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You have a marvellous opportunity to upgrade your approach to tree risk with VALID in the UK this summer. Find out more, and see what they're saying about VALID here. https://validtreerisk.help/Tree-Risk-Training If you manage or asses tree risk, here are 3 compelling reasons why VALID is simpler, clearer, and smarter. 1) You get a Tree Risk-Benefit Management Strategy Whether you manage or assess risk, the Strategy is your most valuable tree risk asset. Read more: Speaking truth to power 2) You'll manage and assess risk more effectively where it matters most In built-up areas, and busy roads. On average, more than one person, more than one vehicle, or more than one person AND more than one vehicle are exposed to the risk. Read more: Very High Occupancy 3) Likelihood of Failure - the toughest part of a risk assessment We've got 'Decision Hygiene' and 'Noise Reduction' built into it. Read more: Decision Hygiene & Noise Reduction

We've carried out a substantial overhaul and update of our t/R ratio guide. It's called, Why t/R ratios don't work You can download it with additional explanatory commentary here. https://validtreerisk.help/Why-tR-Ratios-Do-Not-Work

Hi Paul Mattheck's t/R = 0.3 is a terrible 'guide', though. t/r = 0.3 is a point on a spectrum of hollowness, that's only considering some of one part of the 'Form' in a tree's Safety Factor (which is what we're trying to figure out). t/R = 0.3 would be too much hollowness for a particular species of tree (Material properties). With particular crown dimensions and location (Load). And a particular stem diameter and geometry (Form). Improve the Material properties, and t/R = 0.3 would be fine. Or, lower the height or location (Load), and t/R = 0.3 would be fine. Or, increase the section modulus by widening the diameter, and t/R = 0.3 would be fine. Your critical t/R could be any ratio. It's just one part of the 'Form' in the tree Safety Factor puzzle.

Thanks, Rich It was a pleasure to have you come along.

Just following up on this because I've finished Validator training for North Yorkshire Council Tree Officers, and Basic Validator training for their Highways Officers. Now that North Yorkshire Council has customised and adopted VALID's Government Agency Tree Risk-Benefit Management Strategy. A problem you're likely to face with any tree risk assessment report which requires their consent is unless it's an emergency job, they're only going to accept VALID reports. Not least because the risk rating thresholds they're managing the risk to in their Strategy are VALID's take on the Tolerability of Risk Framework. The issue they have is they don't know what your 'Moderate' risk means - ie where it sits in ToR. The same would apply to any tree risk assessment system that's not using these risk ratings. My understanding is they'll not accept QTRA reports because of the known structural faults in that method. There's also an issue with any risk between 1:10 000 and 1:1 000 000 being labelled as a Tolerable risk by QTRA Users without them working out whether it is ALARP (As Low as Reasonably Practicable). In this region, the risk is ONLY Tolerable IF it is ALARP. Who is the Tree Officer who dismissed your report? - PM me with the reply they sent you if you'd rather not share publicly. I'm sure the last thing they'd want to do is come over as condescending and I might be able to help North Yorkshire Council with the wording when they refuse reports. Because of demand for Validator and Basic Validator training, we're going back to Harrogate this autumn. The dates will be up on the Training page in the next few weeks. You can stay in touch here. https://validtreerisk.help/Lets-stay-in-touch

Taking the Defect Out of Tree Risk - Article Update 'Taking the Defect Out of Tree Risk' is published in the current NZArb 'Tree Matters' magazine. Taking Defect Out of Tree Risk - NZArb 2022.pdf It first appeared in the UK's Arboricultural Association's (AA) Arb Magazine (Spring 2001). There are a couple of important improvements in the latest version. Like the Obvious Tree Risk Features Guide, which now includes construction damage. VALID - Obvious Tree Risk Features Guide v8.pdf We've also improved the VALID Likelihood of Failure mnemonic to prepare for v2 our Tree Risk App. In our excitement about dumping the red DEFECT and replacing it with the neutral DECAY in the AA version, we neglected how this affected some subheadings.

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'.

