Results from numerical simulations of neutral, turbulent flow over small forested hills using a first-order turbulence closure model are presented. The presence of the hill drives a strong mean flow into and out of the forest canopy. Such a flow would not be predicted by the more common roughness length parametrization of a forest. This can lead to an increase in the predicted drag caused by the hill, increased flow separation and increased transport of gases and other tracers between the forest canopy and the atmosphere. Preliminary results for large-eddy simulations (LES) show very similar features. The use of LES however allows a more detailed study of the turbulence within and above the canopy and are useful in validating the first-order closure scheme