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Emerald ash borer

Megan Walton, Neil Broshears, Alex Eades, and Amanda Hendricks
Conservation Biology, BIO 342, Biology Department, DePauw University
Spring semester 2008

The emerald ash borer is an invasive species of beetle that is native to Asia.  It was accidentally introduced to North America in wooden shipping crates in 2002.  The emerald ash borer feeds on the phloem of ash trees and lays its eggs underneath the bark.  This activity cuts off the water supply to the tree and eventually causes death of the tree.  This poses a threat to the ecosystem and economy of the areas affected.  We investigated whether or not the emerald ash borer has arrived in the DePauw Nature Park.  We also predicted the potential impact of the emerald ash borer on the ash tree population in the Nature Park. 

We set up 50 plots in randomly selected locations in two forested areas of the DePauw Nature Park.  Each plot was 0.04 hectares in size with an 11.3 meter radius.  We measured height and diameter of all trees within each plot.  We counted the number of saplings and shrubs within a 5 meter radius of each plot.  We checked ash trees for evidence of emerald ash borer invasion.  Evidence includes D-shaped holes, vertical splitting of bark, epicormic shoots on the trunk, and defoliation of the canopy. 

Ash trees comprised 4 percent of the trees in our plots.  Ash saplings comprised 8 percent of the saplings and shrubs in our plots.  We found no evidence of the emerald ash borer infestation on the ash trees. 

Since ash trees comprise only 4 percent of the forests in the DePauw Nature Park, we conclude that the emerald ash borer will not have a detrimental effect on the forest composition.  We suggest that future studies be conducted to investigate the presence of the emerald ash borer in the DePauw Nature Park.  We also suggest that future studies include data collection in residential areas because ash trees comprise a greater proportion of trees in these areas.