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: Philip van Wassenaer
Date: Feb 23 2021 22:01:34
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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To unsubscribe send mailto:uktc-unsubscribe@xxxxxx.tree-care.info

The UKTC forum is supported by Bosky Trees arboricultural consultancy and
Stockholm Tree Pits
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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