Study: Spruce Trees Anticipate Solar Eclipses, Synchronize Bioelectrical Behavior Hours in Advance

Regular light-dark cycles greatly affect organisms, and events like eclipses induce distinctive physiological and behavioral shifts. While well documented in animals, plant behavior during eclipses remains largely unexplored. In their new research, scientists from Italy, the United Kingdom, Spain and Australia monitored multiple spruce trees (Picea abies) to assess their individual and collective bioelectrical responses to a solar eclipse.

Sunlight and its periodicity drive global weather patterns, seasons and climate and make life possible on our planet.

Daily and seasonal cycles of natural light organize biological systems by synchronizing their internal clock with the geophysical cycles of the Earth.

At a time marked by growing human-induced changes to natural cycles, unusual astronomical events such as eclipses effectively function as natural experiments, providing valuable insights into how living organisms respond to sudden and infrequent changes in their environment.

“Our study illustrates the anticipatory and synchronized responses we observed are key to understanding how forests communicate and adapt, revealing a new layer of complexity in plant behavior,” said Professor Monica Gagliano, a researcher at Southern Cross University.

“Basically, we are watching the famous ‘wood wide web’ in action!”

In the study, the researchers leveraged a new remote measurement system to simultaneously monitor multiple trees in a forest.

This allowed the authors to directly test whether and to what extent individual trees respond to a solar eclipse together, functioning as a larger living collective.

They investigated the electrical signals of spruce trees to characterize their bioelectrical activity during a partial solar eclipse that occurred in a forest located in the Dolomites mountain region, northeastern Italy.

Their results demonstrate that individual trees’ electrical activity became significantly more synchronized before and during the eclipse, indicating that trees function as a unified living system that coordinates its response to external events.

“By applying advanced analytical methods — including complexity measures and quantum field theory — we have uncovered a deeper, previously unrecognized dynamic synchronization not based on matter exchanges among trees,” said Professor Alessandro Chiolerio, a researcher at the Italian Institute of Technology and the University of the West of England.

“We now see the forest not as a mere collection of individuals, but as an orchestra of phase correlated plants.”

“The findings support calls for the preservation of wise old trees,” Professor Gagliano added.

“The fact that older trees respond first — potentially guiding the collective response of the forest — speaks volumes about their role as memory banks of past environmental events.”

“This discovery underscores the critical importance of protecting older forests, which serve as pillars of ecosystem resilience by preserving and transmitting invaluable ecological knowledge.”

The study was published in the journal Royal Society Open Science.

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Alessandro Chiolerio et al. 2025. Bioelectrical synchronization of Picea abies during a solar eclipse. R. Soc. Open Sci 12 (4): 241786; doi: 10.1098/rsos.241786