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.

We've updated our Summer Branch Drop Guide (v8), and have a short article on the News page about managing the risk. https://validtreerisk.help/News VALID - Summer Branch Drop (SBD) Guide v8.pdf

Can you help everyone manage tree risk? We're after high quality obvious tree risk feature photos for a free multi-language App we're developing called Tree Alert. Full credit will be given to you as the photo source. What is Tree Alert? It's an App version of the free Obvious Tree Risk Features Guide. You can download the guide here. https://validtreerisk.help/Risk-Management Here are wireframe sketches of how Tree Alert is currently looking. We're after high quality photos of: 1) Partial root failure 2) Broken or hanging branches 3) Cracks or splits 4) Advanced decline or death 5) Fungal brackets (an abundance of them) 6) Construction damage As you'll see from the Guide, they need to VERY obvious. If you can help by sharing any of these photos, please email them to [email protected] Why? Trees with the highest risk are the easiest to find. When a tree has a risk that might not be Acceptable or Tolerable, it'll usually have an obvious tree risk feature that you can't help but notice. High volume lower quality citizen science tree risk assessment is most likely to pick up 'red risk' trees before any scheduled visit from a trained Arborist carrying out 'Active Assessment.' In VALID's free Tree Risk-Benefit Management Strategies, this is called 'Passive Assessment'. Passive Assessment is a duty holder's most valuable risk management asset because it can be done by anyone and it's going on day in day out. How? Tree Alert will be used by members of the public and trained Basic Validators to alert duty holders or contact Arborists that they've seen a tree that might be 'dangerous'. The App user will be able to check what they're looking at against a rogue's gallery of obvious tree risk features. If it matches one of them, they geolocate the tree and take several photos of the tree in its setting, and of the obvious tree risk feature. The duty holder or contact Arborist will then get an alert with where the tree is and photos. A trained Arborist can then swipe right if they 'fancy' the tree and it needs a closer look, or swipe left if they reject the alert because it's not an obvious tree risk feature. Each alert will produce a brief photographic driven one-side report that will stand as a record of the alert.

Occasionally, during the night when it's very dark, from my bedroom window, I catch the street light reflecting off his night-vision goggles.👀

The point about risk is that once it's below a certain level it becomes Acceptable, and you're not expected to do anything to try and lower it. Incredibly low risks DO sometimes happen. People win the lottery but you'd be hard pushed to pick the winner, or winning numbers, before the draw. I'd be interested to hear more about this incident. Was someone killed or injured? Do you have any links? <<Trees throughout scone palace and the events field are now regularly surveyed by a very competent person. I don’t believe this sign was put up as an arboricultural recommendation but more reflects the anxieties of the property owners. Surely the fact that they are regularly surveyed over rules a sign asking people not to sit there?>> I'm not questioning the competence of whoever surveys the trees. I to would've thought the sign is likely down to the anxieties of the property owners, which is one of the points of the post. I don't see how regular surveys overrule what the SBD sign is or isn't doing. It's not helping the visitors and it's a possible noose for the duty holder. Also, from the SBD Guide: "Branches that might fail because of SBD, on trees that don’t have a history of it, lack obvious tree risk features. This means an Arborist can’t tell the difference between branches that have a high likelihood of failure from those that have a low likelihood of failure before they unexpectedly fail." <<You seem very eager to criticise, which is easy when you’re spouting off on the internet as opposed to putting your name on a survey.>> Really? I've put my name on a Summer Branch Drop Guide that can be used by anyone, including your friend who's surveying Scone's trees, to manage or assess SBD risk and given it away for free under a creative commons licence. I'd say that's quite a lot more than 'spouting off' off on the internet.

Yes, that went all the way to a civil court case, Harry Bowen and Others v Felbrigg. But it wasn't claimed to be SBD that caused the stem to fail though. There was a tremendous and sudden squal and a tree risk feature that couldn't reasonably have been picked up from the ground. I remember talking to a couple of local Arborists at the AA conference not long after the court case and they said the squal that ripped through and caused this tragedgy left a distinct path of tree failure in the area.

