Prognosis for severely decaying apple tree trunk?

When we moved in this tree was already somewhat rotted. It’s a Gravenstein, and clearly it had formerly had three major scaffolds, and one had been outrageously badly sawed off in a way that it couldn’t callus over. I consulted a tree guy that first year, and he said there was nothing I could do about it. However, I’ve since become somewhat disenchanted with that particular tree expert (thanks partly to the expertise on this forum) and I wonder if there’s anything I can do, and, failing that, how long I have left with this tree. Its apples are quite good, especially for juice and pies, but also I’ve got about 15 thriving grafts on it of other varieties, so I hope it will last. I’m in coastal Northern California, so it’s not rainy here, but we do get a lot of fog, so there is moisture in the air, in case that’s relevant to rot issues. Thanks, all!

that’s a huge gaping one! ouch!

IMO, it is impossible to have it completely sealed in a short period of time, not artificially, and especially not naturally. I have saved some trees with gaping wounds, but not as big as this one.
not sure if that’s callous cambium creeping up from the upper left. If it is, it could be a while before it engulfs the entirety, and regain its structural strength. Am not an expert, but i have saved similarly injured ones by trimming or whittling away at non-structural dead wood, then at the interior, pounding several 9" nails into the top, bottom and sides, or better yet, using long lag screws. Thereafter pouring cement into the gap, which will literally bind those nails for strength. If you’re not handy with tools, you could do away with the nails/screws, simply just pour cement into the gap, it will add some strength by itself but is not as strong.
for the next two or three years, i will be pruning off the flowers to prevent any fruiting. And lavished with as much extra nitrogen it could tolerate to max out vegetative growth and finally engulf the concrete and deadwood, resuming the cylinder of cambium needed to regain strength. (without the space-filling concrete, it would be a longer wait, since it is way slower engulfing into the hollow, as opposed to just over the rim of the hole and over the cement, which is far less surface area traversed. Also, the nails and concrete stuffing strengthens the trunk a good deal while waiting)
not sure though about the age of your apple tree, and if it is even worth doing if apple trees aren’t really long-lived in your locale.
good luck!

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Quite a bit will depend upon how far the rot extends into the trunk. It is a bit hard to say from that photo but it looks like there is some rot further in, not just on the surface.

I would do some careful probing/rot removal with say a screwdriver or small chisel, removing only rotted wood, by hand (no hammers or power tools). You should be able to see fairly quickly how far that rot extends and where the solid wood begins. Do a small area at first to gauge the extent of the problem.

Then if it seems like the tree can survive, carefully remove the rot down to good wood. And I would cover it with a pruning paint (to seal the wood off from water and air, just in case all the rot wasn’t removed).

While I have seen concrete/mortar used to fill large gaps in trees, I have my doubts about using it. Mortar/cement tends to hold moisture and can provide a breeding environment for rot, which you would not see under the layer of concrete. Especially if you’re in a moist area. If the tree needs reinforcing, I would think a set of guy wires to stakes on ground from the tree would provide more support than a concrete plug, and the wires can be placed to handle prevailing winds.

Caveat that this is my theory only, as I have never had to try and save a tree with that much rot in it. So if folks here have experience that they know works, I’d go with that.

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I have not tried it, but as I understand it, there is a technique called inarching used to save trees with dying understock. Seedlings are planted circumferentially around the base and allowed to grow to a height above the damaged area and then grafted into the trunk where they will grow and become a new root system for the tree. Here is an a diagram.

I have heard that one of the first U.S. ‘Navel’ orange tree in Riverside has been kept alive this way when its original rootstock failed.

