Budburst in White Spruce
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Project Overview
Trees use two different mechanisms to escape winter frost damage: chilling requirements and heat sum requirements. Chilling requirements primarily prevent growth during warm spell in the middle of winter where heating requirements prevent damage from last spring frosts. Both of these mechanisms need to be in tune to ensure trees initiate spring growth at the optimal time. As these mechanisms are internally set and adapted to local environmental conditions, there is concern that climate change will disrupt optimal timing of spring and put populations at increasing risk for frost damage. Increasing frost damage coupled with other stressors expected to increase in the future (e.g. drought) could threaten population survival.
In this study we examined whether the wide-ranging boreal species, White Spruce (Picea glauca), shows genetic differentiation among populations in either its heat sum requirements or chilling requirements. We further investigated what local environmental conditions might drive adaptation in heat sum requirements. |
Figure 1. Closeup of White Spruce buds in Spring. The green bud has burst and the brown buds are still dormant.
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