Cold adaptation recorded in tree rings highlights risks associated with climate change and assisted migration

Area of Science:

• Forest genetics
• Climate change adaptation
• Plant ecophysiology

Background:

• Climate change is altering growing seasons and increasing temperature variability, posing risks of frost damage to plants.
• Poleward planting of warm-adapted seed sources may exacerbate frost damage risks, especially with increased temperature variability.
• Understanding cold adaptation in tree populations is crucial for effective seed transfer strategies.

Purpose of the Study:

• To investigate cold adaptation in western North American coniferous tree populations.
• To inform limits for seed transfer under changing climate conditions.
• To assess the genetic differentiation of populations concerning frost damage.

Main Methods:

• Utilized common garden trials to study genetic population differentiation.
• Analyzed tree-ring signatures to identify and quantify cold damage.
• Examined geographic clinal variation in response to spring and fall frosts.

Main Results:

• Identified opposing geographic clines for spring and fall frost damage.
• Northern provenances showed sensitivity to spring frosts.
• Central and southern provenances, while more productive, were more susceptible to fall frosts.

Conclusions:

• Transferring southern, warm-adapted genotypes northward resulted in significant growth loss and rank changes after spring frost.
• Cold adaptation remains a critical factor in seed transfer strategies aimed at mitigating climate change impacts.
• Genetic considerations for cold hardiness are essential for sustainable forest management.