UKTC Archive

RE: Assessing retained tree stability following part clearance of a tree group

Subject: RE: Assessing retained tree stability following part clearance of a tree group
From: BENJAMIN FUEST
Date: Feb 24 2021 14:19:22



I think Heraclitus the Greek phylosopher sumed it up nicely when he said.

No man ever steps in the same river twice, for its not the same river and he is not the same man

The idea being that the only universal constant is change. Assesing the likely hood of trees falling over via formula is asking for trouble why I ask would you want to do it. Is such work driven by insurance companies, courts and lawers? Is it a product of a litigeous society and an industry looking for more and more to add to service lines.




------ Original Message ------
From: "Jim Quaife" <jq@xxxxxxxxxxxxxxxxx.co.uk>
To: "UK Tree Care" <uktc@xxxxxx.tree-care.info>
Sent: Wednesday, 24 Feb, 21 At 10:58
Subject: RE: Assessing retained tree stability following part clearance of a tree group Those of us who experienced the "Great Storm" in SE England in October 1987 will be familiar with the random impact of very high winds. My brother-in-law flew me over north Kent 2 days afterwards and although there was an overall general direction of windblow, it was nowhere near as uniform as one might have expected.
Jim
-----Original Message-----
From: uktc-request@xxxxxx.tree-care.info [mailto:uktc-request@xxxxxx.tree-care.info] On Behalf Of Michael Richardson
Sent: 24 February 2021 10:05
To: UK Tree Care
Subject: Re: Assessing retained tree stability following part clearance of a tree group
Here on the north shore of Lake Ontario in Canada we had a very strong
(100+kph gusts) wind storm last November.  Some of the very interesting
results were the geographical scattering of down trees and the species.
I have worked in the Northumberland County Forest for many years now. This forest was planted (1930s through present day) after initial logging then
farming resulted in the loss of top soils.  The predominant natural
vegetation would be a mix of oaks (Quercus nigra, alba, rubrum) and White Pine (Pinus strobus), oak parklands, and tall-grass prairies. There were
bands of trees uprooted; what was most interesting was that all were
planted pines (Pinus strobus, sylvestris, banksiana) and Spruce (Picea
abies and glauca); failed trees tended to have remarkably small root balls (depth and spread), small roots, and often J-hook root systems even though
they were 50-80+ years old.  The native oaks, all of which were natural
regeneration all stood wind firm.

Michael Richardson B.Sc.F., BCMA
Ontario MTCU Qualified Arborist
Richardson Tree Care
Richardsontreecare.ca
613-475-2877
800-769-9183
<http://www.richardsontreecare.ca/images/Tree_Doc_logo_email.png <http://www.richardsontreecare.ca/images/Tree_Doc_logo_email.png> >

On Wed, Feb 24, 2021 at 3:29 AM BENJAMIN FUEST <uktc@xxxxxx.tree-care.info>
wrote:


