in addition to their beauty, these trees contribute valuable ecosystem services. as of june 2016 the emerald ash borer, an invasive beetle from asia, has been found in thunder bay and has the potential to kill every ash tree in the city. in order to determine the economic risk the university is facing, an analysis was completed to determine the value and annual contributions of the ornamental ash on thunder bay campus. three methods: the leaf benefits calculator, the national tree benefits calculator (ntbc), and the i-tree my tree benefits calculator were used to estimate the annual contributions from the trees. values of the trees were also calculated using the basic method. the cost of removal, replacement, and treatment with treeazin was determined with the help of a local arborist. once all factors were calculated, an economic risk analysis was completed to determine the best plan of action for management of ash trees and the emerald ash borer. the only scenario which yielded positive benefits was the 100% treatment according to the ntbc. therefore, it makes economic sense to save the ash trees on campus.