When developing models to describe the early development of settled agriculture in the Near East, reconstructions of climate and vegetation are a subject of consideration. During the glacial period, it is thought that lower temperatures or higher aridity resulted in sparse or non-existent forest cover similar to steppe type terrain in the area of the Zagros Mountains and varying forest cover in the territories of modern-day Turkey and Syria. Northwest Syria, dominated in ancient times by deciduous oak, is thought to have been less arid between 10,000 BCE and 7000 BCE than it is today. Scholars believe that wild cereal grasses probably spread with the forest cover, out from the glacial refugia westward into the Zagros.