A scrubby ground devoured by flames. Thick reddish smoke from which the fire trucks can barely be seen. A “fire tornado” forming in the middle of this desolate landscape, a sign that the fire has become powerful enough to create its own wind system. The images of the forest fire that started from Saumos, in Gironde, Wednesday July 22, 2026 at midday, are impressive.
In twenty-four hours, the fire has already covered 3,700 hectares and led to the evacuation of 20,000 people this Thursday. The Landes forest, already ravaged by flames in 2022, combines several specificities which make it particularly vulnerable to fires.
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Les Landes, artificial forest
Until the middle of the 19th century, however, Gascony, which extends between the departments of Landes, Gironde and Lot-et-Garonne, had a completely different face. In winter, it is a marshy region, where farmers walk on large stilts to guide their herds. In summer, a hostile desert described as a “French Sahara” by Théophile Gautier in his poem Le Pin des Landes.
At the end of the 18th century, towns and individuals began to plant pine trees on these sandy and infertile lands. The objective? Drain the soil and limit the advance of dunes, which threaten villages and cultivated lands.
It was in the following century that this landlocked region would become the largest artificial forest in Western Europe. Under the impetus of a law promulgated by Napoleon III in 1857, a large part of the communal lands were put up for auction. The new owners planted maritime pines, a species well adapted to the poor, sandy soils of Gascony. In half a century, a pine forest covering 850,000 hectares has emerged from the ground, recalls the Atlas of Landes landscapes site.
Destructive fires between 1937 and 1949
In the midst of the industrial revolution, wood grown in Gascony made it possible to produce poles for mines and sleepers for railway tracks. However, as soon as it is planted, the Landes forest often finds itself prey to flames. “The tradition of scouring the moors by shepherds has for a long time been the cause of numerous fire outbreaks,” underlines the Atlas of Landes landscapes.
The most destructive fires occurred between 1937 and 1949. In twelve years, approximately 450,000 hectares burned, notably because of the railway’s steam locomotives. Implementing better forest management will help limit these phenomena. Gradually, watchtowers sprouted among the pines to monitor fire outbreaks. A large network of roads and tracks was also created to facilitate access for firefighters to the massif.
With peat, the fire also spreads underground
While global warming makes droughts more frequent and intense, these measures are no longer enough to contain fires. In summer, dry pine monocultures light up like matches. The fire sometimes becomes convective: the mass becomes so hot that the flames go in all directions and explosions occur, which complicates the work of the firefighters.
The sandy soil of the Landes de Gascogne also contains a large quantity of peat which, when heated, spreads the fire through the subsoil. In 2024, two years after the giant Landiras fire was officially declared out, smoke was still rising from beneath the forest floor.
