Enigmatic Blue Tree Rings Uncover History’s Harshest Summers
Blue rings visible in one of the tree samples. (Pawel Matulewski/Liliana Siekacz)A simple blue stain may unlock trees’ memories of cold summers and volcanic winters, offering scientists a precise new tool to reconstruct ancient climates through timber anatomy.By combining the biological stains safranin and astra blue, researchers can highlight areas with low lignin, a compound...