May 8, 2025 • 29 mins
In this Thursday episode of Talking Trees, we delve into the use of acoustic tomography—specifically the PiCUS Sonic Tomograph and TreeTronic systems—for diagnosing hidden internal decay in trees.
We discuss:
- How sound waves and electrical resistance are used to map internal wood structure without damaging the tree
- The key steps in setting up, calibrating, and interpreting tomograms, including common challenges like the “cogwheel effect”
- Insights into the biology of wood-decay fungi and how tomographic tools can detect and predict the development of decay
- Case studies from managed spruce and oak stands, comparing tomographic data with stump analyses and visual assessments
- The value of combining acoustic and electrical tomography in urban tree risk assessments and long-term tree preservation strategies
Acoustic tomography represents a powerful, non-invasive way to understand what’s going on beneath the bark—helping arborists make informed, science-based decisions.
Background information:
- Göcke. 2017. PiCUS Sonic Tomograph Software Manual Q74.pdf
- Schwarze. 2008. Diagnosis and prognosis of the development of wood decay in urban trees.pdf
- Tamu et al. 2022. The Application of Sonic Tomography (PiCUS 3 Sonic Tomograph) to Detect and Quantify Hidden Wood Decay in Managed Norway Spruce Stands.pdf
- Wang et al. 2007. Acoustic Tomography for Decay Detection in Red Oak Trees.pdf
- iml. 2021. Picus Treetronic Manual.pdf
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Roger (00:02):
Talking Trees with Lily and Jad.
Welcome to today's episode.
We're diving into the world oftree stability assessment, with
a focus on methods for detectinginternal decay in trees.
We'll dive into sonictomography and the PICUS
Treetronic device, an advancedtool for measuring wood
resistance.
(00:22):
These tools offer arborists amore comprehensive understanding
of tree stability andmechanical integrity.
Let's get started.
Jad (00:35):
Welcome back everyone Ready for another deep dive.
This time we're focusing onsonic tomography, especially for
all you professionals out there.
Sounds good.
We're going to figure out howit's used, what its advantages
are, what are the limitations,and we've got some interesting
cases to look at too.
Lilly (00:51):
Yeah, definitely.
Jad (00:52):
And we've got a mix of sources this time, which is
always fun.
We've got a software manual,We've got some of those really
in-depth scientific papers andeven some visuals you sent over
which are pretty cool.
Lilly (01:01):
Yeah.
Jad (01:02):
So first things first.
What exactly is sonictomography?
I mean, I think a lot of ourlisteners have probably heard
the term, but maybe not everyoneknows exactly how it works.
Lilly (01:13):
Well, think of it this way it basically lets us see
inside a tree without having to,you know, chop it down or
anything.
Jad (01:19):
Whoa hold on.
That's like x-ray vision fortrees.
Lilly (01:22):
Exactly.
It uses sound waves, so youmeasure how those waves travel
through the wood and thatreveals the internal structure,
like you know, is there decayhidden in there?
Are there cavities, things likethat.
Jad (01:36):
That's got to be so useful for like assessing the health of
a tree right Absolutely.
Lilly (01:38):
You can detect problems really early, even before you
see any signs on the outside.
Jad (01:41):
Wow, that's incredible.
So what would you say are thebiggest advantages of sonic
tomography?
And we've touched on a couplealready, but for the
professionals listening, whatreally makes this stand out?
Lilly (01:53):
Well, like I said, it's non-invasive right.
You're not harming the tree atall.
Jad (01:58):
True, true.
Lilly (01:59):
Which is huge, especially when you're dealing with, you
know, maybe a really old tree orone that's important for
historical reasons.
You don't want to be drillinginto that just to see what's
going on inside, Right?
Jad (02:09):
right.
Lilly (02:09):
And then those tomograms, those visual representations
you get, those are really easyto understand, even if you're
not, you know, a tree expert.
Jad (02:18):
Oh, so you can actually show those to clients and they
can kind of get a sense of OK,this is what's happening inside
my tree.
Lilly (02:25):
Exactly.
It makes it much easier toexplain things.
And then, of course, the earlydetection part is huge.
Catching decay early can make abig difference in how you
manage the tree, maybe even saveit.
Jad (02:37):
Okay.
So it's non-invasive, it givesyou these easy to understand
visuals and it helps with earlydetection, but every tool has
its limits, right.
Lilly (02:45):
Of course.
Jad (02:46):
What are some of the limitations of sonic tomography
that we should be aware of?
Lilly (02:50):
Well, one of the biggest things is that the accuracy
depends a lot of how you setthings up, like where you place
those sensors, how accurate yourmeasurements are.
That all plays a role.
Jad (02:59):
So it's not just point and shoot.
There's definitely some skillinvolved.
Lilly (03:02):
Exactly, and then even once you have those tomograms,
interpreting them correctly.
That takes some expertise too.
You got to be able todistinguish between different
types of decay, or maybesomething that looks like decay
but isn't.
It's not always straightforward.
Jad (03:15):
So training is important.
Lilly (03:16):
Oh yeah, definitely, and it's important to remember that
tomography shows you what'sgoing on, but it doesn't
necessarily tell you why it'shappening.
Jad (03:26):
That's a good point.
Lilly (03:26):
Like, you might see decay , but you don't know what kind
of fungus is causing it, right?
So you might need to do somemore investigating to figure out
the best way to treat it.
Jad (03:35):
That makes sense.
So it's a really valuable tool,but it's not a standalone
solution.
It's part of a bigger approach.
Lilly (03:42):
Exactly, exactly.
Jad (03:43):
Okay, so we've talked about the basics, the advantages, the
limitations.
I think it would be reallyhelpful to see this in action.
Lilly (03:50):
Well, sonic tomography relies on the principle that
sound travels at differentspeeds through different
materials.
Jad (03:56):
So if the wood is solid and healthy, the sound waves will
zip right through.
But if there's decay or a crack, those sound waves will slow
down.
It's like the differencebetween running on a smooth
track versus slogging throughmud.
Lilly (04:07):
And the tomograph measures those subtle
differences in sound velocity.
Jad (04:12):
And translates them into a visual map.
Now, this isn't a photograph ofthe inside of the tree.
Lilly (04:16):
It's a representation of how well the wood transmits
sound waves.
Jad (04:20):
And that transmission ability is directly related to
the wood's density.
Lilly (04:24):
And its ability to bear weight.
Jad (04:25):
Which is why sonic tomography is so valuable for
assessing tree health and risk.
Lilly (04:30):
Absolutely so.
Let's break down the process ofcreating a sonic tomogram step
by step.
Jad (04:35):
The first step is visual inspection.
Lilly (04:37):
Before we even think about placing sensors, we need
to carefully examine the tree.
Jad (04:41):
We're looking for cracks, damaged bark, fungal growth
cavities.
Lilly (04:46):
Anything that might indicate underlying structural
issues.
Jad (04:49):
So this initial assessment helps us figure out where to
place the sensors.
Lilly (04:53):
Exactly and we can focus on the areas of greatest concern
.
Jad (04:57):
For example, if we see Crutchmeria diosta fungus.
Lilly (05:00):
Which often grows upwards from the roots.
Jad (05:02):
We know, to focus on the root system and choose a lower
measuring level.
Lilly (05:06):
Makes sense right.
Jad (05:07):
It does so after playing detective.
Lilly (05:08):
We move on to installing the nails that will hold the
sensors.
Jad (05:11):
These nails are our measuring points.
Lilly (05:13):
And placement is crucial.
Jad (05:15):
First things first.
Lilly (05:16):
Make sure those nails are clean and free of rust.
Jad (05:19):
Why is that?
Lilly (05:20):
Because rusty nails can interfere with the electrical
conductivity and mess up ourmeasurements.
Jad (05:25):
And, speaking of accuracy, the spacing between those nails
is also critical.
Lilly (05:29):
Not too close, not too far.
Goldilocks Exactly.
A minimum spacing of 12 to 15centimeters ensures we capture
enough data.
Jad (05:37):
But we don't want them too far apart either.
Lilly (05:39):
Right.
A maximum spacing of 45centimeters prevents us from
missing important details.
Jad (05:44):
But those are just guidelines.
Lilly (05:46):
We can adjust them based on our visual inspection.
So if we see a large crack, wemight cluster nails more closely
around that area to get abetter picture of the damage.
Jad (05:55):
But be careful not to place nails directly into heavily
damaged areas.
Lilly (06:00):
Right, because that can distort the color scale of the
tomogram.
Finding the sweet spot betweencapturing detailed information
and maintaining the integrity ofour data.
Jad (06:09):
Got it.
So once the nails are in place,what's next?
Lilly (06:12):
Geometry measurement.
Jad (06:13):
Time to channel our inner mathematicians.
Lilly (06:15):
That's right, because precision is absolutely key here
.
