Scots pine vs pine tree

Scots pine and pine tree both are nouns.

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

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

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

Other hypernyms of Scots pine include pine, true pine.

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