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Lizzy, that tree is very old and has, for the most part ran it’s course. You might very well be surprised how long it will hold out, perhaps longer than you and I (I’m guessing we are roughly the same age). I’ve already seen many trees like this continue to live on (still today) for way, way longer than I thought possible. BTW…from what I see, I don’t think that cut was all that bad, for all we know the rot was present then…maybe , maybe not. Perhaps it broke away in a storm and what you see was the best that could be done. Feasibly speaking, I think your tree guy was right.
Reality is, it’s impossible to say how long it might live, so as an informed person you should do what you already know how to do now.
If it’s near any structure or anything else to which it could do damage, or a driveway it could block or whatever…get ready for the inevitable demise. Get an offspring going…hope for the best, and expect the worse.
The method Vohd speaks of I’ve heard called Bridge Grafting (I may be assigning the wrong term), I’ve never tried it (never needed to), and it may be worthwhile as an academic exercise with potential benefits, but personally I wouldn’t bother. It would be kinda cool though if you were willing to go to all that work so everyone else could see the results. It’s far more work than replacement though, and that would be near 100% successful with little work.
Do lay the fungicide and insecticide to that area of rot when you spray though, that will buy it a little time it otherwise would not have. Scraping out the rot (it will be super easy) is a good idea…it will remove some places for wood destroying insects and fungi to harbor. You can’t really “seal” it, but if you had some paint handy (and only if was really handy) it might be worth slopping some in, if only to give a clean edge.

FWIW…if I was a betting person…I’d bet that tree lives a whole lot longer yet. Like a WHOLE lot longer, but I know nothing of northern California, but I’m thinking it’s not so different than here.

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I’d get started on making grafts of your desirable tree. It may live a long time, but clones can help it live forever.


Lizzy, I manage hundreds of ancient specimens like yours and have for years and years but still cannot predict the future of yours. It may well outlive you (and I’m assuming a long life on your part), that’s certain, and it has not “run its course” unless it has lost its vigor and doesn’t send out vigorous annual wood. Trees don’t suffer the same kind of aging humans do and new wood behaves like young trees growing in old wood instead of soil.

As the tree rots it is growing new structural wood and in doing so will hold on as long is it wins the race against rot. I have trees I manage that have tunnels at the base but are still strong and send up 3-4’ shoots every year along the scaffolds. The old trees are also capable of putting out large and delicious fruit. As I said, it is not age but vigor that is most important.

I used to manage a 150+ year old Gravenstein with almost a 70’ spread. In the 20 years I was taking care of it it did decline and lost a lot of that spread when a couple of huge scaffolds broke off but the remaining tree was vigorous last I saw it. The customer sold the property so who knows if the tree is still standing?

Because it is impossible to do a controlled study of the subject it is hard to know the exact best way to manage such trees for longevity. The longest lived oaks in the world are in England and they are trees which were annually pruned to harvest wood for tool handles. I think you want to keep the tree from sprawling out any more than it already has by pruning it into a more compact form, but not too much and don’t allow it to bear extremely heavy crops.

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yeah…I agree “ran it’s course” was a very bad choice of words, what I meant, was that this condition is pretty typical of old apple trees I see. I’m actually surprised I stated it that way, as I am particularly drawn to old trees and especially apple trees.

I did however state emphatically that it may live a long time. It may be on the ground in the next storm too, but I think the odds are strongly in it’s favor. I’d still get one started if I really liked the apple.

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Thanks, all, this is a rich collection of information and expertise!

Since the tree is pretty vigorous I’m guardedly optimistic. For various reasons, including the angle of the trunk and how open it is, and the issue of further rot, I don’t think I’ll do the concrete. But I will gently scrape out the insides and use the tree sealer or paint.

I should have mentioned that a cut on an old limb showed tunnels through the wood about a third of an inch wide, so there are things boring through it–could that be termites? I’ve been gradually getting rid of the oldest wood and have younger scaffolds that are in great shape. I’m reasonably handy with my tools so if it needs structural support that’s simple enough.

I’ve been letting a few root suckers survive at various distances from it–the root system is vast and vigorous, it would be a thicket of apple trees if I let it!-- with the plan that I’d graft on to them if the tree failed, and take advantage of the existing root system. But I’m very intrigued by @Vohd 's suggestion and I"m tempted to use the closest ones as inarches. However, there may not be any healthy bark on that side to attach the suckers to.

@alan, I had NO IDEA that an apple could live 150 years! Wow! I prune this one fairly hard and it doesn’t have heavy crops so no worries there. I think we don’t have quite enough chill for it to do big crops, and I thin the bunches, AND we have apple coddling moth so I lose a few to that. (Now I’m bagging with organza bags so we’ll see…)

Thanks again, folks!

