Multiple Air layers on tree

All'
I have a Sweetgum that was donated to me this year. It's outside out my needs for size (too Straight and tall 48") and would like to air layer it in several sections along the main trunk. ???? Can I layer the tree simultaneously along the trunk without loss on the higher layers?
Thanks,
KJ

You will have the most success if there is a direct connection between the tree above the airlayer and roots. This generally means one airllyer per trunk/stem at a time. The reason for this is to insure the portion above the airlayer receives plenty of water from the roots. You may be able to do more than one at a time if you leave enough xylem at each cut for really good water transport. However, the problem is that not cutting into the xylem very far often results in leaving some of the phloem which then leads to bridging and minimal root formation. If you decide to do more than one airlayer at a time along the trunk, I would apply a really tight girdling wire (perhaps 2 wraps) at the top of the area where the bark was removed to constrict any remaining phloem.