26 February 2026 | Article

Trees Sense Winter’s Rhythm 

Trees don’t respond to winter cold alone. New research shows they also react to short warm spells, adjusting the timing of budburst to avoid frost damage. This flexible strategy helps forests cope with increasingly mild and unpredictable winters. 

Across much of Sweden, the climate is cold and snow covers the landscape. To survive the winter, trees enter dormancy and then require a period of chilling before they can resume growth in spring. New research shows that the timing of spring budburst is a complex process. It is not controlled only by the total amount of cold. Studies show that trees also respond to short warm periods during winter and use them as signals to adjust when budburst occurs. 

Repeated mild interruptions early in the winter can act as a warning signal that slows the processes leading to budburst. This reduces the risk that buds open during temporary thaws and are then damaged by returning frost. At the same time, trees spread the risk by allowing different buds to break at different times – a strategy that increases the chance that some will survive if weather conditions change. 

As winters become warmer and more unpredictable, this flexibility may become increasingly important. The new knowledge also improves the basis for developing more climate-resilient trees and for understanding how forests and fruit trees are affected by climate change. 

Photo: fightCOtwo