In ancient Hawaii, chiefs managed the economy by creating a land division system, the Ahupua'a, which divided the islands into pie slice shapes. Each Ahupua'a covered the three main regions of the islands: the mountains, the valleys, and the beach. This system was designed to allow all Hawaiian communities equal access to the limited natural resources of the islands. However, it took a lot of time and energy to gather and grow all these resources, which were often spread out over great distances and located at different elevations. Many Hawaiians began to specialize in fishing and farming, and soon there was a need for Hawaiians to trade with one another to receive items they were no longer growing or gathering for themselves.