Scotch pine vs pine tree

Scotch pine and pine tree both are nouns.

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

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

Scotch pine: medium large two-needled pine of northern Europe and Asia having flaking red-brown bark
pine tree: a coniferous tree

Other hypernyms of Scotch pine include pine, true pine.

Scotch pine (noun)	pine tree (noun)
medium large two-needled pine of northern Europe and Asia having flaking red-brown bark	a coniferous tree