It's interesting and certainly a beautiful color use. However I'm not really seeing it in your example. I chose big leaves because I feel they are attractive; I am looking for Secret of Mana art style, not the same Secret of Mana tree types if you know what I mean. It's gorgeous and I'd like to see your final product if you're ever interested. Still, I am sticking with big leaves for this tree.
Okay, so I revamped it a bit and here's what I've come up with:

I changed the colors a little to something I felt a little more asthetically pleasing. I decided to add some branches near the leaves to make it look more unified. I continued the trunk upward as well to make it look like a whole tree. Now I need help with shading it a lot.