Most of North Sulawesi is mountainous, with extensive uplifting and faulting, and it has many active volcanoes. The coastal lowlands are narrow, the soils are fertile, and there are coral reefs offshore. The uplands are drained by many fast-flowing streams, including the Milango and the Marsa. The highlands are covered with rainforests of oak, chestnut, and various conifers; hillslopes have teak, ebony, and a dense ground cover of grasses and shrubs.
