swamp ash vs ash tree

swamp ash and ash tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
swamp ash	Yes	No	No	No
ash tree	Yes	No	No	No

As nouns, ash tree is a hypernym of swamp ash; that is, ash tree is a word with a broader meaning than swamp ash:

swamp ash: small ash of swampy areas of southeastern United States
ash tree: any of various deciduous pinnate-leaved ornamental or timber trees of the genus Fraxinus

Other hypernyms of swamp ash include ash.

swamp ash (noun)	ash tree (noun)
small ash of swampy areas of southeastern United States	any of various deciduous pinnate-leaved ornamental or timber trees of the genus Fraxinus