Shakespeare used the term ‘under the greenwood tree’ as a generalised evocation of the pastures and forest of Tudor England, which was largely rural at that time.
Thomas Hardy used the expression as the title of a 1872 novel of rural life. Hardy followed the Bard’s lead in that the novel is set in an anonymous pastoral forested scene, somewhere in the fictionalised county of Wessex. Hardy did in fact locate most of his stories in the real county of Dorset and adapted real place names to suit his stories. Avid readers enjoy matching the fictional places with real towns and villages – the primary location being, in the stories, Casterbridge and, in reality, Dorchester. That being said, most Victorian readers would have taken ‘under the greenwood tree’ to be, as Hardy intended, an unidentified English Acadia.