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

Strange blue rings found in Scandinavian trees leave scientists perplexed - Rings hint at unusually cold summers in Norway ...

Trees need a certain number of warm days in their growing seasons to grow properly; otherwise, the cell walls of new growth ...

The scientists collected core samples from 25 Scots pine trees and stem discs from 54 juniper shrubs, creating paper-thin ...

those trees have similar tree-ring patterns. By starting with a living tree and using wooden objects of different ages, dendrochronologists can work back through time and create a continuous plot ...

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

carbon isotopes in the growth rings of trees. Her team dissected tree rings from ancient wood samples, burned the cellulose — the main component of wood — to determine the radiocarbon content ...

Trees need a certain number of warm days in their growing seasons to grow properly; otherwise, the cell walls of new growth don’t lignify properly, creating ‘blue rings’ that appear when wood samples ...

The trees grow a new ring each year and are particularly sensitive to how wet it has been during the summer months. The widths of the rings were studied, as well as the chemistry of the wood.

creating ‘blue rings’ that appear when wood samples are dyed. Since trees and shrubs can live for hundreds of years, identifying these blue rings allows us to spot cold summers in the past.

Well, tree-ring dating, or dendrochronology, can be this precise, and even more so. Dendrochronologists showed that an ancient wooden road uncovered in southwestern England not only was built in ...