yellow birch vs birch tree

yellow birch and birch tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
yellow birch	Yes	No	No	No
birch tree	Yes	No	No	No

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

yellow birch: tree of eastern North America with thin lustrous yellow or grey bark
birch tree: any betulaceous tree or shrub of the genus Betula having a thin peeling bark

Other hypernyms of yellow birch include birch.

yellow birch (noun)	birch tree (noun)
tree of eastern North America with thin lustrous yellow or grey bark	any betulaceous tree or shrub of the genus Betula having a thin peeling bark