Plant xylem water samples were collected from Cornus drummondii (rough-leaf dogwood), Andropogon gerardii (big bluestem), Quercus macrocarpa (bur oak), and Quercus muehlenbergii (chinquapin oak) during the summer of 2016. Soil cores were also collected during the summer of 2016 to collect soil water from the surface to 200 cm depth. Isotope values (δ18O and δ2H) were analyzed for each water sample to determine depth of plant water uptake.