Ok, I've been poking at the Yinfara landscape model that JFT made and came up with a plan of what can go where in the way of plants.
Here's a color coded map I made.
http://lontahv.googlepages.com/color_coded_yinfara_map2.jpg
Alright I'll admit it, the key for it is kind of crude and slapped-together and hard to understand, but... I hope you get the idea.
The main idea is to have the bulk of the island be covered in jungle--this gives some nice exploring and also, it makes it so there don't have to be as many multi-color Yinfara-trees which makes them more special. The idea for the Yinfara-trees at the peaks of the mountains/hills is that there will be more lighting up there and maybe a different climate. Up there will seem kind of like "Up there" ie. you have to be feeling adventurous to want to go up there. The storms would be more often and more powerful. This is the exact reason why the trees have such interesting properties.
Justin, if you don't like any aspect of it, just let me know and I'll change it.
Everyone else: Feedback, feedback, feedback. We need as much of it as we can get.
Lontahv