Huntingdon elm vs elm tree

Huntingdon elm and elm tree both are nouns.

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

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

Huntingdon elm: erect vigorous hybrid ornamental elm tree
elm tree: any of various trees of the genus Ulmus: important timber or shade trees

Other hypernyms of Huntingdon elm include elm.

Huntingdon elm (noun)	elm tree (noun)
erect vigorous hybrid ornamental elm tree	any of various trees of the genus Ulmus: important timber or shade trees