red elm vs elm tree

red elm and elm tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
red elm	Yes	No	No	No
elm tree	Yes	No	No	No

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

red elm: North American elm having rough leaves that are red when opening; yields a hard wood
elm tree: any of various trees of the genus Ulmus: important timber or shade trees

Other hypernyms of red elm include elm.

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

red elm: autumn-flowering elm of southeastern United States
elm tree: any of various trees of the genus Ulmus: important timber or shade trees

Other hypernyms of red elm include elm.

red elm (noun)	elm tree (noun)
North American elm having rough leaves that are red when opening; yields a hard wood	any of various trees of the genus Ulmus: important timber or shade trees
autumn-flowering elm of southeastern United States