Larix decidua vs larch tree

Larix decidua and larch tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
Larix decidua	Yes	No	No	No
larch tree	Yes	No	No	No

As nouns, larch tree is a hypernym of Larix decidua; that is, larch tree is a word with a broader meaning than Larix decidua:

Larix decidua: tall European tree having a slender conic crown, flat needlelike leaves, and hairy cone scales
larch tree: any of numerous conifers of the genus Larix all having deciduous needlelike leaves

Other hypernyms of Larix decidua include larch.

Larix decidua (noun)	larch tree (noun)
tall European tree having a slender conic crown, flat needlelike leaves, and hairy cone scales	any of numerous conifers of the genus Larix all having deciduous needlelike leaves