River Birch, Red Birch
Betula nigra
(aka Black Birch, a name more often used for Sweet Birch, Betula lenta)
by Martin (Mort) Schmidt for Simply Living
River Birches (Betula nigra) are popular landscaping trees. But are they actually trees?
The definitions of trees vary a bit, but most indicate that a tree is a perennial plant with a woody stem, a minimum height of 15 feet at maturity (or 3 meters, more or less), and it has a single trunk at least 3 inches in diameter at breast height. Smaller woody perennials, and those with multiple trunks are shrubs. Many trees have multiple trunks if they sprouted up from stumps, but trees grown from seed ideally have just one. But the River Birch often has multiple trunks, which, arguably, makes it a shrub. But their height averages 40 to 80 feet, and their trunk diameter averages 1 to 2 feet. Those are mighty big shrubs! I often say that nature doesn’t care about our classification schemes. We simply have to accept that this tree violates the single-trunk requirement. (Incidentally, Donald Culross Peattie’s A Natural History of Trees of Eastern and Central North America says that many riparian [river-loving] trees tend to have multiple trunks).
Betula nigra has alternately-arranged, simple leaves. Alternately-arranged leaves and branches are not attached directly across from each other, while oppositely-arranged leaves and branches are. (Most Ohio trees are alternately-arranged. The oppositely-arranged trees are the “MADBucks” – Maple, Ash, Dogwood, and Buckeye). But while River Birch leaves are attached at alternate points on the tree, they often occur in pairs, and occasionally, groups of 3 or 4.
Simple leaves have their own stems, and are not attached to the tree in consistent groups of 3, 5, 7, etc. River Birch leaves are pinnately-veined, i.e., they have one primary vein running the leaf’s length, with secondary veins attached to it at various points. Palmately-veined leaves have multiple primary veins converging at the stem.
River Birch leaves are shaped like pointed ovals, but often with straight bases, giving them a rhomboidal shape. Mature leaves are typically 1.5 to 3 inches long and 1 to 2.5 inches wide, with straight, unbranched secondary veins, and 0.5-inch stems. The leaves are coarse-toothed, and sometimes double-toothed. The leaves turn dull yellow or brown in fall.
River Birch flowers consist of green catkins in the spring, and the tree is monoecious, having male and female flowers on the same tree. Like other trees with catkins, the flowers are primarily wind-pollinated. Wind-pollinated flowers don’t need showy or aromatic parts to attract insects. B. nigra is the only birch that produces seeds in the spring. B. nigra does not typically propagate from shoots, but it will sprout up vertically from stumps. The most distinctive feature of River Birch, and one thing that makes it popular for landscaping, is its bark. The bark is salmon-colored, and like most other birches, papery in younger trees, becoming darker and scalier with age. But don’t mistake it for the considerably darker orange bark of the Paperbark Maple (Acer griseum, aka Bloodbark Maple), an Asian tree also used in landscaping.
Mature River Birches typically have a height of 40 to 80 feet and a trunk diameter(s) of 1 to 2 feet. Ohio’s Champion River Birch, located in Hamilton County, has a height of 66 feet, a trunk diameter of 5.6 feet, and a crown width of 85 feet.
ID Summary: Most readily distinguished by its salmon-colored, papery bark, and multiple trunks. Pointed oval to arrow-shaped leaves, with catkins in spring.
Similar Trees: Other birches have similar leaves, but lack the pink, papery bark. Paperbark Maple has similar bark, but it’s darker orange, has compound leaves with 3 leaflets, and of course, the paired samaras unique to maples.
As the name suggests, River Birch prefers moist to wet soils, and is often found near river banks and flood plains with sun exposure. B. nigra is native to the central and south-eastern U.S., and is the southernmost New World birch. According to Lucy Braun’s The Woody Plants of Ohio, River Birch occurs in 15 southeastern Ohio counties, and 2 counties bordering Lake Erie. In central Ohio, I rarely or never see River Birch outside of landscape settings. The Columbus, Ohio Street Tree Inventory indicates that Betula nigra ranks 54th in popularity, making up 0.37% of the City’s street trees.
River Birch lumber has a Janka hardness of 970 lbf and a density of 0.59 g/cc, according to the Wood Database, compared to the median of my list of 73 Ohio trees of 1,075 lbf and 0.64 g/cc. It’s relatively easy to work with, but has low rot resistance, and is limited to indoor applications. Only trees with a single vertical trunk provide useful boards, since branches and trunks growing at an angle tend to warp severely on drying. River Birch’s tendency to grow along rivers, rather than in pure stands, also limits its value as lumber. Several birches are widely used to make veneer, plywood, and pulp. and according to Wood Magazine, River Birch and Sweet Birch (aka Black Birch, B. lenta) are often mixed with the more widely-used Yellow Birch (B. alleghaniensis).
According to the Native American Ethnobotany Database, Native uses for River Birch include the following:
Cherokee:
- Chewing leaves or drinking infusions for dysentery,
- Infusion [of bark?] as a cold remedy,
- Infusion of bark for stomach ailments,
- Infusion of bark for urinary problems,
Chippewa:
- Infusion of bark for stomach pain.
Like Black Birch, the tree’s sap could be boiled down to make a sweet drink or syrup enjoyed by the Natives.
