Where does “берест” come from?

берест (Russian) comes from Proto-Slavic berstъ, from Proto-Balto-Slavic berˀźtas, from Proto-Indo-European bʰerHǵ-tó-s, from Proto-Indo-European bʰerHǵós — birch.

берест (Russian): elm

Definitions

Ancestry of “берест”, step by step

Step	Language	Word	Meaning
1	Proto-Slavic	berstъ	elm
2	Proto-Balto-Slavic	berˀźtas	—
3	Proto-Indo-European	bʰerHǵ-tó-s	—
4	Proto-Indo-European	bʰerHǵós	birch

Every word from Proto-Indo-European bʰerHǵós →

берест — Etymology, Origin & Word History | Etymology Explorer