I was looking at this tree, and thinking that they’d want to keep things as simple as possible for Animal Crossing in general, thought that they must have had a trick to making this. It looks a bit like loads of leaf planes, but wouldn’t that be overly complex for such a simple model?
One leaf is triangle/2triangles(quad), and there are quite a lot of them, boot look at root. Its too smooth to be low poly, i think its only stylized to be low poly.