UKTC Archive

Re: stability of surviving stem of a split co-dominant tree.

Subject: Re: stability of surviving stem of a split co-dominant tree.
From: Michael Richardson
Date: Jan 18 2022 11:27:31
Should you not be considering the distribution of roots and natural bracing?

M

Michael Richardson B.Sc.F., BCMA
Ontario MTCU Qualified Arborist
Richardson Tree Care
Richardsontreecare.ca
613-475-2877
800-769-9183

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On Tue, Jan 18, 2022 at 5:52 AM "Rupert Baker" <uktc@xxxxxx.tree-care.info>
wrote:

Dear Dave et al,
Thanks for the responses so far; the link to treecalc is useful; many
thanks. I do however have reservations about using it in this situation.
As I said in my original post, the x-sectional area supporting the
remaining stem has not changed; on the hypothetical tree -
 (and it is hypothetical! - I do not have a particular specimen in mind at
present; it is just something I've come across many times over the years)
- there were once two stems each connected to the main trunk below; by
definition with a codominant stem, there is minimal or zero connectivity of
wood fibres between the two stems.

Each stem is therefore being supported by its own cross sectional area of
wood. If there is no defect or decay within this wood, what is the
difference between a single stem with the other one broken out and a pair
of such co-dominant stems on a whole, undamaged tree.

 I understand the effect of an open cavity on a circular cross section of
wood - one only has to split logs to realise that once one has made the
initial split the others are all easier. Trees have evolved to cope with
loadings on cylindrical stems by pre-stressing the wood in cylindrical
section (Wessolly et al amongst many others).

        The key thing I don’t know is: does the presence of the other stem
in a pair of whole co-dominant stems act in any way to assist in the
pre-stressing of its neighbour? Or does each stem behave as -in effect - a
cylinder with a section missing; and thus be prone to failure through
bending stresses.

Rupert

-----Original Message-----
From: uktc-request@xxxxxx.tree-care.info On Behalf Of David Evans
Sent: 17 January 2022 17:10
To: UK Tree Care <uktc@xxxxxx.tree-care.info>
Subject: RE: stability of surviving stem of a split co-dominant tree.

<<I've been musing about this for some time; if one has a tree which was
double-leadered, with a pair of codominant stems and a tight compression
fork between them>>

Hi Rupert

Put your remaining stem through TreeCalc.

https://www.treecalc.com/?lang=2

It'll give you a starting point Safety Factor.  You'll then have a
conservative measured assessment, that'll be free of all hidden noise,
bias, and error that are endemic to qualitative opinions about what is
difficult and complicated decision.

Cheers

Acer Ventura




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