Again from the Forestry Journal:
Scientists at the University of Washington claim that trees can communicate with each other. Experiments on stressed trees found that they produce a natural insectacide against insects. Scientists put caterpillars on some trees but not on others. The ones with insects on duly produced the chemical but then came the surprise. The trees not under attack also started producing the chemical. They found that pheromone hydrocarbon ethylen was emitted by the trees through their leaves and became a danger signal from one tree to another even though they were hundred of yards apart.
