Unstable winters are quietly killing young boreal forest trees
Riikonen J, Domisch T, Martz F
Climate Adaptation
If you've ever planted a young conifer or shrub and watched it struggle to leaf out after a strange winter, this is the same problem playing out across entire boreal forests, where warmer, less predictable winters are messing with the internal clock that tells seedlings when it's safe to grow.
Snow isn't just scenery in northern forests, it's a blanket that protects tree roots from deep cold and controls how wet the soil gets when it melts. As winters get warmer and snowier or patchier in unpredictable ways, that blanket is failing: roots freeze deeper or drown in meltwater, and seedlings lose track of when spring has actually arrived, waking up too early and getting hit by frost. Scientists reviewing the research say nurseries and foresters need to rethink how they raise and plant seedlings to help them cope with these messier winters.
Key Findings
Snow depth, structure, duration, and melt timing directly control soil temperature, gas exchange, and root stress in boreal forests
Warming winters can delay cold acclimation in seedlings, increasing vulnerability to sudden warm spells and advancing spring phenology, which raises frost-damage risk
Soils, microbes, and roots continue emitting CO2 through winter, making winter carbon flux one of the most uncertain parts of the boreal carbon budget
chevron_right Technical Summary
Winter is becoming more unpredictable for boreal forests, and that's bad news for young trees. Changes in snow cover and soil freezing are stressing seedling roots and confusing their internal timing, making it harder for planted forests to regenerate successfully.
Abstract Preview
Original paper
Winter climate change in the boreal forest-what does it mean for the forest tree seedlings?
Winter physiological processes are often overlooked in climate change studies of boreal forests, despite their critical role in determining tree survival and carbon balance. Winter climate change i...
open_in_new Read full abstractAbstract copyright held by the original publisher.
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