red alder vs Oregon alder

red alder and Oregon alder both are nouns.

Word	Noun	Adjective	Verb	Adverb
red alder	Yes	No	No	No
Oregon alder	Yes	No	No	No

As nouns, red alder and Oregon alder are synonyms defined as:

red alder and Oregon alder: large tree of Pacific coast of North America having hard red wood much used for furniture

Other synonyms of red alder include Alnus rubra.

red alder (noun)	Oregon alder (noun)
large tree of Pacific coast of North America having hard red wood much used for furniture	large tree of Pacific coast of North America having hard red wood much used for furniture