hackmatack vs poplar

hackmatack and poplar both are nouns.

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

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

hackmatack: 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 hackmatack include poplar tree.

hackmatack (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