Do Trees Really Talk to Each Other?

Walk through an old forest and it can feel as though everything is silent and still. Beneath your feet, however, scientists believe a busy exchange is under way. Almost every tree is connected to a network of fungi, whose microscopic threads wrap around roots and spread through the soil, sometimes linking trees that stand dozens of metres apart. The idea that these networks allow trees to share resources and even send warnings has captured public imagination, but the reality is more complicated than the headlines suggest. The fungal partnership itself is not in doubt. In exchange for sugars produced by the tree through photosynthesis, the fungus supplies water and minerals such as phosphorus, which it can extract from the soil far more efficiently than roots can. For most forest trees, this relationship is not a luxury but a necessity, and seedlings that grow without it tend to struggle. The more exciting claim emerged in the late 1990s, when a Canadian forest researcher, Suzanne Simard, reported experiments using tracer carbon. She found that carbon moved between neighbouring trees of different species, and she suggested that larger, older trees might support shaded seedlings through the fungal threads. Popular books and documentaries soon described forests as cooperative communities, with "mother trees" nursing their young. Many of Simard's colleagues, however, urge caution. Some argue that the amounts of carbon transferred in experiments are small and may be of little benefit to seedlings in natural conditions. Others point out that fungi are not passive pipelines; they may be keeping most of the sugar for themselves, which would make the network less a gift economy than a market in which the fungus drives a hard bargain. A review published in 2023 concluded that several widely repeated statements, including that mother trees deliberately feed their offspring, were not yet supported by enough evidence. None of this makes the forest less fascinating. If anything, the debate illustrates how science works: a striking early finding attracts attention, then is tested, challenged and refined. What most researchers do accept is that soil fungi shape forests in powerful ways, and that cutting down woodland disturbs far more than the trees above ground. Whether we call it communication or simply chemistry, the hidden network deserves a place in any conversation about protecting forests.