Whether real or fake, many Americans think of a Christmas tree when they imagine the holiday. But who invented this symbol of merriment?
The answer lies in a long history of invention, from the first spherical pine in Germany to the mighty giants that decorate our homes today. It’s a story of innovation, necessity and the human tendency to turn living things into commodities—and then to use them in a way they never intended.
Scientists once thought that trees helped each other mainly through their roots, which intertwine or grow together like an extended nervous system. But a new frontier of research has shown that trees may have other means of helping each other, too. For example, a Douglas fir that had been damaged by insects might send a chemical warning signal to a nearby ponderosa pine. The pine would then produce defense enzymes to protect itself.
Researchers are also finding that trees talk to each other, which has inspired a flurry of best-selling books and documentary films. One popular theory, led by Peter Wohlleben and Suzanne Simard, is that trees share information through a “Wood Wide Web” of fungal connections underground, much like the Internet.
Justine Karst, a mycologist who studies mushrooms, says there isn’t much evidence of such a network between trees, but she is not convinced that Wohlleben and Simard are completely off the mark. She and her colleagues have examined their claims in detail. They have found that, in fact, trees do convey alarm and distress signals through a kind of electrical system that’s similar to an animal’s nervous system (although they don’t have neurons or brains). But they haven’t been able to establish that trees can communicate love, care and even joy through this system.