The VTA Method, lets talk

[arb culture]

There's some more references here...

 

Some are more focussed on the issue of tree pulling than others, but all contain useful and relevent info.

 

Gilman, E. F. (2003) Branch to stem diameter ratio affects strength of attachment. Journal of

Arboriculture, 29(5) 291-294

Cullen S. (2005) Trees and Wind a practical consideration of the drag equation velocity exponent

for urban tree risk management. Journal of Arboriculure 31(3) 101-113

Kane, B. and Farrell, R (2008) Failure mode and prediction of the strength of branch attachments.

Arboriculre and Urban Forestry 34(5)308-316.

Kane, B. and Clouston, P. (2008) Tree pulling of large shade trees in the genus Acer. Arboriculture

and Urban Forestry 34(2) 101-109.

Brudi, E (2001) Longitudinal prestresses in Tilia cordata and Acer Pseudoplatanus. Thesis

dissertation accessed online 20/4/09 via http://www.tree-consult.org/html/eng/articles/statics.htm

Brudi, E, and Wassenaer, P. (2001) Fracture diagnostics of trees Stadt und Grün 1995, No.6, pp.

416-422.accessed online 18/4/09 via http://www.tree-consult.org/html/eng/articles/statics.htm

Mattheck, C, Bethge, K., and Kraft, O. (2008) Are the failure criteria of SIA and tree pulling tests

wrong? Arboricultural Journal 31(3) 181-188.

Gordon, J.E. (1978) Structure: or why things don't fall down. Penguin Books, London.

Gordon, J.E. (1968) The new science of strong materials: or why you don't fall through the floor.

Penguin Books, London.

 

The books by Gordon I would suggest are essential reading for anyone wanting to go down the engineering principles route of tree assessment. But that's probably just me.

[arb culture]

I have extracted the following from the thermal imaging thread:

 

 

 

 

I have shown this list now to a number of arborists from different backgrounds and have had no reason to change it.

 

How much would you charge to do all of the above on a tree?

Edited July 23, 2010 by arb culture
typo

[Bundle 2]

Quite an interesting thread guys.....!

Some useful links and reading lists. I approve!

 

I note with interest, the comments about simplification. I thought I saw a degree of confusion in the comments. I have revised this view and indeed, Claus maybe guilty of oversimplifying.

I certainly dont think that in a scenario where the numbers and values cannot be ascertained with any certainty, they should be extrapolated upon any further in an attempt to extend credence to the scholarly nature and pseudo reliability (robustness)of said analysis.

Robustness is the issue with the data from the T/R ratio isnt it...I mean basically, too small a sample distribution? This flaw is hereditary when comparing other sample distributions against it. Why would you if you know its' flawed? I mean, what's to be gained?

It was precisely because of the impossibilty of attaching real values to the equations that I was (personally) happy to see Claus at the latest UK seminar, quite deliberately making this important point and consciously moving to strike!

The thread has highlighted some important points for me.

 

When we talk about "how much we value trees.." I am conscious we are engaged in a two way street.

We value trees as a professional, require expensive(relatively) assessment techniques, we succeed in being very "right-on" but not for the customer (the public perception of trees) Ownership and maintenance along with modern techniques and practices become onerous!

Ignore your gut feelings about the apparent contradictions of drilling samples from a stressed tree because you have its longevity, welfare as the central issue and you compromise the treecare issues .

Ive a feeling Marcus contradicted your empiric assessment of inspection steps Andrew but cant find the thread to confirm whether this was a significant alteration or not.

Good thread and appreciate the contributions. Nice one!

[BatiArb]

When it comes to the cascade of assessments methods we have for trees I would suggest that the following order should be considered:

 

• Visual Tree Assessment by an Arborist

• Acoustic hammer (Elison style)

• Thermal Imaging to observe functional heat flow

• PICUS / TreeTronic / Radar

• Resistograph / DDD / core sampling

 

The above list is ordered with a view to:

 

• Surveyor expertise

• Speed of application (therefore cost)

• Requirement for visual evidence

• Invasiveness of equipment

 

How much would you charge to do all of the above on a tree?

 

 

Well that is an interesting question.

 

So much would depend on the site in question and on the value of the tree to justify such effort. Also you have to consider whether it would be appropriate to commission and employ all of these survey tools at once or over a period of time.

