Canadian Forest Service Publications
Frost tolerance and bud dormancy of container-grown yellow birch, red oak and sugar maple seedlings. 1994. Calmé, S.; Bigras, F.J.; Margolis, H.A.; Hébert, C. Tree Physiology 14: 1313-1325.
Available from: Laurentian Forestry Centre
Catalog ID: 16902
CFS Availability: PDF (request by e-mail)
Container-grown seedlings of red oak (Quercus rubra L.), sugar maple (Acer saccharum Marsh.) and yellow birch (Betula alleghaniensis Britton) in their first year of growth were overwintered outdoors. Tolerance of roots and stems to freezing were compared from late summer to the following spring. Mitotic activity in the apical bud was related more closely to air temperature than to bud dormancy as defined by days-to-bud-break. In all species, stem hardening was observed before days-to-bud-break reached a maximum. Dormancy release (days-to-bud-break equal to zero) of yellow birch coincided with loss of stem hardening in the spring. Roots hardened more slowly, had a lower frost tolerance than stems in fall and winter, and dehardened earlier than stems in the spring. There were differences in stem and root hardiness among the species, with yellow birch being the most tolerant, followed by sugar maple and red oak. Primarily because of root sensitivity to frost, winter was a critical period for all three species, but particularly for red oak.
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