Yellow Birch, and to a lesser degree, Black Birch and River Birch, are used to make furniture. The hard, smooth, light-colored wood was popular for Mid-Century Modern furniture. Birch resembles maple, but it’s somewhat softer and easier to work with, lighter weight, and less costly. Birch is, or was widely used to make sewing spools, clothes pins, Shaker pegs, golf tees, toys, tongue depressors, wooden spoons, and other woodenware with a smooth surface. Birch was once also used for prosthetic limbs, where its lower weight but sufficient strength would make it preferable to harder, denser woods such as maple. Birch is a good firewood, and the bark can be peeled off to make a water-resistant fire starter. River Birch tolerates poor soil and acidic soil. And while it’s highly tolerant of water, it also tolerates moderately dry conditions, making B. nigra useful for land reclamation.
Environmentally, River Birch is important for anchoring the soil along river banks. Illinois Wildflowers lists a number of insects that feed on birches, including:
- Moths,
- Butterflies,
- Sawflies,
- Wood-boring beetles,
- Shield bugs, and
- Aphids.
Birds that eat the seeds, buds, and catkins of birch trees include:
- Ruffed Grouse,
- Greater Prairie Chicken,
- Pine Siskin,
- White-Winged Crossbill,
- Purple Finch, and
- Black-Capped Chickadee.
Twigs, bark, and leaves are also consumed by squirrels, beavers, deer, and rabbits. River Birch is more tolerant of birch borers than other birches, especially in warmer climates. According to Trees for Shelter and Shade, For Memory and Magic, by Charles Fenyvesi, the European White Birch (B. pendula) thrives in where winter temperatures dip below 20 degrees Fahrenheit, but is attacked by beech borers in warmer climates. In contrast, River Birch, especially of the Heritage variety, resists borers and can therefore survive much farther south. Fenyvesi also discusses the natural tendency of birches to develop multiple trunks, but recommends planting them in clusters, or coppicing them, to further encourage this growth pattern.
Simon Wells’ A History of Trees, describes the use of slender birch twigs in European culture that are bound together for flagellating one’s body after a sauna. Sturdier switches were widely used to punish children, to the point where “birching” became synonymous with spanking. In fact, according to Colin Tudge’s The Tree, A Natural History…, the genus name “Betula” is derived from the Latin word for beating.
Diana Wells’ Lives of the Trees, an Uncommon History informs us that most birch bark contains the compound betulin, which makes the bark light colored and water resistant. Wells also discusses betulin’s potential medicinal value. According to Feyisayo O Adepoju, et al., report Pharmacological Potential of Betulin as a Multitarget Compound, “Betulin is a natural triterpene, usually from birch bark, known for its potential wound-healing properties. …….. Betulin has protective effects against cardiovascular and liver diseases, cancer, diabetes, oxidative stress, and inflammation.
As a geologist, I doubt the claims of magical properties attributed to rocks and plants, but the storyteller in me loves them. Also, much of the lore associated with birches is tied to European species, but who knows? If European birches ward off evil spirits, perhaps so does our River Birch!
As pioneer species, birches often establish themselves on barren ground that has been stripped by people, fires, landslides, and glaciers. This might explain why birches have been associated with nurturing and protection, and baby cradles were often built of birch, to ward off evil spirits.
The Dragon Oak website indicates that birch is a symbol of rebirth and renewal, and that a birch wand is useful for many cleansing rituals. Birch twigs and rods were used to drive off evil spirits in many European communities, especially at the turn of the New Year. Dragon Oak goes on to say that birch is, “Controlled by Moon influences to include; birth, Lunar spells, healing, and protection”.
The Order of Bards, Ovates, and Druids tells us that in ancient times, birch twigs were bound to birch broomsticks to sweep out the bad spirits of the previous year. Maypoles were often made of birch, and the Yule log was also made of birch, to help ensure a good New Year. Carrying a small piece of birch would protect a person from the Faerie Folk.
Alexander Porteous’s The Forest in Folklore and Mythology relates a Russian folktale, in which a shepherdess was spinning wool in a birch forest. A wild woman came to her and made her dance for three whole days. At sunset on the third day, the wool was all spun, and the shepherdess’s pockets were filled with birch leaves, which turned into gold coins.
In American history, Spike Carlsen’s A Splintered History of Wood relates the story of one of the largest airplanes ever built, and certainly the largest wooden airplane, the infamous H-4 Hercules, aka, the “Spruce Goose”. During World War II, a great deal of lives and goods were lost from the sinking of merchant ships, so one potential solution was to build huge airplanes. Due in part to the shortage of metals, the aviator, aerospace engineer, and film maker, Howard Hughes designed a plane made partly of spruce, but primarily of birch plywood (probably mostly Yellow Birch). The so-called Spruce Goose was completed too late to be used in the war, and the U.S. Senate accused Hughes of wasting $47 million of taxpayers’ money. So Hughes took the floating airplane up for a one-mile flight at an elevation of 70 feet, to prove that at least it was airworthy. The plane is now on display at McMinnville, Oregon.
Prior to taking the throne as the Emperor of Mexico in 1864, Austrian prince Maximilian I toured North America, and declared the River Birch to be our most beautiful tree. While not our most useful tree, I certainly agree that River Birch is beautiful.
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You can also listen to my talks on Ohio Broadleaf Tree Identification on YouTube, Part 1 and Part 2.