Morning Philip.
Im too old and too bent myself to continue working in the field, but
when I did I useualy worked withing a radious of 50 odd miles from home.
The topography of the land the prevailing wind conditions and
importantly soil structure were all fermilier to me. for example if one
were North of the Malvern hills, it would be primeraly a flat flood
plane with heavey soils that dont wear well under the weight of
extraction equipment especialy when wet. If you go South West toward
Glouster it changes, perhaps to a more sandy type. The tree species for
harvest also adapts perhaps from Oak to Beech. Crossing the boarder into
Wales and again we see changes to the landscap as it becomes
progresivley more hilly with Larch, Douglas and spruce. The soils are
shallow and yet they support enormuse trees. High winds to be expected
comming in from the Atlantic, skimming past southern Ireland, bashing
into the south west. The point Im making is local knowledge plays a key
role in the understanding of our tree stocks and the soil typs that
support them. Harvesting contractors develop this understanding not
because they have a scientific intrest in it, rather a vested interest.
Will is suport the wieght of the machines, when not to go in, when its
ok to go in and importantly the cost of getting it wrong. A good
contractor with the experiance will make choices bassed on his knowledge
and apply his experiance to the task, this is almost in the  sub
concious, just as his thoughts are on how many trees to remove from a
stand and how stable the remaining trees may be after the event.
We have many names for a bunch of trees growing together. Cops, Spinny,
Stand, Plantation, Crop, Forest, Wood, Dingle and Coppice. There are
probably more that others can think of depending again on locality.
Importantly the name gives us a clue to what we are talking about.
The question in the heading. Re:Assessing retained tree stability
following part clearance of a tree group.
A tree group, a group of trees. This is a new one to me, and happy to
learn it. It does nt however provide any idea as to what it actually is.
Its a title with all the sutleties and pointers absent. Im not very good
at but Latin as a langauge and trees is helpful in so much as a name
provides many clues to type and origin. Provenance and context. The
title in the header has none.
David has done some interesting work and I have enjoyed his company over
a cup of tea. But the idea that a mothod/formala can be applied to
remaining trees re stability, Im not so sure. I have been lucky and
spent much time working as a consultant for the Davey tree expert Co.
Taking part in many heritage tree care workshops accross the USA. They
put together an interesting event called Tree Bio machinics Week. People
from all over could attend while stuff was done.
One such thing was to attach loading devices to trees and apply pulling
forces to see how the tree would perform. While good fun and all that I
think the data gained from such an experiment is O

