Tree of the Month, March 2023

Red Maple (Acer rubrum)

by Martin (Mort) Schmidt for Simply Living

March is the month for Red Maple – or one of the months. It’s small red flowers lend a beautiful red glow to forests and streets in the spring, and its leaves turn scarlet in the fall. 

Maple is the M in MADBuck – Maple, Ash, Dogwood, and Buckeye – trees that have oppositely-arranged leaves and twigs, i.e., leaves and twigs arranged directly across from each other. Except for Boxelder (Acer negundo), all of the maples native to Ohio have simple leaves with individual stems (petioles). Compound leaves have multiple leaflets that share a stem, so they’re often large and need stout twigs to support them. The diminutive dogwood and most native maples have simple leaves, and therefore delicate twigs. So a large native tree with delicate, opposite twigs is probably a maple. (But then Red Maple is the most common tree in American cities, and the most common tree in North America generally, so Red Maple is typically a good guess. 

Typical maple leaves resemble the leaf on the Canadian flag. They are palmately veined, meaning that there are multiple primary veins radiating from the stem. Pinnately-veined leaves have a single primary vein. 

Red Maple sinuses – the low spots on leaf margins in between tips – are deeper than the sinuses on Sugar Maple (Acer saccharum) and the non-native Norway Maple (Acer platanoides), but not as deep as those on Silver Maple (Acer saccharinum). Red Maple sinuses are also V-shaped, compared to the U-shaped sinuses of Sugar Maple. (The Sugar Maple sinus is shaped like the U in sugar). Also, remember that Red Maple has numerous teeth, unlike Sugar Maple, because sugar makes you lose your teeth. A final identification feature of the Red Maple leaf is its tendency to have only three lobes. The University of Kentucky’s College of Agriculture, Food, and Environment, says that “The leaves of southern forms tend to have only three lobes compared to five lobes on northern forms”. https://www.uky.edu/hort/Kentucky-trees

There’s very little red in a Red Maple leaf in summer. If the leaf has any red at all, it will be in the stem. The leaves turn scarlet in fall, often without passing through stages of yellow and orange typical of Sugar Maple. Some varieties of Norway Maple have reddish or purplish leaves in summer, but they’re found in landscaping, not Ohio forests, and they show no good fall colors. Norway Maple can be distinguished from Red, Sugar, and Silver Maple by plucking a leaf and looking for a drop of milky sap on the tip of the stem. To summarize, Red Maple leaves have teeth, V-shaped sinuses, clear sap, and a tendency to have three lobes. 

Red Maples typically reach heights of 70 or 80 feet, with trunk diameters up to 2.5 feet. Ohio’s Champion Red Maple, located in Lake County, is 84 feet tall, with a trunk diameter of 6.5 feet. The Monumental Trees website reports a Red Maple in Tennessee with a height of 143 feet. https://www.monumentaltrees.com/en/usa/ 

Red Maple can usually be distinguished by its bark, but as is true of many trees, Red Maple’s bark changes character with age. Young Red Maples, and the young upper branches of mature trees, have smooth silvery bark easily confused with American Beech. With age, the lower bark develops shallow fissures with smooth, thin scales between them. When identifying trees by their bark, be sure to look at the whole tree. 

Like all maples, Red Maple fruits consist of paired samaras (wafer seeds). Maple seeds flutter down like helicopters, allowing them to propagate over considerable distances on windy days. Red Maple seeds go from red to brown and disperse in the spring, before the arrival of leaves, whereas Sugar Maple seeds remain after the leaves emerge, and disperse in autumn. 

As discussed in previous Tree of the Month articles, some species of trees are monoecious, having male and female flowers on the same tree. Other species are dioecious, having female flowers on some trees and male flowers on others. Red Maple is polygamodioecious – some individuals are female, some are male, and some are hermaphroditic. And under proper conditions a Red Maple can change from one to the other, potentially existing in all three states over the course of its life. Red Maple flowers are small, but their bright red color is a welcome reminder that spring is approaching. 

American Sycamore (Planatus occidentalis) leaves resemble maple leaves, but sycamore has distinctive camouflage-looking bark. Sweetgum (Liquidambar styraciflua) has star-shaped leaves that somewhat resemble maple, but it has persistent spiny fruits most of the year and much more rugged bark. 

