Climate change is expected to increase winter temperatures in boreal climates. White spruce (Picea glauca (Moench) Voss) is vulnerable to spring frost damage due to its habit of early budbreak, which may be exacerbated or lessened with increasingly warm winters at its southern range edge. We tested the effects of episodic warming during the quiescent stage on budbreak time and growth of seven seed sources grown in a common garden setting in Minnesota, USA. Treatment plots were warmed with infrared lamps for 4 days each in February, March, or February and March to simulate a midwinter thaw. Control plots for each treatment and an overall control were included for comparison. Trees warmed in February experienced a slight delay in spring budbreak, but differences in budbreak time were generally not significant. Terminal growth was significantly and negatively correlated with time of budbreak but not with time to growth cessation. Our results suggest that white spruce is relatively resilient to the effects of intermittent warming but that warming early in the season may delay budbreak time, which is expected to reduce terminal growth.
Bibliographical noteFunding Information:
This project was supported by a grant from the Minnesota Department of Natural Resources, the University of Minnesota Regents’ scholarship, and generous assistance from the staff of the Cloquet Forestry Center and members of the Minnesota Tree Improvement Cooperative.
© Her Majesty the Queen in right of Canada 2017.
- Climate change
- White spruce
- Winter warming