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Here are your opportunities to upgrade your approach to tree risk with VALID in 2025. https://validtreerisk.help/Tree-Risk-Training Because of demand from NZ, AU, and USA, it looks like we won't run more workshops in the UK until June 2026. VT = Validator Training VU = Validator Update

This question comes up frequently on social media, so we've put these resources together to help you. Risk Assessment Review https://validtreerisk.help/Tree-Risk-Assessment-Review Peter Gray's 2020 article in Arboriculture Australia's The Bark looks at the strengths and weaknesses of TRAQ, QTRA, and VALID. The post in the link addresses some points Peter raises about VALID. Western Springs Pines, Auckland, NZ https://validtreerisk.help/Western-Springs-Pines This high profile dispute ended up in the Environment Court. It's the only case we know where TRAQ, QTRA, and VALID risk assessments were carried out on the same trees. You can download the reports. If you want a geeky deep dive into what's going on with the wildly different risk ratings, have a look at Andrew Benson's report. Tasmanian Government QTRA to VALID https://validtreerisk.help/Tas-Gov-QTRA-to-VALID Tasmanian Department of State Growth (DSG) - State Roads has customised and adopted VALID's Government Tree Risk-Benefit Management Strategy. They did this after a Coroner's Inquest into Brendon Smith's tragic death when a tree fell on his ute whilst he was driving on a state road during a storm. When putting together the Strategy, DSG upgraded their approach to tree risk from QTRA to VALID. The head of the DSG's tree risk framework review asked us to put together a briefing note for the General Manager State Roads, to explain why they were moving from QTRA to VALID. We thought this note was confidential, but as DSG is a Government organisation, anyone can access it with Freedom of Information request. Several times people asked whether we could make it public because there is valuable technical information in it about tree risk assessment.

This from our socials might interest you. If you're a UK Arborist, you'll know that Professional Tree Inspection (PTI) is often the most requested credential for surveying and inspecting trees. A common concern raised by Arborists at VALID tree risk training is PTI doesn't actually teach you how to assess risk! So how can you spend all that time and effort training to inspect a tree - then go inspect one for a client - without producing a risk rating? Even worse, if you don't understand what the risk is, how can you recommend risk-reduction tree work with very specific timeframes? That's a core requirement of PTI. Is PTI really fit for purpose? Let's look at this key learning objective from the PTI course blurb, which cuts to the heart of the issue. "You'll learn how to clearly and competently inspect potentially hazardous trees." PTI Cover.pdf Here's the problem: we've moved beyond hazard-based thinking. We now focus on 𝘳𝘪𝘴𝘬-based thinking. One reason is the definition of a hazard is something that has the potential to cause death, injury, or property damage. And by that definition, every tree has this potential. So, almost every tree is a hazard. That's not helpful when you're managing or assessing the risk from tree failure. The PTI's poor grasp of risk becomes even clearer when you examine the phrase "potentially hazardous trees". If a hazard is something with the potential to cause harm, then a "potentially hazardous tree" is a tree that potentially has the potential to cause harm. That's a whole lot of weasel-phrase bafflegab. With PTI, "hazardous" is a lazy shortcut to imply the risk is too high - without putting in the work to actually assess the risk.

I appreciate your concern about the stability of your embankment. But VALID is all about managing and assessing the risk from trees and branches falling. The risk of slopes failing is an entirely different discipline. You'd need to speak to someone like a Geotechnical Engineer, not an Arborist.

