It's a simple suggestion, Just add a texture for Rubber leaves into the block_0.png texture sheet so that it's not pulling the texture from the fast oak texture.
I play with everything but leaves on fancy, and It just bugs me to death that the only tree that doesn't conform is the rubber trees. So I think it would be great for people who do texture support (like myself) to have seperate textures for fast/ fancy leaves, or have it switch the texture from the terrain.png when you switch from fast to fancy graphics.