Commentary Par XXVI 85-90

This is an at least somewhat puzzling simile, equating Beatrice with a gust of wind, forcing the top of a tree down from its normal inclination upward.  It then goes on to equate Dante with that treetop, regaining its natural upward direction once the gust has blown itself out.  The meaning is plain, but the negative associations that surround Beatrice seem strange; nonetheless, the positive ones that accompany Dante's desires to do something of which Beatrice approves eventually govern our understanding.