Plants talk and share and sing “Let It Be”
Dr. Suzanne Simard’s family were loggers. She was too, for a while, but she wondered why young mono-cropped Douglas fir saplings planted in the wake of a clear cut struggled when the same species had been healthy living among other species in the mixed forest before the cut.
Traditional logic had been trees competed for resources, but Simard noticed the firs transplanted into the clearcut area had their autonomous territory with the birches and others over there in the woods, so there was no competition, yet those in the woods did better. Her scientific instincts took over, and now she’s famous.
In one of those clear cuts, she interplanted fir and birch saplings and covered some of them to isolate them. Then she injected radioactive carbon isotopes into the saplings to see if she could track where the carbon went. Good thing she owned a Geiger counter because she could follow the peregrinations of the isotopes, and she found carbon found its way to all the trees, isolated trees included.
The roots were the initial conduits for the exchanges, but she discovered the other intermediary was mycorrhizal fungi which stretched between roots throughout the forest – an underground network… not competition but community.
Not only was there an apparent community, but the elements and nutrients being exchanged varied with the seasons depending on what each species needed. Her data indicated the firs fed more carbon to the birches when birches lost their leaves and birches returned the favor to firs if they were too shaded, for example. This was all happening underground through roots and the fungal network – organisms coordinating for mutual benefit.
Though the lumber industry and many scientists were skeptical of her research, she had her data. A few researchers replicated her work and her results were validated. Word spread and the world began to view forests differently because of Simard’s curiosity and hard work.
It is now accepted that plants exude chemicals called exudates into the soil. The fungi absorb these nutrients to their benefit but reciprocate by delivering chemicals and whatnot from deeper in the soil to the roots. Interestingly, studies indicate plants apparently share more with family members – podmates – than with non-family members of the same species or with others. Roots of podmates seem to negotiate crowded spaces with each other better than with plants from a different mother.
There is also allelopathy, the name for the mechanism within some plants in which they secrete chemicals that affect nearby plants or animals for better or worse. You will have noticed nothing much grows under pine trees or walnut trees.
Goldenrod and sunflowers also negatively affect growth of nearby lettuce or red clover. However, extensive studies indicate tomato plants neighboring with basil plants matured faster, had stronger roots and produced more fruit. Part of the positive effect is the strong scent of basil discouraging insect pests.
Marigolds are effective in this way also, but there is still the underground activity. Marigold root exudates frighten away evil bad nematodes and marigold flowers make me smile – two different kinds of communication.
Also, plants can smell. Since the 1980s, studies have determined that at least 30 species of plants under attack by insect pests release volatile organic compounds into the air to communicate with other plants that it is time to protect the neighborhood. Once the alarm is received (smelled), cotton and corn, for example, release compounds to attract parasitic wasps that will target insect pests. Scientists in flannel shirts and overalls figured this out, but more impressive is plants have been doing this since before Sumerians invented beer.
The concept that plants communicate underground and through scent with mutually beneficial intent has been called the “wood wide web.” Organisms sharing and watching out for each other… no passwords required… no need for fences… plants deserve respect for behaving that way. What if…