pistachio tree vs nut tree

pistachio tree and nut tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
pistachio tree	Yes	No	No	No
nut tree	Yes	No	No	No

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

pistachio tree: small tree of southern Europe and Asia Minor bearing small hard-shelled nuts
nut tree: tree bearing edible nuts

pistachio tree (noun)	nut tree (noun)
small tree of southern Europe and Asia Minor bearing small hard-shelled nuts	tree bearing edible nuts