Aokigahara jukai is an ancient forest stretching over the northwest base of Mount Fuji in Yamanashi. The forest grows on a lava plateau generated by lava flowing out from Mount Nagao, which erupted halfway up Mount Fuji. It is called Jukai (Forest Sea) because the trees as viewed from above look like a rolling sea. In Jukai there are many old-growth coniferous trees, such as hemlock and Japanese cypress, that have lived 330 to 360 years. They are all covered with moss, which supply water necessary for their growth.