Scientists at the University of Washington in Seattle claim to have evidence to prove that trees can talk to each other. Human beings cannot hear their conversations but trees are supposed to understand the messages that they are relaying to each other.
In spite of sounding like something out of a science fiction movie, scientists have claimed that trees can communicate to each other. The scientists at the University of Washington began a series of experiments by placing hungry caterpillars on willow trees. Half of the trees were covered with caterpillars and the other half were kept clean. The caterpillars seemed to have their way at first, but then the infected trees produced a chemical called proanthocyanidin which is a natural insecticide. After a few weeks the unaffected trees also started producing the chemical as a defensive mechanism. The unaffected trees somehow knew that there was danger in the area.
image vis Wikipedia
The scientists wondered if the trees were signaling the trees through the soil or roots. Repeated experiments proved that this was not the case. The trees were somehow communicating among themselves of the danger. Some of the trees using the defensive chemicals were over 100 yards from the affected trees. Scientists then concluded that the trees must be emitting airborne pheromones.
Insects have been known to release pheromones as a way of attracting the opposite sex. It only takes a small amount to signal a specimen of the same species several hundred yards away. The scientists concluded that trees were emitting pheromone hydrocarbon ethylene through their leaves. This was a signal that danger was in the area and the other trees should take defensive measures.
The scope of the communication is thought to only extend to defensive warnings. Trees may never form social clubs, but if you are a trees enemy you had better watch out. They may gang up on you.