In his book, "The Hidden Life of Trees: What They Feel, How They Communicate", German forester Peter Wohlleben discusses how tress are far more alert, social and sophisticated than we may think. He writes about how trees communicate with other trees using their root systems, pheremones and other scents, sending distress signals during times of drought and disease or insect attacks, and how trees receiving these signals alter their behaviour as a result. It's a fascinating read if you are at all interested in trees.
The trees below are communicating the coordinates of a cache. You can assume N 43 and W 80. 