Tree Carnegiea gigantea [Saguaro] Arms form only after the plant reaches 50 or 60 years old. Plants may live 200 years. The ribs expand or contract depending on the amount of water being stored. Found mostly on gravelly slopes. Gila woodpeckers make their homes in the trunk. Young plants need protection from sun. Transplant readily but more difficult with older plants. State flower of Arizona. Protected. Must be transplanted from construction site. Transplant with same orientation to sun as…