Small crack thru center of xylem after felled

R.Boreal

Today I felled a dead mossycup oak, big mother. As I have seen from other jobs, in the center of the tree, crossing dead center and extending in both directions, is a thin crack that is widest as it passes through the center, narrowing and disappearing about 2" radius from either side of center. Is this because of the stress of the tree toppling? Or is it a symptom of the problem that killed it? (oak wilt, I believe.) I have felled big trees before, where the heartwood seems strong and healthy, but there exists a single crack in the center, seen on both the cut trunk and the stump. Is it silly to wonder if this was there before I cut it? I imagine it was, but the wood seems so dense and strong that something tells me it could be from the fall or the stress of wedging and pulling before the fall. There is no decay up the center at all.

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derwoodii

Yer seen, I think? what you sayin and unsure if its just remnant medullary rays leaving cracks or reaction stress wood crackin during tree growth or after your have removed sections allowing it to open up. I been up a gum blocking off sections when the tension in it let go with a crack/bang scared me cold an crack appeared though the block top where nuthin was before.
lets see if this link helps

Medullary ray of Oak - Karelia parketti

Grr I'd send you more links for Shigo or treedictioary that may help but the billy lids have chewed up all ma download this month

R.Boreal

Thanks! I'll take a pic today and post later.

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R.Boreal

Here's some pics, one at the felling cut about 3 ft high, next much higher, maybe 10 ft, and the 3rd is prolly 30 ft up the trunk. (Having trouble uploading more than 2 atchmnts) So this crack extends thru almost the entire tree. Can't say about the pieces I blocked down before. Since I have seen this phenomenon prev, I thought it worth asking about.

I checked out that link to the rays - I'm currently studying for my ISA Arborist cert, and know that rays are the lateral mechanism of cell growth and nutrient distribution thru the xylem. Since this crack is obviously 30-40 ft in depth, I don't know if one has anything to do with another.

Scary bit about that stress fracture you decribed.

Attached Thumbnails

   

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Garry Brockley

I find on Eucs that are exposed and take wind directly from all sides that when you are blocking down the tension and compression built up in the main trunk is huge, you hear it release like the crack of a pistol over the sound ofthe chainsaw and everyone around hears it too.
then you see the rays open afterwards

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derwoodii

I reckon it rays opening up with tension comin out as you section the trunk. However its not the same one though the 30foot just separate sections havin separated rays acting the same. You got a stressed out log there give her a cup a tea and a little lie down. Yup it gives ya fright when you feel the timber pop under your spikes.
Hmm unusual to see a crack down so low in a trunk..
ISA certs a worthy journey enjoy it.

Jeroen Shiran

Almost all cracks like this are pre-existing stress cracks resulting from external forces on the tree. The additional forces during removal would open these cracks even more. So they might start as very small cracks, but they become more defined after additional loading. It has nothing to do with any disease of the tree.

R.Boreal

Right right - thanks. Yes, I believe oak wilt killed this one.

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Brent Ferris

How would this knowledge be known? How could it be ascertained while the tree is standing?

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Jeroen Shiran

Ah, well I suppose we could get into a very interesting philosophical argument. Like if a tree falls in the forest and no one is there, does it make sound? From what I have read on the subject (mostly by C. Mattheck) it stands to reason that any cracks that are seen after a tree is felled is to some extent due to previous external forces to the tree. The forces during removal will find these weaker places in the wood and as a result a bigger crack would form.

It would be fun to remove a piece of trunk that has a crack and then take some slices off the remaining trunk. Then put those slices under a microscope and see if there are cracks or not. Until then I stick with Mattheck.

Brent Ferris

Mr Mattheck seems to have written a number of books - which one(s) are you referring to?

Of course it makes a sound. That no one is around to hear it or record it is irrelevant. That suggests that a person's presence is more important than physics or nature -- a ludicrous suggestion -- wouldn't you say?

That's like saying, if you can't hear a tree talking to you, it must be mute. Never mind people aren't tuned in to trees.