 

On the right tree you could use all in one go and on one visit and in which case you would save a great deal of expense in duplicating the site time and travel costs. In such a case you would also get a very complete picture of the situation and be able to make a very robust informed decision on its future supported by a comprehensive management plan. Estimated cost between £750.00 - 900.00 +VAT.

 

However, chances are that such a series of surveys would be completed over a period of time from the initial site inspection completing the VTA, taking the acoustic hammer out of the back pocket and producing a recommendation for further investigation using the thermal imaging camera and/or PICUS depending on how much of the tree was giving concern (Thermal Imaging on the whole tree, branch attachment and root system or PICUS just on the trunk). The initial site visit with hammer in back pocket and probably a good billhook in there as well is likely to be £200 +VAT

 

Following up the recommendations of the above with a more detailed inspection TI / PICUS is going to range from £250 - 500.00 +VAT depending on the combination of tools used.

 

Finally depending on the result of the Thermal Imaging / PICUS then you go in with your invasive inspection tools, which will be targeted by the thermograms and tomographs. This would require your third site visit so again price would range from£250 - 500.00 +VAT depending on the combination of tools used.

 

If you use the Thermal Imaging it could well reveal root issues with the tree so it may be prudent to consider undertaking an investigation with an AIR-SPADE to look at root damage and decay issues in more detail. This would need an average of half a day on site with the compressor and spade followed by a photographic report. Range again would be between £250 - 500.00 +VAT depending on the combination of tools used.

 

All a bit broad but then every job would be worked out on a unique set of circumstances so will vary a lot from the above.

[Tony Croft aka hamadryad]

Quite an interesting thread guys.....!

Some useful links and reading lists. I approve!

 

I note with interest, the comments about simplification. I thought I saw a degree of confusion in the comments. I have revised this view and indeed, Claus maybe guilty of oversimplifying.

I certainly dont think that in a scenario where the numbers and values cannot be ascertained with any certainty, they should be extrapolated upon any further in an attempt to extend credence to the scholarly nature and pseudo reliability (robustness)of said analysis.

Robustness is the issue with the data from the T/R ratio isnt it...I mean basically, too small a sample distribution? This flaw is hereditary when comparing other sample distributions against it. Why would you if you know its' flawed? I mean, what's to be gained?

It was precisely because of the impossibilty of attaching real values to the equations that I was (personally) happy to see Claus at the latest UK seminar, quite deliberately making this important point and consciously moving to strike!

The thread has highlighted some important points for me.

 

Good thread and appreciate the contributions. Nice one!

 

I think that people focus too much on the simplification, one has to remember that Claus has developed this system to empower all to read the body language of trees. In doing so he is making it a viable subject for even the most modest of tree owners to get to grips with. it also has the benifit of inspiring poeple to go further with it, and lets face it, you can get as deep and complex as you like with this subject.

 

Imagine if every owner of a tree had the VTA symptom poster to view? i wonder how many contractors would get "sussed" for thier flannel!

 

When you empower the little people and make them informed it pushes the whole subject up a notch, sure a little knowledge can be dangerous, but even so i personaly think that this simplification is a powerful tool that is yet to be fully realised and appreciated:thumbup1:

 

Im glad your enjoying the thread, and its only just begun.

[BatiArb]

Ive a feeling Marcus contradicted your empiric assessment of inspection steps Andrew but cant find the thread to confirm whether this was a significant alteration or not.

Good thread and appreciate the contributions. Nice one!

 

It was not a contradiction just an addition. See below:

 

 

I Would like to propose the following amendment to the above.

 

VTA

Acoustic hammer

Thermal Image

Evaluation of tree height and dbh followed by canopy density and degree of sheltering if necessary

Picus etc

Invasive inspection

 

At the end of it all it is about using the tools available, so why not use them?

When you look at it critically, none of these methodologies are that expensive compared to the cost replacing a mature tree.

[arb culture]

Well that is an interesting question.

 

So much would depend on the site in question and on the value of the tree to justify such effort. Also you have to consider whether it would be appropriate to commission and employ all of these survey tools at once or over a period of time.

 

On the right tree you could use all in one go and on one visit and in which case you would save a great deal of expense in duplicating the site time and travel costs. In such a case you would also get a very complete picture of the situation and be able to make a very robust informed decision on its future supported by a comprehensive management plan. Estimated cost between £750.00 - 900.00 +VAT.

