pine vs pine tree

pine and pine tree both are nouns.

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

As nouns, pine and pine tree are synonyms defined as:

Other synonyms of pine include true pine.

pine (noun)	pine tree (noun)
a coniferous tree	a coniferous tree
straight-grained durable and often resinous white to yellowish timber of any of numerous trees of the genus Pinus

pine (verb)	pine tree (verb)
have a desire for something or someone who is not present