Birch sap

[2] However, the wounds caused by tapping birches consistently lead to dark staining in the wood.

[2] Ancient Balts, Slavs and Finns regarded birch as one of their most sacred trees[3][4] and made a traditional beverage from it.

In Slavic regions the sap is known as birch juice as in Russia (Russian: берёзовый сок, romanized: byeryozovyi sok), Belarus (Belarusian: бярозавы сок, romanized: biarozavy sok, Byarozavik), Bulgaria (Bulgarian: брезов сок, romanized: brezov sok), Poland (Polish: sok z brzozy, oskoła), Slovakia (Slovak: brezová šťava), Ukraine (Ukrainian: березовий сік, romanized: berezovyi sik).

It is also widely used among the Pennsylvania Dutch, both as a traditional beverage in its own right, and particularly as a key ingredient in birch beer.

[17] Folk uses have been documented which include medicinal use, supplementary nutrition, and cosmetic applications for skin and hair.