The Great East Japan Earthquake occurred on March 11, 2011 and the coastal zones along the Pacific Ocean in Tohoku area have received severe damage by tsunami. Most of coastal forestations have been severely damaged or swept away due to a gigantic tsunami. In this paper, historical background of coastal forestation was studied by detailed literature surveys. An instructive formula was developed between damage level of houses and a distance from coastal forestation by field investigations at the coast of Sendai plain. Furthermore, damage level of houses was clarified as a function of inundation depth of tsunami with influence of a housing code.
