CONEY ISLAND - The Coney Island boardwalk won't be made of boards for much longer as the city approved a plan to revamp the summer hot spot. The Public Design Commission voted Monday night to start replacing stretches of wooden planks with plastic and concrete materials. Parks Department officials say they stopped using tropical wood in 2008 to help preserve the rainforests and have been in need of a replacement. More than three dozen Coney Island and Brighton Beach residents turned out in protest of the vote. They argued the traditional boardwalk will become nothing more than a large sidewalk. Members of the Boardwalk Alliance say the changes will take place between Brighton 15th Street and Coney Island Avenue. Parks Department officials say the amusement area will remain untouched.