western larch vs Larix occidentalis

western larch and Larix occidentalis both are nouns.

Word	Noun	Adjective	Verb	Adverb
western larch	Yes	No	No	No
Larix occidentalis	Yes	No	No	No

As nouns, western larch and Larix occidentalis are synonyms defined as:

western larch and Larix occidentalis: tall larch of western North America have pale green sharply pointed leaves and oblong cones; an important timber tree

Other synonyms of western larch include Oregon larch, western tamarack.

western larch (noun)	Larix occidentalis (noun)
tall larch of western North America have pale green sharply pointed leaves and oblong cones; an important timber tree	tall larch of western North America have pale green sharply pointed leaves and oblong cones; an important timber tree