Aspen poplar and Poplar tree

Aspen poplar noun - A poplar that is widely cultivated in the United States; has white bark and leaves with whitish undersurfaces.

Poplar tree and aspen poplar are semantically related. In some cases you can use "Poplar tree" instead a noun phrase "Aspen poplar".

Poplar tree noun - Any of numerous trees of north temperate regions having light soft wood and flowers borne in catkins.

Aspen poplar and poplar tree are semantically related. Sometimes you can replace phrase "Aspen poplar" with "Poplar tree", this phrases are similar.