Cost of potential emerald ash borer damage in U.S. communities, 2009-2019

Emerald ash borer (Agrilus planipennis Fairmaire), a phloem-feeding beetle native to Asia, was discovered near Detroit, Michigan and Windsor, Ontario in 2002. As of March 2009, isolated populations of emerald ash borer (EAB) have been detected in nine additional states and Quebec. EAB is a highly invasive forest pest that has the potential to spread and kill native ash trees (Fraxinus sp.) throughout the United States. We estimate the discounted cost of ash treatment, removal, and replacement on developed land within communities in a 25-state study area centered on Detroit using simulations of EAB spread and infestation over the next decade (2009-2019). An estimated 38 million ash trees occur on this land base. The simulations predict an expanding EAB infestation that will likely encompass most of the 25 states and warrant treatment, removal, and replacement of more than 17 million ash trees with mean discounted cost of $10.7 billion. Expanding the land base to include developed land outside, as well as inside, communities nearly double the estimates of the number of ash trees treated or removed and replaced, and the associated cost. The estimates of discounted cost suggest that a substantial investment might be efficiently spent to slow the expansion of isolated EAB infestations and postpone the ultimate costs of ash treatment, removal, and replacement.