Rough, black basalt stones compose its shoreline and surface in many places, though the soils (where present) are rich. The island appears to be covered in nearly unbroken vegetation; inhabited areas feature large gardens and managed forests above, with coconut and cacao plantations usually closer to shore. There are no reliable sources of surface water (rivers, streams, or lakes), save the crater lakes which are inaccessible. Water for all human uses comes from cement-lined wells or water tanks filled with rainwater.