Do not scrape it and leave it be. Sealer will only give the rot a leg up against the cambium by keeping things wet for it. Trees don’t “heal” like animals, they wall off the invasive fungus. Sealers and the like have pretty much been discarded based on now about 30 year old research, particularly work by the late Alex Shigo if you want to do a search (please do a search).

I have done inarching but it is only useful if the tree looses vigor IMO, but I could be wrong about that. It did seem to save an old tree I performed it on that had lost most of its vigor.

I doubt Ju Ju saved any tree with his methodology- those are long discarded techniques and concrete creates a nightmare if the tree needs to be cut up. Trained arborists no longer use fillers to attempt to strengthen a tree, to my knowledge. They also have methods to gauge the relative strength of the tree but it requires boring a small hole into the wood.

Are you really a doctor Ju Ju?

sorry, Alan, but here’s another rebuttal. Wood is several times more hydrophilic than concrete. Concrete is denser, and will keep out moisture more than wood. The relatively porous pavers that you see at home depot, they do get soaked easily because those were engineered with porosity(aired) so as not to be very heavy. Solid concrete set straight from the cement bag is dense and will resist soaking. If this is not enough reasoning, then let me ask you-- would you rather have concrete shingles for your roof, or wooden tiles?
now, there are certain things which promote decomposition of wood. Wood is made of carbs, one of the largest molecules known to man in fact. And so happened that the vast majority of consumers of wood are aerobes. When organisms consume wood, by far the most common pathway would be to oxidize the carbon and the hydrogen of the carbo(carbon)-hydrates(hydrogen). If you’re not aware, oxygen is the rootword of the chemical process ‘oxidation’, and by oxidizing the carbon bond, CO2 is produced, and by oxidizing the hydrogen bond, H2O is produced.
logs from archaeology diggings were found practically intact even though they were soaked hundreds, if not thousands of years because they were lacking oxygen, due-- in fact, to the enormous amounts of moisture. Sure there maybe anaerobes which help decompose, but they are definitely minor decomposers of wood given the archaeology findings. If you’ve ever been instructed by compost experts to turn your compost regularly, it is because when compost degrades, they disintegrate into finer pieces and block oxygen out, delaying aerobic fungal and bacterial activity. Thus said, oxygen is actually the limiting reagent when it decomposition.

also, i doubt if you’ve chopped down a live tree before, but if your worried about ‘keeping things wet for it’ as being THE problem, try chopping a tree in your free time. You’ll be surprised how wet the wood is, even at the bullseye of the heart wood–no matter how big the tree is.
if there’s anything, it is the wood which will actually get the concrete stuffing moist, and not the other way around…

the limited availability of oxygen which will delay the rotting, no matter how wet the wood is. Stuffing the gaping hole, with anything(that is less ‘spongy’ than the wood itself) would help block out oxygen, and thus prevent decomposition. Reason i advocate concrete is because of its strength and availability, and binding power(when used with lag screws)

yes, there might be a horde of trained arborists who’d think differently, but i am not inclined to follow their management style as it runs counter to the cause-effect scenarios i just posted above


Please Ju, Ju do a search and stop the baffling with BS. Concrete is not a tool in modern arboriculture and no authority I know of recommends your methods as does no major tree care company in the U.S. I’m not a doctor and this subject is where my training lies.

I have cut down a great many living trees and have heated my house for the last 25 years by running a wood stove continuously for about 5 months of the year and intermittently during other months entirely on wood I harvest. I personally cleared my land to turn it into a nursery. I’ve also had to deal with ancient apple trees that are filled with concrete and had to replace chains because of inadvertently striking hidden concrete inside wood. It is always concrete applied many years ago because no trained arborist uses this technique anymore.

Hydrophyllic? that is so silly. Plastic is hydrophobic, put it against wood and the wood stays more wet. There, saved you the effort of a search- that took 1 minute.

