Looks like a tree hooked on halucinogyns. 

I don't know the answer, but I assure you that if you give this thread a day or so some very knowledgable people will help you out.  Sorry I couldn't help.

Just an idea though, since I don't do animation work, would there be a way of controlling the various parts of the tree growth?  For example, are your current settings effecting both the trunk and the branches?  If so, could you restrict the tree growth just to the branches and leaves?
Just an idea.....