eucalyptus tree vs eucalyptus

eucalyptus tree and eucalyptus both are nouns.

Word	Noun	Adjective	Verb	Adverb
eucalyptus tree	Yes	No	No	No
eucalyptus	Yes	No	No	No

As nouns, eucalyptus tree and eucalyptus are synonyms defined as:

Other synonyms of eucalyptus tree include eucalypt.

eucalyptus tree (noun)	eucalyptus (noun)
a tree of the genus Eucalyptus	a tree of the genus Eucalyptus
	wood of any of various eucalyptus trees valued as timber