The mangrove structure index is classified into 5 levels of wave preven- tion based on its relation to wave height (Figure 6; Table 2). The required mangrove band width decays exponentially with the vegetation index (V). When the mangrove forest is tall and dense, and the canopy closure high (i.e. a high V index), a narrower forest band is required. When the mangrove forest is short, the tree density and canopy closure low (i.e. a low V index), a wider mangrove band is required.