It is surprisingly easy to wonder if the trees around you are conscious of anything at all when you spend enough time in a forest in the kind of profound silence where you can actually hear the wind blowing through the canopy. Whether they sense the drought, the axe, or the insect methodically biting through a leaf. Most people quickly brush this kind of thought aside, usually with a chuckle. However, despite everything, a version of that question has been the subject of debate among plant biologists for more than 50 years, and the debate remains unresolved.
The current debate began in the 1970s when David Rhoades, a researcher at the University of Washington, found that injured plants release volatile chemical compounds. This is a type of airborne signal that nearby plants seem to detect and react to by fortifying their own defenses. The term “talking trees,” which was warm enough for a headline and loaded enough to appall the scientific establishment, was used enthusiastically by the popular press to describe these interactions. Funding stopped coming in. According to Elizabeth Van Volkenburgh, a biology professor at Washington who lived through that time, the topic became practically taboo. For posing a legitimate query about plant behavior in language that sounded too much like sentience, Rhoades was essentially ignored.
| Topic Reference: Plant Consciousness & Pain Debate | Details |
|---|---|
| Core Question | Do plants experience pain or conscious awareness? |
| Scientific Consensus | Majority view: No — plants lack brain, nervous system, and nociceptors |
| Key Researcher (Skeptic) | Lincoln Taiz, Professor of Biology, UC Santa Cruz |
| Landmark Skeptic Paper | “Plants Neither Possess nor Require Consciousness” (2019) |
| Key Researcher (Open View) | Elizabeth Van Volkenburgh, Professor of Biology, University of Washington |
| Pivotal Early Work | David Rhoades, 1970s–80s — plants emit volatile distress compounds when wounded |
| Notable 2019 Study | Tel Aviv University — certain plants emit ultrasonic sounds under stress |
| 2014 University of Missouri Finding | Plants respond chemically to sound vibrations of feeding caterpillars |
| 2018 Study Finding | Leaf cells signal danger to other parts of the plant during feeding events |
| Professional Body | Society of Plant Signaling and Behavior (originally Society of Plant Neurobiology, founded 2006) |
| Notable Popular Book | The Secret Life of Trees — Peter Tompkins (1973), sparked the original debate |
| NIH-Published Rebuttal | Mallatt et al., 2020 — plant consciousness claims “highly speculative, lack sound scientific support” |
However, the science persisted. After a period of silence, it returned with improved equipment and more cautious language. Researchers at the University of Missouri discovered in 2014 that before any physical harm is done, plants react to the sound vibrations of caterpillars chewing on their leaves by creating chemical defenses. A team at Tel Aviv University recorded what they called “ultrasonic emissions” from stressed plants in 2019. These sounds are too high for human hearing and occur at different frequencies depending on the kind of stress the plant is experiencing. The term “screaming” appeared in a few headlines. Most likely, that was excessive. However, the underlying discovery was significant enough to merit consideration.
The prevailing biological perspective is still strong and should be taken seriously. One of the more vocal opponents of the plant consciousness theory, Lincoln Taiz of UC Santa Cruz, concluded in a 2019 paper that the possibility of plant consciousness is “effectively nil.” His argument is structural: plants don’t have brains, neurons, or the integrative information processing that seems to be necessary for animal consciousness.
The Society of Plant Neurobiology, which discreetly changed its name to the Society of Plant Signaling and Behavior in part to avoid the political implications of its original name, works in this same cautious field, attempting to investigate plant responsiveness without overstating its significance. Despite decades of studying plant behavior, Van Volkenburgh herself draws a clear distinction: “We anthropomorphize so readily,” she has stated, “and that’s why we use the word ‘pain.'” However, it is inappropriate to apply to a comparable plant response.
Sitting with all of this, there’s a sense that the question is becoming more difficult to answer with precision because the research keeps revealing behavior that appears to be surprisingly intentional. plants that alert their neighbors. sound-detecting plants. plants that use their own tissue as a slow-moving internal alarm system to transmit distress signals. None of it qualifies as pain in the human sense, which is the acute, subjective, emotionally processed perception of harm. Since it doesn’t fit into any of the categories we’ve developed from animal biology, it’s possible that the proper framing isn’t pain at all but something completely different that doesn’t yet have a satisfying term.
Beyond the science, what people want the answer to be is what makes this debate culturally fascinating. It is sometimes used by vegans as an excuse to reevaluate plant-based diets, which is generally not supported by biology. For others, the concept of plant awareness is philosophically problematic, and they would rather live in a cleaner world where only living things can be harmed. These two impulses reveal more about human psychology than they do about botany. In the meantime, the trees are doing whatever it is they do—sensing, signaling, responding—completely unaffected by our choice of classification.
