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: Wayne Tyson
Date: Feb 24 2021 22:07:00
Beyond common sense and "experience" (both good and bad), upon what
disciplined- and fundamentally-sound metrics are the conclusions based?
Anyone can think critically and test hypotheses, and I have found that a
lot of practitioners do so. On the other hand, I have known more who have
not and do not, usually those with rigid minds who reject any such
questioning out-of-hand. If one embraces "tradition" and rejects everything
else, one can spend a lifetime, regrettably, repeating the same mistakes
and expecting different results. If one ceases to entertain, and work with
others to objectively engage in such questions, one tends to believe in
whatever conventions one has been "carefully taught."
https://www.youtube.com/watch?v=VPf6ITsjsgk

WT

On Tue, Feb 23, 2021 at 2:01 PM Philip van Wassenaer <
pwassenaer1022@xxxxxxx.com> wrote:

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> Cheers
Acer Ventura


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The UK Tree Care mailing list
To unsubscribe send mailto:uktc-unsubscribe@xxxxxx.tree-care.info

The UKTC forum is supported by Bosky Trees arboricultural consultancy and
Stockholm Tree Pits
https://www.stockholmtreepits.co.uk




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The UK Tree Care mailing list
To unsubscribe send mailto:uktc-unsubscribe@xxxxxx.tree-care.info

The UKTC forum is supported by Bosky Trees arboricultural consultancy and
Stockholm Tree Pits
https://www.stockholmtreepits.co.uk