Plants Reacted to Eclipse—But Was It Really About the Darkness? | Science News
- A controversial claim that spruce trees in the Italian Dolomites could “anticipate” a solar eclipse is facing significant pushback from other researchers in the field.
- The original study, published in April 2025, detailed how a forest of Norway spruce trees (Picea abies) appeared to synchronize their electrical signaling in the 14 hours leading...
- The initial interpretation posited that the trees were somehow sensing an impending environmental change and coordinating a response, with older trees potentially “remembering” previous events and transmitting that...
A controversial claim that spruce trees in the Italian Dolomites could “anticipate” a solar eclipse is facing significant pushback from other researchers in the field. A new critique, published in the journal Trends in Plant Science, suggests the observed electrical activity in the trees was more likely caused by mundane environmental factors like temperature drops, thunderstorms, and lightning strikes, rather than any form of pre-emptive sensing of the eclipse.
The original study, published in , detailed how a forest of Norway spruce trees (Picea abies) appeared to synchronize their electrical signaling in the 14 hours leading up to a partial solar eclipse on . Researchers, led by Alessandro Chiolerio of the Italian Institute of Technology and plant ecologist Monica Gagliano of Southern Cross University, attached electrodes to trees and stumps in the Costa Bocche forest to create what they described as an “EKG for trees.” They observed a marked increase in bioelectrical activity peaking during the eclipse, with older trees exhibiting stronger and earlier signals.
The initial interpretation posited that the trees were somehow sensing an impending environmental change and coordinating a response, with older trees potentially “remembering” previous events and transmitting that knowledge to younger trees. However, the new critique, led by Ariel Novoplansky and Hezi Yizhaq from Ben-Gurion University of the Negev in Israel, challenges this interpretation.
Novoplansky argues that the study leaned towards a “more seductive idea” – that the trees were anticipating the eclipse – instead of considering simpler, well-documented environmental factors. “To me, [the previous study] represents the encroachment of pseudoscience into the heart of biological research,” he stated. The critique points to the fact that similar electrical signaling responses in plants have been previously linked to temperature fluctuations and electrical disturbances caused by storms and lightning.
The researchers behind the critique emphasize that observed tree reactions to external stimuli don’t necessarily indicate tree-to-tree communication. They also note that the eclipse was only partial, resulting in a reduction of light comparable to a cloudy day, which wouldn’t necessarily trigger a significant coordinated response.
Chiolerio and Gagliano defend their research, acknowledging its preliminary nature and stating they have ongoing work to further investigate the phenomenon. Chiolerio told Ars Technica that they measured temperature, humidity, rainfall, and solar radiation, but found no strong correlation with the observed electrical activity. He also admitted they did not measure environmental electric fields or gravitational effects, leaving open the possibility that nearby lightning strikes could have played a role.
Gagliano, in a statement to Ars Technica, pushed back against the characterization of their work as pseudoscience. She clarified that their paper reported an empirical pattern of electrophysiological synchrony during the eclipse window, including changes occurring before maximum occultation, and presented candidate cues as hypotheses, not proven causes. She argued that simply noting the occurrence of lightning strikes in the region doesn’t establish a causal link without site-specific, time-aligned measurements.
“Describing weather/lightning as ‘more parsimonious’ is not evidence of cause,” Gagliano stated. “Regional lightning strike counts and other proxies can motivate a competing hypothesis, but they do not establish causal attribution at the recording site without site-resolved, time-aligned field measurements. Without those measurements, the lightning/weather account remains a hypothesis among other possibilities rather than a supported or default explanation for the signals we recorded.”
Gagliano also emphasized that their study was an initial field report with a limited sample size and that follow-up work is underway. She declined to engage with the “pseudoscience” label, stating that scientific disagreements should be resolved through transparent methods and rigorous testing.
Chiolerio expressed frustration with the public attention the critique has received, stating that their team’s primary motivation was to share the results of years of research and interesting data, not to seek public appeal. The original research was published in Royal Society Open Science in (DOI: 10.1098/rsos.241786) and in Trends in Plant Science (10.1016/j.tplants.2025.12.001).
The debate highlights the challenges of interpreting complex biological signals and the importance of considering multiple hypotheses before drawing conclusions, particularly when dealing with phenomena that could capture the public imagination.