Jad (06:19):
Even small errors in these measurements can significantly
impact the accuracy of the finaltomogram.
Lilly (06:25):
Imagine a builder using inaccurate measurements for the
foundation of a house.
Oh, the whole structure couldbe compromised.
Jad (06:32):
So no pressure right.
Lilly (06:34):
Not to worry, there are tools and techniques to help us
get it right.
Jad (06:37):
Like what.
Lilly (06:38):
Well, the simpler method assumes the tree trunk is a
perfect circle.
Jad (06:43):
We measure the circumference and the distances
between each nail along thatcircumference.
Easy peasy.
But trees are rarely perfectcircles, are they?
Lilly (06:51):
You're absolutely right so what then?
That's where the ellipticalmethod comes in.
Jad (06:55):
Tell me more.
Lilly (06:56):
This method involves measuring the circumference plus
the longest and shortestdiameters of the tree trunk.
Jad (07:02):
Recognizing that most trees have a slightly oval shape.
Lilly (07:05):
Exactly, and for those really irregularly shaped trees.
Jad (07:08):
What do we do then?
Lilly (07:09):
We have more advanced options like triangulation
methods.
Jad (07:12):
How do those work?
Lilly (07:13):
They use a series of baselines to pinpoint the exact
location of each sensor.
Jad (07:18):
Sounds complicated.
Lilly (07:19):
It can be, but the key is to be meticulous in our
measurements and use the correctunits.
Jad (07:24):
Which are Millimeters, millimeters, got it.
Lilly (07:27):
And thankfully we have software tools like the Pi CUS
program.
Jad (07:30):
That helps us calculate those theoretical distances
based on our measurements.
Lilly (07:34):
So we don't have to rely on mental math alone.
So, with our nails in place andour geometry measured, it's
time to install the sensors andbegin the sonic measurement.
Jad (07:45):
This is where the magic happens.
Lilly (07:46):
We carefully attach each sensor to its corresponding nail
, making sure they're secure andwon't get damaged during the
measurement process.
It's like equipping our treewith a network of listening
devices.
Jad (07:57):
Very cool.
Lilly (07:58):
And just like with any wiring job, organization is key.
Jad (08:02):
We don't want a tangled mess of cables.
Lilly (08:04):
That's right.
So we'll use clips to keepthose sensor cables organized.
So with everything set up,we're ready for the sonic scan
itself.
Jad (08:10):
This is where we tap each nail with a specialized hammer.
Lilly (08:14):
Sending sound waves through the wood and collecting
data from all the measuringpoints.
Jad (08:18):
But wait a minute, I thought we only attached sensors
to some of the nails.
Lilly (08:21):
Yes.
Jad (08:22):
Do we need to collect data from all of them, even the ones
without sensors?
Lilly (08:26):
Yes, absolutely.
Jad (08:27):
Why is that?
Lilly (08:28):
Because the software analyzes how long it takes for
those sound waves to travelbetween each and every measuring
point.
Jad (08:35):
Even those without a sensor directly attached.
Exactly so if we have moremeasuring points than sensors.
Lilly (08:41):
We'll need to do a sensor changeover during the scan.
Jad (08:43):
Moving the sensors around to collect data from all the
nails.
Lilly (08:46):
You got it.
Jad (08:47):
This all sounds pretty intricate.
Lilly (08:49):
It is, but the software guides us through the process.
Jad (08:52):
So how does all of this sonic data get transformed into
that visual tomogram?
Lilly (08:57):
It is pretty amazing the tomograph software downloads all
the data.
Jad (09:01):
And then what?
Lilly (09:02):
It starts crunching the numbers.
It analyzes the velocitydifferences between all those
measuring points.
Jad (09:08):
Looking for patterns.
Lilly (09:09):
Exactly Patterns that indicate potential defects.
Jad (09:13):
So it's not just about individual sound speeds.
Lilly (09:16):
No, it's about the relationships between them.
Jad (09:18):
The software is looking for anomalies.
Lilly (09:20):
Right Areas, where the sound waves slowed down
significantly.
Jad (09:24):
Which often means.
Lilly (09:24):
Decay cavities, cracks or other structural weaknesses.
Jad (09:28):
And then all of that gets translated into the tomogram.
Lilly (09:31):
That colorful visual representation.
Jad (09:33):
Okay, so let's talk about those colors.
Sure, we mentioned earlier thatblack and brown are generally
good signs.
Lilly (09:38):
Those dark colors represent high sonic velocities.
Jad (09:41):
Meaning.
Lilly (09:41):
The sound waves are traveling through the wood
quickly.
Jad (09:44):
So that indicates D dense healthy wood.
It's like a strong bone in thetree.
Lilly (09:48):
That's a great analogy, but remember the tomogram
doesn't show us wood densitydirectly.
Jad (09:53):
Right.
Lilly (09:54):
The wood's ability to transmit sound waves.
Jad (09:57):
Which tells us about the density and strength.
Lilly (09:59):
Exactly.
Jad (10:00):
So what about when we start seeing green on the tomogram?
Lilly (10:04):
Green is a bit of a caution flag.
What would it mean?
It could mean a few thingsMinor variations in wood density
.
Early stages of decay.
Jad (10:12):
So it's not necessarily a huge problem.
Lilly (10:15):
Not always, but it's a signal to pay closer attention.
Jad (10:18):
And investigate further.
Lilly (10:19):
Right.
We need to consider thetomogram, our visual assessment
and the specific tree species.
Jad (10:25):
So a green area in a young tree might be normal.
Lilly (10:29):
But in an older tree, especially with visible signs of
decay, it could be a biggerissue.
Jad (10:34):
Makes sense.
What about those blues andwhites?
Lilly (10:38):
Those are the ones to be more cautious about.
Jad (10:39):
What do they represent?
Lilly (10:41):
They represent low sonic velocities.
Jad (10:44):
Meaning.
Lilly (10:44):
Significant disruptions in the wood structure.
Jad (10:47):
Like fractures in the tree's skeleton.
Lilly (10:48):
That's a good way to visualize it.
Jad (10:50):
So these low velocity zones often indicate.
Lilly (10:52):
Advanced decay cavities or other major defects.
Jad (10:56):
That weaken the tree.
Lilly (10:57):
Exactly so.
If we see a large area of bluein the center, what could that
mean?
It could indicate a cavitythat's been present for a while.
Jad (11:04):
And the tree has compartmentalized it.
Lilly (11:06):
Right, it's formed a strong boundary around the decay
.
Jad (11:09):
Like a wall to contain the damage.
Lilly (11:10):
Exactly, but if we see a smaller area of bright white,
Then what that might suggest anewer, more active area of decay
.
Jad (11:24):
So the size, shape and location of those blue and white
areas, combined with our otherobservations, Give us a clearer
picture of the problem.
It sounds like there's a realart to reading these tomograms.
Lilly (11:31):
There is.
It's like learning a newlanguage.
Jad (11:33):
Understanding the nuances of those color patterns Exactly.
Speaking of patterns, are thereany specific ones we should
look for?
Lilly (11:40):
Absolutely.
There are a few classicpatterns that often show up.
Jad (11:44):
Like what.
Lilly (11:45):
One is the bullseye.
Jad (11:46):
What does that look like?
Lilly (11:47):
A circular area of low sonic velocity in the center,
surrounded by rings of highervelocity.
Jad (11:53):
So the center is the most affected area.
Lilly (11:55):
Right.
It often suggests decayspreading outwards from the
center.
Jad (11:59):
Like ripples in a pond.
Lilly (12:00):
Exactly.
What about the pie slicepattern?
Jad (12:02):
I've heard of that one.
What is it?
Lilly (12:04):
It appears as a triangular or wedge-shaped area
of low velocity.
Jad (12:08):
Usually extending from the edge towards the center.
Lilly (12:10):
Right, often indicating decay that's entered through a
wound.
Jad (12:14):
Or a branch attachment point.
Lilly (12:15):
Makes sense.
Right the decay follows thepath of least resistance.
Interesting, and then there's alinear pattern that one appears
as a straight or slightlycurved line of low velocity.
Jad (12:27):
Running vertically.
Lilly (12:28):
Often yes.
Jad (12:29):
So what does that usually mean?
Lilly (12:30):
It could indicate a crack , a split or decay following the
grain of the wood.
Jad (12:35):
Wow, these visual patterns provide so many clues.
Lilly (12:38):
They do, but remember.
These are just a few examples.
Jad (12:41):
Right and interpretation can vary.
Lilly (12:43):
Depending on the tree species, its age, location and
other factors.
Jad (12:47):
So we still need to use our professional judgment.
Lilly (12:49):
Absolutely so.
Let's shift gears for a momentand talk about sonic velocity
and wood strength.
Jad (12:54):
Okay, this is where things get a bit more technical.
Lilly (12:56):
It is, but it's important .
