mountain pine vs true pine

mountain pine and true pine both are nouns.

Word	Noun	Adjective	Verb	Adverb
mountain pine	Yes	No	No	No
true pine	Yes	No	No	No

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

mountain pine: low shrubby pine of central Europe with short bright green needles in bunches of two
true pine: a coniferous tree

Other hypernyms of mountain pine include pine, pine tree.

mountain pine (noun)	true pine (noun)
low shrubby pine of central Europe with short bright green needles in bunches of two	a coniferous tree
tall pine of western North America with stout blue-green needles; bark is grey-brown with rectangular plates when mature
evergreen tree of New Zealand resembling the kawaka