambrey, head of the department of gardens and natural spaces in the town.

We do not know how the colored canker arrived on this axis, crossed by the tram. Maybe a wound, on the bark. “It could be a vehicle that hit an infected plane tree 200 km from here, and that hits a plane tree here, and infects the tree,” notes Stéphane Jouault. Or even a bird, by nibbling a piece of bark affected by the canker to make its nest. In Montpellier, another site could be affected by the colored canker: the Tastavin park. Studies are underway to try to confirm whether or not it is the disease. If this is the case, it will also be necessary to cut down trees.

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