Chinese Elm Trunk Decay (Looking for solutions)

[LittleTrees101]

Hello everyone,

I’m new to this site, but thought I’d post for some advice. I have had this Chinese (Lacebark) Elm for over 25 years. It likely attained its initial shape through hack back before I owned it which left large scares all over the trunk. Over the years, the scars have decayed, but remained as dead wood. Due to their size, they never healed over (at least not yet). However, one scar facing upward at the top of the trunk, has slowly rotted over the years. I’ve sealed it periodically with clay and some wood sealant, but because of the position, over the years, water has penetrated it. The decay through this upper scar (now trunk hole) has resulted in years of inner trunk decay, which has more or less hallowed out almost the entire inner cavity up and down the trunk. If I shined a light through it in the dark, you would now see the light peering through the other deadwood scares. Despite this, the tree is quite hardy. It pushes out healthy spring foliage. I defoliate in June and then it pushes out compact growth, year after year. Never any branch dieback, etc. However, I imagine it is only time until the inner decay pushes outward to the living layer and ultimately kills the tree. Or maybe I am wrong?

I’ve included some photos of the wounds and another of a poorly made highlight of where the inner decay extends to inside the truck.

Does anyone have any creative solutions about what I might do to halt the inner decay? My thought is to maybe fill the cavity with something, then seal off every wound that the decay has extended to. My first thought was to fill it with some sort of expanding insulating foam, but I’d be worried about the toxicity. Anyway, ideas are appreciated.

Thanks so much!

 

[rockm]

The best way to get these to to heal is to accelerate the callus tissue already formed. That can be done by planting in the ground allowing it to grow unrestricted for a few years. That means you’ll lose a lot of the finer twigging and branching.

An alternative would be to graft sapling elms into the calluses and letting those graft grow unrestricted. Might work but growth might be spotty and limited

The problem with the pruning scars is that they have never been carved back and are blocking the callus from rolling over the wound. Either way you choose carve that deadwood down below the trunk line.

As for the rot. That isnt going away. You can carve it all out and hollow the tree. That means the hollow portion is going to be a weak point structurally. Carve it out until you reach sound wood and seal that.

 

[jeremy_norbury]

I use a nano pentrating wood sealer on my deciduous trees - seems to work very well.

I reapply it every other year or so. Here are some photos:

1. I burnt the surface to increase the aged look and to dry it out.
2. Applied the sealant
3. Five weeks later
4. Photo 4 months later.
5. September last year

IMG_4325 by Jerry Norbury, on Flickr

IMG_4328 by Jerry Norbury, on Flickr

5 weeks
IMG_5826 by Jerry Norbury, on Flickr

IMG_8423 by Jerry Norbury, on Flickr

IMG_2650 by Jerry Norbury, on Flickr

 

[ponderingsage]

Personally ,l would just embrace the rot as part of the tree’s story.

 

[BobbyLane]

Nice tree! I would hollow out the other holes like whats happened in the second photo.

 

[Attmos]

A bonsai tree with a built in bird house... has that ever been done before? lol

 

[Jorgens86]

Use cement. Even bjorn told that japanese do it to cover big holes like yours. And the callus will roll over the cement area

 

[LittleTrees101]

I use a nano pentrating wood sealer on my deciduous trees - seems to work very well.

I reapply it every other year or so. Here are some photos:

1. I burnt the surface to increase the aged look and to dry it out.
2. Applied the sealant
3. Five weeks later
4. Photo 4 months later.
5. September last year

IMG_4325 by Jerry Norbury, on Flickr

IMG_4328 by Jerry Norbury, on Flickr

5 weeks
IMG_5826 by Jerry Norbury, on Flickr

IMG_8423 by Jerry Norbury, on Flickr

IMG_2650 by Jerry Norbury, on Flickr

Thanks! I tried to Google this stuff, but can't find it. I'm in the US. What might be an equivalent here? Thanks so much for your advice.

 

[LittleTrees101]

Use cement. Even bjorn told that japanese do it to cover big holes like yours. And the callus will roll over the cement area

What kind of cement? My idea was to just fill it with something airtight. From the other posts, it seems a sealant would hold off the decay but the inner decay needs something more, a filler? If cement, what are the specifics of this? Something natural? Home Depot cement? I'm saying this almost laughing because I am asking a bunch of experts what kind of cement I should fill my bonsai with. This, however seems the closest to my solution. Thoughts?

 

[LittleTrees101]

Use cement. Even bjorn told that japanese do it to cover big holes like yours. And the callus will roll over the cement area

What kind of cement? My idea was to just fill it with something airtight. From the other posts, it seems a sealant would hold off the decay but the inner decay needs something more, a filler? If cement, what are the specifics of this? Something natural? Home Depot cement? I'm saying this almost laughing because I am asking a bunch of experts what kind of cement I should fill my bonsai with. This, however seems the closest to my solution. Thoughts?

 

[LittleTrees101]

Nice tree! I would hollow out the other holes like whats happened in the second photo.

 

[Jrmcmich]

2 part epoxy would possibly work too

 

[Mike Westervelt]

@MACH5 has some great posts here detailing how to heal wounds such as these, essentially you remove all of the rotten/soft/punky wood, fill with epoxy or concrete, then periodically
activate the callous tissue edges adjacent to the wound by gently scraping to expose the cambium and treating with kirikuchi (bonsai tonight) cut paste to stimulate healing.
The more vigorously your tree is growing the faster healing will occur.

 

[WNC Bonsai]

Take a look at Terry’s job on a trident maple.

 

[nuttiest]

From the other posts, it seems a sealant would hold off the decay

There is nothing that will stave decay at this point it is just wdo taking care of dead wood, and different than something that harms live wood. and if you add a sealer it will create a new channel for some new fungus to bother the live wood and root zone. The cement looks ridiculous. There is no structural reason this tree might fall on a person. Now blue sparkle epoxy with high polish spalted wood that might be a thing... maybe.
Also hollow trees are easy to pick up

 

[Deep Sea Diver]

Time for ye olde die grinder… aka Dan Robinson

Cheers
DSD sends

 

[Jorgens86]

Just any concrete/cement will do fine. Or like here people say use epoxy. Eather will do fine.
Like i sad japanese will even do that

 

[Shibui]

First up we need to accept that decay inside a trunk will rarely harm the tree. Trees only rely on the outer layers for sap flow. The internal wood is just there for physical support rather than life support. Look at all the really old hollow trees in ancient forests all around the world. Decayed interior is not a big problem.
A hollow trunk Japanese maple was featured today in a demo at the bonsai weekend I'm currently at. Began as sunburn on the bark many, many years ago and now extend right through the main trunk.
Not much of a photo. What may appear to be twin trunks is actually a single trunk with a long, thin hollow right through but the tree is healthy.


You can embrace the hollow trunk as a natural feature of many trees and your bonsai. Decay appears close to the remaining dead wood scars. You could poke or carve through to link some or all of the scars and make a feature of the hollow trunk.

However, if you don't like the look of hollow tree and really want the holes to heal over you need to supply a firm surface for the callus to grow on. That's where we use some sort of filler. Concrete is an older solution which has been used by arborists for many years and will usually work. Epoxy fillers are the modern version. Neither will stop the rot. They just give a surface to support cambium growth.

 

[Paradox]

Use cement. Even bjorn told that japanese do it to cover big holes like yours. And the callus will roll over the cement area

But you need to get all the wet wood out and dry it out or it will just keep rotting