Aoshima Shrine: Vegetation
Aoshima is almost entirely covered in subtropical forest. The most common tree on the island is the evergreen biro or fountain palm (Livistona chinensis), which has been identified with Aoshima for centuries. Some of the approximately 5,000 biro trees are up to 350 years old. The biro can grow up to 15 meters tall and produces small white or yellow flowers in spring, and its green fruit ripen and fall to the ground in late autumn. Its fan-shaped leaves were prized in the Heian period (794–1185), when biro leaves from Aoshima were presented to the court in Kyoto. These were used to cover carts pulled by oxen, to protect the nobles and high-ranking officials riding in them from the elements. Why the biro grows on Aoshima but not on mainland Miyazaki is not entirely clear, but two theories have been put forth. One suggests that seeds or trunks may have drifted to the island from the south on the Japan Current, which flows northeast along the Pacific coast of Japan. The other proposes that the biro is native to Aoshima and a survivor of a time millions of years ago, when the local climate was much warmer than it is now.
Among the 225 other kinds of plants on Aoshima, noteworthy species include the poisonous kuwazuimo (Alocasia odora) taro, the white hamayu (Crinum asiaticum) spider lily, which blooms in summer, and the sharinbai (Yeddo hawthorn; Rhaphiolepis umbellata), a small shrub that is traditionally boiled to produce a dyeing agent. Visitors may also be able to spot the higiri (Japanese glorybower; Clerodendrum japonicum), a shrub that is usually about 2 meters tall, whose bright red flowers bloom from early summer to early autumn; the futokazura (Piper kadsura) pepper vine, whose berry-like fruit turn orange in late autumn; and the tabunoki (Machilus thunbergii), a type of broad-leaved evergreen bay tree that can reach a height of 30 meters and towers above the biro forest, which it predates.