I have air layerd a branch here or there but my trees i feel are not large enough for that yet. but next year who knows. here is my question. if you have a tree can you air layer the main possibly the only trunk. cut it from the tree leaving a fig stump and the stump grow again. or will doing this sacrifice the one. may seem silly but id like to know.

My first propagation was from a cutting taken by cutting the trunk (only one) and both the cutting and the stump flourished.  The decision to cut the trunk came from frustration with the tree not growing.  I cut it and the stump grow three trunks 5+ feet tall and had a bumper crop of figs, all in the same season.  I was prepared to sacrifice the tree  but ended up stimulating it instead.

I think, if there is at least one node left, it will put out branch and grow again. But, I haven't tried to know for sure.

Ok thats nice to know. i am putting in a small orchard. i want 15 varieties and at least three trees of each selected variety. some of them i may only be able to get one of. so if this works it will help alot.

Don't air-layer all the way to the ground. If it is a single trunk tree, the lower portion will most likely sprout new growth even before the airlayer is rfooted and removed.

Thanx Jon

Many trees have winter die-back to the ground or pretty darn near it and they come back!  I think that is why the conventional wisdom of planting the fig tree several inches deeper in the ground then the nursery pot it came in.  With part of the trunk protected it may insure new growth if the tree does die-back.