Scotch fir vs pine tree

Scotch fir and pine tree both are nouns.

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

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

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

Other hypernyms of Scotch fir include pine, true pine.

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