To achieve this with standard tools you would:
1: make flat green tree forms - "dem plywoods." These dominate the theme of the work.
2: Render the scene normally.
3: Since the buildings are quite basic - no distracting details - they lend themselves to a "posterized" look where subtle gradations of color are eliminated. Matte, cartoonish material selections.....
4: This can be done with any finished Archicad image in Photoshop by applying a Photoshop filter "Posterize," where the number of colors in a scene can be reduced.
Dwight Atkinson