Flora of Oosima-gun, Yamaguti Prefecture

The Oosima-gun (Oosima County)consists of Oosima Island and its adjacent islets, and is the easternmost islands of Yamaguti Prefecture. It is located in the Suonada Sea and composed chiefly of volcanic rocks. The main island, Oosima or Yasirozima, is highly mountainous and its highest point is Mt. Kanozan (659.3 m). The rivers and plains are very scarce. The coast-line is much iniented ani furnishes excellent harbours for fishing boats. The annual mean temperature is 16.6 °C, and the annual rainfall is 1621.0 mm. The region is much warmer than other places of the prefecture ani the snow very rarely falls. According to the Koziki (the first official record of Japansse history) the island Oosima has been known from the era of Izanagi-no-Mikoto as oni of Ooyasima (main eight islands). In the medieval period the people of the islands went abroad on their ships far to Korea, China and South Sea region, and made commercial communication with foreign countries. The population is extremely high in density, and a great number of the inhabitants imigrated into foreign countries such as North America or South America. The area is well utilized for agricultural purposes, and even the hillside is all cultivated nearly up to the summit. The primary forests are unable to be recognized, and small areas of virgin or subvirgin forests are rarely found in the precincts of the Shinto Shrines. The types of the virgin or subvirgin forests are various, and the line-transect survey was dene by the writers. The list of plants found wild or cultivated in the Oosima-gun is mentioned at pages 270-309.