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

David Montwé,Miriam Isaac-Renton,Heinrich Spiecker,Andreas Hamann

doi:10.1038/s41467-018-04039-5

David Montwé, Miriam Isaac-Renton + Show 2 more

Open Access

https://doi.org/10.1038/s41467-018-04039-5

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Abstract

With lengthening growing seasons but increased temperature variability under climate change, frost damage to plants may remain a risk and could be exacerbated by poleward planting of warm-adapted seed sources. Here, we study cold adaptation of tree populations in a wide-ranging coniferous species in western North America to inform limits to seed transfer. Using tree-ring signatures of cold damage from common garden trials designed to study genetic population differentiation, we find opposing geographic clines for spring frost and fall frost damage. Provenances from northern regions are sensitive to spring frosts, while the more productive provenances from central and southern regions are more susceptible to fall frosts. Transferring the southern, warm-adapted genotypes northward causes a significant loss of growth and a permanent rank change after a spring frost event. We conclude that cold adaptation should remain an important consideration when implementing seed transfers designed to mitigate harmful effects of climate change.

Highlights

With lengthening growing seasons but increased temperature variability under climate change, frost damage to plants may remain a risk and could be exacerbated by poleward planting of warm-adapted seed sources
It appears that the blue ring captures a cold event at the end of the growing season that leads to cambial damage and irregular growth upon re-activation in the following spring
These were labeled as frost rings in position 2 and we interpret them as damage caused by late spring frost events

Summary

Introduction

With lengthening growing seasons but increased temperature variability under climate change, frost damage to plants may remain a risk and could be exacerbated by poleward planting of warm-adapted seed sources. Moving southern seeds northward can test the performance of warm-adapted populations under currently colder environments, thereby suggesting limits to seed transfer Within these designs, genetic adaptation to cold in tree populations has been studied by observation of tissue damage after sporadic natural frost events and by exposing collected tissue samples to artificial freezing tests in the laboratory[17,31,32,33,34]. We study these cold and frost signatures in trees grown in provenance trials, allowing us to quantify genetic differentiation in susceptibility to cold among populations This can inform limits to seed transfers designed to address projected climate change. We further analyze frost imprints in the context of long-term growth data to quantify potential impacts of cold damage on productivity

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Conclusion