Moist, protected northerly or easterly slopes are considered most favorable for sweet birch in both northern and southern parts of its range. Life History Reproduction and Early Growth Flowering and Fruiting Sweet birch flowers are monoecious and borne in catkins. Pistillate catkins appear with the leaves and are borne terminally on short, spurlike branches. Seed Production and Dissemination Seed fall is during mid-September through November. Seed dispersal is normally by wind and seeds may be blown some distance over crusted snow.
Nothing is known about quantities of seeds produced or how far they are spread.
Under forest conditions, seeds normally germinate during the spring after they are dispersed. Nursery experience indicates that germination may extend over 4 to 6 weeks. Germination is delayed when the embryo is dormant. Moist mineral soils, rotten logs, and humus are suitable germination media. In nursery practice, birch seed is usually sown in the fall after collection in the late summer or fall.