Flora of Heigun Island, Yamaguti Prefecture

Heigun Island is located between Yasirozima ans Yasima in Suonada Sea, and the area of the island is 18.34 sq. km. It is chiefly composed of pyroxene andesite, and tuff or conglomerate is occasionally found. The annual mean temperature is roughly 17℃., and the annual rainfall is 1600 mm. The island is higyly mountainous and the highest point is 460m. The streams and plains are very scarce. The coast-lune is rather indented. The inhabitants is 3111, male being 1580 and famale 1531. The paddy field is 6.1 hectares and the crop field is 19.2 hectares. The forest is 109.1 hectares and the grassland is 3.8 hectares in area. The type of the forests of the island is almost secondary, and the forests of Pinus thunbzrgii are predominant. The primary forests are unable to be recognized at present. According to the writers' survey the original forest should be the forest of Cinnamamum japonicum or Machilus thunbzrgii associated with certain broad-leaved trees. The higher plants found wild in the island are 290 species, as listed on pages 278-289. The plants belonging to Betulaceae and Ericaceae are not found in the island.