The islands were found to be completely uninhabited, and their colonization by the Portuguese began around 1420 or 1425. To get the minimum conditions for the development of agriculture, they had to cut part of the dense forest and to construct a large number of canals ("levadas") to carry water, since in some parts of the island there was excess water, while in others water was scarce. During this period, fish constituted about half of the settlers' diet, together with vegetables and fruits cultivated from small pieces of land. Initially, these colonists produced wheat for their own subsistence, but later the quantity cultivated was sufficient to begin sending wheat to continental Portugal.