One of Simard’s most thrilling beliefs is that trees can recognise us. “Trees perceive many things. They know when they’re infected and have an instantaneous biochemical response. When we manipulate trees, they respond.” Would she go as far as to suggest a tree can feel pain or grief? “I don’t know. Trees don’t have a brain, but the network in the soil is a neural network and the chemicals that move through it are the same as our neural transmitters.” She is currently collaborating on research to see whether trees can distinguish us as humans.