The archipelago's original vegetation is Valdivian temperate rainforest, a forest with a very dense understory and a large diversity of plant species, including many mosses and ferns. The western and southern portions of the island are still largely covered by the native forest. Notable species include arrayán ("Luma apiculata"), roble ("Nothofagus dombeyi"), quila ("Chusquea quila"), Chilean rhubarb, and the avellano ("Gevuina avellana"). "Fitzroya cupressoides" and tepú ("Tepualia stipularis") grow in the poorly drained soils of the Piuchén and Pirulil ranges. Before the end of the Llanquihue glaciation, the southern parts of Chiloé Island constituted open landscapes. This changed around 12,500 years ago when the climate became warmer and forests colonized the region. The upper portions of Cordillera del Piuchén, locally known as "la Campaña", has a Magellanic moorland vegetation.