Laboratory experiments were performed to study wave transmission and wave reflection capacity of circular Cylinders as coastal protection from waves. The energy dissipated in circular cylinders may be evaluated by using the drag forces acting on the cylinders and wave particle velocities. A theoretical analysis based on application of the continuity and energy equations to flow through the rows of circular cylinders were made to evaluate wave transmission and wave reflection capacity of mangroves and trees in coastal area. The reflection coefficient Kr is significant for large value of the ratio of the circular cylinders area to the unit bed area in the array of circular cylinders. The theoretical analysis were also made to evaluate wave transmission and wave reflection capacity of mangroves in coastal area. The significant wave reflection from mangroves with large and dense canopy was estimated.
