The Arboretum d'Olhain (2 hectares) is an arboretum located in the Forêt Domaniale d'Olhain near Olhain, Fresnicourt-le-Dolmen, Pas-de-Calais, Nord-Pas-de-Calais, France. It is open daily without charge.
References
Arboretum d'Olhain Wikipedia(Text) CC BY-SA