Ah, yes! That is indeed the barrier I was speaking about! It looks different on the Wingly side... in the game, though, she can hear/sense the presence of Winglies from the Human side of it. Humans just can't because, well, they're not Winglies. ^^;;

The Wingly side looks like this: the opening of the cave on the left side. I always imagined the mouth of the cave having that same green glow that is shown in the picture you linked.

But, yes! Having it between some of the trees in the forests would be perfect! She would totally freak at seeing it there, looking just like it does back in Endiness. XD