You might find this recent post from our social media useful... 𝗗𝗲𝗮𝗱𝘄𝗼𝗼𝗱 𝗥𝗶𝘀𝗸-𝗕𝗲𝗻𝗲𝗳𝗶𝘁 We're elbow deep in v2 of VALID's risk model, and the Tree Risk App you use to carry out a Detailed Assessment. One of many substantial improvements in v2 is 𝘩𝘰𝘸 𝘸𝘦 𝘮𝘢𝘯𝘢𝘨𝘦 𝘢𝘯𝘥 𝘢𝘴𝘴𝘦𝘴𝘴 𝘵𝘩𝘦 𝘳𝘪𝘴𝘬 𝘧𝘳𝘰𝘮 𝘋𝘦𝘢𝘥𝘸𝘰𝘰𝘥. As with the Policy section in our Tree Risk-Benefit Management Strategies. Let's take an ISO 31000 approach and 𝘌𝘴𝘵𝘢𝘣𝘭𝘪𝘴𝘩 𝘵𝘩𝘦 𝘊𝘰𝘯𝘵𝘦𝘹𝘵. First… 𝗧𝗵𝗲 𝗕𝗲𝗻𝗲𝗳𝗶𝘁𝘀 𝗼𝗳 𝗗𝗲𝗮𝗱𝘄𝗼𝗼𝗱 𝗛𝗮𝗯𝗶𝘁𝗮𝘁 For a range of organisms, like insects, fungi, lichens, mosses, birds, mammals, and amphibians 𝗜𝗺𝗽𝗿𝗼𝘃𝗲𝘀 𝗧𝗿𝗲𝗲 𝗦𝘁𝗮𝗯𝗶𝗹𝗶𝘁𝘆 In particular, mass damping (dissipating wind load). Here are 3 ways. 𝟭) 𝗠𝗼𝗿𝗲 𝗠𝗮𝘀𝘀 Deadwood adds weight. This increases inertia, which reduces sway. Especially in the upper crown. 𝟮) 𝗚𝗿𝗲𝗮𝘁𝗲𝗿 𝗦𝘁𝗶𝗳𝗳𝗻𝗲𝘀𝘀 Deadwood is stiffer than live wood. It dances to a different rhythm than live wood in the wind. This out-of-phase syncopation helps dissipate kinetic energy. 𝟯) 𝗜𝗿𝗿𝗲𝗴𝘂𝗹𝗮𝗿 𝘀𝗵𝗮𝗽𝗲 Helps the tree smooth out the strain and stresses from wind loading. 𝗧𝗵𝗲 𝗥𝗶𝘀𝗸 What does the data tell us about the risk from Deadwood falling? We know our annual risk of being killed or seriously injured from ALL trees or branches falling is 𝘭𝘦𝘴𝘴 𝘵𝘩𝘢𝘯 𝘰𝘯𝘦 𝘪𝘯 𝘢 𝘮𝘪𝘭𝘭𝘪𝘰𝘯. That's so low, we're at greater risk driving on about a 400km/250mi round trip to visit friends for a weekend than from branches or trees falling over an entire year. Nearly all these deaths and serious injuries are from live wood. The risk from Deadwood HAS to be much lower. The overall risk from Deadwood falling is mind-bogglingly low. An annual risk somewhere south of 𝙤𝙣𝙚 𝙞𝙣 𝙤𝙣𝙚 𝙝𝙪𝙣𝙙𝙧𝙚𝙙 𝙢𝙞𝙡𝙡𝙞𝙤𝙣. 𝗗𝗲𝗮𝗱𝘄𝗼𝗼𝗱 𝗖𝗵𝗮𝗿𝗮𝗰𝘁𝗲𝗿𝗶𝘀𝘁𝗶𝗰𝘀 Deadwood has already shed its lower order twigs, shoots, and branches. It falls in smaller lengths than live wood. If it falls, the footprint is much smaller than an equivalent diameter branch that's alive. Deadwood is not only 𝘴𝘮𝘢𝘭𝘭𝘦𝘳 than live wood, it's 𝘭𝘪𝘨𝘩𝘵𝘦𝘳. As Deadwood provides habitat benefits. And Deadwood reduces the Likelihood of Failure of branches and trees. Why is so much 𝘵𝘪𝘮𝘦 𝘢𝘯𝘥 𝘮𝘰𝘯𝘦𝘺 spent on removing the benefits from Deadwood? In v2 of VALID's risk model. Deadwood under 10cm diameter is a Tolerable or Acceptable risk. We're only going to carry out a Detailed Assessment in Very High, High and Moderate Occupancy where Deadwood is 10cm diameter or more, and longer than 1m. 𝗩𝗔𝗟𝗜𝗗 - 𝗜 - 𝗦𝗽𝗲𝗰𝗶𝗲𝘀 𝗣𝗿𝗼𝗳𝗶𝗹𝗲 When you make Likelihood of Failure decision about Deadwood with VALID v2. We'll pre-colour V, A, L, and D for you. You make a decision about I for IDENTITY, and whether the Species Profile is green or red. That will determine whether the risk is 𝗧𝗼𝗹𝗲𝗿𝗮𝗯𝗹𝗲 or 𝗡𝗼𝘁 𝗧𝗼𝗹𝗲𝗿𝗮𝗯𝗹𝗲.

A recent post had this old thread resurface. I've just re-read it, and see there's an issue with the link above. It takes you to the News page of the website. The post referred to was at the top of the News at the time. There are now more News posts, so the article is much further down. Here's a link that takes you directly to the post. VALID - Tree Risk Assessment Review

The Validator Tree Risk-Benefit Management Strategy, I shared in the previous post, answers these questions. If you're concerned about the risk from the trees, have you thought about asking the land owner whether they'll share a copy of the report?

We never use the S word in VALID. That's because to just about everyone, 'safe' means a complete absence of risk. If a tree falls and kills or injures someone, it can't have been 'safe'. The only 'safe' tree is a felled tree. So, you can't assume all the trees on the embankment are 'safe'. It sounds like a Validator carried out the assessment, under the protective umbrella of a Validator Tree Risk-Benefit Management Strategy. The risk from the remaining trees will be Acceptable or Tolerable, as outlined in the Strategy. Validator - TRBM Strategy NH v9.1.pdf

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'.