UKTC Archive

Re: Windshield/Drive-by | Speed Limit

Subject: Re: Windshield/Drive-by | Speed Limit
From: Michael Richardson
Date: Dec 01 2019 13:20:39
David, after re-reading your website I am still left asking how do you

1) It's not reasonable
2) It's not proportionate
3) It's not reasonably practicable

Here I am asking for specifics, I have no idea why you propose 5 years, not
4 or 6 or 7 years 2 months.  In the case of KEW we know the number of
visitors per year and the number of hours workers have been on the
grounds.  We wold know similar numbers for many roads and public places,
but we don't know for many other places, thus how do you determine under
VALID your three criteria.


Michael Richardson B.Sc.F., BCMA
Ontario MTCU Qualified Arborist
Richardson Tree Care


On Sun, Dec 1, 2019 at 3:48 AM David Evans <> wrote:

<<David from your writings I have learned that TRAQ, QTRA, and PTI are no

Hi Michael

I've not said they're all 'no good'.

They all have some value, but as you know they all have substantial issues
in their construction and in their application by the assessor.  PTI
doesn't even assess risk - which, if you think about it is rather odd when
you're taking all that time and effort to inspect a tree.  It's why I put
so much work into getting VALID going because I thought the whole thing
could be done so much better.  As well as being so much easier on the
assessor and duty holder.

<<Can you please tell us exactly what is reasonable, practical and
proportionate for one single example?>>

I'm not being pedantic here but it's not 'practical'.  It's 'reasonably
practicable'.  The term has a very particular meaning in risk management.

At the risk (acceptable) of enraging the usual suspects, it's all set out
in the Tree Risk-Benefit Management Strategies on the Risk Management page
of VALID's website here.

Have a look at the Government one, which is the most comprehensive.  The
single most important document is the Policy.  It's a position statement.
Everything flows from the Policy.  In the unlikely event of a claim being
made, it sets out the ground on which a duty holder would mount their

Kew Gardens Questions
Have a read of the Active and Passive Assessment Note in the Strategy, and
the three levels of Active Assessment - Basic, Detailed, and Advanced.
 This answers most of your questions.   How frequently Kew would carry out
an Active Assessment is their call - VALID proposes a 5 yearly Active
Assessment frequency in high use zones as being reasonable, proportionate,
and reasonably practicable.

Really importantly, Active Assessment is forever being topped up by
Passive Assessment, which is happening all of the time.  One of the things
I've been doing in Tasmania is putting all their Highways Inspectors
through a one day 'Tree Risk & Obvious Trees Defects' course.  If Kew were
to follow what the Tasmanian Government have done, then all of their
outdoor staff would be trained to recognise obvious tree defects.  They'll
then be carrying out thousands of 'free' Passive Assessments each week.  As
such, I'd have thought they could make a very strong case to manage their
risk by Passive Assessment alone, and carry out Advanced Active Assessments
on those few trees that they're monitoring, at whatever period of time has
been specified.

<<exactly how many minutes and seconds per tree>>

<<Further can you please tell us the exact risk vs. benefit for the
massive *Quercus castaneifolia*.>>

Sorry, I can't on both counts.  VALID doesn't do 'exact'.  There's way too
much uncertainty in tree risk assessment to be exact.  I'd have to see the


Acer Ventura

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