Good points. The tree hasn't dropped a large section. Nor the tree next to it that has the same sign. Other much larger trees on the site have dropped large limbs and none of them have SBD warning signs under them. Most likely during storms, but some may have been dropped in calm hot conditions outside of storms. The critical point about the sign is it's ineffectually managing the risk and making the duty holder MORE vulnerable to a claim being made in the extremely unlikely event of the risk happening. All of the biggest trees don't have any SBD signs under them. Why is it okay to walk under the trees but not sit? Can you stop for a chat, or dwaddle? If sitting is too high a risk and walking is an Acceptable or Tolerable risk, how was that difference in the likelihood of occupancy changing the risk from being Not Acceptable or Not Tolerable to Acceptable or Tolerable worked out? Had the tree had a history of dropping limbs after bouts of hot dry weather, then given its location a risk-benefit assessment would've been necessary. The risk would've needed to be managed by fencing off/mulching (people are reluctant to sit on mulch), or pruning, or felling. <<I've witnessed SBD on 3 occasions, but I've never witnessed a failure due to decay first hand. Anecdotally that would suggest that if the risk of SBD is 'mind-bogglyingly low' then the risk of failure due to decay is... bamboozlingly low? I'm not sure what the technical term for this level of risk would be in the VALID system.>> A quick point of clarification. The risk from SBD is the likelihood of someone being there, the tree part falling, and then causing significant consequences. Likelihood of failure is not the risk. As for your experience. The risks we're dealing with are so mind bogglingly low that none of our first-hand experiences, mine included, are likely to be representative of the underlying truth because of the small sample size. What we do know (citations in the SBD Guide) is that of the 64 deaths over 10 years in the DARM database they put together for the National Tree Safety Group, none of them sounds like anything close to SBD. Similarly, when the database for Australian trees deaths in coronial inquests since the 1870s is searched, and wind being a factor is filtered out, there's a similar magnitude of order lower than our base rate from ALL deaths by tree failure by x10 or so.

I've heard similar anecdotes. I suspect sheep just bolts soon as they hear a crack, whereas people are likely to stop texting and look up. In this video, the dog makes a much better decision. I've heard one story of someone getting killed by a branch because they had headphones on didn't hear the crack that their friends did which had them move. However, it might be apocryphal because I've not yet found it on the interweb. Avoidance Dance.mp4

Ha, ha, ha. Those alternative facts, eh. You were banned from the UKTC, largely because of your disturbing behaviour on there towards me and your appalling and threatening behaviour to Chris Hastie (UKTC owner) off forum. If you're in doubt, email Chris Hastie. Curiously, one of the reasons for your ban was exactly the kind of behaviour you're displaying in this thread - the one that's supposed to be about Summer Branch Drop. You're attempting your usual weird mix of ham-fisted coercive control and playground bullying to try and stop me from sharing information about tree risk. Your behaviour towards me is so oddly creepy and obsessive that in your posts on this thread, which I started to share information about SBD that might be of interest to other Arbtalk members, you've not yet managed to write anything on the topic of SBD.

Blunt, but that's the essence of it. Mind-bogglingly low risks sometimes happen.

Nice bit of what psychologists call projection there, Julian. The only person to have ever been banned from the UKTC - largely for your disturbing and weirdly obsessive single-white-male pursuit of me; which you're continuing on here. When will you get it into your creepy addled mind that I just don't fancy you, or your ideas. It's not straight in, is it. Mick was trying to fob off the post with a bit of lazy name-calling. I could've let it go, but I've called him out on it. A quick fact-check. These usually makes you uncomfortable. The SBD Guide is free and released under a creative commons license. Anyone can use it. It's part of the mission in setting up VALID as a not-for-profit Community Interest Company. When I'm running training, which people pay for, I post on the Training and Education Forum.

Have you got a link to that thread, please?

