FAMILY: Betulaceae
SYNONYMS: B. capinefolia, cherry birch, southern birch, mahogany birch, mountain mahogany.
GENERAL DESCRIPTION: A graceful tree about 25 metres high which has a pyramidal shape while young. It has bright green leaves and a dark reddish-brown aromatic bark, which is broken into plates or patches.
DISTRIBUTION: Native to southern Canada and southeastern USA; produced mainly in Pennsylvania.
OTHER SPECIES: There are numerous species of birch, spanning several continents, such as black birch (B. nigra) found in North America. Not to be confused with the European white birch (B. alba), which produces birch tar oil used in chronic skin diseases.
HERBAL/FOLK TRADITION: The cambium (the layer directly under the bark) is eaten in the spring, cut into strips like vermicelli. The bark, in the form of an infusion, is used as a general stimulant and to promote sweating. As a decoction or syrup, it is used as a tonic for dysentery and is said to be useful in genito-urinary irritation. The flavour of wintergreen and birch bark, in the form of a tea, was popular with the American Indians and European settlers. More recently, this has been translated into a preference for ‘root beer’ flavourings.
ACTIONS: Analgesic, anti-inflammatory, antipyretic, antirheumatic, antiseptic, astringent, depurative, diuretic, rubefacient, tonic.
EXTRACTION: Essential oil by steam distillation of the bark macerated in warm water.
CHARACTERISTICS: Colourless, pale yellow or reddish tinted liquid with an intense, sweet-woody, wintergreen-like scent.
PRINCIPAL CONSTITUENTS: Almost entirely methyl salicylate (98 per cent), produced during the maceration process. It is almost identical in composition to wintergreen oil.
SAFETY DATA: Methyl salicylate, the major constituent, is not exactly toxic but very harmful in concentration.’ It can be absorbed through the skin, and fatal poisoning via this route has been reported.’. ’ It is also classed as an enviromental hazard or marine pollutant.
AROMATHERAPY/HOME: USE None.
OTHER USES: Limited use as a counter-irritant in anti-arthritic and antineuralgic ointments and analgesic balms. Limited use as a fragrance component in cosmetics and perfumes; extensively used as a flavouring agent, especially ‘root beer’, chewing gum, toothpaste, etc. (usually very low-level use).