I've actually been looking into this quite a bit lately, and I'm surprised to say there are not any good options out there. It seems every software suite has severe limitations.
Basically, I'm are looking for something that satisfies most of these requirements:
-integrates into 3ds max (no Speedtree, no xfrog)
-comes with a wide variety of ready-made trees or offers a catalog of ready-made trees (no growfx)
-integrates with forest pro
-provides easy animation via wind force
Basically, I would love a plugin/program that I can choose from a large library of ready made trees (like HQ Plants), drop a few into my scene, animate with wind, and let Forest Pro do the proxy/scatter/render work. I have no desire to design or create my own trees, I just need something that can animate them a bit easier.
Correct me if I'm wrong, but I just can't find anything that accomplishes this. Maybe TreeStorm does, but I've called Onyx and can't even demo the software.