VALID 2017

At JPA, we take CPD seriously and grab every chance we get to find out what’s new and trialling in our field. We recently attended the Arboricultural Association seminar on the theme of 'Tree Risk - What's the Likelihood of Failure?'

As qualified advanced QTRA (Quantified Tree Risk Assessment) practitioners, the JPA team was particularly intrigued to hear a talk by Acer Ventura, a.k.a. David Evans, on his new tree risk assessment methodology known as VALID.

Mr Evans originally established VALID in 2015 simply as a way to help in the determination of the ‘probability of failure’ component of a tree risk assessment: useful but of limited value to those of us in the field. Now, however, he has evolved VALID into a full-blown tree risk-benefit assessment system, which applies the internationally accepted approach to risk-benefit assessment - the Tolerability of Risk (ToR) framework – to the field of tree surveying and management. 

He has also set up a non-profit organisation behind VALID to deliver training and guidance on tree risk-benefit assessment and management. He hopes this venture will help fund research he is doing for his PhD on the Likelihood of Failure decision-making at the Centre for Decision Analysis and Risk Management (DARM - the risk experts used by the National Tree Safety Group) - and ultimately provide breakthroughs in the field of tree risk assessment.

This session was particularly memorable for Mr Evans’ famous ‘Likelihood of Failure Club’ that always involves robust and rigorous debate as attendees are challenged to defend or redirect their oft-entrenched opinions.

The collective JPA team evaluation: VALID looks promising, and could be a really useful tool for tree risk assessors in the future.


Bio-mechanics and trees

We also heard from Frank Rinn, the brilliant German inventor of the Resistograph drill and the Arbotom.

His talk on tree static loads was highly complex, involving a level of mathematical gymnastics that many attendees struggled to follow. However, he charmingly persevered and the application of his equations is undoubtedly of solid value to those of us on the ground (or in the canopy), converting theory into practical tools and strategies that enable us to help our clients resolve their tree-related issues.

Moreover, it is safe to say we now know an awful lot more about wood anatomy, tree safety factors, wind load and pruning, and international tree inspection standards than we ever thought we needed to.  His insights into legislation relating to trees in Germany and other countries were particularly mind-blowing: some of the regulations beggar belief and left us really rather relieved to be operating in the UK.