Air layers that fail almost immediately

[andrewiles]

I've had several air layers over the past few years that have failed almost immediately. Within a few weeks they dried out and died. I only have a few data points -- for example, both of my attempts on a dawn redwood called, ironically, "Bonsai". Another on a palmatum dissectum called Filigree. This is against a backdrop of many other layers that are either successful, or last a season or two before finally giving up.

Regarding the "Bonsai" failure, dawn redwood cultivars range from being trivial to layer, such as the plain species, to almost impossible, such as Schirrmann's Nordlicht. But even at the failing end of that layers will stay alive on the tree for 2 or more years before finally succumbing without producing roots.

When creating the layer I don't think I'm damaging the xylem. The girdle can cut slightly into it of course, but certainly not a meaningful percentage of the way through. And given that most of my layers succeed it seems unlikely to be a problem with technique.

I'm curious whether anyone has ideas about why a layer could fail almost immediately and why it may be correlated with particular cultivars.

 

[andrewiles]

The only thing I can think of is that the xylem is being disrupted. One possibility could be that a cultivar like "Bonsai" only has a very thin ring of sapwood, with heartwood appearing early and accounting for the majority of the branch thickness, even on thin branches. That could explain the reduced vigor in this cultivar. In that case the act of cutting through to the cambium could also inadvertently sever the only viable sapwood layer(s).

 

[Wires_Guy_wires]

It could be that either your blade is carrying microbes that kill them, or your moss is.
It would be interesting to see what happens progressively when they die, in which order and what tissues are affected. That would tell a lot.

 

[andrewiles]

It's possible, but in each failing case the the same blade was used for other air layers on the same day, both before and after. All of which are fine. So it would be an unusual conincidence.

 

[19Mateo83]

It's possible, but in each failing case the the same blade was used for other air layers on the same day, both before and after. All of which are fine. So it would be an unusual conincidence.

Do you clean your blade with alcohol before you use it each time? Also have you tried the tourniquet method?

 

[0soyoung]

Maple airlayer turning brown

Hi team, around the start of spring (September 15th) I began my first ever airlayer. My Sangu Kaku is a multi leader and a great opportunity for multiple projects. Contrary to my own doubts it has managed to spout roots and leafed out amazingly. Everything was going great, I noticed so solid...

www.bonsainut.com

There is yet another possibility, that being a normal CODIT reaction. Auxin in the Polar Auxin Transport (PAT) chain is a signal of life above. This flow is a bucket brigade, moving auxin from one cambium cell to the next. PIN proteins that are preferentially located in the cell wall at the bottom of each cambium cell off-load auxin from the cambium cell 'above' to the one(s) below. If there is no input, the cambium cell gets emptied of auxin and it dies. In the process it releases compounds that trigger the living cells in the wood to plug up the xylem lumens, compartmentalizing the damage. This is pretty much what happens when one prunes a stem after some time and what eventually happens just below the site of a girdled stem.

Auxin produced by the leaves and buds is also actively loaded into the phloem along with the carbohydrate products of photosynthesis. The active loading (as opposed to passive osmotic) actually pressurizes the phloem tubes. Even though the phloem sap predominantly goes down the tree by the force of gravity, it is possible for the flow to go upward a small distance above the point (leaf/bud) of its origin. This is a key part of how vegetative buds get morphed into being flower buds, btw, but it means that the cambium at at pruning site and/or immediately below a girdle can stay alive for some time - auxin is driven upward to the cut site and off-loaded into the PAT stream. There are threads within the phloem tubes, themselves, that can break loose and fall against the sieve plates to seal the phloem as another aspect of CODIT.

In brief, the tissues immediately below the site of a wound can stay alive for a length of time, depending on the auxin levels required to maintain the variety's living cells, the phloem pressures that can be maintained and a few other things. All things considered, I find it remarkable that anything can be layered, but we've all done it, take it for granted, and are dismayed when the tree does what it does to compartmentalize damage, thereby making the layer into a giant unwieldy failed cutting.

Generally, I don't believe that you are doing anything wrong @andrewiles, it is just how the variety compartmentalizes damage.

 

[BrightsideB]

Maple airlayer turning brown

Hi team, around the start of spring (September 15th) I began my first ever airlayer. My Sangu Kaku is a multi leader and a great opportunity for multiple projects. Contrary to my own doubts it has managed to spout roots and leafed out amazingly. Everything was going great, I noticed so solid...

www.bonsainut.com

There is yet another possibility, that being a normal CODIT reaction. Auxin in the Polar Auxin Transport (PAT) chain is a signal of life above. This flow is a bucket brigade, moving auxin from one cambium cell to the next. PIN proteins that are preferentially located in the cell wall at the bottom of each cambium cell off-load auxin from the cambium cell 'above' to the one(s) below. If there is no input, the cambium cell gets emptied of auxin and it dies. In the process it releases compounds that trigger the living cells in the wood to plug up the xylem lumens, compartmentalizing the damage. This is pretty much what happens when one prunes a stem after some time and what eventually happens just below the site of a girdled stem.

