The VTA Method, lets talk

[BatiArb]

In response to the core sample question - there is a very real danger that when extracting a core sample you will damage the sample in the process of extraction. Next time you take a core sample have a look at the direction of grain at both ends of the sample, often the sample is twisted - this shows that there is at least some damage to the sample.

 

The precise strength and stiffness of a sample can be greatly influenced by the way in which the sample was obtained.

 

 

And this in turn can depend on the tree and its species, not to mention the location and method used for taking the core. Really there are so many variables in this that the whole methodology can only offer indicative observations that should only be used as supporting evidence.

 

IMO this is an invasive assessment tool that is a last resort used to back up other non invasive survey tools such as PICUS and Thermal Imaging. The latter can be used to effectively target the point where to take cores. At this point I do not believe that the fractometre is really going to give you much more information.

 

I certainly think that going around taking core samples of healthy trees is inappropriate unless scientifically justified by a research project.

[BatiArb]

Back to VTA - It's really good.

 

Out of interest, for those people who criticise it, what alternative methods would you use?

 

 

I do not believe that there is any comparable method. VTA is THE METHOD !

 

 

However, it is only as good as the Arborists who has (or has not) the level of knowledge to use it........

[BatiArb]

 

Claus himself in 2006 showed that the relationship for t/R was statiscally random...in other words no single t/R value exists that predicts stem failure. This is presented quite clearly in Jerry Bonds paper. Unfortunately there are a great many consulting Arbs providing advice (for a fee) applying the t/R ratio as if it were a golden rule....this is not Claus's fault, but it is simptomatic (IMO) of what happens when you try to reduce complex relationships down very simple formulae.

 

From my perspective much of the criticism of the supporting evidence for tR or some of the other areas of Claus Mattheck's research of don't lead me to devalue VTA or its underlying principles....it does make me suitably dubious about anyone that lays claims to have magic numbers in relation to tree strength or tree "safety".

 

 

It all comes down to a healthy respect and understanding for the limitations of the system being used.

 

EVERY methodology, survey technique or system has limitations. No ONE method should be used exclusively.

 

AND of course any method is only as good as the Arborist using it.

[arb culture]

It all comes down to a healthy respect and understanding for the limitations of the system being used.

 

EVERY methodology, survey technique or system has limitations. No ONE method should be used exclusively.

 

AND of course any method is only as good as the Arborist using it.

 

[arb culture]

I do not believe that there is any comparable method. VTA is THE METHOD !

 

That's what I thought.

 

But if there is another method people use then it would be good to hear about it.

 

[Tony Croft aka hamadryad]

I dont think there is any derailing here at all, the thread is hear for the discussion of the method, and all the arguments there in.

 

Slenderness ratios

 

TR ratios

 

increment core method robustness

 

its all goo and part of the method so as far as I am concerned were having a good thread.

 

Andrew, just explain why YOU feel increment cores are a bad idea in any but a research scenario?

 

Claus has presented a lot of work from various associates on the subject of repeated drilling, cores or resitograph, and told me that he has no concerns due to the research.

 

He has pointed me in the direction of another paper but I havent fully digested it yet so wont comment on that till later.

 

I was anti drill, that was until i did my own reading into the various research on it, and to be honest im still undecided, but definatley dont hold much fear as I used to.

 

Insects bore holes into trees on a daily basis.

 

There is of course shigos work on drillling which is contradictory to others findings so the jury is still out for me, till i can do my own.

 

As for the method and whos using it, one of the things I love about it is that on some level, you could teach a 10 year old basic VTA, sure there will always be some who are better at it than others, but essentialy the system is empowering even laymen to have some basic understanding of when and why a tree is a bit iffy!

 

and if that doesnt save trees, because folk feel able to make a fair call on wether or not they need an expert then surely less trees will be worked when it really isnt needed.

 

Now as for this BS about TR ratios, lets just look at this for a mo, as I said I havent read it all yet, but as far as i can tell the "oponent/s" are claiming that they have pull tested x amount of thousand hollow trees above clauses terminal ratio, the ratio that claus says is proven by the lack of these trees in existence.

 

Now, were all tree people, mad and keen as hell, Ive been racking my brains trying to think just how many Hollow trees with FULL crowns I see on my travels, especialy within a woodland scenario and right now i know of one above the ratio or close to it, I will be looking in detail Very soon!

 

that tree is very sheltered, completley hollowed from the root to some distance up the trunk internaly, Pholiota aurivella the decay organism at work in this case.

 

Now i havent done the measurements, but as part of my ongoing mental note taking i did remember distinctly telling myself that she would be the next beech down, mmmm its a no brainer realy isnt it?

 

so why is there this group claiming they have so many hollow trees to test!

[BatiArb]

 

Andrew, just explain why YOU feel increment cores are a bad idea in any but a research scenario?

 

 

 

Tony,

 

I am not saying it is a totally bad idea. I just do not see the need or the additional value in doing all the fracto stuff. To me it is the last thing you do before felling the tree. The testing is targeted by other survey methods such as PICUS and Thermo and the core samples are taken to do the final checks on the assessment so far.

 

I do not personally think that taking core samples out of healthy trees is justifiable unless associated with a research project. After all you are deliberately injuring the tree(s).

 

I would be interested to know how much information you think you gain when using the fractometre on decaying wood. Do you think it provides you with additional information that would not be provided any other way without drilling? That is information which is truly influential in the decision as to what should be done with the tree. Not simply nice to have detail.

[Tony Croft aka hamadryad]

I do not believe that there is any comparable method. VTA is THE METHOD !

 

 

However, it is only as good as the Arborists who has (or has not) the level of knowledge to use it........

 

Tony,

 

I am not saying it is a totally bad idea. I just do not see the need or the additional value in doing all the fracto stuff. To me it is the last thing you do before felling the tree. The testing is targeted by other survey methods such as PICUS and Thermo and the core samples are taken to do the final checks on the assessment so far.

 

I do not personally think that taking core samples out of healthy trees is justifiable unless associated with a research project. After all you are deliberately injuring the tree(s).

 

I would be interested to know how much information you think you gain when using the fractometre on decaying wood. Do you think it provides you with additional information that would not be provided any other way without drilling? That is information which is truly influential in the decision as to what should be done with the tree. Not simply nice to have detail.

 

Firstly, why would I on a one off tree survey for example NOT just pull out a core to confirm rather than say oh I will need to go and hire a picus and charge you 500 quid for the survey?

 

As for what I think I might glean from a core, well as you know, fungi do not always come out to play, not every season, and sometimes not for many decades as they happily roam about in the maze that is the woody structure of trees. So for me a core will tell me whos resident, what kind of decay they are into and how far theyve got.

 

It is important to distinguish rot types for obvious reasons, and if we suspect decay, but are looking in summer for winter species then what are you to do?

 

charge to come back in 6 months?

 

or take a core and settle the score?

[Tony Croft aka hamadryad]

Picus and thermo wont ident the fungi/rot type. a core sample can.

[arb culture]

I know this a thread about VTA, but in the discussion there are a number of comments about tree pulling tests.

 

A word of warning about tree pulling tests - see if you can find a convincing explanation in the work of the pro-pullers regarding the ways in which shear stresses affect hollow trees, or how heavy limbs affect the hollow stems they are attached to - I can't.

 

As regards the T/R ratio - I don't think Claus is suggesting that just because a tree is more than 70% hollow it is necessarily dangerous, only that if a tree is less than 70% hollow it should be considered no more dangerous than a solid tree (assuming no other factors of course). His published research data clearly shows many trees more than 70%hollow which haven't fallen over.