This lecture was delivered at New College, Oxford on 10th May 1999. It focuses on the presence and meaning of trees within the Greek landscape, raising questions as to how much of the land was forested, and how the ancients viewed and used trees, such as for fuel, in building domestic structures, temples, ships and boats. Rackham draws on the written sources of the time, with references found in poetry, philosophical works and inscriptions, and on `field evidence'.