Keep her on a leash in the yard.
Don't allow her to practice this behavior.
Work with her on doing something else in the yard, like flirt pole, tug, 2 ball, obedience. All on leash or long line.
eta: I would climb the tree and check out why she may be so interested, without her in the yard watching.
Last edited by David Winners; 12-29-2013 at 02:42 AM.