Abstract
The Elaeocarpus-Ardisia mesic forest at the Sekimon Region in Haha-jima Island is regarded as a remnant of the original vegetation in the Ogasawara (Bonin) Islands. However, most Morus boninensis trees were selectively logged until the World War II, and a large number of M. boninensis stumps occur in the remnant forests of this region. To clarify the ecological characteristics of M. boninensis, we examined the spatial distribution of stumps and living trees of M. boninensis in the Sekimon Region. Most of the scattered stumps were identified with M. boninensis on the basis of wood anatomical and material characteristics. The spatial distribution of the stumps indicated that M. boninensis rarely occurred in the Aridisia-dominant forest on the eastward slope of Mt. Sekimon, and the distribution of M. boninensis was limited to the Elaeocarpus–Ardisia mesic forest on Ueno-dan (flat plain). M. boninensis trees made up the canopy layer with 8.1–11.9 trees/ha, which is almost equal to the currenct density of Celtis boninensis and Melia azedarach in the Elaeocarpus–Ardisia mesic forest. These characteristics suggested that M. boninensis was one of the important canopy species of the original Elaeocarpus–Ardisia mesic forests before logging.
