QTRA , VALID, tree risk

[richyrich]

what's people's opinions of these quantitive risk / survey methods? I did a lantra pti qualification last year. The county council tree consultant in my area appears to be dismissive/condescending if his favoured VALID method is not utilised. Bearing in mind it's only been around since 2018(?)

The Lantra pti course is using your subjective judgement on a tree- observing defects, fungi, etc.

Is use of the 2 former methods a good route to take? I take a common sense approach to assessing a tree. Do these quantitive methods give the surveyor a good advantage when surveying? 

If a tree was surveyed with visual tree inspection,traditional methods and deemed safe but subsequently it failed, then the surveyor wouldn't look too clever legally maybe... Would using either of the other 2 methods give the surveyor a better defence legally if the assessment was wrong? Or are these quantitive methods so good that they never/rarely get it wrong? 

I was considering doing the VALID training but I think it's booked up nearest to me. 

Is the QTRA inferior to the VALID? What methods /systems do most of you use?

Thanks 

[daltontrees]

I am a registered QTRA user, it is a peer-reviewed system that allows the input factors for risk recommednations to be assessed separately and combined in a way that provides a defensible (legally) basis for addressing the tree owner's legal duty of care, pegged to published government risk tolerances.  Because the factors are separate from the start it means there is also a defensible basis for not inspecting small or remote trees or those with no obvious defects. It does not and should not make decisions for you, and occasionally I override it.

My concern with PTI (which is a pretty rigorous course and test) is that it is mainly about hazards but very light on weighing up probability of failure against other components of risk (severity of harm/damage and likelihood of target presence).

I have to disagree with you, the PTI course does not use subjective judgement, quite the opposite it encourages objective judgement. Not to be confused with professional judgement about unseen parts of a tree. Objective judgements should be repeatable across a number of equally qualified professionals. Subjective judgements are worthless.

I don't know about VALID, I have raised questions with its creator and he has generally declined to answer the awkward ones and usually comes back with rude, dismissive or aggressive distraction tactics, makes me wonder about the professionalism behind the system. It appears a bit mickey-mouse to me, like a QTRA-lite in app form. Its reports are horrible looking (to my eyes). But the main concern for me (I am a freelance consultant but also a part time Tree Officer) is that the system is not peer-reviewed and there is no basis to say that it has been accepted as a suitable method by a body of professionals. It does seem popular, though.

It is probably wrong of your local TO to favour one system, but I respect anyone that holds out for an objective basis for risk-reduction works and I am comfortable recommending rejection of applications that do not give a basis. PTI initslef is not a risk assessment system, it is only a hazard identification and recordins system. As Tree Life says "The course is not aimed at covering report writing however, presentation of findings will be
examined and advice given."

You could also look at the ISA system, known as TRAQ. If QTRA is numbers, TRAQ is the same in words but loses some precision as a result.

 

My one piece of advice is this - don't let a system make your decisions for you. Let it inform and record the basis of decisions. Be prepared to override it if professionalism requires it. Never, ever, use a system if you don't understand what it is doing inside. The buck stops with you, not with the system.

[richyrich]

Thanks for the detailed reply. I maybe got my wording wrong regards PTI being subjective, etc. I might book onto the qtra course.. 👍

[daltontrees]

No worries, I just wanted to be clear about 'subjective' which means 'based on or influenced by personal feelings, tastes or opinions' and is the very antithesis of professionalism. It does tend to get used to mean 'cannot be proven by direct observation or measurement', that's where professionalism steps in to make reasonable assumptions based on experience, that which can be seen or measured and the entire body of accepted professional knowledge. 

Whichever course you go on (don't know about VALID but do know about QTRA and TRAQ) it should be an eye-opener to a whole world of thinking about risk not just as the thing that might fail but the consequences of faliure. It's very refreshing and (in my experience) makes objective decisions and recommendations much easier and more consistent.

I dont know you but I expect you won't regret it or the cost of training. It's like fog being blown away, suddenly everything is much clearer.

"There are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don't know. But there are also unknown unknowns. There are things we don't know we don't know.

Donald Rumsfeld"

Know what it is you know and don't know. Find out those unknowns that you can find out. Make reasonable assumptions about the ones you can't find out and let the client know about them.  The law does not expect anyone to guard against unknown unknowns.

