Blue growth rings found in woody plant stems represent years when cells did not lignify properly because of summers too cold for growth When the going gets cold, even tough trees struggle with ...

Scientists studying pine trees and juniper shrubs in northern Scandinavia are revealing the weather of the past by looking at tree rings — which can tell us far more than just the trees’ age. ‘Blue’ ...

Overall, only 2.1% of the pine trees' rings and 1.3% of the juniper shrubs' rings were blue; the cells which hadn't lignified properly were mainly found at the end of growth rings, in latewood ...