The German army constructed Stützpunkt Pommern, filled the coast with mines and set up the beach with asparagus barriers. In German, they are called Rommelspargel, after Field Marshal Erwin Rommel. The wooden logs or steel rails were built to stop amphibious vehicles or ships. Moreover, a landmine was often mounted to it.
Erosion
The Rommelspargel had an unexpected side effect. Wissant Beach is subject to erosion, but during the Second World War, the logs appear to have held the sand, and the erosion stopped somewhat. After the mine clearance and the demolition of the Rommelspargel, the sand was quickly washed away again. As a result, after more than half a century, the bunkers were no longer in the middle of the dunes, but right on the beach.