Quantifying the effects of frost anomalies and cold hardiness on the growth of red spruce (Picea rubens Sarg.) populations
University of New Brunswick
Climate change adaptation strategies such as assisted migration require a better knowledge of the genetic variations in climate sensitivity, including cold hardiness. In this thesis, I compared the cold hardiness of seven mature provenances of red spruce (Picea rubens Sarg.). under controlled conditions and detected significant differences in autumn acclimation between the most cold-adapted and warm-adapted seed sources. Looking at tree rings of the past 50 years in the same provenances, I found no significant impact of frost on growth since the 1990s, but a large drop in growth occurred in 1987 in synchrony with a severe frost event. The growth decline was significantly higher in southern seedlots and covaried with their experimental levels of cold hardiness. My results suggest limited evidence for recent frost damage in southern provenances and support red spruce as a good candidate for assisted migration.