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Early Flowering and Seed Production in a Yellow Birch Progeny Test

Trees in a yellow birch progeny test began to bear seed when 7 years old and the proportion of fruiting trees increased in the following 2 years. Male catkins were produced at age 8 and the number of trees with males increased greatly the following years. Although there is much variation between and within families in earliness of flowering and in number of flowers and fruiting catkins, about one-third of the families have borne seed and 45 percent have produced males. The number of catkins per tree has ranged up to 429 for females, 196 for fruiting, and 1379 for males. Seed yield varied greatly between and within families, but 49 percent of the trees had between 100 and 200 seeds per catkin. Certain families and trees are more prolific than others and trees of northern origin appear to start flowering earlier and more heavily than those of southern origin. The early and heavy seed production of such early tree ages argues well for seedling seed orchards of this species.

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Author(s): Knud E. Clausen

Publication: Tree Improvement and Genetics - Central States Forest Tree Improvement Conference - 1976