Echoes of “Avatar”: Spruce Trees Communicate During A Solar Eclipse

Editor’s note: In the “Avatar” film series the interconnectedness of trees and other life forms is at the core of Pandoran ecosystems. On Earth, large expanses of trees exists wich are clones are connected by vast root systems. The “Pando” Aspen tree “super organism” which spans 42.8 ha (106 acres) being one example. Elsewhere, a widerange of trees and other plants are known to interact with one another and are connected by complex webs of fungal and bacterial networks. As such, immense collections of plants and other species can interact as a whole.

Grace and Norm examine the interconnectedness of Pandoran forests – “Avatar” 20th Century Fox.

All life on Earth reacts to the activity of our local star directly or indirectly – whether it is light for photosynthesis, the driving of short-term weather systems, and long-term climate cycles. Life on Earth also has to contend with radiation sources from beyond our solar system. When the celestial conicidence of a solar eclipse reduces or cuts off light to plants there are ways that these networks interact in repsonse.

This study examines how Spruce trees have the ability to react to solar eclipses and indeed prepare in advance to respond to them. As we search for life on other worlds, we have examined systems orbiting M-dwarf stars in close proximity to one another, often tidally locked where light levels can vary in different ways. How will life evolve within and react to such variations in stellar irradiation?

A ground breaking international study has revealed spruce trees not only respond to a solar eclipse but actively anticipate it by synchronising their bioelectrical signals hours in advance into a cohesive, forest-wide phenomenon.

The discovery, published in the journal Royal Society Open Science, shows older trees exhibit a more pronounced early response, suggesting these ancient sentinels retain decades of environmental memory and may use it to inform younger trees of impending events.

Experimental set-up to simultaneously monitor the electrome of multiple trees during solar eclipse. (A) The location of the experimental site at the Costa Bocche forest near Paneveggio in the Dolomites area, Italy. (B) Diagram of the Saros 124 event, the solar eclipse that occurred on 25 October 2022. Green continuous lines trace the Sun’s shadow at ground level; the dashed line corresponds to a coverage of 50% of the Sun’s disc and the pink line to the Sun’s path. Eclipse predictions by Fred Espenak, NASA’s GSFC. (C) In situ installation of 10 xylematic electrodes (labelled with Greek letters) on a spruce tree. Stainless steel threaded rods of 6 mm diameter were spaced 50 cm apart along the trunk and in contact with the core of the tree. Each electrode was then connected to the CyberTree devices via low-impedance audio cables. (D) Horizontal view of the phloematic configuration with electrodes in contact with the superficial layer of the tree and radially arranged in two arrays: (i) one array was located at 1 m above ground with electrodes at a radial distance of 60° from each other; and (ii) the other array was located at 3 m above ground with electrodes at a radial distance of 90° from each other. Cardinal and ordinal directions are indicated. — Southern Cross University

This study adds to the emerging evidence that plants are active, communicative participants in their ecosystems, capable of complex, coordinated behaviours akin to those seen in animal groups.

The lead authors are Professor Alessandro Chiolerio of the Italian Institute of Technology and University of the West of England, and Professor Monica Gagliano from Southern Cross University, Australia.

“This 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 behaviour,” said Professor Gagliano.

[L] A spruce tree with recording unit attached. In the Dolomite mountains in Italy. [R] Credit Monica Gagliano/Southern Cross University

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

Using custom-built, ruggedised low-power sensors deployed across a forest in the Dolomites (Italy), the interdisciplinary team—comprising experts from Italy, the United Kingdom, Spain, and Australia—recorded simultaneous bioelectrical responses from multiple trees.

Their analysis demonstrates that individual trees’ electrical activity became significantly more synchronised 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 unrecognised dynamic synchronisation not based on matter exchanges among trees,” said Professor Chiolerio.

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

Professor Gagliano said the findings support calls for the preservation of wise old trees.

“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,” said Professor Gagliano.

Bioelectrical synchronisation of Picea abies trees during a Solar Eclipse, Royal Society Open Science (open access)

Adding to its global impact, this pioneering research is set to be featured in an upcoming feature-length documentary, Il Codice del Bosco (The Forest Code), set to release in May 2025 in Italy. For a glimpse into this fascinating study, watch the official trailer:

Astrobiology