Auxin produced by the leaves and buds is also actively loaded into the phloem along with the carbohydrate products of photosynthesis. The active loading (as opposed to passive osmotic) actually pressurizes the phloem tubes. Even though the phloem sap predominantly goes down the tree by the force of gravity, it is possible for the flow to go upward a small distance above the point (leaf/bud) of its origin. This is a key part of how vegetative buds get morphed into being flower buds, btw, but it means that the cambium at at pruning site and/or immediately below a girdle can stay alive for some time - auxin is driven upward to the cut site and off-loaded into the PAT stream. There are threads within the phloem tubes, themselves, that can break loose and fall against the sieve plates to seal the phloem as another aspect of CODIT.

In brief, the tissues immediately below the site of a wound can stay alive for a length of time, depending on the auxin levels required to maintain the variety's living cells, the phloem pressures that can be maintained and a few other things. All things considered, I find it remarkable that anything can be layered, but we've all done it, take it for granted, and are dismayed when the tree does what it does to compartmentalize damage, thereby making the layer into a giant unwieldy failed cutting.

Generally, I don't believe that you are doing anything wrong @andrewiles, it is just how the variety compartmentalizes damage.

That makes a lot of sense.

 

[andrewiles]

Do you clean your blade with alcohol before you use it each time? Also have you tried the tourniquet method?

I try, though probably forget on occasion. Though now that I think about it, I really doubt disease is an issue here. The failure is too fast.

But yeah, I'm trying a tourniquet layer right now. Figure that if removing the cambium is somehow blocking water flow I should try a technique that avoids that.

 

[andrewiles]

Maple airlayer turning brown

Hi team, around the start of spring (September 15th) I began my first ever airlayer. My Sangu Kaku is a multi leader and a great opportunity for multiple projects. Contrary to my own doubts it has managed to spout roots and leafed out amazingly. Everything was going great, I noticed so solid...

www.bonsainut.com

There is yet another possibility, that being a normal CODIT reaction. Auxin in the Polar Auxin Transport (PAT) chain is a signal of life above. This flow is a bucket brigade, moving auxin from one cambium cell to the next. PIN proteins that are preferentially located in the cell wall at the bottom of each cambium cell off-load auxin from the cambium cell 'above' to the one(s) below. If there is no input, the cambium cell gets emptied of auxin and it dies. In the process it releases compounds that trigger the living cells in the wood to plug up the xylem lumens, compartmentalizing the damage. This is pretty much what happens when one prunes a stem after some time and what eventually happens just below the site of a girdled stem.

Auxin produced by the leaves and buds is also actively loaded into the phloem along with the carbohydrate products of photosynthesis. The active loading (as opposed to passive osmotic) actually pressurizes the phloem tubes. Even though the phloem sap predominantly goes down the tree by the force of gravity, it is possible for the flow to go upward a small distance above the point (leaf/bud) of its origin. This is a key part of how vegetative buds get morphed into being flower buds, btw, but it means that the cambium at at pruning site and/or immediately below a girdle can stay alive for some time - auxin is driven upward to the cut site and off-loaded into the PAT stream. There are threads within the phloem tubes, themselves, that can break loose and fall against the sieve plates to seal the phloem as another aspect of CODIT.

In brief, the tissues immediately below the site of a wound can stay alive for a length of time, depending on the auxin levels required to maintain the variety's living cells, the phloem pressures that can be maintained and a few other things. All things considered, I find it remarkable that anything can be layered, but we've all done it, take it for granted, and are dismayed when the tree does what it does to compartmentalize damage, thereby making the layer into a giant unwieldy failed cutting.

Generally, I don't believe that you are doing anything wrong @andrewiles, it is just how the variety compartmentalizes damage.

That's really interesting. Thanks for the detailed reply.

I read the original thread you linked. I might try a narrow girdle bridge next time. Definitely counterintuitive.

Somewhat off topic, but did you ever get a successful higasayama layer? That's one of the first trees I ever tried, and I was successul with a ground layer. Tourniquet only. I've seen some evidence that tourniquet ground layers tend to work better on hard-to-layer trees than futher up the trunk. Of course it's all or nothing at that point...

 

[0soyoung]

... did you ever get a successful higasayama layer? That's one of the first trees I ever tried, and I was successul with a ground layer. Tourniquet only. I've seen some evidence that tourniquet ground layers tend to work better on hard-to-layer trees than futher up the trunk. Of course it's all or nothing at that point...

Nope.
That is interesting, though. Maybe I'll give it a try.