I tried my first airlayer with Alma as my victim,  It's rooted but I think I changed my mind about severing it.  Can I just knock off the roots and let it remain tall?  
The donor plant is the healthiest looking sapling I have.  It's somehow benefiting from the suspended bag of spagnum moss.

Thanks, Soni

Sever!  Tough Love!  You will have two trees, and you will have to prune in winter anyway! 

If you don't want to cut it or layer it, youc ant just take off the bag and moss the roots will dry up and it will be fine.

 I have a couple sapling Almas.  I havnt seen Alma on anyone's wish list  lol.     Does anyone want one? 

Will it be really be fine?  If it was girdled all the way around, haven't you effectively cut off the flow of nutrients and water between the upper part of the tree (the air layer) and the main tree?  Isn't the air layer fooled into making roots so those roots can supply water up to the leaves?  If you knock the roots off (and it is girdled), isn't the top of the tree doomed?
Maybe the answer is different depending on how the branch was prepped (fully girdled, partly girdled, roughed up, no prep at all)???
Jim

If you want to leave it on the tree, you will need to do some bridge grafting to rejoin the bark, if you girdled it before starting the air layer.

Sorry, I didn't realize you have girdled it, I get lazy sometimes and do not girdle, Jon gave you the right information.

Soni didn't say if he girdled it or not. If he didn't, and doesn't want to cut it, don't ... and do what Chivas said. If he did fully girdle it (360*) as opposed to just a few nicks or cuts or nothing, than it will have to be removed ... or the branch will be lost when the mix and roots in the air-layer dries. Or grafted as Jon said, which sounds like a lot of extra work.

I didnt lay a finger on it.  I just wrapped a plastic cup full of spaghnum moss around a node.  Unless the new roots girdled itself It has had no a wound on it.
( I'm a she), Soni is short for Allesandra

Bridge grafting sounds amazing.. I'm learning a LOT here
 .

Soni: Then you just remove the sphagnum moss and all the roots, the tree will be fine. Thanks for sharing.

Best,
Tam