Thanks for the suggestion but I can't see anything of value in it. Why wait for an agreed explanation? Why ignore the numbers? In the meantime, duty holders are being threatened about their management of SBD by some in our profession. It looks like you've not bothered to read the SBD Guide before posting your opinion about it. Not least because there's no agreement about what SBD is called, or what it is, let alone "when" that's helpful. It did make laugh though. "corporate speak" - is your literacy bar really set that low? And the "sneering" accusation is ironically funny given what you've gone and posted. I agree with you about not putting picnic tables under a "large spready Oak" though. Not because of the mind-bogglingly low risk of SBD but because of the damage likely chronic footfall compaction on a valuable tree.

Signs of the times - Summer Branch Drop We know from the available data that the overall risk from Summer Branch Drop is mind-bogglingly low. The risk is so low, our risk of death from driving for the few minutes it takes to cover 3km/2mi is higher than from Summer Branch Drop over a whole year. Yet, fear-mongering and threats from risk entrepreneurs about legal action if such a mind-bogglingly low risk happens are pushing some anxious duty holders into wasting time and money on putting up confusing and ineffective signs; like this recent photo at Scone Palace, Scotland. Not only are the costs of commissioning and managing these signs grossly disproportionate to any questionable reduction in a risk that's already Acceptable. Their ineffectiveness may backfire on the duty holder and create an opportunity for a risk entrepreneur to act as an expert in the extremely unlikely event of someone being injured or killed. It'd be all too easy for them to claim the duty holder hadn't managed the risk well enough with signs and they could've reduced it more by fencing or pruning. Or if the visitor wasn't an English speaker, why wasn't the sign translated into their language. If you're a duty holder, or advise one, worry not about Summer Branch Drop and where, when, and how many signs to put up - or how many languages to use. We've got you covered with our handy Summer Branch Drop Guide on our Risk Management page. https://validtreerisk.help/Risk-Management

Just to confirm that we're going ahead with these training dates. Tree Risk-Benefit Assessment & Tree Risk Management Training | VALID VALIDTREERISK.HELP An elegantly simple solution to a complex problem - all in the palm of your hand!

Taking the 'defect' out of tree risk-benefit assessment has been published in the spring edition of the Arboricultural Association's Arb Magazine. You're welcome to download a pdf copy from the News page of VALID's website. Here's the introduction to whet your appetite. "We’ve grown up being told that when we assess tree risk we should be looking out for tree ‘defects’. The problem with this approach is what are commonly labelled as defects often aren’t defects at all"

Hi Khriss Sorry, t/R 0.3 isn't a sound guide at all. It's pretty much useless and incredibly misleading.

I thought some of you might find this post from VALID's News page useful, so am sharing it. Recently, I caught a podcast where a tree was declared 'safe' if it's less than 30% hollow. I think they meant 70% hollow. Either way, this isn't right for several reasons. I've posted about this before, but as long as this kind of mistake is being broadcast I think it's worth repeating so the message gradually gets home. The heart of the confusion is the t/R = 0.3 fallacy. t/R = 0.3 is when a residual wall thickness (t) is 30% of the stem radius (R). It's often cited as a failure threshold. It's not. The 'Why t/R Ratios Aren't Very Helpful' pdf explains why in detail. In short, one reason is because of a geometric property called section modulus. Wind load and material properties remaining equal, if you double the diameter you increase the load bearing capacity of a tree by 8 times. To add to the confusion, t/R 0.3 is often referred to as 70% hollow. In fact, a 0.3 t/R ratio is only 50% hollow. 70% is the radius, which is one dimension. t/R 0.3 is the area, which is two dimensions. This graph from Paul Muir shows the relationship of central hollowing on: A = Cross Sectional Area Z = Section Modulus t/R = 0.3 A = 49% loss of cross sectional area Z = 24% reduction in load bearing capacity To make matters worse. A tree with a t/R ratio of 0.3 can have a very high likelihood of failure, or it can have a very low likelihood of failure. If all that wasn't enough, it's seldom that where decay is of concern we're dealing with a cross sectional area of a tree that's a circle. Why tR ratios are not very helpful v5.0.pdf