What you are seeing is correct for that tree. Even without branch seam smoothing (see below), that tree would have 3 draw calls on the highest LOD, and 2 after that (caps are usually dropped with the first LOD).
Any material that gets atlassed can be batched together when the geometry has the same wind shader. So caps and fronds can be batched together. Leaves are batched together.
The only weird thing you are seeing is branch seam smoothing. Branches with the same material are batched together. But when branch seam smoothing is enabled on the material, a small piece of geometry at the base of the branch is broken out to be rendered separately with two texture lookups to do the blending. When you imported the tree, though, you didn’t select the branch seam smoothing option in the import dialog, so basically those materials ended up the same. If you don’t want branch seam smoothing, then disable it on the material in the modeler and that little ring of geometry on each branch won’t be broken out.
EDIT: branch seam smoothing is also usually dropped with the first LOD