Liz, I’m sorry if this exchange bothers you but I really want you to get genuine info which can be a challenge on the internet. Check out the link I provided, I think it will give you confidence on best approach.

it’s not an issue whatsoever. I’d still do it on my own trees and have had faster healing times than when left alone.
life-saving in fact, because those that i left alone were so flimsy they toppled down when the tropical typhoons came to visit… No spray insulation would have protected them when upright, and no spray insulation would resurrect them from the dead.
those strengthened with lag screws and concrete resisted the onslaught, and if until today they continue to be abraded from within during windy conditions— they are still alive at least!

let me explain. Hydrophilic substances will promote hydration when it is already saturated with fluid and when the source of moisture is from outside the substance you want to be moist. Hydrophobic substances will ‘increase’ hydration(by virtue of resisting leaking out of fluid)when the source of moisture is enveloped inside.
foam is quite hydrophilic, but if it is dry, and you touch it against your moist skin, your skin will actually lose moisture.
Plastic tape is hydrophobic, and regardless of whether or not wet or dry, but if you wrap it around a graft, then the moisture inside is trapped, hence ‘the wood stays more wet’. Because the fluid you are conserving is from within the hydrophobic wrapper, and not from outside.
this is why we will never wrap our grafts with dry foam or anything hydrophilic , because it will suck out moisture, and in the case of foam, will channel it into the wide open gradient working against moisture retention–which are ambient heat and wind.
heat may only cause fogging of liquids from within the graft if wrapped in hydrophobic tape, but prevents leaking them out so saturation is maintained, and when it cools down at night, the fog condenses.
needless to say, the best approach would be to wrap a very damp(and not dry!) hydrophilic foam around a graft or marcot, then wrap it with hydrophobic stuff like plastic.

hope that didn’t sound so ‘silly’ to you.

Ju Ju, you really should start some new form of Scientology to put your skills to better use. You don’t seem to care that you provided advice that would have been injurious to a fine old specimen apple tree. If you happen to be a doctor as you say, you are well aware of the limits of anecdotal observation.

Before you spin more BS please do some research about tree sealants. As I said, Alex Shigo was in the forefront of actual research that has already thoroughly repudiated the claims you are making so just google his name, read for a while and once you actually have some real information maybe you can be a constructive contributor of tree care advice. I already know you are a talented word brawler, but who is that helping?

original poster already indicated she will not use concrete. So relax.
also, why be sore about something which worked for other people?

Hey guys lets try to focus on helping the original poster rather than getting into arguments. Thanks :smile:

I don’t know much about this myself but Google thinks that filling with concrete is an outdated approach that has more negatives than positives. See e.g.,

These are simple questions that have been widely researched. I have no problem with people sharing experiences that seem to contradict general research and useful information can come from that sharing. But it is exhausting to me if the research is not acknowledged and the experiences are supported with interesting “theories” that sound completely logical but have been contradicted by controlled studies, as I believe is the case particularly with wound sealants but also filling cavities with concrete.

That said, I confess that the idea of using concrete as a ballast to help a tree remain upright during typhoons is an interesting concept and has probably never been refuted by research. I would still suggest including caveats before submitting it as general advice.

On another subject, it’s interesting how the literature seems to routinely suggest that cavities in the trunk are always the result of injury or bad pruning. I believe this is not correct and rot can begin when trees loose branches to things like a lack of light as lower branches get shaded in a forest canopy. On aging apple trees large scaffolds seem often to die without apparent injury and the result, over time, will be a cavity. Usually these cavities and trunk rot are not the cause of death of these old apple trees, although sometimes they do snap at the base when it is. More often the roots fail and trees topple over with the trunk still intact. When large scaffolds die that are not being shaded I suspect it is the result of dying roots or inadequate root to support the entire, ever expanding top of the tree. The reduced tree may end up with a cavity where the scaffold was but can remain standing a very long time.

Just a point of data on the concrete and moisture debate here.

New building code requires treated wood for sill plates wherever the sill is in direct contact with a concrete or masonry foundation. Having repaired quite a few old houses where treated wood was not used for the sills, I can attest that untreated wood rots from the moisture masonry materials will wick up from the ground, even if the sill-concrete junction is not exposed to the weather, and even if the foundation is coated with waterproofing. Not 100% the same as concrete in a living tree cavity, but the fact that masonry/wood combo does rot over time is key here I believe.

I learn so much more from debate than just exposition :smiley: