I think that if the resolution were decreased in the greens it may look more like a fairly level ground cover. The highlights in contrast to the darker tiles make some areas look quite high. But I really like your aesthetic and direction with this project.
This is really great work. I think Ettrick is right with regard to the fact that it could use some re-sizing. (although while I was looking at it I came up with 2 or 3 adventure hooks based on giant spiders and a very steamy jungle...) Keep up the incredible work I'm avidly watching :)
I really like what you are doing so far with this project, and I'm very excited about the idea itself! I want to put some particularly elvish ruins in my campaign, along with current elven construction (villages and towns built into the trees), so this concept is dear to my heart. I thought your concept sketches were pretty cool.
Will be watching this thread to see how your project progresses!