cassia bark vs cassia-bark tree

cassia bark and cassia-bark tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
cassia bark	Yes	No	No	No
cassia-bark tree	Yes	No	No	No

cassia bark (noun)	cassia-bark tree (noun)
aromatic bark of the cassia-bark tree; less desirable as a spice than Ceylon cinnamon bark	Chinese tree with aromatic bark; yields a less desirable cinnamon than Ceylon cinnamon