According to the National Forest Inventory, between two and four million cubic meters of elm trees still remain in French forests. However, the towering, mature elms that once shaded village squares and defined the French landscape are almost entirely gone. Today, French elm forests are often described as a "forest of children" — young trees that never reach adulthood. This dramatic change is primarily due to a microscopic fungus called Ophiostoma, which is spread by the elm bark beetle. When infected, the trees attempt to block their own sap flow in a futile effort to stop the fungus, leading to suffocation and death. The disease, known as Dutch elm disease, first appeared in the Netherlands in 1919 and quickly spread across Europe. In France, the first recorded case was in Lorraine in 1920. The initial wave of the disease, caused by a less aggressive strain of the fungus, already devastated thousands of elms. However, the real crisis came in the late 1960s, when a more virulent strain, Ophiostoma novo-ulmi, arrived from North America via contaminated wood. This new strain caused a severe pandemic that wiped out nearly all the large, mature elm trees, marking one of the worst ecological disasters in forest history, according to researcher Jean Pinon. Elms once played a significant role in the French landscape, much like oaks in forests or plane trees along roads. The loss of these trees has dramatically altered the scenery, removing the towering silhouettes that defined the countryside for generations. The fungus spreads through the tree’s vascular system, blocking the flow of sap. In an attempt to contain the infection, the tree produces substances that further clog its own vessels. The elm bark beetle, which feeds on the bark of dying trees, spreads the disease by carrying spores from infected to healthy trees. The fungus can also spread underground through root connections, especially in dense elm hedges, leading to a slow, silent destruction that becomes visible only when leaves suddenly turn yellow. Despite this devastation, the elm has a unique survival strategy: it can regrow from its roots after being cut down. This results in dense hedges filled with young, vigorous elms. However, these young trees rarely live long enough to reach the size that would make them attractive to the beetles. As a result, the species is evolving — elms now produce fruit at a younger age and grow smaller, avoiding the size that makes them vulnerable. In one study, researchers found that only about a hundred elms in a large area had trunks over 20 cm in diameter, while millions of young stems filled the space. Today, the elm is stuck in a kind of biological adolescence, doomed to die before it can fully mature. Efforts to combat the disease have focused on genetic resistance. Researchers have crossed European elms with resistant Asian varieties, where the fungus is native and trees have evolved to resist it. Two resistant clones, Lutèce and Vada, have been developed and are now used in urban areas. However, they are not suitable for large-scale replanting in forests due to their genetic uniformity, which could make them vulnerable to future mutations in the fungus. While these resistant trees are helping to repopulate parks and streets, they cannot restore the ecological diversity lost in rural hedges. The fungus continues to evolve, becoming more aggressive over time. As a result, it is unlikely that France will see the return of its towering, century-old elms anytime soon.