Boxelder Maple

Appearance

"Acer negundo" is a fast-growing and fairly short-lived tree that grows up to 10–25 m tall, with a trunk diameter of 30–50 cm, rarely up to 1 m diameter. It often has several trunks and can form impenetrable thickets. The typical lifespan of box elder is only 60 years. Under exceptionally favorable conditions, it may live to 100 years.

The shoots are green, often with a whitish to pink or violet waxy coating when young. Branches are smooth, somewhat brittle, and tend to retain a fresh green color rather than forming a bark of dead, protective tissue. The bark on its trunks is pale gray or light brown, deeply cleft into broad ridges, and scaly.

Unlike most other maples, "Acer negundo" has pinnately compound leaves that usually have three to seven leaflets. Simple leaves are also occasionally present; technically, these are single-leaflet compound leaves. Although some other maples have trifoliate leaves, only "A. negundo" regularly displays more than three leaflets. The leaflets are about 5–10 cm long and 3–7 cm wide with slightly serrate margins. Leaves have a translucent light green color and turn yellow in the fall.

The yellow-green flowers are small and appear in early spring, with staminate flowers in clusters on slender pedicels and pistillate flowers on drooping racemes 10–20 cm long.

The fruits are paired samaras on drooping racemes, each seed slender, 1–2 cm long, with a 2–3 cm incurved wing; they drop in autumn or they may persist through winter. Seeds are usually both prolific and fertile.

Unlike most other maples, "A. negundo" is fully dioecious and both a male and female tree are needed for reproduction to occur.

Naming

Indicative of its familiarity to many people over a large geographic range, "A. negundo" has numerous common names. The names "box elder" and "boxelder maple" are based upon the similarity of its whitish wood to that of boxwood and the similarity of its pinnately compound leaves to those of some species of elder.

Other common names are based upon this maple's similarity to ash, its preferred environment, its sugary sap, a description of its leaves, its binomial name, and so on. These names include "Manitoba maple", "ash-leaf maple", "cut-leaved maple", "three-leaf maple", "ash maple", "sugar maple", "negundo maple", and "river maple".

Distribution

"Acer negundo" is native across much of the United States and Canada, and can be found as far south as Guatemala.

Habitat

This species prefers bright sunlight. It often grows on flood plains and other disturbed areas with ample water supply, such as riparian habitats. Human influence has greatly favored this species; it grows around houses and in hedges, as well as on disturbed ground and vacant lots.

Food

The sap has been used to make syrup by Native Americans, including the Dakota, Omaha, Pawnee, the Ponca, Winnebago, Cree, Sioux, and the indigenous people of Montana. The Chiricahua and Mescalero Apache dry scrapings of the inner bark and keep it as winter food, and they also boil the inner bark until sugar crystallizes out of it. The Cheyenne mix the boiled sap with shavings from the inner sides of animal hides and eat them as candy. The Ojibwa mix the sap with that of the sugar maple and drink it as a beverage.