Try not to call when they are in the tree... Maybe a tree yelp or two.
As mentioned above, if hens are near I might try to get that tom on the ground with a fly-down cackle, or call to the hens in hopes of aggravating the dominant hen to come in...
I have also set up on one bird (that fly down with hens early) and done a fly-down to a further bird (still in the tree), and had success previously. That was the only time I have had a bird actually fly into me (and he was some distance away).
Normally, once on the ground, if they are coming my direction on their own, I stay quiet until they change coarse... If they are headed a different direction, right off, I will get a bit more aggressive, and maybe even try gobbling with some aggressive hen cutting.