and is significantly related to distance (Figure 3). All 92 exponential regression equations of five research areas with different mangrove forest species are highly significant with P values of < 0.001 and R2 > 0.95. The exponential reduction of wave height in mangroves can be explained by the dense network of trunks, branches and above-ground roots of the mangrove trees, increasing bed roughness, causing more friction and dissipating more wave energy (Quartel et al. 2007).