Tree of the Month May 2022 Boxelder (Acer negundo)

by Martin (Mort) Schmidt for Simply Living

Boxelder is the Rodney Dangerfield of Ohio maples; It don’t get no respect. Unlike the October 2021 Tree of the Month, Sugar Maple, Boxelder’s weed-like growth and weak wood make it unloved for landscaping or lumber. Boxelder can be tapped for maple syrup, but the sap is more watery than that of Sugar Maple or Red Maple, and requires too much boiling to concentrate it into
syrup if other maples are available.

Image courtesy of USDA Plants Database.

The widely-planted maples, Sugar Maple, Red Maple, Silver Maple, and the non-native Norway Maple have simple, symmetrical leaves shaped more or less like the leaf on the Canadian flag. Boxelder has compound leaves with asymmetrical leaflets. So how is it that they’re all maples? Remember that leaf shape is useful for identifying trees, but trees are classified primarily on the basis of fruits and flowers. When Carl Linnaeus established the classification scheme for plants, he reasoned that because fruits and flowers are essential to the continuation of species, they should have priority in systemic classification. Boxelder is a maple because of its paired wafer seeds (samaras) that flutter down like helicopters in autumn.

Clockwise from upper left – Sugar Maple, Red Maple, Silver Maple, & Norway Maple. Photos by Mort Schmidt.

Like the other maples, Boxelder leaves, branches, and buds are arranged oppositely, rather than alternately. That is, the leaves, branches, and buds are attached directly across from one another, rather than staggered in a left-right-left-right fashion. Remember that Maple is the M in
“MADBuck” — Maple, Ash, Dogwood, & Buckeye — the main Midwestern trees with opposite branching.

Alternate & opposite arrangements apply to both leaves and twigs. Pinnate & palmate arrangements apply to compound leaf arrangements and veining patterns. Images by Mort Schmidt.

Most maples have simple leaves, i.e., leaves are attached directly to the twigs, branches, and trunk. But Boxelders have compound leaves, such that multiple leaflets share a stem. Stems, unlike twigs, are only used for one year, whereas twigs can remain for the life of the tree, growing larger year by year. Boxelder leaves are pinnately compound, with three, sometimes five, and occasionally
seven leaflets on a stem. The leaflets on pinnately-compound leaves are attached to the stem at multiple points, in contrast to palmately-compound leaves, with leaflets attached at a single point. Because the leaf arrangement of Boxelder resembles Ash, it’s sometimes called ”Ash-Leaf Maple”. Most tree leaves and leaflets look pretty much like every other leaf and leaflet on the tree. Boxelder is an exception, in having a symmetrical leaflet at the end of the stem, and asymmetrical leaflets on the sides, similar to poison ivy. An especially useful trait for recognizing Boxelder any time of year is its green, oppositely-arranged twigs. Sassafras also has green twigs, but alternately arranged.

Trees of the genus Acer (maple) have various reproductive strategies, even within Ohio. Boxelders are dioecious, meaning that they have male and female flowers on separate trees. Silver Maples and Red Maples are monoecious, having male and female flowers on the same tree, but in separate clusters. Sugar maples can be monoecious or dioecious. Tiny female and male Boxelder flowers hang from yellow-green tassels resembling corn silk. Like most wind-pollinated flowers, they don’t
need to attract insects and aren’t showy, nor do they have an attractive odor. And by appearing before the leaves emerge, the flowers take maximum advantage of wind to help them spread their pollen. Boxelders have it all figured out.

The bark is variable, but it’s light in color and lacks distinct grooves or patterns. Boxelder often sprouts numerous twigs from its trunk, giving it a weed-like appearance, and diminishing its attractiveness for landscaping. Its seeds are similar to those of sugar maple, but tend to grow in greater abundance, with distinct seed clumps visible in winter. Boxelder grows as high as 80 feet,
with a trunk diameter of up to 2.5 feet.

Clockwise from upper left: Boxelder leaves. Poison Ivy leaves. Boxelder twigs. Boxelder
flowers. Boxelder trunk. Boxelder seeds. Photos by Mort Schmidt.

Boxelder wood is light and soft, with a density of 0.49 g/cc and a Janka hardness of 720 lbf, according to The Wood Database The median on my list of 83 Ohio trees has an equivalent density of 0.57 g/cc and a hardness of 1,050 lbf. Boxelder has low
rot resistance and tends to be brittle, making it a poor choice for most woodworking. But no matter — it propagates readily and grows quickly, especially in moist soils, so its weaknesses are only a problem to us. And the wood occasionally develops a bright red stain in response to injury, especially in warmer climates, making it prized for vases, bowls, and other decorative pieces. The
wood is sometimes used to make paper pulp and, the last refuge of unloved trees, pallets. Although Boxelder sap is less sugary than other maples, it produces more of it and it has the broadest geographic range. Boxelder seeds are edible to birds, deer, rodents, and people, but they are too
small for most people to bother with.

As their name suggests, Boxelder bugs are attracted to Boxelder trees, and also ash trees. The bugs have piercing mouth parts and live on tree sap. Boxelder bugs are harmless to trees and people, but they can move indoors and become a nuisance if present in large numbers.

Boxelder bugs. Photo courtesy of Ohio State University Ohioline.

According to the Native American Ethnobotany Database, Boxelder was used by the American Indians in the following ways:
● Numerous tribes used it for maple syrup and sugar.
● The Dakota Indians made charcoal from Boxelder for ceremonial painting and tattooing.
● The native people of Montana used large Boxelder trunk burls or knots to make drums.
● The Cheyenne used it for making bowls and for cooking fuel.
● Despite the fact that numerous Native groups consumed Boxelder sap, the Meskwaki made a decoction of the inner bark to induce vomiting.

I typically close these articles by discussing a tree’s place in folklore and human history, but I couldn’t find much about this humble tree. Boxelder provides little of interest to modern people, and not a lot to ancient ones, but its ease in establishing itself, vigorous growth, and hardiness in a wide range of conditions make it a valuable part of the environment and a worthy resident of
forests and fields.

Comments are closed.