In order to grow properly, trees need an adequate period of warmth during their growing seasons; otherwise, the cell walls [… ...

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 ...

Blue rings found in the stems of trees and bushes in Norway point to a historic cold period ... samples from 25 Scots pine trees and 54 common juniper shrubs from a site high on Mount Iškoras ...