Me

Edited April 20, 2023 by daltontrees

[richyrich]

Great advice, thank you. I've only written a couple of reports since I did the pti. The latest one I'm awaiting the council's expert response. 

Of the other report I wrote- I found his response a bit condescending (??). I had roughly based it on the ISA system. He duly dismissed my use of wording such as 'moderate', etc. as 'imprudent'...

Cheers 

[daltontrees]

34 minutes ago, richyrich said:

Great advice, thank you. I've only written a couple of reports since I did the pti. The latest one I'm awaiting the council's expert response. 

Of the other report I wrote- I found his response a bit condescending (??). I had roughly based it on the ISA system. He duly dismissed my use of wording such as 'moderate', etc. as 'imprudent'...

Cheers 

Oh boy! 'Moderate' is one of the risk categories in TRAQ, but calling it imprudent is as you say somewhat condescending. There's the risk of a word based system though, it depends on the individual's understanding of words. QTRA only gives 3 possible outputs, acceptable, tolerable and unacceptable. These terms are derived from the HSE, and have quantified meanings but more importantly they are likely to be admissible in court as the risk bands within which (Acceptable) no action is required (Tolerable) the risk should be reduced to as low as reasonably practicable or (Unacceptable) duty holder must do something about it. It's all about duty of care and negligence, and I find these pretty persuasive.

Rightly or wrongly I have come to equate these terms with TPO application outcomes. Acceptable - no basis for approving the works. Tolerable - basis but Council can refuse if it takes responsibility for compensation if the harm or damage materialises. Unacceptable - don't even apply, use the statutory exemption.

 

Go fog-free in 23!

 

[richyrich]

That sounds the way to go, summed up great 👍

[Acer ventura]

Hi Richy

 

Just to chip in here, and give some balance to Julian's usual misrepresentation of VALID. It's this kind of stuff, and his disturbingly obsessive trolling of me, that got him a lifetime ban from the UKTC (the only person to ever have achieved this sanction). It's sad to see him still trolling me on a forum I seldom post on.

 

Full disclosure

 

I was the other main QTRA trainer from 2006 and drove most of QTRA's v5 (current version) development. I was also on the TRAQ (ISA Tree Risk Assessment BMP) committee in 2011. When I saw the matrices, I was so alarmed about this assessment method I bailed, and asked my name not to be included in the publication's list of acknowledgements.

 

In 2016, I moved on from QTRA to develop VALID. One reason was I thought the whole tree risk thing could be done simpler, clearer, and smarter.

 

My views on VALID are bound to be biased. Why not ask your Tree Officer why they prefer it? Or get in touch with the people who have written glowing testimonials.

 

https://validtreerisk.help/Training

 

Or search the Directory of Validators for someone in your area (Government Validators aren't listed in this).

 

https://validtreerisk.help/Find-an-Arborist

 

Though I'm now an ex QTRA trainer, it's worrying to see a QTRA User get so much wrong about it. For example, it isn't peer reviewed. The 2005 paper where it was introduced is VERY different to the current version. Just one of many examples, the lowest Probability of Failure was 1 in 1000. That makes every tree in a town or city an unacceptable risk by its own metric.

 

Sorry the Harrogate Validator training was booked out ages ago. The new unitary North Yorkshire Council is going full metal VALID and is adopting our Tree Risk-Benefit Management Strategy, so there has been lots of interest. We're also running 2 Basic Validator training workshops for all the Highways Inspectors. I would've put another one on but I've been invited to be a keynote speaker, to talk about Tree Risk Management and Assessment, at the national Arboriculture Australia conference in Sydney at the end of May. I have to fly out there as soon as we're done in Harrogate.
 

Edited April 23, 2023 by Acer ventura

[benedmonds]

THREATS, is another one to look at. I find it nice and simple to use.

 

Forbes-Laird Arboricultural Consultancy
http://www.flac.uk.com

[Acer ventura]

You might find this Australian article that reviews VALID, TRAQ, and QTRA useful.

 

I shared it on our social media the other week, along with a commentary about VALID's risk model, and I've put it up on the News page of the website.

 

https://validtreerisk.help/News

 

The commentary also explains that none of the commonly used tree risk assessment systems have been 'peer reviewed'.