Air layered elm

[PierreR]

i figured I would try to air layer an interesting portion of trunk/branching from a wild Siberian elm this summer on a whim after the leaves hardened off.
Lookin at cutting it free, and potting now. My question, do I leave some/any branches (some will be near 6') or can I cut back to what I want to keep, essentially bare trunk? I am confident there are not enough new roots to support all the foliage that is on the branch. With elm, does the foliage drive root development or vise-versa?

 

[0soyoung]

In all trees, the foliage manufactures sugars by the process of photosynthesis - this is the sole source of real energy for the tree. This other, mythical energy is an expression analogous to the Sampson and Delilah myth. If a tree doesn't tolerate much root reduction, some say the strength comes from the roots; etc.

In general you want to have as much foliage as the roots will support - too much foliage can result in desiccation and death of the whole tree. I find elms somewhat difficult to root, but they will readily sprout again from nothing but a piece root. So, if I were you I would reduce the foliage dramatically when potting your layer.

 

[ConorDash]

Also would like to know more about this.
I separated my Chinese elm less than a week ago and its leaves are falling off all over the place, even green ones. I understand this may be normal as the tree adjusts to the separation and having to rely on its roots etc, but it'd be nice to clean it up at least by cutting back.

From what I know, I thought it best to completely not touch it for at least 6-8months, just let it do what it needs to do.
It has gone through trauma when being seperated and it is now putting a lot of energy in to root development. To also cut back branches and foliage, I feel that'd make it divert energy away from where it's needed.

 

[petegreg]

Foliage reduction helps after AL separation as Osoyoung mentioned. But careful, leave some green, so do some leaf/branch pruning, no chopping too deep. And I think it's a summer dormancy time and it has sth to do with expecting new growth.

 

[0soyoung]

It has gone through trauma when being seperated

There is very little trauma in separating an air layer. All that has happened is that the layer/explant must now depend solely on its own roots. In essence a layer is nothing more than a two step pruning

step 1 = sever the bark, phloem (inner bark), and cambium
step 2 = sever the xylem (wood)​

instead of happening all at once when simply pruned.

In principle one can subsequently grow roots on this cutting - it is just a race against time. The cutting doesn't have the mother tree to provide water, so one must make a humidity tent to keep it from desiccating in the process. There is some evidence that some cuttings root more readily if traumatized near the cut. In other words, the minor trauma of separation isn't a big deal.

 

[ConorDash]

There is very little trauma in separating an air layer. All that has happened is that the layer/explant must now depend solely on its own roots. In essence a layer is nothing more than a two step pruning

step 1 = sever the bark, phloem (inner bark), and cambium
step 2 = sever the xylem (wood)​

instead of happening all at once when simply pruned.

In principle one can subsequently grow roots on this cutting - it is just a race against time. The cutting doesn't have the mother tree to provide water, so one must make a humidity tent to keep it from desiccating in the process. There is some evidence that some cuttings root more readily if traumatized near the cut. In other words, the minor trauma of separation isn't a big deal.

Interesting. Thank you . I understand the separation simply means the top now relies on the new roots, but the transition of that from previously relying on the mother tree, does seem like a trauma to me, but I guess that is perspective. Of which, I don't have much with inexperience and you have more lol. So that's good to know I always thought it was quite a lot of trauma.
I have already pruned mine a bit, from your advice. It looks like crap, as ive no design in mind, but it needs time to grow and heal then I can actually start to do anything proper with it.
Thank you

 

[cbroad]

@PierreR
Thanks for asking this question, you saved me from having to do it. I have a winged elm air layer in the works and was wondering the same thing. Mine is probably around 8 feet tall, and I know there's no way the roots could support all that foliage. I guess it's a balance between enough leaves to drive root growth and enough roots to support the leaves.

My question would be how much foliage is too much, I'm assuming if you prune too much off, the roots will slow or stall? Also, would vertical distance to the apical meristem come into play, could the water make it up to the top? THEORETICALLY: if you have a 6-8 feet tall layer that's been separated with a small root system and you cut the leaves in half (or enough to get the balance: minimal water loss/growth) could you grow roots while not loosing too much moisture through transpiration? Could you potential have a tall layer with minimal stress from water loss (by limiting surface area of leaves but leaving enough to drive photosynthesis). What would be the threshold?

 

[sorce]

You might have enough time to grow new stuff and garden before your winter comes.

I'd cut it back considerably regardless.

Hey feller!

Sorce