Pinus glabra vs pine tree

Pinus glabra and pine tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pinus glabra	Yes	No	No	No
pine tree	Yes	No	No	No

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

Pinus glabra: large two-needled pine of southeastern United States with light soft wood
pine tree: a coniferous tree

Other hypernyms of Pinus glabra include pine, true pine.

Pinus glabra (noun)	pine tree (noun)
large two-needled pine of southeastern United States with light soft wood	a coniferous tree