Decay Detection

[ddhlakebound]

Treevet, I'm not picking any argument with you, I was only justifying the analogy posted by another.

I believe the contention posited by ddhlakebound was that the strength of a tree with difficult to detect damage (wall thickness great enough to mask the damage from sounding) is not mitigated so greatly that it requires condemnation. I believe that his analogy to the strength of a hollow structure like a street light was on target, and is further supported by your own assertion regarding the consequences of removing a chunk from that same structure. Too much damage is both obvious to detect and obviously cause for alarm.

Perhaps I have erred in assuming that the fancy machines are for targeting hidden damage, which seemed to be ddhlakebound's take on this thread. I have always presumed that a big hole in a tree was pretty obvious, and didn't need much more evaluation.

My comments regarding physiological decline in conjuction with elevated risk of failure are based on my personal observations only. I don't think that I have ever encountered a tree that was shown by sounding to be defective and hazardous that did not also have some pretty obvious signs of failure all over the tree. Either it will have fungal growths erupting from the trunk, or prominent cavities higher in the tree, and most often shows crown dieback.

When the procession of disease exceeds the rate that the girth of the tree is increasing, the vigor of the tree declines, and it is obvious that it is time to go. Sounding invariably detects this advanced condition, as you are aware.

Given sufficiently adverse weather, even a perfectly healthy tree will blow over. No amount of currently available hazard assessment can quantify all the risks involving a potential tree failure, except only total removal. This is something that I am quite pleased to do for my customers, but usually only after I advise them that it is going to take a big wind to send it over.

Now if someone could develop a system that could accurately quantify wind loading, tree stem strength, and root ball stability, so that it could be stated that any given tree will blow over at X wind velocity, then I would support that all the way.

Until then, I'll keep my splitting axe ready to pound on the trees a bit before I cut into them.

Thanks pdqdl. I wanted to post a response this morning, but no time....You explained it better than I could have anyway.

 

[treevet]

Points taken pdqdl. You can scope a tree and quantify it and just out of range upward or downward it could be drastically different and you have not read that. I have a great example of that in a centuries old Bur oak nearby which was hit by lightning and has a 70 foot defect that would be prohibitively difficult logistically to read the entire fault. So you do the best you can to mitigate and see if the client can withstand the risk. If you could read it all you likely would do the same thing.

Not many years ago before the Resistograph but long after the Shigometer (which takes a high level of expertise to decipher) I went to an IAA seminar (they have great seminars) at Purdue University where a drill was the only tool used. You simply drilled a hole into the perceived defect with a very small diameter bit (long enough) until you transitioned from sound wood to altered wood which could be judged by the shavings emitted. You took a reading at 4 sites around the perimeter and obtained a percentage that was evaluated against a threshold. This was a very high level group putting on this risk eval. seminar of whom I cannot recall but could find in the material if pressed. Internationally renown.

Invasive....yes...significantly...who knows. The Resistograph requires wounding as does the Shiogometer. Picus...not so. But may be prohibitively expensive for the private tree care owner. Don't even see any large tree co.s employing them likely for that reason around here. I have asked.

 

[treeseer]

The difference between "When I get called out to advise whether or not a decaying tree needs to come out I am always going to recommend removal when it is over the house." and

So you do the best you can to mitigate and see if the client can withstand the risk.

is knowledge and field experience. You're right, Legit--not working in the field is a serious limit. But field work is only half the story; book work is the other.

" You simply drilled a hole into the perceived defect with a very small diameter bit (long enough) until you transitioned from sound wood to altered wood which could be judged by the shavings emitted. You took a reading at 4 sites around the perimeter and obtained a percentage that was evaluated against a threshold. This was a very high level group putting on this risk eval. seminar "

This method has been roundly discredited due to unreliable use of formulas and unjustified wounding and different thresholds for different species, as derwoodii showed.. Plus, stem failures are rare; we need to look more to the flare and the forks.

 

[tree md]

The difference between "When I get called out to advise whether or not a decaying tree needs to come out I am always going to recommend removal when it is over the house." and


is knowledge and field experience. You're right, Legit--not working in the field is a serious limit. But field work is only half the story; book work is the other.

" You simply drilled a hole into the perceived defect with a very small diameter bit (long enough) until you transitioned from sound wood to altered wood which could be judged by the shavings emitted. You took a reading at 4 sites around the perimeter and obtained a percentage that was evaluated against a threshold. This was a very high level group putting on this risk eval. seminar "

This method has been roundly discredited due to unreliable use of formulas and unjustified wounding and different thresholds for different species, as derwoodii showed.. Plus, stem failures are rare; we need to look more to the flare and the forks.

LOL, if I remember correctly Guy, you advised me to not remove that tree I posted the picture of. I am not in the business of taking chances with a client's life and property on the possibility that the tree might be sound enough to make it. I'm in the hazard mitigation business. It's just a tree, another one will grow in it's place. Is it really worth risking life and property over?

 

[treevet]

" You simply drilled a hole into the perceived defect with a very small diameter bit (long enough) until you transitioned from sound wood to altered wood which could be judged by the shavings emitted. You took a reading at 4 sites around the perimeter and obtained a percentage that was evaluated against a threshold. This was a very high level group putting on this risk eval. seminar "

This method has been roundly discredited due to unreliable use of formulas and unjustified wounding and different thresholds for different species, as derwoodii showed.. Plus, stem failures are rare; we need to look more to the flare and the forks.

