Plane tree disease: the early stages of the replanting project
As robust and imposing as they may seem, plane trees can develop a long-known disease called canker stain. It was probably introduced with the landing of American troops in France in 1945, by boxes of ammunition made from infected wood arriving from the United States. The disease is caused by a microscopic fungus which dries the plane tree and inexorably kills it. It was first detected on plane trees along the canal du Midi in 2006, in Villedubert (Aude).
Unfortunately, researchers were unable to find any curative treatment, and the 42,000 plane trees bordering the canal came under threat. Voies navigables de France had no choice but to cut the diseased trees down to ensure user safety, and to replant new species to re-create the canal’s green canopy, recognized as a UNESCO World Heritage Site since 1996.
The beginnings of the canal du Midi tree replanting project
The first trees were replanted in Aude in the winter of 2011-2012, six years after the disease now threatening our plane trees was discovered. The species were chosen not only for their landscape characteristics (colonnades and green canopy), but also for their resistance to disease. Thus Turkey oak, hackberry, Norway maple, small- and large-leaved linden trees, hop-hornbeam and white poplar were planted to replace plane trees.
In the past 10 years, 29,100 diseased or dead plane trees have been cut down, and 16,700 trees have already been replanted along the canal du Midi since the project to restore the green canopy began.
Replanting of canal trees… but that’s not all!
- Canal bank restoration
Bank restoration is a central component of the canal du Midi replanting project, since cutting down plane trees causes the gradual elimination of the root network that supports these banks. Various processes are therefore necessary to stabilize them before replanting new trees to replace the decimated plane trees.
In the space of 10 years, 33.5 miles of banks have been restored.
- Preserving the biodiversity of the canal
The canal du Midi is a boating site with an exceptional architectural heritage. It is also an area rich in biodiversity, an ecological corridor home to many species of animals (fish, amphibians, birds, etc.) and aquatic plants. An action plan has been set up to preserve the canal’s biodiversity by limiting and offsetting the impacts of felling on fauna and flora.
Plane trees affected by canker stain are therefore cut down in the spring and fall of each year, out of respect for the biodiversity, and in particular the breeding and nesting periods of birds, wintering, and the rearing of small animals for bats.
Also, since 2015, bird nesting campaigns and bat houses have been set up to provide shelter for wildlife displaced by felling. At least 1,350 habitats have been introduced along the entire length of the canal du Midi and in the surrounding environment.
Replanting project investments
€79 million has been invested over the past 10 years to carry out this massive project. The estimated overall cost of the project is €220 million.
Since December 2013 and the creation of the VNF patronage program, replanting campaigns have received support to the tune of €8 million, raised by companies, foundations and individuals concerned about preserving this regional historic and environmental emblem. It is thanks to the joint effort of the business world, citizens, local authorities and the government that we are able to carry out this colossal project for the preservation our French river heritage.
A big thank you for all your support!
