France fenced off roughly 1,200 square kilometres of its former World War I front after 1918 because the land was too devastated and littered with unexploded ordnance to farm. Parts around Verdun remain closed a century later, and disposal teams still lift hundreds of tonnes of wartime explosives a year

In an oak and hornbeam forest northeast of Verdun, one patch of ground runs to roughly 18 per cent arsenic by weight, and almost nothing grows on it but moss.

The place is called Place à Gaz, and it is the tidiest available summary of what France chose to do with its ruined battlefields. After the armistice, surveyors walked the front with maps and graded the damage. The worst grade came with unusually blunt wording: total devastation, agriculture impossible, human life impossible. Roughly 1,200 square kilometres fell into it. Fences went up, people were moved out, and the country broadly agreed to look elsewhere.

Why the land was fenced instead of cleaned

Money, mostly, and arithmetic nobody enjoyed doing. Clearing the ordnance would have cost more than the farmland was worth, so the state bought the ground and relocated the survivors. Verdun had been ordinary farming country before 1914, feeding a peacetime garrison of 66,000 men, as the British historian Christina Holstein describes in an account published by the National Geographic Society. By late 1916 the bombardment had erased the trenches themselves, let alone the hedges and barns.

Six villages in the Meuse were never rebuilt.

They still exist on paper, each with a mayor, two councillors, a postcode and a maintenance budget of about €22,000 a year, as The Connexion has reported, spent on mowing grass and keeping signposts upright in places where nobody lives. The ground there is still settling. Every year it pushes a little more of 1916 back to the surface, including bodies, which are reburied as unknowns.

Where the gas shells were burned

In the 1920s a contractor working for the French war ministry took delivery of some 200,000 German chemical shells and dealt with them the cheap way, by burning them in a forest clearing. Arsenic-based warfare agents combust into arsenic oxides, which settle and stay. Sampling the site decades later, Tobias Bausinger, Eric Bonnaire and Johannes Preuß recorded topsoil arsenic of up to 175,907 milligrams per kilogram, alongside heavy loads of copper, lead and zinc, in a paper published in Science of the Total Environment.

One study, one small site, and no claim about the region as a whole. Its more uncomfortable finding sits underneath: raised arsenic at every depth they sampled, down to two metres, and in the water draining off the site.

Five hundred tonnes a year, still

France runs a permanent bomb-disposal service, the Groupement d’Intervention du Déminage, with 26 centres and several hundred certified deminers. Figures published by the Sécurité civile put the annual national haul at more than 500 tonnes of explosive devices from both world wars, and the running total since 1945 at 13 million mines lifted and 35 million shells destroyed or made safe.

Deep ploughing brings them up, and so do roadworks, floods and the slow creep of a hillside.

In 2018 divers spent a day in the Meuse at Vilosnes-Haraumont, where the German army had tipped thousands of shells into the river, and pulled out more than five tonnes in a single operation, as reported by Reuters. Guy Momper, the clearance specialist supervising the job, put it plainly. “We need to tidy up the land,” he said, before estimating the work would take another century.

Age does nothing to make the contents inert. Filler stays explosive, and gas rounds remain the ones deminers dread, because a corroded casing leaks without announcing itself.

What grew back

Trees returned faster than anyone predicted, and the zone now reads as ordinary woodland laid over strangely lumpy ground. Joseph Hupy, a military geographer who has studied how those soils formed, argues that recovery is the wrong word for what happened. “It got set off on a different trajectory of development,” he told National Geographic. Shelling churned the soil layers together, salted them with metals and restarted processes that normally run over thousands of years.

Meanwhile the forest earns money. Timber is cut there, boar and deer are hunted there, and visitors arrive by the coachload to walk the crater fields at Douaumont. Farmers on the reclaimed margins keep hitting iron, and roadside signs mark where to leave whatever the plough turns up. Holstein’s estimate of the work remaining runs to three centuries, with the rider that it will never actually be finished.

That is a strange invoice for four years of shelling. The battle ended, got its ossuary and its anniversaries, and passed into history; the chemistry stayed behind and kept generating work for people whose great-grandparents were not yet born when the guns stopped. Next spring somewhere in the Meuse a plough will hit something hard, a farmer will climb down for a look, and a number in a government report will tick up by a few kilograms.