------ Original Message ------
From: "Philip van Wassenaer" <pwassenaer1022@xxxxxxx.com>
To: "UK Tree Care" <uktc@xxxxxx.tree-care.info>
Sent: Tuesday, 23 Feb, 21 At 22:01
Subject: RE: Assessing retained tree stability following part clearance
of a tree group
Thanks Ben,
I agree that forestry as you describe it is an art and am aware that
this type of management has been under way for a long, long time...Just
wondering how that art was going to be applied to the discussion of the
stability of the trees left behind after others are cleared.
I assume the art here is not exposing them too much?
Philip
Philip van Wassenaer, B.SC., MFC
Urban Forest Innovations Inc.
1331 Northaven Drive
Mississauga ON L5G 4E8
Tel:  (905) 274-1022
Cell: (647) 221-3046
Fax: (905) 274-2170
www.urbanforestinnovations.com
-----Original Message-----
From: uktc-request@xxxxxx.tree-care.info
<uktc-request@xxxxxx.tree-care.info> On Behalf Of
benjaminfuest758@xxxxxxxxxxx.com
Sent: February 23, 2021 11:53 AM
To: UK Tree Care <uktc@xxxxxx.tree-care.info>
Subject: Re: Assessing retained tree stability following part clearance
of a tree group
Hi Philip.
Is it not the same thing. As you no I was a commercial timber
faller/contractor for the better part of 30 years. Many of the
harvesting jobs were of the hardwood variety. If we set aside what we
call it, ie copse, wood stand whatever. And consider a patch of mature
oak and ash mix. Perhaps until now untouched. The brief would often be
along the line of identification of the best stems and fell the rest. Ok
so maybe a tasty stem or two would find its way to road side as a
sweetener to market.
It was not uncommon to take out 80 percent, leaving large openings in
the canopy and large areas of clear space for coppice regeneration. This
is called coppice with standards. The standards being the remaining big
stems. Such Silvicultural practices have been on going for hundreds and
hundreds of years.
Clearly such work has a significant affect on the dynamics of the site
and wind loading in remaining stems.
Early in my career I worked first thinnings, primarily soft wood.
Cutting racks or a some would say line thinnings. Removing every fourth
row, depending. And then thinning either side of that. With the
additional space afforded the remaining stems are able to gerth up. A
few years latter a second thin, a third and so on.
Here is Wales we a blessed with Douglas fir in excess of 160 foot. If
walking the wood it is still possible to make out the original lines in
the planting.
Even timber at this level is not often clear felled, it is thinned.
Many foresters or agents lack the experience or confidence to mark such
trees for felling and turn to the cutter. This is referred to as feller
select. If the feller/cutter has the experience he will consider the
market demands and the expectations of the owner and of course a perhaps
most importantly the woodland itself. In other words, what will it
yield.
The cutter will perhaps start by tickling out a few. Not to many but
enough to achieve the objectives.
Perhaps during this process management make a visit and decide it could
be hit a little harder.
There are a few things to consider such as amenity, sporting use, market
demands and ownership. To name a few.
To live long enough to develop the skills required to do this kind of
work, identifying the appropriate methods is a lifetime in the woods. I
am perhaps a Luddite and do not believe this can be reduced to
mathematical formulae.
It is an art form handed down over generations. Getting it wrong is
usually the result of market demands and or ignorance. In the parlance
of the cutter we have a rather unpleasant expression for such in that we
refer to it as being rapped, he rapped it.
If one was of a mind to and there was the money to pay for it one could
look at topics such as yeld class, basal area and such. In today’s
forests trees are typically grown to an optimal size and then the whole
stand is clear felled in one hit. The ART is lost.
I am a believer in a holistic approach to woodland management. This to
me extends from the sun that provides the power to drive the system to
the soil that supports it.
All the best
Ben
Sent from my iPhone
On 23 Feb 2021, at 15:46, Philip van Wassenaer
<pwassenaer1022@xxxxxxx.com> wrote:
Ben,
Andrew  asked about the stability of the retained trees, not woodland
management.... If Foresters have a way of assessing the likelihood of
failure of these trees, please educate us. Otherwise David pointed out
that the consulting arborist community has definitely devised a method
to give answers to that question. Tree Pull Testing. From my 25 + years
looking at tree risk assessments, I have not discovered another way that
can give good answers about the stability of trees...
I am also not sure how your "art"  of where and when to thin has a lot
of relevance to this specific question...
But I am keen to find out.
Cheers,
Philip
Philip van Wassenaer, B.SC., MFC
Urban Forest Innovations Inc.
1331 Northaven Drive
Mississauga ON L5G 4E8
Tel:  (905) 274-1022
Cell: (647) 221-3046
Fax: (905) 274-2170
www.urbanforestinnovations.com
-----Original Message-----
From: uktc-request@xxxxxx.tree-care.info
<uktc-request@xxxxxx.tree-care.info> On Behalf Of BENJAMIN FUEST
Sent: February 23, 2021 3:33 AM
To: UK Tree Care <uktc@xxxxxx.tree-care.info>
Subject: RE: Assessing retained tree stability following part
clearance of a tree group
Hi David,
This is precisley why Arborists should not take on woodland management.
Arboriculture is ok and has a place in the urban enviroment, maybe. It
is absolutly usseles in the context of Sylviculture.
When to thin how much to thin and where to thin is an art form. Not a
science.
Cheers
Ben
------ Original Message ------
From: "David Evans" <david@xxxxxxxxxxxxxx.com>
To: "UK Tree Care" <uktc@xxxxxx.tree-care.info>
Sent: Tuesday, 23 Feb, 21 At 08:03
Subject: RE: Assessing retained tree stability following part clearance
of a tree group <<I'm interested in the collective's thoughts on
assessing the impact of tree removal on the stability of adjacent
retained trees.>> Hi Andrew The way I'd go about this is to run TreeCalc
on the exposed trees to get a handle on the Basic Safety Factor.  Then
have a look through Paul Muir's 2019 AA Conference presentation, and
head to the section where he talks about modifying the wind load, around
slide 49.
https://valid.tiny.us/2hqg8k4h <https://valid.tiny.us/2hqg8k4h> <https://valid.tiny.us/2hqg8k4h <https://valid.tiny.us/2hqg8k4h> > <https://valid.tiny.us/2hqg8k4h <https://valid.tiny.us/2hqg8k4h> <https://valid.tiny.us/2hqg8k4h <https://valid.tiny.us/2hqg8k4h> > >
Cheers
Acer Ventura
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