Jersey elm vs elm tree

Jersey elm and elm tree both are nouns.

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

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

Jersey elm: a variety of the English elm with erect branches and broader leaves
elm tree: any of various trees of the genus Ulmus: important timber or shade trees

Other hypernyms of Jersey elm include elm.

Jersey elm (noun)	elm tree (noun)
a variety of the English elm with erect branches and broader leaves	any of various trees of the genus Ulmus: important timber or shade trees