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 08:29:19



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> > 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
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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
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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
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https://www.stockholmtreepits.co.uk