Following on from my first set of thumbnails for the forest, it was clear from the feedback that I needed to make it more unique and less generic. As I'm going for a 1950s/classic style, I looked at some old cartoons and looked at how the settings, or backgrounds, were stylised. I noticed a trend in that they looked like they were done with water colour paint alongside very sketchy lines. I, therefore, drew out some forests in a similar sketch style, on paper, and then used some water colour brushes that I downloaded for Photoshop to give them the classic look.
I am quite happy with these, as they do have that style to some degree, but the overall composition of the forests are still quite original. They do look quite friendly environments though, and I think the 2D aspects of the character will work well with the background.