That's a LOT of work. Plus, to make it look good, you'd have to cover up most of the work you'd done already.

So instead, I'm gonna do some C&C on your tree.

You've got the general idea of a tree, but I think your colours are off. Aside from common belief, most trees tend to have more gray than brown. At least that's what I've been told time and time again.

Also, your tree branches go from thick to nothing in almost no time at all. Add some smaller branches and twigs off of the main ones.

One more thing. All of your branches are coming from the front of the tree. Add a few coming out the back. Maybe.

As for the leaves, I've not come across a good way to do it.