As we mentioned earlier, sonicvelocity is a good indicator of
wood density.
Jad (13:02):
And density is a key factor in wood strength.
Lilly (13:05):
Exactly so generally those dark colors on the
tomogram.
Jad (13:09):
The areas of high sonic velocity.
Lilly (13:10):
Tend to be stronger than the blues and whites.
Jad (13:13):
The areas of low sonic velocity.
Lilly (13:15):
Right, but it's not a perfect relationship.
Other factors can affect woodstrength too, Like the type of
wood, moisture content and thepresence of knots or other
defects.
Jad (13:25):
So we can't just look at a tomogram and know for sure.
Lilly (13:28):
No, we need to consider all the available information.
Jad (13:31):
But the sonic velocity data can still give us valuable
insight.
Lilly (13:34):
Absolutely.
For example, a large area ofblue.
Jad (13:38):
Probably means that area is weaker.
Lilly (13:40):
Than an adjacent area of brown.
Jad (13:42):
Even if we can't pinpoint the exact strength.
Lilly (13:44):
Exactly Now.
Let's talk about thelimitations of sonic tomography.
Jad (13:48):
Okay, no, technology is perfect.
Lilly (13:50):
That's right.
So what are some of thelimitations?
Jad (13:52):
I'm all ears.
Lilly (13:53):
One limitation is that sonic tomography only gives us
information about a singlecross-section of the tree.
Jad (13:59):
At the height where we place the sensors.
Lilly (14:01):
Exactly so.
It's a snapshot, a slice of thetree's internal structure.
Jad (14:05):
But the tree structure can vary above and below that level.
Lilly (14:09):
Absolutely.
Jad (14:09):
So we can't assume that a defect extends throughout the
entire trunk.
Lilly (14:13):
Right, it might just be a localized issue.
Jad (14:15):
And another limitation.
Lilly (14:16):
Sonic tomography is most sensitive to defects located
directly between the measuringpoints.
Jad (14:21):
The nails.
Lilly (14:22):
Exactly so if a defect is hidden behind a nail.
Jad (14:27):
We might miss it.
Lilly (14:28):
That's possible, which is why careful sensor placement is
so important.
Jad (14:32):
Based on our visual inspection.
Lilly (14:33):
Right, we need to think strategically about nail
placement.
Jad (14:36):
Trying to find those hidden defects Exactly.
Lilly (14:39):
And another thing to keep in mind.
Jad (14:40):
What's that?
Lilly (14:41):
Moisture content can affect sonic velocity readings.
Jad (14:44):
How so.
Lilly (14:45):
If the wood is very wet, the sound waves will travel more
slowly.
Jad (14:49):
So it might look like there's decay, even if the wood
is sound.
Lilly (14:53):
That's right.
So it's best to takemeasurements when the wood is
relatively dry.
Jad (14:58):
Or use other tools to confirm our findings.
Lilly (15:00):
Right, we can't rely solely on the tomogram.
Jad (15:03):
It's just one piece of the puzzle.
Lilly (15:05):
Exactly so.
Let's talk about the companiesoffering sonic tomography
systems.
Jad (15:10):
Who are the main players?
Lilly (15:11):
Well, there are three main companies right now.
Jad (15:14):
Tell me about them.
Lilly (15:15):
The first is FUKOP from Hungary.
Jad (15:18):
What are they known for?
Lilly (15:19):
They offer the most affordable systems.
Jad (15:21):
So they make the technology more accessible.
Lilly (15:22):
Absolutely.
The second company is Picus,where are they from?
Germany.
Jad (15:27):
And what about them?
Lilly (15:28):
They're known for their advanced technology and
user-friendly software.
So if you want the latestfeatures, Picus might be a good
option, but regardless of whichcompany you choose, the
principles of sonic tomographyare the same.
Jad (15:47):
That's right.
We're still using sound wavesto map the tree and learn about
its health.
Lilly (15:49):
It's amazing how this technology allows us to see
inside the tree without harmingit, it is.
But remember what's that?
Sonic tomography is just onetool.
Jad (15:55):
We need to combine it with our experience and knowledge
Absolutely To make the bestdecisions for the trees.
Lilly (16:01):
Exactly, and that's what makes this field so fascinating
we're always learning andfinding new ways to understand
trees.
Jad (16:07):
You mentioned some case studies earlier.
Lilly (16:09):
Yeah, I've got a couple of examples from the research
that I think really highlighthow useful sonic tomography can
be.
One study looked at a Norwayspruce that was suspected of
having some internal decay, butthere were no outward signs.
Jad (16:25):
Oh, wow, so you couldn't tell just by looking at it.
Lilly (16:27):
Right.
But when they did the sonictomography it showed the decay
pretty clearly and then later,when they actually cut down the
tree, they were able to confirmthat the tomogram was accurate,
so it really was seeing insidethe tree.
Yeah, and then anotherinteresting case was with a
linden tree that had this bigcavity.
You could see it from theoutside.
Jad (16:44):
Oh, so this one was visible .
Lilly (16:46):
Yeah, but the sonic tomography didn't just show the
cavity, it also showed the areaaround it where the decay was
still active.
Jad (16:54):
So it showed how far the problem actually extended.
Lilly (16:57):
Exactly, and that information was really important
for figuring out how to managethe tree, like should they try
to support it or was it too fargone and needed to be removed.
Jad (17:07):
Okay, so in both of those cases the sonic tomography
really helped to make a moreinformed decision about how to
manage the tree.
Do you have any other?
Lilly (17:15):
examples trees that were infected with this really
aggressive fungus calledCrechmeria deusta, and in those
trees the tomogram showed thisreally distinct pattern, what
they called a conductive center,which is typical of that
particular fungus.
Jad (17:33):
So by seeing that pattern they could be pretty sure what
was causing the problem.
Lilly (17:37):
Exactly, and that can be really helpful for figuring out
the best course of treatment.
Jad (17:41):
These cases are really interesting.
I mean they really show how asonic tomography can be really
helpful for figuring out thebest course of treatment.
These cases are reallyinteresting.
I mean they really show how asonic tomography can be used in
a practical way to help managetrees.
So we've talked about sonictomography as a standalone tool,
but how does it fit in withother methods that professionals
might be using?
Lilly (17:56):
Well, it really complements the other methods
out there.
Like you should still be doingvisual inspections, you know,
looking for those external signsof problems.
And there are other tools likethe resistograph that measure
drilling resistance.
Jad (18:09):
Right right.
Lilly (18:10):
And even sometimes you do a tree-pulling test to assess
stability.
But sonic tomography gives youthis extra layer of information,
that internal view that youwouldn't get otherwise.
Jad (18:20):
So it's like putting all the pieces of the puzzle
together to get a more completepicture of what's going on.
Lilly (18:24):
Exactly.
Jad (18:25):
Okay, so we've talked about what sonic tomography is, the
advantages, the limitations,some case studies.
I think it'd be reallyfascinating to dive a little
deeper into the science of wooddecay itself.
Sure, yeah, what can you tellus about that?
Lilly (18:36):
So wood decay is a really complex process.
Actually, there are differenttypes of decay, like brown rot,
white rot and soft rot, and eachof those is caused by different
types of fungi.
Jad (18:48):
Fungi huh.
Lilly (18:49):
Yeah, these fungi.
They release enzymes that breakdown the wood, basically eating
it, and the way they break downthe wood that's what determines
the type of rot.
Like brown rot fungi, theymainly go after the cellulose in
the wood, so what's left behindis this crumbly brown stuff.
White rot fungi they break downboth cellulose and lignin, so
(19:10):
the wood gets lighter and kindof stringy.
Jad (19:12):
Wow, so it's like they have different tastes in wood.
Lilly (19:15):
Yeah, you could say that.
And then soft rot.
That's usually caused by fungithat thrive in really wet
conditions and it can make thewood soft and spongy.
Jad (19:24):
So depending on the type of rot, it can have a really
different impact on the strengthand stability of the tree.
Lilly (19:28):
Right oh absolutely, and that's why it's so important to
be able to identify the type ofdecay, so you know how to manage
it.
Jad (19:34):
Okay, so the type of fungus determines the type of rot, but
what are some of the otherfactors that influence how decay
develops in a tree?
Lilly (19:42):
Well, the species of tree definitely plays a role.
Some species are more resistantto decay than others.
Jad (19:48):
Oh, that makes sense.
Lilly (19:49):
And then how aggressive the fungus is.
That matters too.
Some fungi are real powerhouses.
They can spread really quickly.
And then the environment playsa big role.
Moisture is key.
Most wood decay fungi need acertain amount of moisture to
thrive.
So if a tree is in a really dryenvironment, it's less likely
to have decay problems.
(20:09):
But if it's in a damp spot,that's a different story.
Jad (20:12):
So, like a tree growing in a swamp versus a tree growing in
the desert, they're going tohave really different decay
risks.
