How to make Background Trees

Foamboard painted green, fine, course and extra course ground foam white glued on leaving distant hills (smoother textured) visible. Pics from Google images were cut and glued to the flat to force perspective and increase the illusion of distance from the center of the diorama to the hazy horizon (lightly dusted with white paint from a spray can). If possible, use pics of actual buildings near your RR to link your model layout to its prototype.