Just who is this tree growing along a roadside and still holding onto its seeds in late winter?
Box elder! Also known as ash-leaved maple, box elder is a unique maple. It has the greatest range of all the North American maples. It is the only North American maple species that doesn’t germinate in the shade and is more likely to be found beside a road or river than in the forest. It’s the only North American maple that’s dioecious (every tree produces only male or female flowers) and the only maple (female trees) that holds many samaras (winged maple seeds) through winter.
Box elder’s lingering samaras make the tree easily recognizable in winter and also provide an important winter food source for birds. Evening grosbeaks (who have had a population loss of 92% since 1970) are especially fond of box elder seeds, and it’s thought evening grosbeaks’ range is tied with the range of the tree.
Because box elder can thrive in poor soil and grow quickly, it was widely planted throughout the East and Midwest for street shade, erosion control, and wind breaks until the early 20th century. In the 1800s evening grosbeaks were uncommon east of the Rockies, but it may be that the expanded planting of box elders, with their steady food supply, allowed for evening grosbeaks’ eastward expansion. Since the 1920s evening grosbeaks have been considered a regular winter visitor to New England, their bright yellow feathers adding a surprising splash of color to the snowy landscape. Look for them in your neighborhood enjoying some box elder seeds.