Lilly (20:18):
Exactly, and then the tree itself can fight back to
some extent.
Some trees have really strongdefense mechanisms, like they
can form these reaction zonesaround the decayed area, trying
to wall it off and prevent itfrom spreading.
But other trees have weakerdefenses.
Jad (20:32):
So it's like a constant battle between the tree and the
fungi.
Lilly (20:35):
Yeah, kind of, and the outcome of that battle depends
on a lot of different factors.
Jad (20:39):
This is all really fascinating stuff but you know,
I keep thinking about all theprofessionals listening who
might be using sonic tomography.
It seems like you really need agood understanding of all of
this the different types ofdecay, the factors that
influence it to really interpretthose tomograms correctly.
Lilly (20:57):
Oh, absolutely.
You can't just look at thepretty colors on the tomogram.
You've got to understand whatthose colors mean.
You can't just look at thepretty colors on the tomogram.
You've got to understand whatthose colors mean.
You've got to know about treebiology, about wood decay
processes, about the specifictree species you're dealing with
.
It's all connected.
Jad (21:09):
So, basically, learning never stops for a tree
professional.
Lilly (21:13):
Definitely not.
Jad (21:14):
You've always got to be up to date on the latest research
and techniques.
Well, I think this has been areally great overview of the
science behind sonic tomographyand wood decay.
Lilly (21:23):
Yeah, definitely.
Jad (21:24):
I'm sure our listeners are eager to learn more about the
practical applications of thistechnology.
Lilly (21:29):
For sure.
But before we move on to thosepractical applications, I think
we should touch on somethingelse that's really important the
ethical side of things.
Jad (21:36):
Oh yeah, that's a good point.
We've been talking about allthe cool stuff sonic tomography
can do, but like any tool, it'sgot to be used responsibly.
Lilly (21:44):
Exactly.
I mean, we've talked about howit's non-invasive, but even
driving those nails into thetree that still creates a wound.
Jad (21:51):
Right.
Lilly (21:51):
Right.
So you have to be reallycareful about, you know,
sterilizing everything, usingthe right size nail for the tree
, placing the sensors in spotswhere you're not going to cause
extra damage.
Jad (22:03):
So it's not completely without risk, even though it's
less invasive than some othermethods.
Lilly (22:08):
Yeah, and then there's also the risk of misinterpreting
the results, right?
Jad (22:12):
Oh yeah, we talked about how that takes some expertise.
Lilly (22:14):
Exactly so.
If someone doesn't have theright training, they might
misinterpret the tomogram andmake a wrong decision about the
tree.
Jad (22:22):
Like maybe they remove a tree that was actually healthy,
or they think a tree is safewhen it's not.
Lilly (22:27):
Right, exactly.
That's why it's so important tohave qualified people doing
these assessments.
Jad (22:39):
And on that note, I guess there's also the risk of bias,
right, Like if someone alreadythinks a tree is dangerous they
might see what they want to seein the tomogram, even if it's
not really there.
Lilly (22:43):
That's a good point.
Yeah, it's important to beaware of that potential for bias
and to try to be as objectiveas possible when interpreting
the results.
Jad (22:50):
So maybe having multiple people look at the tomogram or
using some kind of standardizedguidelines for interpretation?
Lilly (22:57):
Yeah, definitely Anything that can help reduce that bias
and make sure the assessment isas accurate as possible.
Jad (23:03):
Okay, so ethical considerations definitely
important to keep in mind, butI'm also thinking about, you
know, the practical side forprofessionals.
What about the cost of all this?
Sonic tomography?
It sounds pretty high tech, soI'm guessing it's not exactly
cheap.
Lilly (23:17):
Yeah, you're right, it can be a significant investment.
The cost of the equipmentitself can vary a lot depending
on the features and capabilities, and then there's the cost of
training and software andmaintenance.
Jad (23:29):
So it's something professionals need to factor
into their budget definitely.
Lilly (23:32):
Right, but on the flip side you have to think about the
value of the information you'regetting.
Jad (23:44):
Like, if you can identify a hazardous tree before it falls
and causes damage.
That could save a lot of moneyin the long run, true, true, so
it's an investment, but it's aninvestment that could
potentially save you money andheadaches down the road.
Lilly (23:51):
Exactly, and there are ways to make it more affordable.
Headaches down the road Exactly, and there are ways to make it
more affordable.
Like some, companies offersonic tomography services on a
contract basis, so you don'thave to buy the equipment
outright.
Jad (24:01):
Okay.
So there are options out there,but even if the cost is
manageable, you still got tomake sure it's worth it.
Right Like, is there enoughdemand for this kind of service?
Lilly (24:11):
Yeah, that's a good point , but I think the demand is
growing.
Actually, as people become moreaware of the benefits of sonic
tomography, they're starting toask for it specifically.
Jad (24:21):
So it could actually give you a competitive edge if you
offer it.
Lilly (24:24):
Definitely.
Jad (24:25):
Okay, so we've talked about the cost, the demand, but what
about the future?
Where do you see sonictomography going in the next few
years?
Lilly (24:33):
Oh, there are some really exciting developments happening
, like one of the big things isartificial intelligence or AI.
They're starting to use AI toanalyze sonic tomography data,
which could make theinterpretation process much
faster and more accurate.
Jad (24:46):
Wow, ai for trees.
Lilly (24:48):
Yeah, and then there's also this idea of using machine
learning to create predictivemodels, so they could use data
from past sonic tomography scansalong with other information
about the tree to predictwhether it's likely to develop
problems in the future.
Jad (25:04):
Oh wow, that would be amazing, like preventative tree
care.
Lilly (25:07):
Exactly.
And then there's also workbeing done on integrating sonic
tomography with othertechnologies, like ground
penetrating radar, which couldgive you an even more complete
picture of the tree's health.
Jad (25:18):
That sounds really cool.
So it seems like there's a lotof potential for sonic
tomography to become even morepowerful and useful in the
future.
Lilly (25:25):
Definitely.
I think we're just scratchingthe surface of what this
technology can do.
Jad (25:29):
Well, I'm definitely excited to see what the future
holds for sonic tomography, butfor all the professionals
listening who might be thinkingabout getting into this field, I
guess the big question is wheredo you start?
Lilly (25:40):
Yeah, that's a good question.
Well, first and foremost,education is key.
You need to understand thescience behind sonic tomography,
how to operate the equipmentand how to interpret the results
.
Jad (25:51):
So finding a good training program is crucial.
Lilly (25:54):
Absolutely.
There are some great programsout there offered by
organizations like the ISA, ascaand TCIA.
Jad (26:02):
Okay, so you get the training, you understand the
science.
What's next?
Lilly (26:05):
Well then, it's about choosing the right equipment for
your needs and your budget.
There are a lot of differentdevices out there, so it's
important to do your researchand figure out which one is best
for you.
Jad (26:16):
And once you have the equipment and the training, then
it's just a matter of practiceright Exactly.
Lilly (26:20):
The more you use it, the more comfortable and confident
you'll become.
Start with simple assessments,maybe on trees you're already
familiar with, and graduallywork your way up to more complex
cases.
Jad (26:31):
So don't be afraid to start small and build your skills
over time.
No-transcript and a willingnessto learn from others.
Lilly (27:03):
I think that sums it up perfectly.
Jad (27:05):
This has been a really fascinating discussion about how
professionals can incorporatesonic tomography into their work
.
But you know we've beenfocusing a lot on the technical
and practical side of things.
I think it would be reallyvaluable to step back for a
moment and think about thebigger picture, sure.
Lilly (27:21):
Yeah.
Jad (27:22):
How does sonic tomography fit into the broader context of
tree conservation andsustainability?
Lilly (27:27):
That's a great point.
I think sonic tomography has areally important role to play in
those efforts, like it can helpus to identify and preserve
veteran trees, those really oldand valuable trees that are part
of our natural heritage.
Jad (27:39):
Right, those trees are irreplaceable.
Lilly (27:41):
Exactly, and it can also help us to manage urban forests
more sustainably, like if youcan accurately assess the health
of trees in a city, you canavoid unnecessary removals and
make sure those trees are aroundfor as long as possible.
Jad (27:55):
So it's about using technology to make sure we're
making the best decisions forthe trees and for the
environment.
Lilly (28:01):
Exactly, and all of that information can help us to
develop strategies to protecttrees and make sure they're
around for future generations.
Jad (28:08):
That's really inspiring.
Actually, it seems like sonictomography is more than just a
tool.
It's like a way of connectingwith trees on a deeper level.
Lilly (28:17):
I think that's a beautiful way to put it.
It's about seeing beyond thebark and understanding the life
that's going on inside thosetrees, and I think that
understanding can lead to agreater appreciation for trees
and a stronger commitment toprotecting them.