While Acer rubra has an extremely wide north-south range and occurs from Canada to Florida, its natural range is limited to eastern North America. Its wide range is no doubt due to the fact that, “Red maple tolerates the widest variety of soil conditions of any North American forest species“, according to Virginia Department of Forestry, Common Native Trees of Virginia. 

https://dof.virginia.gov/wp-content/uploads/Common-Native-Trees-ID_pub.pdf  Red Maple is more water-tolerant than many trees and often grows in association with American Sycamore and Silver Maple.  

Red Maple and Silver Maple lumber are categorized as soft maple, whereas Sugar Maple and Black Maple are regarded as hard maples. Red Maple has a Janka hardness of 950 lbf and a density of 0.61 g/cc, compared to Sugar Maple with a hardness of 1,450 lbf and a density of 0.71 g/cc. https://www.wood-database.com/?s=Red+maple  Black Walnut has the median hardness in my list of 68 Ohio trees of 1,010 lbf, and a density of 0.61 g/cc. Red Maple wood is diffuse-porous, meaning that the larger pores are scattered evenly on the wood surface, rather than aligned with the trees’ annual rings. https://www.wood-database.com/wood-articles/hardwood-anatomy/ 

Red Maple has low rot resistance and is unsuitable for outdoor use, but it is sufficiently strong for use in furniture, crates and pallets. Because it has fine grain, it is useful for musical instruments and turned objects. On the other hand, Red Maple is soft enough to be used for pulpwood. Red Maple is very workable and readily accepts glues and stains. Its adaptability and hardiness make it very popular for landscaping. Finally, Red Maple makes good firewood, although it provides less heat than hard maples. 

Red Maple is particularly susceptible to ambrosia coloration, caused by compounds the tree produces to defend itself from ambrosia beetles, sugar taps, nails, and other injuries. Ambrosia coloration is not a fungus and does not weaken the lumber or change its properties. In fact it’s often desirable to wood turners and hobbyists, but it’s usually avoided for commercial use, because the colors are too variable. Ambrosia coloration is also responsible for the bright red colors associated with Boxelder (Acer negundo).

Settlers used Red Maple bark to make reddish brown and black inks and dyes. According to the Native American Ethnobotany Database (NAEB), the Cherokee and others used Red Maple for basket splints and furniture. The Iroquois and others carved Red Maple into bowls. http://naeb.brit.org/  The wood’s softness relative to hard maples is a major advantage when working it with hand tools. 

All of Ohio’s native maples produce sweet sap that can be boiled down to make syrup and sugar. Red Maple sap is less concentrated than Sugar Maple but more concentrated than Silver Maple and Boxelder. Like other maples, Red Maple seeds are edible to people, and the wood is good for smoking foods, especially foods with delicate flavors, such as fish and fowl. 

Many Indian tribes used Red Maple for medicinal purposes. The NAEB includes the following: 

• Cherokee – Infusions of bark for cramps, eye wash, dysentery, gynecological aid, and measles,
• Iroquois – Infusions of bark for eye wash and blood purifier,
• Seminole – Infusions of bark for skin conditions and hemorrhoids.

According to Alice Thom Vitale’s Leaves, In Myth, Magic, & Medicine, tca breved from Red Maple leaves was once used for “easing the pains in the sides proceeding from liver and spleen.” 

Red Maple seeds provide food for birds and squirrels. Deer and elk feed on leaves and twigs in winter, but the leaves are toxic to horses and cattle, according to the Illinois Wildflowers website. http://www.illinoiswildflowers.info/trees/tree_index.htm 

Rebecca Rupp’s book, Red Oaks and Black Birches, the Science and Lore of Trees, has an extensive discussion of maples and the production and use of maple sap. The sap was concentrated into syrup and sugar, but also fermented into beer for drinking, and vinegar for preserving and flavoring foods. Maple ashes are high in potash, which was used as fertilizer. Rupp reports that the use of fertilizer from tree ashes allowed one Darius Clark in the early 1800s to grow a 4.5 pound potato! Just this week I was astonished to find a 2 pound, 5 ounce potato in a bag from Aldi’s. It was hardly more than half the weight of Clark’s masterpiece. 

Red Maple, the State Tree of Rhode Island, has long been loved for its red color. Julia Ellen Rogers said in her 1911 book, Trees, “In beauty the red maple excels all the other maples. In early spring its swelling buds glow like garnets on the brown twigs. The opening flowers have red petals, and the first leaves, which accompany the early bloom, are red. In May the dainty flat keys, in clusters on their long, flexible stems, are as red as a cock’s comb, and beautiful against the bright green of the new foliage. In early September in New England, a splash of red in the woods, across a swamp, is sure to be a scarlet maple that suddenly declares its name.”