From Sonic Retro
Green Tornado was Espio's original Tornado Jump technique that was discovered through ASM hacking in Sonic Heroes. The developers of the game decided to replace the tornado jump technique with Leaf Swirl (which allows Espio to turn invisible).
Unlike Shadow's and Sonic's tornado abilities, his tornado does not attract him to enemies. Also, the voice clips to it were also unused as the technique wasn't used.
On the E3 build, the leaves from Leaf Swirl emit at the center of the Tornado.