Jad (28:30):
It's been amazing exploring the world of sonic tomography
with you.
We've really gone deep, fromthe science behind it to the
ethics, the costs, what's comingnext and how it all ties into
taking care of trees in the bestway possible.
Lilly (28:43):
Absolutely.
It's a really fascinating fieldand I think we've just
scratched the surface.
Jad (28:48):
For sure.
Roger (28:52):
Thank you for joining us for this exploration of tree
health assessment techniques.
Today we covered the essentialtools and methods arborists use
to detect hidden decay andstructural weaknesses.
We're grateful for your supporton heroheroco slash
talkingtrees, which enables usto continue bringing you
valuable insights from the worldof arboriculture.
(29:13):
Thanks for listening and we'llsee you next time.
Talking Trees with Lily and Jad.
Welcome to today's episode.
We're diving into the world oftree stability assessment, with
a focus on methods for detectinginternal decay in trees.
We'll dive into sonictomography and the PICUS
Treetronic device, an advancedtool for measuring wood
resistance.
(00:22):
These tools offer arborists amore comprehensive understanding
of tree stability andmechanical integrity.
Let's get started.
Jad (00:35):
Welcome back everyone Ready for another deep dive.
This time we're focusing onsonic tomography, especially for
all you professionals out there.
Sounds good.
We're going to figure out howit's used, what its advantages
are, what are the limitations,and we've got some interesting
cases to look at too.
Lilly (00:51):
Yeah, definitely.
Jad (00:52):
And we've got a mix of sources this time, which is
always fun.
We've got a software manual,We've got some of those really
in-depth scientific papers andeven some visuals you sent over
which are pretty cool.
Lilly (01:01):
Yeah.
Jad (01:02):
So first things first.
What exactly is sonictomography?
I mean, I think a lot of ourlisteners have probably heard
the term, but maybe not everyoneknows exactly how it works.
Lilly (01:13):
Well, think of it this way it basically lets us see
inside a tree without having to,you know, chop it down or
anything.
Jad (01:19):
Whoa hold on.
That's like x-ray vision fortrees.
Lilly (01:22):
Exactly.
It uses sound waves, so youmeasure how those waves travel
through the wood and thatreveals the internal structure,
like you know, is there decayhidden in there?
Are there cavities, things likethat.
Jad (01:36):
That's got to be so useful for like assessing the health of
a tree right Absolutely.
Lilly (01:38):
You can detect problems really early, even before you
see any signs on the outside.
Jad (01:41):
Wow, that's incredible.
So what would you say are thebiggest advantages of sonic
tomography?
And we've touched on a couplealready, but for the
professionals listening, whatreally makes this stand out?
Lilly (01:53):
Well, like I said, it's non-invasive right.
You're not harming the tree atall.
Jad (01:58):
True, true.
Lilly (01:59):
Which is huge, especially when you're dealing with, you
know, maybe a really old tree orone that's important for
historical reasons.
You don't want to be drillinginto that just to see what's
going on inside, Right?
Jad (02:09):
right.
Lilly (02:09):
And then those tomograms, those visual representations
you get, those are really easyto understand, even if you're
not, you know, a tree expert.
Jad (02:18):
Oh, so you can actually show those to clients and they
can kind of get a sense of OK,this is what's happening inside
my tree.
Lilly (02:25):
Exactly.
It makes it much easier toexplain things.
And then, of course, the earlydetection part is huge.
Catching decay early can make abig difference in how you
manage the tree, maybe even saveit.
Jad (02:37):
Okay.
So it's non-invasive, it givesyou these easy to understand
visuals and it helps with earlydetection, but every tool has
its limits, right.
Lilly (02:45):
Of course.
Jad (02:46):
What are some of the limitations of sonic tomography
that we should be aware of?
Lilly (02:50):
Well, one of the biggest things is that the accuracy
depends a lot of how you setthings up, like where you place
those sensors, how accurate yourmeasurements are.
That all plays a role.
Jad (02:59):
So it's not just point and shoot.
There's definitely some skillinvolved.
Lilly (03:02):
Exactly, and then even once you have those tomograms,
interpreting them correctly.
That takes some expertise too.
You got to be able todistinguish between different
types of decay, or maybesomething that looks like decay
but isn't.
It's not always straightforward.
Jad (03:15):
So training is important.
Lilly (03:16):
Oh yeah, definitely, and it's important to remember that
tomography shows you what'sgoing on, but it doesn't
necessarily tell you why it'shappening.
Jad (03:26):
That's a good point.
Lilly (03:26):
Like, you might see decay , but you don't know what kind
of fungus is causing it, right?
So you might need to do somemore investigating to figure out
the best way to treat it.
Jad (03:35):
That makes sense.
So it's a really valuable tool,but it's not a standalone
solution.
It's part of a bigger approach.
Lilly (03:42):
Exactly, exactly.
Jad (03:43):
Okay, so we've talked about the basics, the advantages, the
limitations.
I think it would be reallyhelpful to see this in action.
Lilly (03:50):
Well, sonic tomography relies on the principle that
sound travels at differentspeeds through different
materials.
Jad (03:56):
So if the wood is solid and healthy, the sound waves will
zip right through.
But if there's decay or a crack, those sound waves will slow
down.
It's like the differencebetween running on a smooth
track versus slogging throughmud.
Lilly (04:07):
And the tomograph measures those subtle
differences in sound velocity.
Jad (04:12):
And translates them into a visual map.
Now, this isn't a photograph ofthe inside of the tree.
Lilly (04:16):
It's a representation of how well the wood transmits
sound waves.
Jad (04:20):
And that transmission ability is directly related to
the wood's density.
Lilly (04:24):
And its ability to bear weight.
Jad (04:25):
Which is why sonic tomography is so valuable for
assessing tree health and risk.
Lilly (04:30):
Absolutely so.
Let's break down the process ofcreating a sonic tomogram step
by step.
Jad (04:35):
The first step is visual inspection.
Lilly (04:37):
Before we even think about placing sensors, we need
to carefully examine the tree.
Jad (04:41):
We're looking for cracks, damaged bark, fungal growth
cavities.
Lilly (04:46):
Anything that might indicate underlying structural
issues.
Jad (04:49):
So this initial assessment helps us figure out where to
place the sensors.
Lilly (04:53):
Exactly and we can focus on the areas of greatest concern
.
Jad (04:57):
For example, if we see Crutchmeria diosta fungus.
Lilly (05:00):
Which often grows upwards from the roots.
Jad (05:02):
We know, to focus on the root system and choose a lower
measuring level.
Lilly (05:06):
Makes sense right.
Jad (05:07):
It does so after playing detective.
Lilly (05:08):
We move on to installing the nails that will hold the
sensors.
Jad (05:11):
These nails are our measuring points.
Lilly (05:13):
And placement is crucial.
Jad (05:15):
First things first.
Lilly (05:16):
Make sure those nails are clean and free of rust.
Jad (05:19):
Why is that?
Lilly (05:20):
Because rusty nails can interfere with the electrical
conductivity and mess up ourmeasurements.
Jad (05:25):
And, speaking of accuracy, the spacing between those nails
is also critical.
Lilly (05:29):
Not too close, not too far.
Goldilocks Exactly.
A minimum spacing of 12 to 15centimeters ensures we capture
enough data.
Jad (05:37):
But we don't want them too far apart either.
Lilly (05:39):
Right.
A maximum spacing of 45centimeters prevents us from
missing important details.
Jad (05:44):
But those are just guidelines.
Lilly (05:46):
We can adjust them based on our visual inspection.
So if we see a large crack, wemight cluster nails more closely
around that area to get abetter picture of the damage.
Jad (05:55):
But be careful not to place nails directly into heavily
damaged areas.
Lilly (06:00):
Right, because that can distort the color scale of the
tomogram.
Finding the sweet spot betweencapturing detailed information
and maintaining the integrity ofour data.
Jad (06:09):
Got it.
So once the nails are in place,what's next?
Lilly (06:12):
Geometry measurement.
Jad (06:13):
Time to channel our inner mathematicians.
Lilly (06:15):
That's right, because precision is absolutely key here
.
Jad (06:19):
Even small errors in these measurements can significantly
impact the accuracy of the finaltomogram.
Lilly (06:25):
Imagine a builder using inaccurate measurements for the
foundation of a house.
Oh, the whole structure couldbe compromised.
Jad (06:32):
So no pressure right.
Lilly (06:34):
Not to worry, there are tools and techniques to help us
get it right.
Jad (06:37):
Like what.
Lilly (06:38):
Well, the simpler method assumes the tree trunk is a
perfect circle.
Jad (06:43):
We measure the circumference and the distances
between each nail along thatcircumference.
Easy peasy.
But trees are rarely perfectcircles, are they?
Lilly (06:51):
You're absolutely right so what then?
That's where the ellipticalmethod comes in.
