Black Birch

Basic Information
Tree ID: 
66
Family: 
Genus and species: 
Description: 
Betula lenta, known by the common names of black birch, sweet birch, or cherry birch, is a native birch species present throughout much of eastern North America. It is valued for its wood, which when exposed to air darkens to resemble mahogany, as well as being a source of wintergreen oil. It has a dark brown to greyish black color. Unlike most other birches, mature Betula lenta can develop hard, scaly plates. Removed from its industrial history, it is now primarily found in forests and used as an ornamental tree in landscaping. Some visual cues for spotting the black birch include: dark brown bark; green cones in the spring and brown cones in the late summer; dark, shiny, serrated green leaves in the summer and bright golden yellow leaves in the fall.
Surveyors: 
Sarah Landau and Zachary Jacobs
Location
Collected Data
Tree shape: 
Pyramidal to rounded
Date of tree entry: 
02/08/2017
Height: 
10.46 m
Diameter at breast height: 
0.04 m

Bark
The bark of young trees is reddish brown to black with lighter colored lenticels. Mature tree bark turns dark brown to black and breaks up into scales and plates. The inner bark of the black birch has a strong wintergreen scent.
Twigs & branches
Black birch trees have ascending branches with thin, hariless twigs that are dark red/brown in color. A characteristic feature of the twigs of the black birch is that when broken, they have a strong wintergreen aroma. Staminate catkins hang down from twigs during the winter months and pistallate catkins bud off the ends of short-spur like branches.
Foilage
Black birch leaves are simple, alternate, elliptical to ovate with an acute tip and cordate base. They are singly or irregularly doubly serrated on their margins. The leaves tend to be 2 to 4 inches long and are a dark, shiny green during the summer, turning bright yellow and gold in the fall. Black birch leaves densely cover the twigs and branches of the canopy in the late spring to early fall.
Reproductive Structures
The black birch is monoecious with male and female catkin flowers. The male (staminate) catkin is green and 3/4 to 1 inch long. It is formed in the late summer or early autumn, hangs down from thin twigs in the winter, and opens up in the spring to release its pollen. The female (pistallate) catkin forms in early spring within lateral buds, appearing within the leaves of the tree. The female catkin is 1/2 to 3/4 inch in length and when fertilied, gives rise to green cones. The green cones appear in the spring and in the late summer/early fall turn brown and shatter to release their ripened seeds.
Fruit
In general, black birch has low fruit-seed abundance. The fruit of the black birch is a brown, cone-like aggregate, that is 1-1.5 inches in length. The fruit contains very small 2-winged seeds. Upon ripening in the late summer/early fall, the fruit breaks apart, releasing its seeds.
Seasons
  • Black Birch in Spring
  • Black Birch in Summer
  • Black Birch in Fall
  • Black Birch in Winter
Research
Natural range of distribution: 
Habitat: 
Black birch is native to eastern North America, from southern Maine west to southern Ontario, and south down through the Appalachian region into Georgia. It is most abundant in Massachusetts, Connecticut, New York, and Pennsylvania. It is a dominant tree in the northern hardwood forests of northern Appalachia. Found in moist ravines and cool forests with well drained, moist, deep, and rich soil, but also can occasionally be found in rocky or shallow soils. It is tolerant to acidic and alkaline soils as well as salt spray, allowing it to thrive in many conditions. It can be found in elevations ranging from sea level to 4,500 feet in the Southern Appalachians. Black birch habitats average about 45 inches of precipitation per year, half of which falls in the growing season, and average annual temperatures of 45° F to 56° F with extremes from 74° F to 15 °F.
Origin, history, and uses: 

Black birch is a native species to the Appalachian region of the United States. It is often found growing alongside the related yellow birch, which is a closely genetically related species. Efforts to cross the black birch and yellow birch have been successful, though the hybrid generation has low vigor and low seed germination rates.

