We investigated the damage of mangroves by the 2004 Indian Ocean tsunami at Banda Aceh, Indonesia. We clarified that no mangroves could have survived in the west of Banda Aceh affected by more than 10m height of tsunami, although more than 50% of mangroves with 20-25cm stem diameter could have survived in the east of Banda Aceh affected by 5-7m height of tsunami. We simulated the 2004 Indian Ocean tsunami to investigate the impact on mangroves. Based on our field observation and numerical simulation, we estimated the destruction limit of mangroves using the relationship between the stem diameter and computed-tsunami bending moment. Furthermore, we evaluated the potential mitigating effect of mangroves at Banda Aceh using the numerical model with the destruction limit considered.
