Look at the trees around you as you go for a walk. It may seem that the trees are not doing much as you hurry by. But this is not true. Trees are dynamic, busy organisms, carrying on thousands of activities at any moment. The fact that they are rooted to the ground, and only move with the breeze provides a false idea of a placid, quiescent organism.
In recent years, scientists have begun to understand just how dynamic trees are. We have begun to use terms like 'behavior', 'intelligence', 'thinking', and even 'neurobiology.' We have to be careful, though. It is easy to anthropomorphize a tree, to force our human framework upon them and make them into ents or some other mystical creature. Yet trees are not at all like animals. They don't have a central nervous system or a brain, they don't have muscles, and they can't move.
Trees do have immense powers, and the ability to rapidly respond to changes in their environment. They adjust rapidly to subtle changes in their environment that we would scarcely notice, such as the quick passing of a shadow over a leaf, or minute changes in the angle of a branch. They respond to their enemies - insects, fungi, bacteria, or herbivores - with complex and quick changes in their chemistry. Of the trees that we consume - cocoa or coffee or bourbon (oak extract) - most of the flavor comes from compounds that the trees create to defend themselves. Trees send and receive chemical signals, either through the air or the roots, not only to other trees but to many other organisms, especially insects.
We know that trees have senses, just like we do, but they have many more than ours. Plants can see, smell, taste, hear, feel touch, and much more. Their sensory abilities often exceed ours. A slight touch of your finger against a leaf on a calm day can quickly cause a wide variety of changes in the chemistry and growth of a plant. Trees also have senses that we lack. They can instantly detect changes in gravity, so that bending a branch produces a rapid growth response. They can see parts of the electromagnetic spectrum, such as infrared and ultraviolet, that we cannot.
Trees support one another by sharing nutrients, and also support a complex variety of other organisms, especially fungi. The complex networks that allow trees to communicate among themselves and with other organisms, has led some to use the term "Wood Wide Web" by analogy to the World Wide Web that creates the Internet. The idea is that trees are constantly communicating with one another and with other organisms to benefit themselves, and perhaps to help their progeny. Although there is some good science behind this, it is easy to jump to conclusions. There is no evidence that trees are sentient, or aware of people, or that they make decisions in some intelligent way.
What we are beginning to understand is that there is something much more profound taking place. It appears that trees and forests are organized as extremely complex networks, sharing information and materials to benefit themselves, but without a central controlling brain or nervous system. In that sense, trees in a forest may be like ant colonies, bee hives, or other collections of organisms in which extremely complex behavior emerges without any central decision making.
All of this new information, and much to come, makes trees far more interesting and dynamic than we have previously thought. The next time you are out in the woods, ask yourself the question What Do Trees Know?