Hawthorn trunk hollowed out

[Alby R]

Hi everyone,
I just repotted a hawthorn I acquired a few months ago, and when I was finishing noticed a hollow sound on the trunk. Well, a slight push on the base and the side fell in and a bit of a scratch found the middle of the tree has been rotted / eaten out. I scratched the bark on a couple of branches and they are still green underneath.
I don’t know what to do at this stage and was wondering if anyone can give me some advice, not sure if the tree is dead and doesn’t know it yet or if there’s anything I can do to save it.
Feeing very deflated right now.

[Keels]

G'day Alby, That sucks about the hawthorn. It looks like its been like that for a while to create such a big hole. Have you checked that there is no soft left wood inside? Just to be sure that the tree doesn't continue to rot. You can scratch test the branches to see if they are still green too. I don't think its the end of the tree, Hollows can always look interesting.

[Ryceman3]

The centre core of a trunk is dead on all trees. It’s not the living part of the tree, that is really a thin layer under the bark on the outer layers of the trunk. So, in that respect, as long as there is a “highway” between the roots and the foliage intact, there is no reason for it to die. Scraping the rot away and cleaning out the soft tissue is a good idea as already suggested by Keels. You can also apply wood hardener to the exposed areas afterwards to help discourage further rot, assuming that is the cause… be vigilant for any sign of borer too I guess.
All is not lost just yet…

[Alby R]

Thanks guys, I scratch tested the branches keels, looks good in that respect, I scratched out the inside with some wire until I got to the solid wood. Probably a silly question but what / where do I get wood hardener from (the big shed?)


Is there a treatment to use for borers ? Rose shield ?

[Keels]

Thanks guys, I scratch tested the branches keels, looks good in that respect, I scratched out the inside with some wire until I got to the solid wood. Probably a silly question but what / where do I get wood hardener from (the big shed?)

Thats good news that your seeing some green. You could use super glue to harden the wood. Here is an article on the process http://bonsai4me.com/AdvTech/AT%20Prese ... video.html

Thinking outside the box you could extend that hollow up the trunk. Might give it an interesting look to the tree? I've seen it done to elms on Boutiquebonsai on instagram. check it out if your keen

[Ryceman3]

Probably a silly question but what / where do I get wood hardener from (the big shed?)

Earls wood hardener is a pretty decent product for this and yes, it’s at the big shed.

As for borer treatment, I’ve no experience with it so leave it to the advice of others.
Further hollowing the trunk is definitely an option, I’d probably see how it goes for a bit and consider it down the track.

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[BonsaiBobbie]

I think it looks great with the hollow.

I don't know anything about the species, but suddenly it might become a great tree, as just opposed to a good tree.

Just my two cents.

[shibui]

Hollow trunk is no big deal. As already mentioned it is only the outside layers that keep the tree alive.
It is likely that part of the trunk has been dead for years. When you check the edges you'll probably find where the live part has started to heal around the edges.
Trees live for hundreds of years with hollow trunks. Some of the biggest trees on earth are hollow but still alive. Several of the giant redwoods in USA have hollows right through big enough to drive a car through.
Many of our native Australian birds and animals live or nest inside hollow trees, many of which are still alive.
Provided there is still an intact connection from the branches to the roots the tree is OK.
Even if more of the inside wood rots out the tree will still be OK.
Look on your hollow as a feature instead of a problem. Design your bonsai hawthorn to show off the hollow part in some way.

[Rory]

The one point I would add to an exposed hollowed tree is...

Now that you have exposed the hollow, you need to ensure that water isn't pooling inside the hollow.

In other words check that the interior fills up with water, and then drains away so it doesn't remain pooled inside the hollow it and will be fine.

Otherwise if it doesn't and it creates a pool, I personally would fix this, as it will just rot out more of the tree/roots directly under it.
You can carve a direct line through the base of the hollow to ensure adequate drainage.

[GavinG]

The tree should survive well - as Rory said, watch out for pooling at the bottom, it looks very likely. I'm wondering whether the rot has tracked down from the big cut at the top, or up from a large cut root directly underneath the hole. It's quite possible it will enlarge itself over time.... I'd consider lime sulphur on the inside of the hole when everything's dried out, as a disinfectant.

Is that the front of the tree? The trunk seems to lean away at the top, and there seems to be bar branches just underneath. All things to consider long term.

Gavin

[Stevie_B]

Also worth having a look at Harry Harrington on YouTube as well to see what he does with his carving etc. He uses black ink or dye to accentuate his hollows and carvings. It’s very interesting

[BonsaiBobbie]

The tree should survive well - as Rory said, watch out for pooling at the bottom, it looks very likely. I'm wondering whether the rot has tracked down from the big cut at the top, or up from a large cut root directly underneath the hole. It's quite possible it will enlarge itself over time.... I'd consider lime sulphur on the inside of the hole when everything's dried out, as a disinfectant.

Is that the front of the tree? The trunk seems to lean away at the top, and there seems to be bar branches just underneath. All things to consider long term.

Gavin

Assuming the rot etc can be fixed, I was wondering about what you'd do with it. I'm assuming you'd make the hole the front, and therefore when you look at the remainder of the tree, it will need a lot of work to turn it around. Sounds like a good interesting project.

[shibui]

I was wondering about what you'd do with it. I'm assuming you'd make the hole the front, and therefore when you look at the remainder of the tree, it will need a lot of work to turn it around. Sounds like a good interesting project.

Front on is not always the best approach. A bit of subtlety can often give the viewer more to consider and wonder about so maybe a viewing point where the hollow is slightly to one side would be a more interesting front.

If the upper part of the tree doesn't allow showing the hollow so be it. Overall view - trunk, branches and apex - will always trump a single feature no matter how good that feature is. I have an English elm with a hollow trunk almost like this but the trunk leans the other way and the main branches all face the other side so, regretfully, I've had to hide that great hollow trunk at the back of that tree where no-one can see it for more than 20 years.