In Hambantota, southern Sri Lanka, we implemented a survey of the damage-mitigating effect and the endurance of the Casuarina coastal forest against the Indian Ocean tsunami that occurred in December 2004. The tsunami struck by passing over the Casuarina forest on the front dune (height of 5.5 m above sea level), but it was unable to pass over the next dune (height of 5 m); therefore, private houses on the inland side of that dune were not damaged. In contrast, in the shallow trough produced by excavation of part of the dune, the tsunami passed over the front dune (height of 3.5 m) and through the Casuarina forest; it destroyed private houses 250m from the shoreline. Although the Casuarina trees growing on the high dune were not damaged, 57% of the Casuarina trees that were directly hit by the tsunami on the trough withered after it passed. However, few tree trunks were broken during the tsunami, so it was suggested that the Casuarina forests had been able to withstand the physical impact of the tsunami.

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The purpose of this study is to examine the mitigating effects of the mangrove growing on the lagoon shores and near the estuary (not facing the open sea) in Medilla area on the 2004 Indian ocean tsunami. The research methods consisted of a geodetic survey and interviews about the conditions at the time of the tsunami and the damage caused by it. A comparison of the Mangrove Area and Flat Area in Medilla revealed that the distance from the coast and the height from sea level were the same; however, the direction of the propagation of waves, damage caused to buildings, and degree of the deposition of surface soil differed. Thus, it was confirmed that in the case of a tsunami, mangrove forests can mitigate the intensity of waves and reduce the inflow of earth and sand

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To clarify the present conditions of vegetation and the impact of volcanic activity on succession of the vegetation on lava flows resulting from eruptions of Mount Sakurajima, we installed vegetation survey plots on the Showa and Taisho lava flows that erupted from Mount Sakurajima in1946 and 1914, respectively. We conducted field investigations in 2008. Most of the trees in the plots on the Showa and Taisho lava flows invaded since 1999, during a period of low volcanic activity. The numbers of trees and tree species, and the Fisher-Wiliams'index of diversity on the Taisho lava flow were greater than those on the Showa lava flow. The physical properties, including the number of bacteria, of the soil on the Taisho lava were better than that the soil on the Showa lava flow. Moreover, comparing 2008, when vegetation on the Showa and Taisho lava flows suffered a severe impact from volcanic activity of not less than 50 year, with1964, when vegetation on the Showa and Taisho lava flows was only slightly impacted by volcanic activity, the vegetation succession in 2008 was much slower than that in 1964.

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This study analyzed slope failure recurrences and the process of revegetation in the riparian zone of the Kushira River Basin, Kagoshima Prefecture. We used data from aerial photographs and a vegetation survey. Spatial distribution of slope failure scars and tree ages in the study area were analyzed using data from nine sets of aerial photographs taken in 1947, 1966, 1974, 1980, 1984, 1989, 1994, 2000 and 2006, respectively. This analysis revealed that many slope failures occurred on steeps lopes, and that vegetation downstream of a steep slope was inundated by slope failures, debris flows and floods frequently, and vegetation with different tree ages had distributed in a patchy state in the riparian zone of the Kushira River Basin. The number of trees and tree species peaked about 20 - 30 years after an inundation by slope failures, debris flows and floods, and then declined with time. About 60 year after an inundation, an apparent fixed value was achieved. Total volume of tree trunks showed a tendency to increase after reaching a fixed value of the number of trees and tree species at about 60 year after an inundation. Moreover, the dry density of topsoil declined with time after an inundation.

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We investigated on the status of biological flora and land utilization characteristics of the coastal sand dune areas of Ohsan and Dongho locations, Gangwon-do in Korea, and then examined about their management plan. A total of 68 species including 30 families and 60 genus for vascular plants and a total of 35 species including 10 branches, 23 families for inland insects were recorded, respectively. On the other hands, it was revealed that ratio of land occupation as artificial facilities such as unmanaged bare land, housing units, roads and schools has been increased greatly in recent years. Therefore, in order to restore and control the coastal sand dune area, it is considered that an utilization plan considering the land suitability together with the sand dune preservation accompanied by planting and civil works shall be suggested.

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A disaster relief shelter is an important public service but many people are not aware of when and how local relief shelter operates. The purpose of this study is to investigate the circumstances under which the Uwajima City relief shelters operate and to determine the level of public awareness on the Uwajima City shelters. As a result of the investigation, it became clear that the Uwajima City municipal government makes decisions about where and how the shelter operates, public awareness of the shelter island, and that only one district has the ability to provide shelter and security for all the district inhabitants.

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This paper is a summary of the outline of the result report association that did as part of the Grant-in-Aid for Science Research, “ Verification of the effects of coastal forests against the 2004 Indian Ocean Tsunami and the ideal concept for the conservation of coastal area ” on November 30, 2008. The report association was composed of a topic offer, a result report and an integrated discussion, and opinions were exchanged by the specialist in various fields.

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