From a distance, the storm that swept through southeast North Carolina in the summer of 2024 most likely appeared normal. heavy clouds. The thunder rumbled low. Branches bending in the wind with a slight soil-wet smell. However, a small group of scientists were observing something unusual take place inside a modified minivan parked close to a stand of trees.
Faint flashes appeared on the tips of leaves high in the canopy on a grainy monitor. tiny UV light bursts. Short and elusive. Almost spectral.
| Category | Details |
|---|---|
| Phenomenon | Ultraviolet “coronae” electrical discharges on treetop leaves |
| First Direct Observation | Filmed in the wild during thunderstorms in 2024 |
| Lead Researcher | Meteorologist Patrick McFarland |
| Institution | Pennsylvania State University |
| Study Published In | Geophysical Research Letters |
| Observation Location | Pembroke, North Carolina, USA |
| Equipment Used | UV-sensitive camera mounted on a modified storm-chasing vehicle |
| Observed Activity | 41 corona discharges recorded in about 90 minutes |
| Tree Species Observed | Sweetgum and loblolly pine |
| Scientific Importance | Confirms nearly century-old theory about electrical activity in forests |
| Reference Source | https://news.agu.org |
Meteorologists huddled inside a storm-chasing Toyota Sienna, staring at a video feed as lightning cracked somewhere overhead. It’s difficult not to imagine the scene as somewhat surreal. The forest outside appeared gloomy and unimpressive. However, the ultraviolet-tuned camera was displaying a different image. Silently, the tops of the trees were glittering.
Scientists suspected such a thing existed for decades. Measurements of the electrical field during thunderstorms suggested that trees were acting strangely. The theory was fairly straightforward. Strong negative charges are created by thunderstorms, and a positive charge is created on the ground beneath them. The tallest objects are climbed by that charge, which is pulled upward like an unseen tide. That usually refers to trees.
Even so, theories persist in science for years or even generations before anyone notices them. Furthermore, until recently, no one had recorded these electrical discharges that occur in nature and are referred to as coronae. Pennsylvania State University meteorologist Patrick McFarland made the decision to give it a shot.
The plan was a combination of an unplanned road trip and a scientific experiment. After purchasing a used 2013 Toyota Sienna, McFarland and his associates converted it into a mobile storm-watching lab. They made a hole in the roof, mounted sensors and a periscope, added vibration dampers for delicate equipment, and connected everything to a specialized UV camera.
One can assume that the renovations reduced the van’s resale value. But it might have been worth it for the science.
The team searched for the ideal conditions by chasing thunderstorms along the U.S. East Coast from Florida through Pennsylvania during the summer of 2024. Nothing showed up on the screen most of the time. Only the gray haze of rain and branches shaken by the wind. Then, at last, something flickered in Pembroke, North Carolina.
The researchers captured dozens of weak UV signals by aiming the camera at three sweetgum tree branches. 41 different corona discharges in roughly 90 minutes were found by later analysis. Each spark occasionally hopped from one leaf to another and lasted anywhere from a fraction of a second to about three seconds.
After watching the video, one gets the impression that the forest may be more electrically alive than previously thought.
Perhaps all thunderstorms depict the same scene over whole landscapes. Because they are too faint in the visible spectrum and obscured by ambient light, the glows are invisible to the human eye, but the ultraviolet camera makes them sufficiently visible. The top of every forest might resemble a swarm of flickering fireflies if humans possessed what one scientist jokingly referred to as “superhuman vision.” It seems almost poetic. A little unnerving, too.
Because these glitters aren’t just ornamental. According to lab tests, corona discharges have the ability to quickly scorch leaf tips. Chloroplasts, the microscopic structures that plants use for photosynthesis, are harmed by the electrical energy, which also breaks down cell membranes.
The effect is immediately apparent in the lab, where tiny burns form where the electrical field is concentrated.
Things are less obvious in actual forests. It’s unlikely that a single corona causes much harm. However, many ecosystems experience storms on a regular basis, sometimes dozens of times annually. Those recurring discharges may subtly influence how trees develop over decades or even centuries. Forests seem to have endured this electrical stress for thousands of years.
According to some researchers, trees might have adapted to it by developing protective coatings that lessen damage or leaf structures that disperse electric charge. Others believe that the effects could be minor, akin to small scratches in a system that is otherwise robust. No one really knows as of yet.
Chemistry is another wrinkle. Hydroxyl radicals are reactive molecules produced by corona discharges that have the ability to interact with air pollutants. This suggests that natural air cleaning above forest canopies may be occurring in small bursts due to thunderstorms.
It’s probably a minor effect. Nevertheless, the prospect presents intriguing queries regarding the ways in which storms influence atmospheric chemistry locally.
The length of time the phenomenon was concealed is what makes this discovery seem subtly fascinating. Scientists suspected that forests behaved differently under charged skies for almost a century. Even though there were hints from laboratory experiments and strange electric field readings, the visual proof never came.
Until someone with the proper type of camera looked at trees during a storm. As I watch the video now, an odd thought keeps coming to mind. Innumerable leaves may be shooting invisible sparks into the night with each thunderstorm that crosses a forest, be it in the Amazon, North Carolina, or the mountains.