This paper aims at the 3D extension of a ray-tracing based model for radiowave propagation in the presence of trees and vegetation areas. The original propagation model uses the point scatterer formulation to characterize the electromagnetic behavior of trees present in the simulation scenario, providing a relatively good trade-off between complexity and model accuracy. To this extent, 3D re-radiation measurements of various tree specimens and groups of trees, mimicking trees with different thickness, were performed in a controlled environment, inside an anechoic chamber, at 60 GHz. The experimental data obtained from such measurements was subsequently used to modify and enhance the original point scatterer formulation, to include 3D propagation phenomena predictions. Finally, the proposed 3D propagation model was assessed against the 3D re-radiation measurements, providing relatively good agreement between both measured and predicted results was, for the entire angular range of the re-radiation sphere.