Where does “brzózka” come from?

brzózka (Kashubian) comes from Polish brzoza, from Proto-Slavic bèrza, from Proto-Balto-Slavic berźas, from Proto-Indo-European bʰerHǵos — birch.

Ancestry of “brzózka”, step by step

StepLanguageWordMeaning
1Polishbrzozabirch
2Proto-Slavicbèrzabirch
3Proto-Balto-Slavicberźas—
4Proto-Indo-EuropeanbʰerHǵosbirch
Every word from Proto-Indo-European bʰerHǵos →Every word from Proto-Balto-Slavic berźas →Every word from Proto-Slavic bèrza →