From early childhood, thunderstorm safety is drilled into many of us.

Shelter in an enclosed building; get into a car and roll the windows up; stay away from trees – and, importantly, don’t be the tallest thing in an open landscape.

Trees, however, don’t get much choice in where they are during a thunderstorm, hence sometimes you see a burned up tree that has been directly hit by lightning, or one that has toppled from the force.

But direct strikes aren’t the only way that trees are affected by thunderstorms – in fact, according to a new study recently published in the journal Geophysical Research Letters, you won’t know it, but in a thunderstorm, trees actually light up.

While it’s a relatively small effect, the research team have, for the first time, captured evidence of coronae (weak electrical discharges), a faint glow on the tips of tree branches.

Why haven’t you noticed this phenomenon before? Well, because you spend thunderstorms safely sheltering indoors, of course. That, and the fact that the coronae isn’t actually visible to the human eye.

In the lab, however, conditions are very different, as Pennsylvania State University’s Patrick McFarland explained in a statement:

“In the laboratory, if you turn off all the lights, close the door and block the windows, you can just barely see the coronae. They look like a blue glow.”

But how to prove that the phenomenon does actually occur in nature? Well, that required a lot of kit – significantly more than the metal plates the team used in the lab.

Using a weather station, an electric field detector, a laser rangefinder, a roof-mounted periscope, and an ultraviolet camera, the team waited in the car for a storm, then recorded the evidence. And it was worth the wait, with 41 3-second coronae moving amongst the leaves: a truly beautiful sight.

But why do trees act this way? Well, the team suggest that it is an evolutionary capacity in the trees by allowing tips to be burned so that the important leaf canopies remain safe and intact.

Regardless of the why or the how, which are still under investigation, what a spectacle this is.

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