swamp birch vs Western paper birch

swamp birch and Western paper birch both are nouns.

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

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

swamp birch and Western paper 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 birch.

swamp birch (noun)	Western paper 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