Canadian Forest Service Publications
Variation in response to declining photoperiod among families and stands of white spruce in southeastern Ontario. 1979. Pollard, D.F.W.; Ying, C.C. Canadian Journal of Forest Research 9(4): 443-448.
Issued by: Pacific Forestry Centre
Catalog ID: 1815
Available from the Journal's Web site. †
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Newly germinated seedlings of 66 open-pollinated white spruce Piceaglauca (Moench) Voss families from 11 native stands in southeastern Ontario were investigated for responses to declining photoperiod under controlled environments. Amount of height increment (free growth) during a period of declining photoperiod was studied. Variation in duration of free growth was found mostly associated with the family-within-stand component. The stand effect was negligible and decreased as seedlings aged. Lack of stand differentiation suggests that white spruce stands in. southeastern Ontario may have originated from the same base population. High genetic variation at the family level may reflect an adaptive strategy to cope with the extremely variable local climate.