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My business: Tree Pruning and Removals -- Strump Removals -- Advice -- Consulting -- Arborist Reports
If you want an honest opinion, call Brent Ferris...because, Trees want to Live Too !
We do great jobs, even in small yards.

Free Estimates Oakville to Oshawa - North to Bradford (Will travel further if cost of travelling covered)

S.O.P

I transplanted a small Ficus obliqua for bonsai purposes, let it take root and then cut it down to about 200mm high. It has a similar crack and it's only about 100mm in diameter.

It's now got larger and turned into a small hole.

Slightly on a tangent, but the crack was noticeable like the pictures as soon as it was cut.

Brent Ferris

So was it naturally twisted, or twisted to suit somone's purpose, and could that have caused the crack?

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My business: Tree Pruning and Removals -- Strump Removals -- Advice -- Consulting -- Arborist Reports
If you want an honest opinion, call Brent Ferris...because, Trees want to Live Too !
We do great jobs, even in small yards.

Free Estimates Oakville to Oshawa - North to Bradford (Will travel further if cost of travelling covered)

Jeroen Shiran

I believe it was "tree mechanics explained by Pauli the bear". Also in "the body language of trees" he talks about formation of cracks.

As for the falling tree, you just answered your own question. Just because we can't observe the cracks in a standing tree, it doesn't mean they aren't there. I agree that a person's presence is not more important then nature and physics.

The cracks we are talking about here are not a significant structural concern so I can't give you actual research on this specific matter. But I think you agree that every tree has external forces exerting on it. To assume that these cracks only appear after humans work on it, even though the tree has withstood external forces for years, just does not make sense to me.

Brent Ferris

Nor does it mean they are there -- they are unobservable to the outside.


I agree, it doesn't make sense that the cracks only appear after humans work on the tree -- but not all trees exhibit cracks, even those growing in odd ways. I have often seen the basal crack, and the distance it is visible up the trunk varies considerably.

The initial question was how would someone ascertain a crack was present? And if present, would it lead to structural failure sooner.?

It does make sense that trees subject to high winds, or abnormal forces would have interior cracks on an ongoing basis -- or at least weaker structural tissue that once the tree is felled the defects reveal themselves to us.

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My business: Tree Pruning and Removals -- Strump Removals -- Advice -- Consulting -- Arborist Reports
If you want an honest opinion, call Brent Ferris...because, Trees want to Live Too !
We do great jobs, even in small yards.

Free Estimates Oakville to Oshawa - North to Bradford (Will travel further if cost of travelling covered)

Jeroen Shiran

Okay, so we actually agree.
I think that with the kind of cracks that we are discussing here, it is impossible to ascertain if they are present in a standing tree, even with the current diagnostic tools. At the same time these kind of crack do not pose a structural risk at this point in time.

Of course, over the life of the tree, these cracks could develop into something that will become a structural problem. However, even if we could ascertain that these cracks are present there would need to be a research project in order to see how they develop and if they actually become a risk later on in the tree's life or not.

The knowledge of the existence of these cracks would be of little help without the knowledge of how they progress, and even then I would be inclined to recommend monitoring the tree instead of potential unnecessary treatments.

But now I am getting into a hypothetical scenario and I'll stop here, although it is a fun argument.

Eric Frei

The crack is encased, so although it is there it doesn't have to rot or decay if there is no entry point for pathogens.

It could be there forever and never make a difference, get larger or decay etc.

Am I the only one who has ever bought timber boards with cracks? I doubt it.

I once was felling an ironbark trunk log, it was dead straight. It was maybe 700mm DBH, maybe 10m tall with the top removed and branches cut off, Yanks call it a "spar".

I put in the scarf (notch for Yanks and gob for Poms) all was OK. I started the back cut as usual and once I got in about a bar width loud cracking sounds came, crack and CRACK went the tree .... I stopped quickly and looked around, no barber chair etc all is normal so continued cutting faster and yelling out pull pull to the guy on the pull rope worrying something might happen but no idea what. Tree went over normal and there was the inner crack, just like spoken of here. Was it there before? Don't know, but it was tiny and clean, no decay, no worries.

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derwoodii

Dinks? they call it a gob.. Funny fellows those pommies aye.