I'm basing my trees off maple trees because of the seasonal colour variation present in maple trees. I started by making a leaf model using a photo texture. I then placed this around a branch which was also based from a photo. This was baked down to create a new texture for my typical branch. Note that the leaf colour will be controlled through the shader.
Baking offers me a few benefits, chiefly I have been able to apply random colour to the leaves as well as create a suitable texture for their growth. This will help me with my seasonal falling off and regrowing.
I then applied this texture to a plane. I had arranged for gaps in the texture which allowed me to cut the plane up into sections to break the shape of the branch into something which looked good from a variety of angles.
I then used a combination of hand-arranged groups and object painting to populate the following tree.
It is only at this stage that I became aware that I would need more leaves on the texture. Sitting at 11,000 triangles, I cannot reasonably afford to populate the tree with more leaves by placing more planes. So I hope to add more leaves to make the tree seem fuller and reduce the triangle count to around 8,000.
This will make the planes a little more obvious but should improve render time (by having more full cards, there will be less overdraw and fewer triangles so less alpha sorting and less overdraw)