poplar vs poplar tree

poplar and poplar tree both are nouns.

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

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

poplar and poplar tree: any of numerous trees of north temperate regions having light soft wood and flowers borne in catkins

poplar (noun)	poplar tree (noun)
any of numerous trees of north temperate regions having light soft wood and flowers borne in catkins	any of numerous trees of north temperate regions having light soft wood and flowers borne in catkins
soft light-colored non-durable wood of the poplar