mountain birch moun·tain·birch uncommon noun 1. birch of western United States resembling the paper birch but having brownish bark Synonymsswamp birchwater birchmountain birchWestern paper birchWestern birchBetula fontinalis Related words Broader terms birch Parts Betula WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
