The natural history of the northwoods . Margins serrated with very fine teeth. Do not turn color, but remain green until dropped in the fall. Male catkins and female flowers on same plant. Fruit a small dry woody cone.
Twigs have sessile, pointed axillary buds.
Roots shallow, with nodules containing nitrogen-fixing microorganisms. From open tundra to open conifer forest but cannot withstand a dense overstory. Singly or in thickets along streams, lakeshores, coasts, bogs, or muskeg margins, and as an understory component in conifer forests. Usually associated with some source of moisture, but is adapted to somewhat drier conditions than other alders. Wetter sites are more favorable for high nitrogen-fixing activity.