RobArb

yeh my bad, i failed to notice your thanks, i didn't quite perceive that sarcyness of your post:lol: you are absolutely ace!

think you missed the purpose of that one rich!

its turning into Facebook this.. ooo look at me, like me like me!

first one for ya!

took me a while to type that!

I shall argue that to focus on isolated aspects of risk, as is most often the case in studies interested in collecting quantitative data, is rather superficial, and ignores the collective context within which this risk takes place. Given that research is something which happens in this collective context, the objectivity of the researcher, central to traditional methods, is seen as essentially biased by interpretation. As singular arbs studying trees, researchers necessarily have attitudes and values which they bring to their research

I haven't thought of it yet:lol: Seriously though, for its flaws, i think the ISA system is better than QTRA, i need to read more though....

so Paul, Burnt Red or Crimson Orange:lol:

that's a misconception, as to earn power, people have to give it (thanks in this case) EDIT: sorry, forgot the little jesty smilie:biggrin:

Is there a need to put a number on things, what happened to common sense? OK OK, i'm not naive enough to think that this is possible, but there are better systems in place to ascertain the "risk" (there's that word again) of trees in relation to people and objects

there are too many people that just don't know when to say "i don't know"... more trouble than its worth if you ask me:biggrin: (yes i know, nobody did:lol:)

See even before i could finish off my post... he wah 'ere!!

erm pass... you may have to wait till Mr Humphries comes along, he'll sniff those mycelial felts out like a pig with cherries

you've got 1 now!

looks like caramel topping.... mmmmmm caramel topppppingggg:tongue_smilie:

haha, nice one, but was that not fellable from the deck?

Haha, do you sit and digest google all day:thumbup:

But why 1 in 10000? Based on acceptable levels of historic incidents? What one person sees as burnt red, another could see as crimson orange. Its about perception and interpretation and QTRA (IMO:biggrin:) offers no more value (as a system) than me saying the chance of the cherry tree across the road hitting the old lady as she walks past is negligible.

Mycelial felts, of what, i don't know:blush: could be the poly?

you sat fat now adam that ya need a crane to take you to the top?

we shouldn't be wary of "getting caught out", societies "blame" culture has enforced people to create these systems. Sometimes things just happen as Forrest Gump once eloquently put it, but, in retrospect of trees and QTRA surely there must be a better system to cope with today's expectations of our so called perceived state of "risk":biggrin:

I am not dispelling your opinions as we all are clearly entitled to have them, i just like to debate:biggrin: PS this tree exploded, albeit with the help of a lightning bolt! [ame]http://www.youtube.com/watch?v=f6PJdAee7qY[/ame] Don't know why it won't embed?

I think the word "risk" has a lot to answer for on the human psyche, what happened to just being in the wrong place at the wrong time? Why quantify something that isn't a constant? I suppose you could argue (as you did) on how to reduce this "risk" but surely in this day and age we take a risk by getting out of bed in a morning! Risk is a fact of life and not something that IMO needs quantifying

What do you make then of the response of David Lonsdale in the Bowen V National trust case 2011 in regards to QTRA? There is in my opinion no need to use formal risk assessment during general tree inspections. Inspectors should, however, understand the underlying principles sufficiently to be able to identify any trees that clearly warrant further attention. Also, tree risk assessment can be used retrospectively in order to help determine whether a previous general inspection has been appropriately conducted. On the basis of the visual evidence available on 2 January 2007, a retrospective assessment of the incident branch is presented in the following paragraphs, by multiplying numerical values for the three risk factors (A), (B) and © listed below5. General information about the estimation of each of the three values, both in QTRA© and in a modified version that can be alternatively applied5, is given in Appendix 4. 5 In the opinion of the author of the present report, there are instances where a re-definition of the three risk factors in QTRA© would be appropriate. QTRA© Factor (A), Impact-potential, is based on the size of the tree or part thereof, but it does not always represent the likely severity of impact. Factor (B), Probability of failure, is straightforward, albeit inherently subjective in its assessment. Factor ©, Target value, incorporates a formula for including property as well as human life in the estimation of the probability of harm, but it might be more logical to re-configure factors (A) and © so that A is the potential outcome of impact (i.e. degree of harm) and © is simply the probability of the target being present. In the case under consideration, use of this modified approach would, however, not affect the calculation of the risk index, since the outcome of impact is simply related to the weight of the incident branch and the probability of a person being present. 6 This factor is called “target value” in QTRA (rather than “occupancy”), because it includes an estimate of the risk of damage to property, which is valued in proportion to the notional pecuniary cost of a human life. Do you feel it has a place in tree assessments when each tree is so very different?

Not what the website suggest, but i suppose that is based upon entirely how you read it... "The Quantified Tree Risk Assessment (QTRA) system applies established and accepted risk management principles to tree safety management. Firstly, the use of land upon which trees could fail is assessed and quantified, thus enabling tree managers to determine whether or not and to what degree of rigour a survey or inspection of the trees is required. Where necessary, the tree or branch is then considered in terms of both impact potential (size) and probability of failure. Values derived from the assessment of these three components are used to calculate the probability of harm. The system moves the management of tree safety away from labelling trees as either ‘safe’ or ‘unsafe’ and thereby away from requiring definitive judgements from either tree assessors or tree managers. Instead, QTRA quantifies the risk of significant harm from tree failure in a way that enables tree managers to balance safety with tree values and operate to predetermined limits of tolerable or acceptable risk." Ellison himself notes in his paper, with reference to the criterion “Probability of Failure’ that Accurately assessing the probability that a tree or branch will fail is highly dependent upon the skill and experience of the assessor.