My mother-in-law's mystery tree has one nice root about 1" in diameter that has a length completely above ground. The soil that was once covering it has washed away from a 4-5" section. Is it possible to "reverse air layer" this, causing a new trunk to form on the exposed section of root so I could snip it off? I just noticed it the other day and was wondering what I would need to do to get a new tree out of it.

I have a couple of traditional air layers started on it, but several family members are clamoring for their own chunk of the tree and I'm doing my best to satisfy them all.

Aaron

Try cutting the root without digging any of it up.  Perhaps make two cuts and make a gap of about an inch or so.  Earlier this year I moved a bunch of my pomegranate trees from a propagation area.  I cut the roots around the containers and moved the trees.  In most of the area, I turned the soil over and got the remaining roots out.  In the area I did not fully dig up, new shoots are growing up from a root left in place.

There have been many discussions over the years regarding growing trees from roots.  Most (including myself) have been unsuccessful in getting trees from left over or cut roots.  Perhaps, there is not enough energy in a segment of root to get something going.  I was going to start a thread about my tree growing from roots this weekend, but the cat is out of the bag.

~james

Sorry to steal your thunder! I was wondering if I should sever the root entirely or if maybe just nicking it would work better. The tree was supposedly planted in 1921-2 and has been in it's current location for over 40 years so losing this one root won't matter, but I figured I should consult the collective so I didn't squander my chance.

Might it be  possible, at a suitable time of year, to graft buds or branches onto the root at numerous locations?
I do not know.

Grant
z5b

A few days ago I started an informal "experiment" of trying to propagate from root stock.  I had dug up a tree (an inground one) that was in a bad location, and in the process broke some of the roots.  I wondered about propagating from pieces of root, so here's what I did:  I put four pieces of root in small pots.  Two were a little less than a centimeter diameter and 5-7 centimeters long.  One of these I put with about half a centimeter or root showing above soil (at one end), and the other all under the soil on its side (shallowest part about a half centimeter deep).  Both pieces had cuts in the root where they were severed (from the shovel, and from my shears).  The other two pieces are just tangles of small hairy root bits (and I don't have much hope for those, but what the heck, it didn't cost much time or material to include them in the test).  I used a mixture of peat moss and sand (about equal parts), mostly because I had it close at hand.  All four are in bright shade.  I'll keep the pots watered as I would a tree.  I realize this isn't a careful experiment with controls and such, but I just wanted to give it a try and see if it's possible to get a tree this way.  As the season progresses I'll report on what I see happen from it.  

I dont think that our fig trees have any nodes on the roots themselves, in all the root pruning of mine i have yet to see a node on their roots. I have tried growing small roots in moss, potting mix etc but they failed.
Also i always toss pretty large pieces that were sawed off fig tree from top of rootballs and bottom of rootballs and V shaped from sides of rootballs from various size container up to 30 gallon container and tossed them in garden, better than tossing in garbage and they never have grown in all the seasons i have done this.
Usually though its very cold out when there tossed in garden area .

But give it a shot worse thing nothing happens right ?
For it certainly will not harm that tree.

Thanks for the thoughts folks. I see Martin's point about there being no nodes on the root. I like Grant's idea of trying a graft. I've never attempted one before, but it seems like it might be a good opportunity to learn. This one is hard to root from cuttings so it is worth a chance.

if you cut the root off, with a small bit of trunk attached, you would have a better chance of having a bud that would sprout.

I have had roots alive and healthy for more than 2 years, after being severed from a pot, and have never seen a shoot form.

Aaron T....

Old bonsai-growers trick to induce rooting, and possibly awakening dormant buds....

On one end of the exposed section of the root, wrap a heavy copper wire, once around the root and tighten it like a tourniqet, and do the same at the other end, leaving a 4-5" blank space between the wires.  Some, but not all of the juices will be trapped from going and leaving the main trunk through that root, and new roots and buds may pop out of that section to "survive" the choke hold.  Once roots/If roots start growing, hope for a dormant bud to sprout out of that section of original root, and grow into a new stem, which will eventually become a new trunk.  After a few months of growing, or when the tree goes dormant, sever the root section and pot it up.  This will not hurt the original tree.

The process is gradual, and maybe it might work, in contrast to other more drastic methods.

Hope it helps.

Frank

You might also try some gibberelin in a cut on the root.  I haven't tried this, it's just a thought.