yellow spruce vs Picea rubens

yellow spruce and Picea rubens both are nouns.

Word	Noun	Adjective	Verb	Adverb
yellow spruce	Yes	No	No	No
Picea rubens	Yes	No	No	No

As nouns, yellow spruce and Picea rubens are synonyms defined as:

yellow spruce and Picea rubens: medium-sized spruce of eastern North America; chief lumber spruce of the area; source of pulpwood

Other synonyms of yellow spruce include eastern spruce, red spruce.

yellow spruce (noun)	Picea rubens (noun)
medium-sized spruce of eastern North America; chief lumber spruce of the area; source of pulpwood	medium-sized spruce of eastern North America; chief lumber spruce of the area; source of pulpwood