Blue growth rings in woody plant stems indicate years when cells failed to lignify properly due to summers that were too cold ...

which found strange blue rings in samples of trees and shrubs from the northern treeline in Norway. “Blue rings look like unfinished growth rings, and are associated with cold conditions during the ...

These eruptions likely cast a volcanic winter over the northern hemisphere, impacting the trees at Mount Iškoras in Norway, where the study was conducted. "Blue rings look like unfinished growth ...

In Norway, scientists have found blue rings in trees that hint at how volcanic eruptions disrupted growth throughout history.

Volcanic eruptions and cold summers leave lasting marks in the wood of northern trees, unlocking the secrets of past climate extremes.