Ash tree and Hoop ash

Ash tree noun - Any of various deciduous pinnate-leaved ornamental or timber trees of the genus Fraxinus.

Hoop ash and ash tree are semantically related. In some cases you can replace phrase "Hoop ash" with "Ash tree", this phrases are similar.

Hoop ash noun - Vigorous spreading North American tree having dark brown heavy wood; leaves turn gold in autumn.

Ash tree and hoop ash are semantically related. You can use "Ash tree" instead a noun phrase "Hoop ash".