mugo pine vs pine tree

mugo pine and pine tree both are nouns.

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

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

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

Other hypernyms of mugo pine include pine, true pine.

mugo pine (noun)	pine tree (noun)
low shrubby pine of central Europe with short bright green needles in bunches of two	a coniferous tree