UKTC Archive

RE: [EXTERNAL] Re: Windshield/Drive-by | Speed Limit

Subject: RE: [EXTERNAL] Re: Windshield/Drive-by | Speed Limit
From: Howe, Ron
Date: Dec 03 2019 16:15:58
Trouble is Michael, it is reasonable, proportionate and practicable in the 
circumstances ... until something goes wrong ... Which is why rather than 
defining a drive by speed for example David might look to add those very 
three terms to say, "as far is reasonably proportionate and practicable." The 
person doing the job then defines what is appropriate for the day. I like the 
idea somebody suggested that you can do so many miles a day (by foot) and 
maybe that is the way to define it by car as an on average expectation.

Ron Howe
Tree Officer (Planning)
Mole Valley District Council

-----Original Message-----
From: <> 
On Behalf Of Michael Richardson
Sent: 02 December 2019 11:40
To: UK Tree Care <>
Subject: [EXTERNAL] Re: Windshield/Drive-by | Speed Limit

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David I can see that we are getting no where here.

Perhaps one of the list's tree risk experts can tell us how you define:
1) It's not reasonable
2) It's not proportionate
3) It's not reasonably practicable

It seems to me that 5 year inspections as David keeps talking about is as 
arbitrary as  6 years, though he now admits it is a suggestion only and 
perhaps a place holder in his Tree Risk Management Strategy.  If the risk 
managers cannot demonstrate the methodology to make the decision than the 
decision seems to be made on gut feelings and what others are doing and this 
is easily challenged in court.

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


On Mon, Dec 2, 2019 at 2:45 AM Wayne Tyson <> wrote:

The bane of scientific experiments is too many variables. Trying to
reduce such complexity into a formula may be impossible. The test, I
suspect, of any predictive tool, is not the authorities' opinions, so
much as it is feedback on what actually happens (predictive value).


On Sun, Dec 1, 2019 at 10:22 PM David Evans <>

<<David, after re-reading your website I am still left asking how do

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

Hi Michael

I'm a bit baffled about what you're after here.  You first asked me...

<<Can you please tell us exactly what is reasonable, practical and

Which is written up in VALID's Tree Risk-Benefit Management
Strategies, and you seem to be struggling with this*.  If you want
to know more, there's always Chapter 2 & 3 of the NTSG's Common
Sense Risk Management
Trees, which expands on it in more detail.  Or Professor David
Ball's "Public Safety & Risk Assessment".  I'm pretty certain I
can't explain it any further than what already I've set out.

Now, you appear to be asking why Jeremy's highways stuff isn't?

As for the rest.

<<I have no idea why you propose 5 years, not 4 or 6 or 7 years 2

5 Years Active Assessment frequency is a serving suggestion based on
a number of points.  Not least the 'proportionate' factors that the
overall risk from tree failure is extremely low.  The "prospects of
reducing the risk from tree failure below the current level are
remote and comparable
finding a microscopic needle in a gargantuan haystack" - Professor
David Ball (part for the risk advisory team to NTSG)

In application, Kent County Council (who were the first local
government organisation to host VALID training) is one of the main
Highways Authorities in the UK, and they carry out a 5 yearly assessment.
Birmingham City Council is the largest municipality in Europe, and
they carry out a 5 yearly assessment.  Whilst putting VALID
together, when canvassing local governments, urban forestry
academics, and solicitors representing local government in the UK,
New Zealand, Australia, and the US, there seems to be a general
agreement that a 5 year Active Assessment frequency is 'reasonable'
and 'proportionate'; particularly when it's
topped up by Passive Assessment.   Hence, the Tasmanian Government are
going to adopt a 5 year Active Assessment frequency on their roads.
It's why I'm proposing 5 years instead of 7 years 2 months.  Up to
been no benchmark for this.  I'm suggesting one that seems to be
widely agreed.  Have you got a better suggestion?

However, it's up to the duty holder to agree a frequency of
they can go for whatever they want.  They could even go for your
years 2 months if they chose.  It's their call.  But if as a
can get some kind of consistency, then when a legal claim is
inevitably made we're in a better position to justify this frequency
of assessment rather than be held hostage by highly questionable
expert witness testimony, resulting in equally questionable court
Judgments.  The court looks to our profession to set standards.
It's not the other way around, as some might claim.

<< 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
places, thus how do you determine under VALID your three criteria.>>

I really have no idea what you're asking here.  But it looks like
you might've been confusing risk management with risk assessment
from the get go*.


Acer Ventura

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