Jad (06:55):
Tell me more.
Lilly (06:56):
This method involves measuring the circumference plus
the longest and shortestdiameters of the tree trunk.
Jad (07:02):
Recognizing that most trees have a slightly oval shape.
Lilly (07:05):
Exactly, and for those really irregularly shaped trees.
Jad (07:08):
What do we do then?
Lilly (07:09):
We have more advanced options like triangulation
methods.
Jad (07:12):
How do those work?
Lilly (07:13):
They use a series of baselines to pinpoint the exact
location of each sensor.
Jad (07:18):
Sounds complicated.
Lilly (07:19):
It can be, but the key is to be meticulous in our
measurements and use the correctunits.
Jad (07:24):
Which are Millimeters, millimeters, got it.
Lilly (07:27):
And thankfully we have software tools like the Pi CUS
program.
Jad (07:30):
That helps us calculate those theoretical distances
based on our measurements.
Lilly (07:34):
So we don't have to rely on mental math alone.
So, with our nails in place andour geometry measured, it's
time to install the sensors andbegin the sonic measurement.
Jad (07:45):
This is where the magic happens.
Lilly (07:46):
We carefully attach each sensor to its corresponding nail
, making sure they're secure andwon't get damaged during the
measurement process.
It's like equipping our treewith a network of listening
devices.
Jad (07:57):
Very cool.
Lilly (07:58):
And just like with any wiring job, organization is key.
Jad (08:02):
We don't want a tangled mess of cables.
Lilly (08:04):
That's right.
So we'll use clips to keepthose sensor cables organized.
So with everything set up,we're ready for the sonic scan
itself.
Jad (08:10):
This is where we tap each nail with a specialized hammer.
Lilly (08:14):
Sending sound waves through the wood and collecting
data from all the measuringpoints.
Jad (08:18):
But wait a minute, I thought we only attached sensors
to some of the nails.
Lilly (08:21):
Yes.
Jad (08:22):
Do we need to collect data from all of them, even the ones
without sensors?
Lilly (08:26):
Yes, absolutely.
Jad (08:27):
Why is that?
Lilly (08:28):
Because the software analyzes how long it takes for
those sound waves to travelbetween each and every measuring
point.
Jad (08:35):
Even those without a sensor directly attached.
Exactly so if we have moremeasuring points than sensors.
Lilly (08:41):
We'll need to do a sensor changeover during the scan.
Jad (08:43):
Moving the sensors around to collect data from all the
nails.
Lilly (08:46):
You got it.
Jad (08:47):
This all sounds pretty intricate.
Lilly (08:49):
It is, but the software guides us through the process.
Jad (08:52):
So how does all of this sonic data get transformed into
that visual tomogram?
Lilly (08:57):
It is pretty amazing the tomograph software downloads all
the data.
Jad (09:01):
And then what?
Lilly (09:02):
It starts crunching the numbers.
It analyzes the velocitydifferences between all those
measuring points.
Jad (09:08):
Looking for patterns.
Lilly (09:09):
Exactly Patterns that indicate potential defects.
Jad (09:13):
So it's not just about individual sound speeds.
Lilly (09:16):
No, it's about the relationships between them.
Jad (09:18):
The software is looking for anomalies.
Lilly (09:20):
Right Areas, where the sound waves slowed down
significantly.
Jad (09:24):
Which often means.
Lilly (09:24):
Decay cavities, cracks or other structural weaknesses.
Jad (09:28):
And then all of that gets translated into the tomogram.
Lilly (09:31):
That colorful visual representation.
Jad (09:33):
Okay, so let's talk about those colors.
Sure, we mentioned earlier thatblack and brown are generally
good signs.
Lilly (09:38):
Those dark colors represent high sonic velocities.
Jad (09:41):
Meaning.
Lilly (09:41):
The sound waves are traveling through the wood
quickly.
Jad (09:44):
So that indicates D dense healthy wood.
It's like a strong bone in thetree.
Lilly (09:48):
That's a great analogy, but remember the tomogram
doesn't show us wood densitydirectly.
Jad (09:53):
Right.
Lilly (09:54):
The wood's ability to transmit sound waves.
Jad (09:57):
Which tells us about the density and strength.
Lilly (09:59):
Exactly.
Jad (10:00):
So what about when we start seeing green on the tomogram?
Lilly (10:04):
Green is a bit of a caution flag.
What would it mean?
It could mean a few thingsMinor variations in wood density
.
Early stages of decay.
Jad (10:12):
So it's not necessarily a huge problem.
Lilly (10:15):
Not always, but it's a signal to pay closer attention.
Jad (10:18):
And investigate further.
Lilly (10:19):
Right.
We need to consider thetomogram, our visual assessment
and the specific tree species.
Jad (10:25):
So a green area in a young tree might be normal.
Lilly (10:29):
But in an older tree, especially with visible signs of
decay, it could be a biggerissue.
Jad (10:34):
Makes sense.
What about those blues andwhites?
Lilly (10:38):
Those are the ones to be more cautious about.
Jad (10:39):
What do they represent?
Lilly (10:41):
They represent low sonic velocities.
Jad (10:44):
Meaning.
Lilly (10:44):
Significant disruptions in the wood structure.
Jad (10:47):
Like fractures in the tree's skeleton.
Lilly (10:48):
That's a good way to visualize it.
Jad (10:50):
So these low velocity zones often indicate.
Lilly (10:52):
Advanced decay cavities or other major defects.
Jad (10:56):
That weaken the tree.
Lilly (10:57):
Exactly so.
If we see a large area of bluein the center, what could that
mean?
It could indicate a cavitythat's been present for a while.
Jad (11:04):
And the tree has compartmentalized it.
Lilly (11:06):
Right, it's formed a strong boundary around the decay
.
Jad (11:09):
Like a wall to contain the damage.
Lilly (11:10):
Exactly, but if we see a smaller area of bright white,
Then what that might suggest anewer, more active area of decay
.
Jad (11:24):
So the size, shape and location of those blue and white
areas, combined with our otherobservations, Give us a clearer
picture of the problem.
It sounds like there's a realart to reading these tomograms.
Lilly (11:31):
There is.
It's like learning a newlanguage.
Jad (11:33):
Understanding the nuances of those color patterns Exactly.
Speaking of patterns, are thereany specific ones we should
look for?
Lilly (11:40):
Absolutely.
There are a few classicpatterns that often show up.
Jad (11:44):
Like what.
Lilly (11:45):
One is the bullseye.
Jad (11:46):
What does that look like?
Lilly (11:47):
A circular area of low sonic velocity in the center,
surrounded by rings of highervelocity.
Jad (11:53):
So the center is the most affected area.
Lilly (11:55):
Right.
It often suggests decayspreading outwards from the
center.
Jad (11:59):
Like ripples in a pond.
Lilly (12:00):
Exactly.
What about the pie slicepattern?
Jad (12:02):
I've heard of that one.
What is it?
Lilly (12:04):
It appears as a triangular or wedge-shaped area
of low velocity.
Jad (12:08):
Usually extending from the edge towards the center.
Lilly (12:10):
Right, often indicating decay that's entered through a
wound.
Jad (12:14):
Or a branch attachment point.
Lilly (12:15):
Makes sense.
Right the decay follows thepath of least resistance.
Interesting, and then there's alinear pattern that one appears
as a straight or slightlycurved line of low velocity.
Jad (12:27):
Running vertically.
Lilly (12:28):
Often yes.
Jad (12:29):
So what does that usually mean?
Lilly (12:30):
It could indicate a crack , a split or decay following the
grain of the wood.
Jad (12:35):
Wow, these visual patterns provide so many clues.
Lilly (12:38):
They do, but remember.
These are just a few examples.
Jad (12:41):
Right and interpretation can vary.
Lilly (12:43):
Depending on the tree species, its age, location and
other factors.
Jad (12:47):
So we still need to use our professional judgment.
Lilly (12:49):
Absolutely so.
Let's shift gears for a momentand talk about sonic velocity
and wood strength.
Jad (12:54):
Okay, this is where things get a bit more technical.
Lilly (12:56):
It is, but it's important .
As we mentioned earlier, sonicvelocity is a good indicator of
wood density.
Jad (13:02):
And density is a key factor in wood strength.
Lilly (13:05):
Exactly so generally those dark colors on the
tomogram.
Jad (13:09):
The areas of high sonic velocity.
Lilly (13:10):
Tend to be stronger than the blues and whites.
Jad (13:13):
The areas of low sonic velocity.
Lilly (13:15):
Right, but it's not a perfect relationship.
Other factors can affect woodstrength too, Like the type of
wood, moisture content and thepresence of knots or other
defects.
Jad (13:25):
So we can't just look at a tomogram and know for sure.
Lilly (13:28):
No, we need to consider all the available information.
