Effects of emerald ash borer (Agrilus planipennis) induced ash mortality on forest soil microenvironments

With the introduction of the emerald ash borer (Agrilus planipennis Fairmaire) (EAB), there has been an increase in ash (Fraxinus spp.) mortality throughout eastern deciduous forests. Forest disturbances caused by EAB have resulted in an increase in coarse woody debris (CWD) as well as the formation of light gaps within forest canopies, altering the soil microenvironment. This accumulation of ash snags and decaying woody debris by EAB may increase habitat heterogeneity in forest ecosystems, potentially providing more essential resources for the soil invertebrate community. To better understand how EAB induced ash mortality influences the forest floor microenvironment, the presence of light gaps and CWD were investigated at the NASA Plum Brook research station located southeast of Sandusky, Ohio. Eight blocks containing four plots were manipulated for the presence or absence of light gaps and CWD. Each block included an experimental plot containing light gap present with CWD (+/+), light gap present without CWD (+/-), light gap absent with CWD (-/+), and light gap absent without CWD (-/-). Abiotic soil characteristics (e.g. temperature, pH, moisture) were determined as well as total C and N to assess the changes in soil microenvironment in the presence and absence of light gaps and CWD. Canopy gaps were measured with a densiometer to determine percent canopy closure. Decomposition rates were assessed for each experimental plot using mesh bags filled with a homogenized sample of forest litter. Differences between abiotic soil characteristics and decomposition rates were found based on the presence of light gaps and CWD.