Overstory Effects of Emerald Ash Borers (EAB) on a Riparian Forest

Abstract

Agrilus planipennis (Emerald Ash Borers) (EAB) are an invasive beetle from Asia that discovered in the USA in 2002 and have decimated Fraxinus (ash) forests throughout the country. The ash trees of Stevenson University in Owings Mills, MD have not been spared from EAB infestation. This research study sought to understand how important ash trees are to the overall local forest, how EAB have affected those ash trees and the forest habitat, and considered ways to restore the forest because of EAB infestation. Trees and canopy cover were surveyed in 5 randomly placed plots throughout a 6-hectare section of riparian forest. Individual ash trees were examined for EAB exit holes and status rating. This study found that ash trees are the most important tree in the forest but with spatial variation. Majority of the ash trees are dead with signs of EAB infestation, but canopy openness does not correlate with EAB ash infestation. There are opportunities for future studies that could be conducted on the local forest with our data as a starting point. One potential study could analyze the genome of the four living ash trees that were found. Restoration options include planting already present non-ash tree seedlings in certain plots to restore the canopy, injecting the 4 living ash trees in plot 4 with insecticide, and releasing non-native parasitoid wasps to reduce EAB populations. We could also collect and mail seeds from the living ash trees to a US Forest Service project in Ohio to preserve and understand EAB-resistant ash trees. From this study, we learned how important Ash trees are to Stevenson’s ecosystem and that the ash population has been severely affected by EAB infestation.