Trees in cities can alter the wind field in and around buildings and thus impact the transport and dispersion of airborne contaminants in urban areas. In this paper, we describe modifications to forest canopy mean flow parameterizations and turbulence parameterizations in the Quick Urban & Industrial Complex (QUIC) wind and dispersion solvers. We compare measurements of mean velocity, turbulent kinetic energy, and the Reynolds shear stress within a forest canopy to model output using the new schemes. Using the Joint Urban 2003 Field Experiment held in downtown Oklahoma City, we show how trees in the urban core can alter air flow and plume dispersion.