During thunderstorms, electric discharges in the air cause trees to glow with an ultraviolet aura. You can't see it with your eyes, but researchers have finally managed to measure it & recreate it in the lab.

https://news.agu.org/press-release/thunderstorms-conjure-ghostly-coronae-in-treetops-observed-outdoors-for-the-first-time/ #science #nature