The Pinus thunbergii coastal forest in Misawa, Aomori Prefecture, Japan, was partially damaged by the 2011 Tohoku Earthquake tsunami. The forest extended 110-370 m from the beach, and the tsunami reached a residential area 440 m from the beach. The height of the tsunami was 7.4 m above the beach. Trees within 200 m of the beach were felled by the tsunami. The inundation depth of the tsunami was 4.2 and 1.8 m at 150 and 370 m from the beach, respectively. Tree size, crown height and forest age increased from the sea inland. The mean diameter at breast height (DBH), mean height, mean crown height, and forest age of the forest stand 180 m from the beach were smaller than those of the forest stand 212 m from the beach. The density of stems in the forest stand at 180 m was greater than that at 212 m. In conclusion, the increase in DBH caused by self-thinning with aging is important for tsunami resistance. From a management perspective, increasing diameter growth by thinning is important.

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The Pinus thunbergii coastal forest in Misawa City of the Aomori Prefecture was partially damaged by the 2011 earthquake tsunami, which occurred off the Pacific coast of Tohoku. Using the numerical simulation of the inundation flow caused by the tsunami, we investigated the cause of the partial damage and the mitigation of the inundation flow by the coastal forest. The results of the numerical simulation showed that the maximum inundation depth and maximum discharge flux at the inland edge of the coastal forest were reduced by the coastal forest and the tree damage index, which was calculated as the ratio of the turning moment to the section modulus at the stem base, accounted for the approximate distribution of the damage to the coastal forest.

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Using ALOS data, this study analyzed the damage to the Arahama coastal forest in Sendai caused by the tsunami that followed the Great East Japan Earthquake on March 11, 2011. The satellite data used, was ALOS/AVNIR-2 data and ALOS/PALSAR data. Analysis of the tsunami damage indicated that the NDVI for coastal forest without fallen trees tended to be lower than before the tsunami damage. By comparing NDVI images from before and after the tsunami prepared using AVNIR-2 data, we analyzed the state of fallen trees in the coastal forest. As a result, the area of the standing trees after the tsunami was measured by NDVI images. The backscattering coefficient for the coastal forest tended to be lower overall after the tsunami compared to before. This study found that the NDVI images based on optical satellite data were more effective for assessing tsunami damage to wide areas of coastal forest.

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The purpose of this study is to examine how much the existence of the coastal forest influenced the grade of the house damage caused by the 2011 off the Pacific coast of Tohoku Earthquake tsunami. The research methods consisted of a geographic survey and damage grade investigations of the building by a foundation survey and aerial photos. A comparison of the area which had the coastal forest in the coast and the area which didn't have it revealed that the level in both areas were flat and the height from sea level and the height of the tsunami were the same, however the damage caused to buildings differed. Thus, the mitigating effects of the coastal forest against the tsunami were examined. The ratio of complete collapse in the area as the coastal forest where the distance from the coast was same was high. Therefore, it has been interpreted as existence of the coastal forest having prevented the damage of the building, and generating of rubble. And it is an important consideration matter in the plan of the development and maintenance of the coastal forest and the overall community including the coastal forest that the damage of the building at the side end of the coastal forest was serious

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The 2011 off the Pacific coast of Tohoku Earthquake Tsunami surged through the Pinus Thunbergii coastal forest of Ichikawa-cho, Hachinohe City in Aomori Prefecture with about T.P.(Tokyo Peil) +7-8 m (4 m above ground). The tsunami height in the forest was presumed to be about T.P.+7.0 m (3-4m above ground). The tsunami moved drifts such as fishing boats (20 or more) into the coastal forest. The fishing boats etc. mowed down much of the coastal forest, but were eventually stopped and did not reach the residential area to its rear. In other words, the coastal forest demonstrated a catching drift function. Conversely, the coastal forest sustained larger damage based on the scale of the tsunami than suggested by existing knowledge, which indicated the significant influence of the drift. In addition, although the width of the coastal forest was considered sufficient, it was actually insufficient depending on the direction in which the fishing boats flowed.

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In order to clarify the effect of temporal forest development on shallow landslide prevention, we examine the recurrence of shallow landslides and recovery of shallow landslide prevention owing to temporal forest development. The study is for slopes in coastal areas of the Aira Caldera western wall in Kagoshima Prefecture, Japan. Aerial photographs taken in 1947, 1962, 1965, 1966, 1967, 1969, 1974, 1981, 1989, 1992, 1993, 2000, 2001, 2004 and 2005 were interpreted. A total of 110 shallow landslides were detected in the study area. These landslides were found to have occurred not only on previously unaffected slopes, but also on slopes subjected to prior shallow landslides. Many of these landslides had areas no more than 400 m², and were on slopes with inclinations in excess of 30 degrees. Moreover, the greatest number of shallow landslides occurred at altitudes between 100 m and 200 m. The number and area of these landslides for 20 years of tree age or less were between 1.5 and 76 times greater than for 20 years of tree age or more. The increase in landslide prevention attributed to temporal forest development on coastal-area slopes of the Aira Caldera western wall reduces the frequency of shallow landslides and their resultant debris flows, protecting coastal forest and coastal ecosystems

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