UKTC Archive

Re: How does one inspect big hairy common limes, allowed to grow a secondary forest of basal sprouts?

Subject: Re: How does one inspect big hairy common limes, allowed to grow a secondary forest of basal sprouts?
From: Wayne Tyson
Date: Oct 29 2019 21:54:19
How does one professionally define "risk to a tolerable or acceptable
level?"

Cheers,
Wayne

PS:
I *never* use the "S" word (safe), period. Too many variables. Nor to I
feel competent to use the ASL/R word. I prefer a solid foundation of
observed facts and statements of relative comparisons with similar past
failures (this does not NOT mean that comparisons can be reliably used to
*determine* safety or failure potential); only that they are data or data
points that, in a statistically competent manner, can be used as
illustrations of principles and consequences. I take as much care as
possible to reveal what I have not observed (access, cost, etc.), as well
as discuss the observations that demonstrate greater stability than
instability (without actually saying so). Most people are smart enough to
reach more or less sensible conclusions based on the evidence. I never use
the RR words either.

Consider and explain the number of trees left standing (as well as those
which failed) in the midst of clear evidence of destruction in the
aftermath of a tornado or hurricane, for example.

Guesses and biases just won't do. Nor, for that matter, will "professional
opinion." But a clear exposition of observed factors that either weaken or
strengthen a given tree is *possible*, (usually to an indeterminate degree)
but only with sufficient data. Why there appears to be resistance to this
in some quarters I cannot explain.

"The suspension of judgment is the highest exercise in intellectual
discipline."  --Raymond Maurice Gilmore

On Tue, Oct 29, 2019 at 3:12 AM David Evans <david@xxxxxxxxxxxxxx.com> wrote:

Hi Mike

<<I would suggest that one could be held negligent by pronouncing a tree
to be safe when it hasn't been inspected properly (due to epicormics, ivy
or whatever).>>

I'd strongly suggest never using the S word no matter how thoroughly a
tree is inspected.  Safe, to most people, means the complete absence of
risk.  You can't make a tree safe.  What a duty holder should be looking to
do is manage the risk to a tolerable or acceptable level.  Not minimise or
reduce the risk.  If a tree fails and kills someone clearly it wasn't
safe.  It could be a tolerable or acceptable risk though.

<<when it hasn't been inspected properly How would one defend that
decision in court?>>

What's inspected properly?

I'm guessing you're okay with inspecting trees and assessing the level of
risk without climbing each one and checking the upper side of all the
branches you can't see?  Or not entering every garden that's necessary to
see a tree from all angles.  Or without carrying out sonic tomography and
running it through some software like TreeCalc on each tree to see whether
there's significant strength loss from decay?  Or without carrying out a
Static Load test on each tree in case the roots are decayed?  The same
principle applies to ivy, climbers, bramble, rhododendron, epicormics, very
steep slopes etc.

If you look at the issue through the spectrum of risk, because we know the
overall level of risk is extremely low (our base rate, on which
proportionality is founded), you should only be looking closer if there was
an obvious defect, like dieback, to trigger the extra effort and cost.  As
an assessor, you simply note the limitations of the assessment.

Cheers

Acer Ventura


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