A great earthquake hit the Tohoku District, eastern Japan, on March 11th 2011. This Great East Japan Earthquake including great tsunami that followed claimed the lives of about 20,000 people, though we made best possible prediction and preparation for natural disasters with full use of the newest science and technologies. Tide prevention forests of pine trees alone did not serve the purpose, but not a tree from the local potential natural vegetation fell in the earthquake and the tsunami. In order to survive in such flat areas, it is essential to build high coastal levees with native forests of indigenous tree species. Most of the debris from disaster areas is ecologically an earth resource. After removing poisonous materials, debris should be utilized to make well aerated mounds along the 300 km-long coasts of disaster areas. Saplings of native tree species with fully developed root systems are planted mixed and densely on the mounds. They will grow to form tsunami-preventing native forests a "Great Wall of Forests". This afforestation on embankments should spread as a government project and a national movement.