bluejack oak vs oak tree

bluejack oak and oak tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
bluejack oak	Yes	No	No	No
oak tree	Yes	No	No	No

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

bluejack oak: small semi-evergreen shrubby tree of southeastern United States having hairy young branchlets and leaves narrowing to a slender bristly point
oak tree: a deciduous tree of the genus Quercus; has acorns and lobed leaves

Other hypernyms of bluejack oak include oak.

bluejack oak (noun)	oak tree (noun)
small semi-evergreen shrubby tree of southeastern United States having hairy young branchlets and leaves narrowing to a slender bristly point	a deciduous tree of the genus Quercus; has acorns and lobed leaves