Хотя бы из Вики. "Birch sap is a traditional beverage in the Russian Federation (Russian: берёзовый сок, translit. byeryozovyi sok) as well as Latvia (Latvian: bērzu sula), Estonia (Estonian: kasemahl), Finland (Finnish: mahla), Lithuania (Lithuanian: beržo sula, beržų sula), Belarus (Belarusian: бярозавы сок, translit. biarozavy sok, Byarozavik), Poland (Polish: sok z brzozy, oskoła), Ukraine (Ukrainian: березовий сік, translit. berezovyi sik), France, Scotland, Norway[3], Sweden[4] and elsewhere in Northern Europe[1] as well as parts of Northern China. It is also widely used among the Pennsylvania Dutch, either as a traditional beverage in its own right but particularly as a key ingredient in birch beer.[5]"Но читала про Скандинавию в других источниках, сейчас не найду так сразу.