Well, if you drag the wind arrow at a non zero time, you should see awind keyframe in the timeline, so you could play with the wind parameter a bit, and reset it to zero wind before the end of the animation, so the geometry could get back into it's original shape at the end of the animation. Problem is I don't know how long it takes to get back to normal, and there's the breeze problem too. Breeze is either on or off, and you cannot act upon it, other than the breeze parameters in the wind tab of the atmosphere editor.
Maybe you could get away with it with the animation wizard. Select your tree, open the wizard, select a "loop" animation, without animating anything, and close the wizard. Then do as above and see if it really loops ( ease in/out) the whole thing.
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