Jad (13:31):
But the sonic velocity data can still give us valuable
insight.
Lilly (13:34):
Absolutely.
For example, a large area ofblue.
Jad (13:38):
Probably means that area is weaker.
Lilly (13:40):
Than an adjacent area of brown.
Jad (13:42):
Even if we can't pinpoint the exact strength.
Lilly (13:44):
Exactly Now.
Let's talk about thelimitations of sonic tomography.
Jad (13:48):
Okay, no, technology is perfect.
Lilly (13:50):
That's right.
So what are some of thelimitations?
Jad (13:52):
I'm all ears.
Lilly (13:53):
One limitation is that sonic tomography only gives us
information about a singlecross-section of the tree.
Jad (13:59):
At the height where we place the sensors.
Lilly (14:01):
Exactly so.
It's a snapshot, a slice of thetree's internal structure.
Jad (14:05):
But the tree structure can vary above and below that level.
Lilly (14:09):
Absolutely.
Jad (14:09):
So we can't assume that a defect extends throughout the
entire trunk.
Lilly (14:13):
Right, it might just be a localized issue.
Jad (14:15):
And another limitation.
Lilly (14:16):
Sonic tomography is most sensitive to defects located
directly between the measuringpoints.
Jad (14:21):
The nails.
Lilly (14:22):
Exactly so if a defect is hidden behind a nail.
Jad (14:27):
We might miss it.
Lilly (14:28):
That's possible, which is why careful sensor placement is
so important.
Jad (14:32):
Based on our visual inspection.
Lilly (14:33):
Right, we need to think strategically about nail
placement.
Jad (14:36):
Trying to find those hidden defects Exactly.
Lilly (14:39):
And another thing to keep in mind.
Jad (14:40):
What's that?
Lilly (14:41):
Moisture content can affect sonic velocity readings.
Jad (14:44):
How so.
Lilly (14:45):
If the wood is very wet, the sound waves will travel more
slowly.
Jad (14:49):
So it might look like there's decay, even if the wood
is sound.
Lilly (14:53):
That's right.
So it's best to takemeasurements when the wood is
relatively dry.
Jad (14:58):
Or use other tools to confirm our findings.
Lilly (15:00):
Right, we can't rely solely on the tomogram.
Jad (15:03):
It's just one piece of the puzzle.
Lilly (15:05):
Exactly so.
Let's talk about the companiesoffering sonic tomography
systems.
Jad (15:10):
Who are the main players?
Lilly (15:11):
Well, there are three main companies right now.
Jad (15:14):
Tell me about them.
Lilly (15:15):
The first is FUKOP from Hungary.
Jad (15:18):
What are they known for?
Lilly (15:19):
They offer the most affordable systems.
Jad (15:21):
So they make the technology more accessible.
Lilly (15:22):
Absolutely.
The second company is Picus,where are they from?
Germany.
Jad (15:27):
And what about them?
Lilly (15:28):
They're known for their advanced technology and
user-friendly software.
So if you want the latestfeatures, Picus might be a good
option, but regardless of whichcompany you choose, the
principles of sonic tomographyare the same.
Jad (15:47):
That's right.
We're still using sound wavesto map the tree and learn about
its health.
Lilly (15:49):
It's amazing how this technology allows us to see
inside the tree without harmingit, it is.
But remember what's that?
Sonic tomography is just onetool.
Jad (15:55):
We need to combine it with our experience and knowledge
Absolutely To make the bestdecisions for the trees.
Lilly (16:01):
Exactly, and that's what makes this field so fascinating
we're always learning andfinding new ways to understand
trees.
Jad (16:07):
You mentioned some case studies earlier.
Lilly (16:09):
Yeah, I've got a couple of examples from the research
that I think really highlighthow useful sonic tomography can
be.
One study looked at a Norwayspruce that was suspected of
having some internal decay, butthere were no outward signs.
Jad (16:25):
Oh, wow, so you couldn't tell just by looking at it.
Lilly (16:27):
Right.
But when they did the sonictomography it showed the decay
pretty clearly and then later,when they actually cut down the
tree, they were able to confirmthat the tomogram was accurate,
so it really was seeing insidethe tree.
Yeah, and then anotherinteresting case was with a
linden tree that had this bigcavity.
You could see it from theoutside.
Jad (16:44):
Oh, so this one was visible .
Lilly (16:46):
Yeah, but the sonic tomography didn't just show the
cavity, it also showed the areaaround it where the decay was
still active.
Jad (16:54):
So it showed how far the problem actually extended.
Lilly (16:57):
Exactly, and that information was really important
for figuring out how to managethe tree, like should they try
to support it or was it too fargone and needed to be removed.
Jad (17:07):
Okay, so in both of those cases the sonic tomography
really helped to make a moreinformed decision about how to
manage the tree.
Do you have any other?
Lilly (17:15):
examples trees that were infected with this really
aggressive fungus calledCrechmeria deusta, and in those
trees the tomogram showed thisreally distinct pattern, what
they called a conductive center,which is typical of that
particular fungus.
Jad (17:33):
So by seeing that pattern they could be pretty sure what
was causing the problem.
Lilly (17:37):
Exactly, and that can be really helpful for figuring out
the best course of treatment.
Jad (17:41):
These cases are really interesting.
I mean they really show how asonic tomography can be really
helpful for figuring out thebest course of treatment.
These cases are reallyinteresting.
I mean they really show how asonic tomography can be used in
a practical way to help managetrees.
So we've talked about sonictomography as a standalone tool,
but how does it fit in withother methods that professionals
might be using?
Lilly (17:56):
Well, it really complements the other methods
out there.
Like you should still be doingvisual inspections, you know,
looking for those external signsof problems.
And there are other tools likethe resistograph that measure
drilling resistance.
Jad (18:09):
Right right.
Lilly (18:10):
And even sometimes you do a tree-pulling test to assess
stability.
But sonic tomography gives youthis extra layer of information,
that internal view that youwouldn't get otherwise.
Jad (18:20):
So it's like putting all the pieces of the puzzle
together to get a more completepicture of what's going on.
Lilly (18:24):
Exactly.
Jad (18:25):
Okay, so we've talked about what sonic tomography is, the
advantages, the limitations,some case studies.
I think it'd be reallyfascinating to dive a little
deeper into the science of wooddecay itself.
Sure, yeah, what can you tellus about that?
Lilly (18:36):
So wood decay is a really complex process.
Actually, there are differenttypes of decay, like brown rot,
white rot and soft rot, and eachof those is caused by different
types of fungi.
Jad (18:48):
Fungi huh.
Lilly (18:49):
Yeah, these fungi.
They release enzymes that breakdown the wood, basically eating
it, and the way they break downthe wood that's what determines
the type of rot.
Like brown rot fungi, theymainly go after the cellulose in
the wood, so what's left behindis this crumbly brown stuff.
White rot fungi they break downboth cellulose and lignin, so
(19:10):
the wood gets lighter and kindof stringy.
Jad (19:12):
Wow, so it's like they have different tastes in wood.
Lilly (19:15):
Yeah, you could say that.
And then soft rot.
That's usually caused by fungithat thrive in really wet
conditions and it can make thewood soft and spongy.
Jad (19:24):
So depending on the type of rot, it can have a really
different impact on the strengthand stability of the tree.
Lilly (19:28):
Right oh absolutely, and that's why it's so important to
be able to identify the type ofdecay, so you know how to manage
it.
Jad (19:34):
Okay, so the type of fungus determines the type of rot, but
what are some of the otherfactors that influence how decay
develops in a tree?
Lilly (19:42):
Well, the species of tree definitely plays a role.
Some species are more resistantto decay than others.
Jad (19:48):
Oh, that makes sense.
Lilly (19:49):
And then how aggressive the fungus is.
That matters too.
Some fungi are real powerhouses.
They can spread really quickly.
And then the environment playsa big role.
Moisture is key.
Most wood decay fungi need acertain amount of moisture to
thrive.
So if a tree is in a really dryenvironment, it's less likely
to have decay problems.
(20:09):
But if it's in a damp spot,that's a different story.
Jad (20:12):
So, like a tree growing in a swamp versus a tree growing in
the desert, they're going tohave really different decay
risks.
Lilly (20:18):
Exactly, and then the tree itself can fight back to
some extent.
Some trees have really strongdefense mechanisms, like they
can form these reaction zonesaround the decayed area, trying
to wall it off and prevent itfrom spreading.
But other trees have weakerdefenses.
Jad (20:32):
So it's like a constant battle between the tree and the
fungi.
Lilly (20:35):
Yeah, kind of, and the outcome of that battle depends
on a lot of different factors.
Jad (20:39):
This is all really fascinating stuff but you know,
I keep thinking about all theprofessionals listening who
might be using sonic tomography.
It seems like you really need agood understanding of all of
this the different types ofdecay, the factors that
influence it to really interpretthose tomograms correctly.
