The Canal du Midi Continues its Painful Surgery


Long Stretches of the famous Canal du Midi won't be quite the same for some time due to drastic but necessary tree surgery currently under way

At the time of writing, some 1,830 trees on the Canal du Midi are being cut down and destroyed between Carcassonne and Agde. From now until the end of November 2013, the chopping will continue, bringing the total up to 2,200 plane trees. This is on top of the 1,600 trees that were cut down along the banks of the Canal in spring. The centuries-old waterway – a triumph of engineering – has never known such a brutal transformation in all its years of existence.

Since 2006, when the appearance of a coloured canker in the Canal’s plane trees led to the decision to destroy the terminally infected rows, 4,000 of them have been cut down. With a little more than 2,000 more adding to that figure, the surgery is not over yet.

“We estimate that between 8,000 and 10,000 trees have been infected out of the 42,000 plane trees in double alignment along the Canal du Midi,” epxlains Jacques Noisette of the VNF (Voies Navigables de France); the French inland waterways authority.

This means that a quarter of all the trees that line both sides of the banks of the canal for 200 of its 240km course will disappear. Although the disappearance will be provisional (the gaps will be filled with newly-planted fungus-resistant varieties), plane trees do take some time to grow and it’s estimated that the Canal won’t look quite the same until another 50 years – the time it takes for them to reach the level of maturity that the rest of them have attained.

The VNF are hopeful that it won’t take that long and their policy is to replace the plane trees with faster-growing varieties such as Hackberry, Hickory, White Poplar, the Chestnut Leaf Oak and the Pecan.

The current project of removing the infection from the ancient waterway will now affect all the western end of the Canal, all of which is situated in Languedoc. Several well-known spots are included in this operation, including the Puichéric Lock and the famous Round Lock at Agde.


Initial figures released show that traffic on the inland waterways of France has fallen. A luxury pastime and tourism activity, the numbers collected covering the period from January to July are not good: there was a drop of 8.7% on visitor numbers to the Canal du Midi compared to the same period last year. The data compiled by the VNF shows that the number of vessels of all types going through the locks on the Canal du Midi went from 39,632 down to 36,185.

"It's for your own good!" Workers clear away hopelessly diseased trees while a hired cruiser is moored nearby

“It’s for your own good!” Workers clear away hopelessly diseased trees while a hired cruiser is moored nearby

The question is whether or not the hacking away of significant parts of the famous green canopy of the Canal (something which helped its inscription into the hallowed list of UNESCO World Heritage Sites) is the main reason behind this drop in traffic?

The cruiser rental agencies are slow to jump to conclusions: “It’s mostly French customers who are interested in that particular subject. Up to now at least, it hasn’t been much of a factor for us,” said a spokesperson at the Le Boat base in Castelnaudary.

A smaller rental company in Somail doesn’t agree. He says that he is “worried” about the state of the Canal and fears a collapse in the market: “The larger companies won’t admit it but their reservation books aren’t full. Lots of their boats are sitting at the quay this year.”

Is this to be believed? On the websites of cruiser-hire companies, there no shortage of promotions at the moment, with discounts as high as 45 or even 50%.

Taking the period from January to July 2013, the traffic generated by rental boats was, however, the sector that dropped the least: 25,794 passages through locks as against 27,866 for the same period in 2012; representing a drop of 6.8%.

According to Patrick Portier of boat rental agency Caminav in Carnon, this drop has much more to do with the continuing economic crisis rather than the tree slaughter: “It’s the first year that we’re not booked out in August and we haven’t had a good start to September. But our market is concentrated mostly on the Camargue.” The Camargue is covered by the lagoons and the Rhône-Sète Canal – an area completely unaffected by the Plane tree fungus effect.

So what role has the fungal infection played in the drop in traffic? One figure that is worth focusing on is that which indicates the navigation activity of privately-owned vessels. This is a sector that are most inclined to choose where they want to bring their boats in direct relation to where they want to go. This is the sector that has diminished most: 7,553 passages through locks on the Canal du Midi from January to July 2012. This year, the figure was just 6,435 – a drop of 15%. A significant figure, even taking into account the exceptionally cold weather that France experienced for the first half of the year.

Questions on the Plane Tree Canker

  • When did it happen? The microscopic fungus is said to have been transported in wooden ammunition boxes that came over to France with the invading American armies in 1944. It remained undetected in the south-east of France for a number of years before attacking the trees of the Canal du Midi. The first victims were spotted in the Villedubert area of Aude in 2006.
  • Why is the Canal so badly affected? There are two reasons why the Canal has been so badly affected. The first is historical; when Pierre-Paul Riquet first built the canal between 1666 and 1681, no trees were planted. The first trees that were planted along the canal were put there by residents who wanted to mark their boundaries, create some privacy and provide timber and fruit. During the 19th century, the Compagnie du Canal du Midi, in order to help stabilise the banks, embarked upon a programme of plantation of plane trees. Most of the trees being cut down now date from that period and the decision to only choose one variety has contributed to the fragility of the plantations. The second reason is down to the Canal itself. The fungal infection survives in the water which serves as an excellent carrier. When boats anchor along the banks, they often scrape off the roots of the plane trees, allowing the canker to get into the tree. Once inside the heart of the giant plant, the infection blocks the vessels that carry sap in the tree.
  • How can one fight against it? The only solution, according to the experts, is to destroy all the affected trees with infinite precaution to ensure that there’s no chance of the disease returning. Thus, the wood is immediately burned in specially-prepared pits. The saw-dust is allowed to fall only on sheets prepared with disinfectant and then hoovered up on site. People leaving the site must pass through a process of disinfection, meaning that the areas are completely closed to the general public while the tree-cutting is going on.


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