Leaf's departure was because she needed an excuse to find the world of her own.
Wind- comes and goes freely. It may be a strong gust of wind that carries leaf away from tree but how long can wind carry her along his journey?
Leaf was carried away by wind but was also left alone by wind.
Without wind's pursuit or without tree asking her to stay, one day, leaf will also detach herself from tree. Not because of wind, but because she wants to grow into something more...
***The ending of the story of tree, leaf and wind is up to us...***