birch (v.) Look up birch at Dictionary.com
"to flog," 1830, from the noun in the sense "bunch of birch twigs used for flogging" (1640s); see birch (n.). Related: Birched; birching.
birch (n.) Look up birch at Dictionary.com
"hardy, slender northern forest tree noted for its white bark," Old English berc, beorc (also the name of the rune for "b"), from Proto-Germanic *berkjon (source also of Old Saxon birka, Old Norse börk, Danish birk, Swedish and Icelandic björk (which is also a girl's given name), Middle Dutch berke, Dutch berk, Old High German birihha, German Birke), from PIE *bhergo (source also of Ossetian barz, Old Church Slavonic breza, Russian bereza, Lithuanian beržas, Sanskrit bhurjah, all names of birch-like trees, Latin fraxinus "mountain ash"), from root *bhereg- "to shine; bright, white," in reference to the bark. Birch beer is by 1827, American English.