balsam poplar vs poplar

balsam poplar and poplar both are nouns.

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

As nouns, poplar is a hypernym of balsam poplar; that is, poplar is a word with a broader meaning than balsam poplar:

balsam poplar: poplar of northeastern North America with broad heart-shaped leaves
poplar: any of numerous trees of north temperate regions having light soft wood and flowers borne in catkins

Other hypernyms of balsam poplar include poplar tree.

balsam poplar (noun)	poplar (noun)
poplar of northeastern North America with broad heart-shaped leaves	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