There are an estimated 8 billion ash trees in the United States[7] – the majority being white ash trees and green ash trees.[8][9][10][11] White ash trees are threatened by the spread of the invasive emerald ash borer (Agrilus planipennis), whose larvae kill ash trees.[1] It was detected in Detroit, Michigan in 2002, and later found in eastern Canada and the majority of U.S. states.
^Griffith, Randy Scott (1991). "Fraxinus americana". Fire Effects Information System (FEIS). US Department of Agriculture (USDA), Forest Service (USFS), Rocky Mountain Research Station, Fire Sciences Laboratory. Retrieved 9 May 2018.
^Gucker, Corey L. (2005). "Fraxinus pennsylvanica". Fire Effects Information System (FEIS). US Department of Agriculture (USDA), Forest Service (USFS), Rocky Mountain Research Station, Fire Sciences Laboratory. Retrieved 9 May 2018.