A 19-year-old volunteer fireman in northern Alberta has been charged by RCMP with setting 18 fires, including the spectacular blaze that destroyed the wooden CN railway trestle at Mayerthorpe last Tuesday. Mayerthorpe Mounties said Lawson Schalm is in jail pending his court appearance Wednesday in Stoney Plain court. His father, Albert Schalm, a former mayor of the community, said his family is shocked by the development. Officials have been suspicious in recent weeks about possible arson in local fires. The destruction of the bridge will temporarily paralyse lumber and oil industry in the area.