Black birch trees are classified as intolerant of shade and in densely populated areas where there is no access to sunlight, the trees will succumb to competition. Black birch are also susceptible to fire damage. However, the black birch is not very susceptible to winter killing and is moderately resistant to drought. Specifically, the black birch is fairly resistant to glaze (ice) in comparison to other hardwood species of the northern hemisphere. Ice damage usually causes death of black birch by making the tree more susceptible to wood decaying organisms. Several species fungi and leaf-feeding insects attack the black birch and can cause decay and/or disease, ultimately proving lethal. The most important fungi include white trunk rot (Phellinus igniarius), yellow cap fungus (Pholiota limonella), and Nectria canker (Nectria galligena), while the most prevalent leaf-eating insects include birch tubemaker (Acrobasis betulella), birch skeletonizer (Bucculatrix canadensisella), oriental moth (Cnidocampa flavescens), gypsy moth (Lymantria dispar), and dusky birch sawfly (Croesus latitarsus).

Black birch has many commercial uses. At one point, the black birch was the only source of oil of wintergreen, an essential oil known for its antibacterial, antifungal, antiviral, insecticidal, and antioxidant properties. The wintergreen oil (methyl salicylate) is distilled from the wood of the black birch. Today, the use of the black birch for essential oil has declined as synthetic oil products have gained popularity. The hard, heavy lumber and veneer of bark is used commercially (furniture, cabinets, boxes, woodenware, handles). Not only is the wood valuable for its hardness, but when air it darkens to a color resembling mahogany and, in times past, was used as an inexpensive substitute for mahogany. An additional commercial use for the black birch is paper; paper pulp from the black birch is used in conjunction with paper pulp from other species to produce various types of paper products (e.g. boxboards, newsprint paper, paper towels, etc.).

Phenology: 
Staminate catkins form on the black birch in late summer or autumn. After growing to about ¾ of an inch, they open in the spring. Pistillate catkins form alongside leaves and are present on the ends of short, spurlike branches. In April and May, flowers open. From mid-August to mid-September, seeds ripen and are housed in erect strobili. They fall from mid-September to November, and in natural conditions will normally germinate the following spring.
References: 

Betula Lenta Fact Sheet. (n.d.). Virginia Tech, Department of Forest Resources and Environmental Conservation. http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=11

Department of Horticulture, (n.d.). Sweet Birch. University of Kentucky Department of Agriculture, Food, and Environment. http://www.uky.edu/hort/Sweet-Birch.

Division of Forestry. (n.d.). Black Birch Betula lenta. Ohio Department of Natural Resources. http://forestry.ohiodnr.gov/blackbirch.

Flora of North America. 2012. Betula lenta Linnaeus [family BETULACEAE]. In: JSTOR Global Plants. https://plants.jstor.org/stable/10.5555/al.ap.flora.fna003_betula_lenta?searchUri=filter%3Dname%26so%3Dps_group_by_genus_species%2Basc%26Query%3Dbetula%2Blenta

Go Botany. (n.d.). Betula lenta L. New England Wild Flower Society. https://gobotany.newenglandwild.org/species/betula/lenta/.

Lamson, N.I. 1990. Betula lenta L. Sweet Birch. Silvics of North America. Department of Commmerce, Bureau of the Census, Center for Demographic Studies. https://www.na.fs.fed.us/spfo/pubs/silvics_manual/Volume_2/betula/lenta.htm

Northern Research Station. (n.d.). Sweet birch (Betula lenta). United States Department of Agriculture Forest Service. https://www.fs.fed.us/nrs/atlas/tree/372.

Prabuseenivasan, S., Jayakumar, M., Savarimuthu, I. 2006. In vitro antibacterial activity of some plant essential oils. BMC Complementary and Alternative Medicine 6: 39.

The Morton Arboretum. (n.d.). Sweet birch. The Morton Arboretum. http://www.mortonarb.org/trees-plants/tree-plant-descriptions/sweet-birch.

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