How do trees tell one another they are under attack?

When insects damage leaves or bark, many trees release volatile organic compounds into the air that can trigger defensive responses in nearby plants. Roots can also release chemical signals into the soil, and some plants are connected by mycorrhizal fungi that may help transfer nutrients and warning signals between roots. Scientists have studied these interactions for decades, but the exact importance of each pathway can vary by species and environment. The idea is not that trees “talk” like animals, but that they respond to chemical cues from neighbors and fungi.