Just pointing out that this was THE state of the art by those that do the crediting and discrediting with far more credentials than you or I. How far have we come since then? Not very....but working on it. Will or can it every be science? I say no because just too many variables.

In that case the tools were simple and available and affordable. Tomography tools are complicated, unavailable and unaffordable. Got to look at the whole picture just like you advised in regards to the tree.

Tell me a little about your recent "sounding" readings.

PS. If you think stem failures are rare take a walk through the woods and find most shears in the 4 foot range. Decay more often than not the villain.

 

[tree md]

Just pointing out that this was THE state of the art by those that do the crediting and discrediting with far more credentials than you or I. How far have we come since then? Not very....but working on it. Will or can it every be science? I say no because just too many variables.

In that case the tools were simple and available and affordable. Tomography tools are complicated, unavailable and unaffordable. Got to look at the whole picture just like you advised in regards to the tree.

Tell me a little about your recent "sounding" readings.

PS. If you think stem failures are rare take a walk through the woods and find most shears in the 4 foot range. Decay more often than not the villain.

I spend a lot of time in the woods and see this as well. I'll try to take some pics next time I go to one of my favorite areas in the woods. There are 4 mature white Oaks that are broke over 3-4 feet on the stem within about a 250 yard strip of woods. I'm sure there are more around but these are just the big, mature trees that I have noticed.

I have have also cleaned up the mess on more than a few that have failed at the stem over the years. I think I've got some pics of some somewhere... I'll look.

 

[treevet]

That is the prob w finding evidence in the residential setting. Stumps are Ghandi...where as in the woods...still there for all to see.

 

[derwoodii]

Well I had a old gum with some nasty decay looked at by Thermal camera and the best determination assumptions were made with this new technology. We then dismantled and sectioned up the trunk so able to see what was going on inside. The thermal results kinda got some bits right but missed lead us in others areas. Its tricky and much to learn on how to interpret the images, this twas more a suck it n see test piece.
For me I,m not so convinced at the mo of any great future, but I reckon like all new ideas you need to be patient and supportive of any who wish to try. Perhaps in time it may show things that we can not see now.

 

[treeseer]

Well I had a old gum with some nasty decay looked at by Thermal camera and the best determination assumptions were made with this new technology. We then dismantled and sectioned up the trunk so able to see what was going on inside. The thermal results kinda got some bits right but missed lead us in others areas. Its tricky and much to learn on how to interpret the images, this twas more a suck it n see test piece.

Good on you for giving it a go. is the camera yours? would be interested in more about that experience. looking at tomographs myself now, as you may have seen in arbor age.

 

[pdqdl]

Never done it, so my comments might be way off track, but what the heck. Everybody has an opinion, right?

Thermal imaging is likely to only show areas of very active biological growth, which probably translates to moist areas that are really simmering with decomposition organisms working overtime. These conditions are very likely to occur where there is lots of decay, but that does not mean that decay will be restricted to the hot spots.

You will most likely find the hot spots where there is lots of bacterial decomposition in addition to fungal, and there is most likely to be a requirement that the affected areas have some sort of stratification present that restricts air movement and cooling. Otherwise, it might be growing a lot, you just wouldn't see it.

On the other hand, heavily decomposed areas that are dry are probably not going to show up because the decay has sucked most of the energy out of the wood, and the heat producing bloom of decay organisms just isn't supported by the local conditions anymore.

 

[pdqdl]

A foolproof decay technology, waiting to be invented.

There is technology available that can easily and accurately tell us the extent of decay in a tree. Plus it is non-invasive, and would not even spread disease. Too bad it doesn't exist in any form useful for tree diagnosis that I am aware of:

Ground penetrating radar!

These contraptions can see through solid objects and generate 3-D views of them:Ground-penetrating radar - Wikipedia, the free encyclopedia

"Pipe Penetrating Radar (PPR) is an application of GPR technologies applied in-pipe where the signals are directed through pipe and conduit walls to detect pipe wall thickness and voids behind the pipe walls."

I suspect that it will be a long time before this technology graduates to trees.

 

[treeseer]

i saw this demo'd in 2005, and know guys who use it to find roots (dependably) and also trunk decay (kinda sometimes)

o and the hotspots seen by thermal cam are of tree growth, not fungal growth.

 

[jefflovstrom]

I am still waiting for a lab report so we can procede.
Jeff :msp_smile:

 

[jefflovstrom]

Yeah, I sprelled proceed rong! I know!
Jeff :msp_tongue:

 

[jefflovstrom]

In California, we deal with ' heat sink'.
Jeff

 

[sgreanbeans]

I am still waiting for a lab report so we can procede.
Jeff :msp_smile:

A little garlic, some Goya Mojo sauce and a hot grill, we in bizness

 

[sgreanbeans]

With dollars and cents in mind, how much is the shigo one as compared to resisto? I like the resistograph, going to get one this year if the season goes as as planned

 

[Legit_Arborist]

I am still waiting for a lab report so we can procede.
Jeff :msp_smile:

Try omphalatus oleatus - pretty common

 

[Legit_Arborist]

I am still waiting for a lab report so we can procede.
Jeff :msp_smile:

You should take a bite out of it....yummy! Let me know how the diarrhea festival that will ensue treats you.

 

[Legit_Arborist]

You should take a bite out of it....yummy! Let me know how the diarrhea festival that will ensue treats you.

However...due to it's location on the stem...it could actually be Pleurotus oysterus "oyster mushroom" in if so....very very edible! Get out the butter!