Lilly (20:57):
Oh, absolutely.
You can't just look at thepretty colors on the tomogram.
You've got to understand whatthose colors mean.
You can't just look at thepretty colors on the tomogram.
You've got to understand whatthose colors mean.
You've got to know about treebiology, about wood decay
processes, about the specifictree species you're dealing with
.
It's all connected.
Jad (21:09):
So, basically, learning never stops for a tree
professional.
Lilly (21:13):
Definitely not.
Jad (21:14):
You've always got to be up to date on the latest research
and techniques.
Well, I think this has been areally great overview of the
science behind sonic tomographyand wood decay.
Lilly (21:23):
Yeah, definitely.
Jad (21:24):
I'm sure our listeners are eager to learn more about the
practical applications of thistechnology.
Lilly (21:29):
For sure.
But before we move on to thosepractical applications, I think
we should touch on somethingelse that's really important the
ethical side of things.
Jad (21:36):
Oh yeah, that's a good point.
We've been talking about allthe cool stuff sonic tomography
can do, but like any tool, it'sgot to be used responsibly.
Lilly (21:44):
Exactly.
I mean, we've talked about howit's non-invasive, but even
driving those nails into thetree that still creates a wound.
Jad (21:51):
Right.
Lilly (21:51):
Right.
So you have to be reallycareful about, you know,
sterilizing everything, usingthe right size nail for the tree
, placing the sensors in spotswhere you're not going to cause
extra damage.
Jad (22:03):
So it's not completely without risk, even though it's
less invasive than some othermethods.
Lilly (22:08):
Yeah, and then there's also the risk of misinterpreting
the results, right?
Jad (22:12):
Oh yeah, we talked about how that takes some expertise.
Lilly (22:14):
Exactly so.
If someone doesn't have theright training, they might
misinterpret the tomogram andmake a wrong decision about the
tree.
Jad (22:22):
Like maybe they remove a tree that was actually healthy,
or they think a tree is safewhen it's not.
Lilly (22:27):
Right, exactly.
That's why it's so important tohave qualified people doing
these assessments.
Jad (22:39):
And on that note, I guess there's also the risk of bias,
right, Like if someone alreadythinks a tree is dangerous they
might see what they want to seein the tomogram, even if it's
not really there.
Lilly (22:43):
That's a good point.
Yeah, it's important to beaware of that potential for bias
and to try to be as objectiveas possible when interpreting
the results.
Jad (22:50):
So maybe having multiple people look at the tomogram or
using some kind of standardizedguidelines for interpretation?
Lilly (22:57):
Yeah, definitely Anything that can help reduce that bias
and make sure the assessment isas accurate as possible.
Jad (23:03):
Okay, so ethical considerations definitely
important to keep in mind, butI'm also thinking about, you
know, the practical side forprofessionals.
What about the cost of all this?
Sonic tomography?
It sounds pretty high tech, soI'm guessing it's not exactly
cheap.
Lilly (23:17):
Yeah, you're right, it can be a significant investment.
The cost of the equipmentitself can vary a lot depending
on the features and capabilities, and then there's the cost of
training and software andmaintenance.
Jad (23:29):
So it's something professionals need to factor
into their budget definitely.
Lilly (23:32):
Right, but on the flip side you have to think about the
value of the information you'regetting.
Jad (23:44):
Like, if you can identify a hazardous tree before it falls
and causes damage.
That could save a lot of moneyin the long run, true, true, so
it's an investment, but it's aninvestment that could
potentially save you money andheadaches down the road.
Lilly (23:51):
Exactly, and there are ways to make it more affordable.
Headaches down the road Exactly, and there are ways to make it
more affordable.
Like some, companies offersonic tomography services on a
contract basis, so you don'thave to buy the equipment
outright.
Jad (24:01):
Okay.
So there are options out there,but even if the cost is
manageable, you still got tomake sure it's worth it.
Right Like, is there enoughdemand for this kind of service?
Lilly (24:11):
Yeah, that's a good point , but I think the demand is
growing.
Actually, as people become moreaware of the benefits of sonic
tomography, they're starting toask for it specifically.
Jad (24:21):
So it could actually give you a competitive edge if you
offer it.
Lilly (24:24):
Definitely.
Jad (24:25):
Okay, so we've talked about the cost, the demand, but what
about the future?
Where do you see sonictomography going in the next few
years?
Lilly (24:33):
Oh, there are some really exciting developments happening
, like one of the big things isartificial intelligence or AI.
They're starting to use AI toanalyze sonic tomography data,
which could make theinterpretation process much
faster and more accurate.
Jad (24:46):
Wow, ai for trees.
Lilly (24:48):
Yeah, and then there's also this idea of using machine
learning to create predictivemodels, so they could use data
from past sonic tomography scansalong with other information
about the tree to predictwhether it's likely to develop
problems in the future.
Jad (25:04):
Oh wow, that would be amazing, like preventative tree
care.
Lilly (25:07):
Exactly.
And then there's also workbeing done on integrating sonic
tomography with othertechnologies, like ground
penetrating radar, which couldgive you an even more complete
picture of the tree's health.
Jad (25:18):
That sounds really cool.
So it seems like there's a lotof potential for sonic
tomography to become even morepowerful and useful in the
future.
Lilly (25:25):
Definitely.
I think we're just scratchingthe surface of what this
technology can do.
Jad (25:29):
Well, I'm definitely excited to see what the future
holds for sonic tomography, butfor all the professionals
listening who might be thinkingabout getting into this field, I
guess the big question is wheredo you start?
Lilly (25:40):
Yeah, that's a good question.
Well, first and foremost,education is key.
You need to understand thescience behind sonic tomography,
how to operate the equipmentand how to interpret the results
.
Jad (25:51):
So finding a good training program is crucial.
Lilly (25:54):
Absolutely.
There are some great programsout there offered by
organizations like the ISA, ascaand TCIA.
Jad (26:02):
Okay, so you get the training, you understand the
science.
What's next?
Lilly (26:05):
Well then, it's about choosing the right equipment for
your needs and your budget.
There are a lot of differentdevices out there, so it's
important to do your researchand figure out which one is best
for you.
Jad (26:16):
And once you have the equipment and the training, then
it's just a matter of practiceright Exactly.
Lilly (26:20):
The more you use it, the more comfortable and confident
you'll become.
Start with simple assessments,maybe on trees you're already
familiar with, and graduallywork your way up to more complex
cases.
Jad (26:31):
So don't be afraid to start small and build your skills
over time.
No-transcript and a willingnessto learn from others.
Lilly (27:03):
I think that sums it up perfectly.
Jad (27:05):
This has been a really fascinating discussion about how
professionals can incorporatesonic tomography into their work
.
But you know we've beenfocusing a lot on the technical
and practical side of things.
I think it would be reallyvaluable to step back for a
moment and think about thebigger picture, sure.
Lilly (27:21):
Yeah.
Jad (27:22):
How does sonic tomography fit into the broader context of
tree conservation andsustainability?
Lilly (27:27):
That's a great point.
I think sonic tomography has areally important role to play in
those efforts, like it can helpus to identify and preserve
veteran trees, those really oldand valuable trees that are part
of our natural heritage.
Jad (27:39):
Right, those trees are irreplaceable.
Lilly (27:41):
Exactly, and it can also help us to manage urban forests
more sustainably, like if youcan accurately assess the health
of trees in a city, you canavoid unnecessary removals and
make sure those trees are aroundfor as long as possible.
Jad (27:55):
So it's about using technology to make sure we're
making the best decisions forthe trees and for the
environment.
Lilly (28:01):
Exactly, and all of that information can help us to
develop strategies to protecttrees and make sure they're
around for future generations.
Jad (28:08):
That's really inspiring.
Actually, it seems like sonictomography is more than just a
tool.
It's like a way of connectingwith trees on a deeper level.
Lilly (28:17):
I think that's a beautiful way to put it.
It's about seeing beyond thebark and understanding the life
that's going on inside thosetrees, and I think that
understanding can lead to agreater appreciation for trees
and a stronger commitment toprotecting them.
Jad (28:30):
It's been amazing exploring the world of sonic tomography
with you.
We've really gone deep, fromthe science behind it to the
ethics, the costs, what's comingnext and how it all ties into
taking care of trees in the bestway possible.
Lilly (28:43):
Absolutely.
It's a really fascinating fieldand I think we've just
scratched the surface.
Jad (28:48):
For sure.
Roger (28:52):
Thank you for joining us for this exploration of tree
health assessment techniques.
Today we covered the essentialtools and methods arborists use
to detect hidden decay andstructural weaknesses.
We're grateful for your supporton heroheroco slash
talkingtrees, which enables usto continue bringing you
valuable insights from the worldof arboriculture.
(29:13):
Thanks for listening and we'llsee you next time.
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