Morois, Morris, Morroiz
Tristan and Isolde lived there for a time, at the Wise Damsel’s Rock, after an escape from execution at Mark’s court. Isolde eventually went back to Mark, through the hermit Orgin’s mediation (in Beroul) or Mark’s kidnapping (in the Prose Tristan). Tristan roamed the forest of Morrois during his period of madness.
In another adventure, King Mark sent Kay and Gaheris into the forest for an “adventure” – in truth, Mark intended to kill them by the Perilous Lake, but he was unsuccessful. Morrois has been identified with locations in Cornwall and Scotland. Malory places it near Tintagil Castle in Cornwall.
Probably Morris would stretch roughly between Tintagil and Bodmin Moor; possibly it would even take in Bodmin Moor, accommodating Dozmary Pool as the Perilous Lake of Morris. I have read the statement somewhere that Cornwall has no trees, but that is not quite true; it does have some littel wood areas, and would have had more in Arthurian times.