An advanced model for radio wave propagation in vegetated urban areas is proposed. The new model is based on uniform theory of diffraction (UTD) and so appropriate for numerical calculation. We have recently proposed a new UTD-based model for multiple diffractions by buildings and in this paper we have endeavored to extend the new model to involve tree effects. We have supposed that apart from the high-rise urban core, a city’s buildings are of nearly the same height and spacings and are organized by street systems into rows. In addition, trees are assumed to be situated adjacent to the buildings. The canopies of trees are modeled as discrete ensembles of leaves and branches. It is revealed that the new model including tree effects provides reasonable and convincing predictions.