loblolly pine vs pine tree

loblolly pine and pine tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
loblolly pine	Yes	No	No	No
pine tree	Yes	No	No	No

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

loblolly pine: tall spreading three-needled pine of southeastern United States having reddish-brown fissured bark and a full bushy upper head
pine tree: a coniferous tree

Other hypernyms of loblolly pine include pine, true pine.

loblolly pine (noun)	pine tree (noun)
tall spreading three-needled pine of southeastern United States having reddish-brown fissured bark and a full bushy upper head	a coniferous tree