Category: Medicines - plant based
Introduction and description
Betula lenta (sweet birch, also known as black birch, cherry birch, mahogany birch, or spice birch) is a species of birch native to eastern North America, from southern Maine west to southernmost Ontario, and south in the Appalachian Mountains to northern Georgia.
Betula lenta was used commercially in the past for production of oil of wintergreen before modern industrial synthesis of the oil; the tree's name reflects the wintergreen scent of the shoots.
The sap flows about a month later than maple sap, and much faster. The trees can be tapped in a similar fashion, but must be gathered about three times more often. Birch sap can be boiled the same as maple sap, but its syrup is stronger (like molasses).
Betula lenta is a medium-sized deciduous tree reaching 25 m (82 ft) tall with a trunk up to 60 cm (2.0 ft) diameter.
In younger trees the bark is characteristic of most birches, with smooth bark and distinct horizontal lenticels. It is sometimes mistakenly identified as a cherry tree. In some older tree specimens the bark can (unlike most birches) develop vertical cracks into irregular scaly plates revealing rough darkish brown bark patterns. This, however, does not occur in all specimens.
The twigs, when scraped, have a strong scent of wintergreen due to methyl salicylate, which is produced in the bark.
The leaves are alternate, ovate, 5 to 10 cm (2.0–3.9 in) long and 4 to 8 cm (1.6–3.1 in) broad, with a finely serrated margin.
The flowers are wind-pollinated catkins 3 to 6 cm (1.2–2.4 in) long, the male catkins pendulous, the female catkins erect.
The fruit, maturing in fall, is composed of numerous tiny winged seeds packed between the catkin bracts. Seed production mainly occurs in trees that are between 40 and 70 years old, although light crops may occur as early as 20 years. The average lifespan of B. lenta is 100 years, with a maximum of 150.
Betula lenta's leaves serve as food for some caterpillars (see List of Lepidoptera that feed on birches) and the solitary leaf-cutter bee Megachile rubi cuts pieces from the leaves to line the cells of its nest.
Much of the medicinal interest in this tree revolves around the methyl salicylate, which is produced in the bark, along with both betulin and betulinic acid. These chemicals together have shown antiviral activity against herpes, flu and HIV amongst other viruses.
They have the added value of being analgesic and anti-inflammatory, antiradicular [pain relieving], and counterirritant.
The bark also shows Antibacterial activity, with betulinic acid showing promising Antimalarial [IC50=19-26 ug/ml ] and Antiplasmodial activity.
The woodsman's diary [internet]
Make a cold infusion with Black/Sweet Birch. Betula lenta, was used by the Cherokee Indians; a bark and/or twig tea was traditionally used to treat bladder infections, digestive problems, gout, and kidney stones. It was used for sore muscles and pain relief as well. It has a very intense wintergreen smell when the fresh twigs are snapped. I’ve been keeping a steady “Old Man Work Trade” batch of Sweet Birch, chaga (Inonotus obliquus) and coffee on the wood stove to drink throughout the day
For more details see the observations.
- Dr Duke's list of Chemicals and their Biological Activities in: Betula lenta L. (Betulaceae) -- Cherry Birch 019503
- Dr Duke's list of Plants with Herpetifuge activity 019494