UKTC Archive

Re: VALID Tree Risk-Benefit Management Plan - Risk Reduction Work Priorities

Subject: Re: VALID Tree Risk-Benefit Management Plan - Risk Reduction Work Priorities
From: Michael Richardson
Date: Dec 20 2017 15:37:09
Estimating, let alone quantifying the probability of failure associated
with any defect is I think the hardest part of any risk assessment.  I
recently saw a report where 1338 of 7500 trees was described as being at
high probability of failure over the next 18 months.  Two years after the
report not a single tree had failed!

If you are interested in forks Slater is not the only person.  If you look
at morpho-physio approach to forks we find works by Halle, Rimbaud, Millet
and Drenou.  Brian Kane has done some work and has a student or two who
have completed thesis on branch failure and strength.  Matt Follett (who
seems to have disappeared) did a lot of work on sway motion in limbs.

I can try to did up the thesis written by Kane's student.

Michael Richardson B.Sc.F., BCMA
Ontario MTCU Qualified Arborist
Richardson Tree Care
Richardsontreecare.ca
613-475-2877
800-769-9183

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On Wed, Dec 20, 2017 at 10:22 AM, Dom Gane <uktc@xxxxxx.tree-care.info>
wrote:

[Text converted from HTML]
Thanks David. Still doesn't explain how I place a value on a risk though.
I strongly suspect that drawing attention to the statement below will
lead to the kind of circular arguments I remember from a few years ago.
I think Duncan has made some headway into quantifying the relative
failure probability of tree forks, I'm awaiting delivery of his book.
We have Matthecks work, but his data has, perhaps, limited application.
We may apply a load test, in some circumstances, if budgets allow.
These new data logging devices are intriguing. I'm quite interested in
modelling and they appear to make use of non linear dynamics in order to
predict a phase transition. If you have any info on them I would really
love to read it. I think there is great potential there, but am puzzled
by the cost of what appears to amount to the guts of a budget mobile
phone.
I suppose we might collect and analyze masses of data on tree failures
and estimate the probabilities of failure in certain classes. The woods
are a good place to see tree failures.
This allows us to refine what we really have to go on which is our
experience.

"VALID's amber risks require the likelihood of failure to be benchmarked
from
red"



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