 

However, chances are that such a series of surveys would be completed over a period of time from the initial site inspection completing the VTA, taking the acoustic hammer out of the back pocket and producing a recommendation for further investigation using the thermal imaging camera and/or PICUS depending on how much of the tree was giving concern (Thermal Imaging on the whole tree, branch attachment and root system or PICUS just on the trunk). The initial site visit with hammer in back pocket and probably a good billhook in there as well is likely to be £200 +VAT

 

Following up the recommendations of the above with a more detailed inspection TI / PICUS is going to range from £250 - 500.00 +VAT depending on the combination of tools used.

 

Finally depending on the result of the Thermal Imaging / PICUS then you go in with your invasive inspection tools, which will be targeted by the thermograms and tomographs. This would require your third site visit so again price would range from£250 - 500.00 +VAT depending on the combination of tools used.

 

If you use the Thermal Imaging it could well reveal root issues with the tree so it may be prudent to consider undertaking an investigation with an AIR-SPADE to look at root damage and decay issues in more detail. This would need an average of half a day on site with the compressor and spade followed by a photographic report. Range again would be between £250 - 500.00 +VAT depending on the combination of tools used.

 

All a bit broad but then every job would be worked out on a unique set of circumstances so will vary a lot from the above.

 

Thanks Andrew, I didn't expect you to reply to that question (some people are a bit sensitive about sharing pricing information).

 

I think we are agreed then that in the vast majority of cases a quick visual check by a competent surveyor is all that can be reasonably expected - and is undoubtably the best value for money.

 

In the very rare and unusual cases where a competent surveyor cannot make a decision based solely on the visual evidence then other more expensive investigative procedures should be adopted. These further investigations can rapidly become very expensive, and tie the owner in to further expense for an ongoing period of time.

 

Of course, if the cost of felling the tree is less than the cost of your surveys, then often the tree will be felled rather than further investigated.

[BatiArb]

Thanks Andrew, I didn't expect you to reply to that question (some people are a bit sensitive about sharing pricing information).

 

I think we are agreed then that in the vast majority of cases a quick visual check by a competent surveyor is all that can be reasonably expected - and is undoubtably the best value for money.

 

In the very rare and unusual cases where a competent surveyor cannot make a decision based solely on the visual evidence then other more expensive investigative procedures should be adopted. These further investigations can rapidly become very expensive, and tie the owner in to further expense for an ongoing period of time.

 

Of course, if the cost of felling the tree is less than the cost of your surveys, then often the tree will be felled rather than further investigated.

 

 

 

Well again that all depends on the perceived value of the tree(s) in question.

 

Value is a very subjective thing and influenced by both the arboricultural profession and the wider general populous.

 

Personally I am of the opinion that we are moving into a time when trees will be the focus of far more attention with perceived and appreciated values increasing, however that is another story all together.

 

Having said that though I do think it is important for arborists to persistently promote the value of trees and it is important to maintain a level of service that reflects a high value for trees as an asset that justifies a significant financial investment to ensure their longevity of benefit.

[BatiArb]

Imagine if every owner of a tree had the VTA symptom poster to view? i wonder how many contractors would get "sussed" for thier flannel!

 

When you empower the little people and make them informed it pushes the whole subject up a notch, sure a little knowledge can be dangerous, but even so i personaly think that this simplification is a powerful tool that is yet to be fully realised and appreciated:thumbup1:

 

 

I could not agree more. This is something that Cassian Humphries and I are working on. Education is incredibly important.

 

I understand and respect the saying that 'a little bit of knowledge is dangerous' but on the other hand if our clients and the public as a whole have a greater appreciation for trees, how they live, the dynamics of their reactive growth, etc. This can only be a good thing because understanding creates respect.

 

If people generally have a better appreciation of trees this will reduce the fear factor associated with them and this is one of the biggest issues when it comes to attributing value.

 

Increased tree value means increased value for the arboricultural profession - the people who care for these valuable trees......

[arb culture]

Having said that though I do think it is important for arborists to persistently promote the value of trees and it is important to maintain a level of service that reflects a high value for trees as an asset that justifies a significant financial investment to ensure their longevity of benefit.

 

I partially agree, but if you agree to be employed as a consultant you have a duty to give your client the information which they need to make an informed decision - even if that information, and their informed decision, is contrary to your own personal values or beliefs.