The technique used here was simply to apply 'puff ball' trees directly to the backdrop. While the puff ball trees have much less intricate detail than the 'Super Tree' kits, they work well as backdrop trees, mounted behind the foreground trees. Instead of an obviously amateurish painted forest canopy, now viewers see real, three dimensional forest canopy, with a distant painted hill to appear miles away.
This is much more pleasing to the eye than the scene in the link above, right? I'm pleased at how this came out, and will model all additional shallow scenes in the same way. My eye is fooled by the backdrop and my focus goes to the railroad.
I had to play with some black & white imaging in Photoshop - I'm very happy how this looks now.
And, finally, for you locomotive fans, here's a shot of recently-finished C40-8W 6155 sitting at Onondaga Yard. This is an Atlas model I purchased used. I have added a DCC sound decoder and a few details, along with weathering, and now the 6155 can join the fleet. I was never much of a fan of Quality-painted Dash-8 W's, but they do make a pleasing model of a 'plain Jane' unit that was a regular in the Syracuse area.
Here comes the autumn!