Great suggestions, they give me some ideas. Perhaps the problem is the leaf and bark colors. I could go for a more black/silver bark it would probably be more accurate than the browner tones anyhow, and the blue green balance of the leaves is also up for some contrast with a brown/yellow green background. Part of the problem is I envisioned that several of these might exist in a stack to represent a multistory house, so the background on all but the first layer where the ground is still visible (and there is an entry) should realistically be more treetops, but I'm going to need that to be blurred and darkened to indicate that its below the current layer. This is easily the most problematic of the set so far, and I am torn between the fact that its a less common setting and its an interesting setting that sees fewer mapping attempts.