swamp birch vs Western birch

swamp birch and Western birch both are nouns.

Word	Noun	Adjective	Verb	Adverb
swamp birch	Yes	No	No	No
Western birch	Yes	No	No	No

As nouns, swamp birch and Western birch are synonyms defined as:

swamp birch and Western birch: birch of western United States resembling the paper birch but having brownish bark

Other synonyms of swamp birch include Betula fontinalis, mountain birch, water birch, Western paper birch.

swamp birch (noun)	Western birch (noun)
birch of western United States resembling the paper birch but having brownish bark	birch of western United States resembling the paper birch but having brownish bark