Abstract
The forest on the Pacific coast of Tohoku was severely damaged by the tsunami triggered by the 2011 Tohoku Earthquake. The characteristics of the changes to the groundwater level must be clarified for the regeneration of a healthy coastal forest. Groundwater levels were observed in the coastal forest in Miyagino-ku, Sendai, Miyagi Prefecture in December, 2011 after the earthquake. Precipitation and groundwater level were low during the winter. The groundwater level was high during heavy precipitation in the rainy season and during typhoons from July to October. The monthly maximum groundwater level increased with increasing monthly precipitation. We estimated the monthly maximum groundwater level for the last ten years based on observations. The monthly maximum groundwater level was estimated to range from -0.73 to 0.30 m (mean: -0.46 m) in the area where pines were uprooted by the tsunami. This result suggests that a high groundwater level has influenced the development of the root systems. The pines on the embankment of the Teizanbori Canal escaped damage by the tsunami. The groundwater level at the embankment was estimated to range from -3.05 to -1.99 m (mean: -2.77 m). This result suggests that the embankment was the site environment that was able to develop healthy root systems.
