When Trees Talk, Dartmouth Researchers Jack Schultz and Ian Baldwin Listen
The voice did not belong to a poplar—or any other deciduous tree, for that matter—but to Schultz's research assistant, Ian Baldwin, 25. Baldwin, in interpreting data from an experiment the pair had been conducting, had come to a remarkable conclusion: that trees are able to communicate with each other. Specifically, Schultz and Baldwin's experiments seemed to confirm a hypothesis put forth by University of Washington researcher David Rhoades: that if a tree is attacked by bugs, it somehow alerts nearby trees, which in turn take defensive action by increasing the level of phenols—digestion-inhibiting chemicals—in their leaves. Rhoades at first thought that trees might communicate via chemicals released through their roots (in effect, by playing footsie)—but the experimenters now suspect the communicating agent is a chemical released in the air by damaged leaves.
Not surprisingly, claims of gossiping poplars have elicited a far-from-reverent response. Newspaper headlines have run from "A Branch of a New Language" to "Reading Tree Leaves"; the Washington Post's Tony Kornheiser penned a fine column describing favorite tree topics (alternative sources of paper), problems (dogs) and heroes (Leif Garrett, Twiggy). Much of the to-do came on the heels of a recent $225,000 National Science Foundation grant to Rhoades, 42. "Rhoades took the heat for this all along," says Schultz, 36. "He suggested the idea and published the first observations. Our work tries to identify the evidence." Although Rhoades encountered chuckles when he first presented his ideas at a scientific conference last year, the concept has taken tenuous root. If trees do emit a chemical that causes other trees to become less vulnerable to insects, it may be possible to duplicate that chemical. The potential benefit of such ecological pest control is enormous.
Even as a child in Chicago, Schultz recalls having strong feelings about trees—"I was mainly interested in not falling out of them," he says—and also about rock 'n' roll. One of his favorite memories is of jamming with guitarist and boyhood hero Les Paul after meeting him at a music competition. After earning an A.B. in biology at the University of Chicago, Schultz considered "for about 30 seconds" applying to medical school, "until I cut my finger and realized I was too squeamish to deal with vertebrates." Instead, he headed for the University of Washington and helped support himself by playing guitar and writing radio jingles while earning a Ph.D. in zoology. He also became friends with fellow grad student Rhoades. Faced with a career decision while completing his degree, Schultz dropped music to pursue science because he thought it would be more secure. "Boy, was I wrong," says Schultz, now a research assistant professor of biology, who has been living grant-to-mouth for most of his 12 years in academia.
The significance of his tree-talking experiments may change that. Among colleagues, "Our work has been well received," says Schultz, who will go to Sweden next month to present his findings at the Third International Ecological Society Congress. He's also pleased to help dispel the notion that trees "lead lives of quiet desperation. They have a few tricks up their leaves," he contends. "They aren't just static things waiting to be eaten. Trees are like slow animals; the only thing they can't do is run away when attacked." Proving that may be a tall order, but Rhoades and Schultz and Baldwin think they're on the right track—knock on wood.