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Did trees sense the approaching solar eclipse?
11.2.2026
Translation: machine translated
A solar eclipse disrupts nature, at least for a short time. Can plants anticipate it in advance and react? Or is this pseudoscience?
On 25 October 2022, a partial solar eclipse took place over northern Italy, close in time to which scientists led by Alesandro Chiolerio from the Genoa Institute of Technology observed an interesting phenomenon in pine trees in the Dolomites: The trees began to synchronise their bioelectrical activity 14 hours before the event, which the scientists interpreted as anticipation of the approaching light-dark-bright cycle, especially as the activity continued during the eclipse. However, Ariel Novoplansky and Hezi Yizhaq from Israel's Negev University now firmly contradict this assumption - and present a much simpler explanation: A thunderstorm triggered the activity,
The two researchers analysed the data from Chiolerio's team and at the same time looked for other explanatory patterns such as local weather events. In fact, in the run-up to the partial eclipse, a strong thunderstorm also developed in the region, during which temperatures dropped significantly, it rained heavily and several lightning bolts struck in the vicinity of the pine trees. In the eyes of Novoplansky and Yizhaq, this meteorological phenomenon provides a much better explanation than the astronomical one. In their view, the thunderstorm with the nearby lightning strikes triggered the bioelectrical synchronisation and not the relatively weak local darkening.
«For me, this work represents the advance of pseudoscience into the core of biological research», says Ariel Novoplansky. It is well documented that plants receive signals and react to them when environmental conditions change. However, this type of response only occurs when the expected event poses a significant challenge to the plants and is closely linked to predictable cues, such as increasing competition from neighbouring trees. In the case of the solar eclipse, however, the event was not significant enough for the plants to anticipate and react to it, according to the researchers. Their relatively short duration and weak expression reduced the light intensity less than, for example, passing, larger clouds.
The data from the two Israeli scientists showed that the light intensity was reduced by only 10.5 per cent over the two hours of the partial solar eclipse. This meant that there was still more than enough solar radiation than the trees could use for photosynthesis.
Even a larger eclipse would not have ensured that the trees could have predicted it. The eclipse was the 53rd in the Saros cycle 124, a sequence of eclipses lasting 18 years, 11 days and 8 hours. Chiolerio's team showed that the bioelectrical activity of older, larger trees increased more than that of younger specimens. They concluded from this that the older trees communicated with the younger trees due to their previous experience with solar eclipses. Novoplansky and Yizhaq also strongly disagree with this: every solar eclipse is unique in terms of its course, strength and duration. So even if older trees could remember previous solar eclipses «» , they would not be able to draw conclusions for future solar eclipses.
In view of the harsh criticism of the explanatory model, it hardly matters that the original study was based on data from only three trees and five tree stumps. Or as Novoplansky puts it: «Forests are already wondrous enough without inventing irrational but superficial, fantastical claims about anticipatory responses or communication based only on a simple correlation.»
Spectrum of Science
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Header image: © NASA/Keegan Barber / Seeing Totality (detail)
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