Flood insurance premiums for Coeur d’Alene’s Fort Ground neighborhood could rise astronomically if the city doesn’t cut down the trees growing on the dike road levee, the city’s engineer warned Monday. Thwarting the Army Corps of Engineers’ order to remove the trees could result in the Fort Grounds being classified as within the 100-year flood plain, City Engineer Gordon Dobler said Monday. If that happened, homeowners would have to pay thousands of dollars each year for flood insurance, he said. In addition, Coeur d’Alene would have difficulty insuring its wastewater treatment plant and North Idaho College couldn’t insure its campus at face value, Dobler said.