western hemlock vs Pacific hemlock

western hemlock and Pacific hemlock both are nouns.

Word	Noun	Adjective	Verb	Adverb
western hemlock	Yes	No	No	No
Pacific hemlock	Yes	No	No	No

As nouns, western hemlock and Pacific hemlock are synonyms defined as:

western hemlock and Pacific hemlock: tall evergreen of western North America; commercially important timber tree

Other synonyms of western hemlock include Tsuga heterophylla, west coast hemlock.

western hemlock (noun)	Pacific hemlock (noun)
tall evergreen of western North America; commercially important timber tree	tall evergreen of western North America; commercially important timber tree