Since last summer, the Girondin landscape has been transformed. The hectares of burnt pines gave way to plains. And one question remains: how to regenerate these forests?
Everywhere in the Landes de Gascogne forest, between Landiras and the shores of the Arcachon basin, trucks are busy. You have to cut, carve, clean and transport the wood burned last summer. A real race against the clock to prevent the bark beetle from taking hold, a small parasite that can only be fought by cutting down the healthy pines that it contaminates, and to be able to use as much wood as possible. And in view of the plains which now stretch as far as the eye can see, the site is progressing.
>> REPORT. Gironde: six months after the fires, elected officials and residents live with the fear that everything will start again
There now remains a question: what to do with these plains? Already last year, when the ashes had not yet cooled, the question began to arise. And the response of the inhabitants is unanimous: this forest must be replanted. Nearly eight months after the start of the fires in Gironde, which decimated nearly 30,000 hectares of forest, discussions have advanced, with different choices depending on the actors concerned.
At the center of these reflections is the National Forestry Office. Owner and manager of the national forest of La-Teste-de-Buch, the ONF also plays an advisory role for the municipalities concerned, for the department, owner of the domain of Hostens where the fire is still smoldering, and also for the owners and foresters via the DFCI, the association for the defense of forests against fires. And the NFB’s first advice is simple: wait.
Hope for natural regeneration
“Our overall technical choice is the natural regeneration of coastal forestsexplains Francis Maugard, risk manager at the ONF Landes-Nord-Aquitaine. We have kept all the clumps of living pines preserved by the fires on the national forest, because they will bring the seed that will help us regenerate the forest in a natural way. A choice that others will replicate, like the Gironde department: “There are places where we won’t touch at allexplains Jean-Luc Gleyze, president of the Gironde department. You really have to let nature take over. And we’ll see how she does it.”
Anyway, according to Francis Maugard, even if we wanted to replant, we would have to wait at least two years. “If we reason from a phytosanitary point of view, it is better to wait at least two years because we have insects which can attack the young plants. But after, the preparation of the soil, everything that ‘you have to do it beforehand, it lasts about two years so this wait, in fact, is not a sacrifice. “We can already see young plants, young maritime pines that reach 20 cm”notes the head of the ONF.
“In three or four years, we will measure the density. If we have between 3,000 and 3,500 pine plants per hectare, we consider that it is regenerated.”
Francis Maugard, risk manager at the ONF Landes-Nord-Aquitaineat franceinfo
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If natural renewal is not enough, he says the ONF will replant where necessary to boost regeneration. Still on the side of La-Teste-de-Buch there is also the question of the user forest, this forest with a special status which also suffered from the flames last summer. “All the forest has not burned down. There are still a lot of old pines in the used forest which will make it possible to maintain this landscape and support the reconstitution of the forest of tomorrow. And tomorrow we will have a new generation of pines maritime which will grow”explains Mathieu Cabaussel, general trustee of the user forest, very optimistic. “We are counting on natural regeneration, and on the collection of seeds to accompany this regeneration when it will be a little more difficult.”
“In the coming months, we will above all have to withdraw from the forest and let nature do its work.”
Mathieu Cabaussel, general trustee of the user forest of La teste-de-Buchat franceinfo
The Gironde department is also considering two other avenues. On a part of the formerly swampy forest, he wants to let wetlands return. And then, on a last place still to be defined, Jean-Luc Gleyze wants to initiate the creation of a “departmental nursery”. “The idea is to be able to make tree stocks available, perhaps also seeds at certain times, for communities”, explains the elected Girondin. With three objectives: to vegetate more, to be able to replant more quickly in the event of a new disaster and, with INRA, to cultivate “vegetation conducive to territories and climate change” with some “more resilient species”.
In production forests, replanting at all costs?
The situation is a little different on the side of Landiras and Guillos, the other place where the Girondin forests were reduced to ashes last year, because they are essentially working forests. The wood is therefore the livelihood of the owners. The mayor of Landiras notes that some owners have already started to replant. “The sooner it is replanted, the sooner it will start to be exploited”observes Jean-Marc Pelletant, who recalls that it takes almost fifteen years to be able to harvest a crop. “The foresters are masters in their own house. I’m not going to impose anything on them, anyway I don’t have the authority.”
“Some have lost everything for 30 years: there was the storm of 1999, that of 2009, and now the fires of 2022.”
Jean-Marc Pelletant, Mayor of Landirasat franceinfo
But those who replanted are “exceptions”jointly assure the mayor of Landiras and the president of the DFCI, Bruno Lafon, who also heads the union of foresters. “In any society, there are people who want to go faster than others. It’s a mistake because you have to wait two years.”
And then this question of timing leads to another: what to replant? And how ? The DFCI is advocating for foresters to expand firebreaks and reduce the size of unprotected patches of forest to prevent the fire from reaching the magnitude of summer 2022 again.
Towards a pine forest framed by deciduous trees?
The question of what is trickier. “Here is the pine”, loose Mylène Doreau, mayor of Guillos. Just like the mayor of Landiras, a few kilometers further. “If our ancestors planted pine, it is not by chance”, believes Jean-Marc Pelletant. The rest, “it does not grow”. In fact, on the sandy soils of the moors of Gascony, the pine flourishes perfectly. And replanting pine is unanimous everywhere as it is part of the region’s heritage.
However, elected officials and experts agree: we must diversify. “Replanting identically and finding a major fire risk again means taking the risk of losing the pines”worries the president of the Gironde department. “You have to find the right balance between the necessary economic profitability of a production forest and the fact that this forest is more resistant, more resilient”, argues Jean-Luc Gleyze. And to make it more resilient, an idea is starting to take hold: plant leafy trees.
“We see that where there were hardwoods, the fire did not spread as quickly.”
Mylène Doreau, Mayor of Guillosat franceinfo
In fact, the only trees still standing in the areas devastated by the flames are hardwoods. Enough to make some people imagine hardwood barriers, in addition to existing firewalls, in order to slow the progression of fires, but also to limit their number. They are more resistant to fire when it is launched and above all, they ignite less well and less quickly. Planting them on the edge of the tracks would therefore perhaps limit the outbreak of fires, particularly by criminals, if the undergrowth is properly cleared. From there to imagine a pine forest framed by hardwoods? “It’s a bit cartoonish but in spirit, in some areas, it could be that”says Bruno Lafon, boss of the DFCI and the forestry workers’ union.
Hardwood barriers are also an idea supported by the NFB. Francis Maugard puts forward another argument. “It has advantages against phytosanitary risksexplains the specialist. For example, we see a lot of the pine processionary caterpillar. When you have a leafy edge that protects a stand of maritime pines, the processionary has a much harder time settling in.”
The future of the forest also depends on more prevention and information on risks, insist all the players. Who for some say they are ready to completely prohibit access to the forests in the summer in the event of a significant fire risk. In the meantime, the little green shoots emerging from the dark, sandy forest floors will continue to grow. And to give everyone in the region some hope.