@ajillustrates
firstly i think you rendered the picture just fine and i looks really nice.
I just wondered if he is kneeling in the water, because it looks odd like this, being above the water. You could push this a bit more though.
Also i took a look at some pictures of palmtees and where an how they grow. mostly you find single palmtrees on a beach and a palmtreewood in the jungle but since you can see the background it doesnt align wit the beach look or the jungle look.
In order for the Water to be in this cave it runs down or in the same level of the floor and you are looking a little bit from above in the cave, so i would think the level of the background vulcano/Hills isn't right.
Maybe it's just me but it doesn seem to fit.