UKTC Archive

RE: Ganoderma resinaceum

Subject: RE: Ganoderma resinaceum
From: Brewster, Ian
Date: Aug 03 2021 14:31:26
Hi Dave,

‘Brown rot doesn't really stop a tree from flexing any more than white rot 
makes it flex more.’ Not clear on what this sentence is actually suggesting.
My prior understanding with ‘bottle butt’ has been associated with outward 
expression of enhanced root flare thought to signify slow deterioration of 
main stem lignin providing opportunity for the tree to react, stimulating 
growth of reaction wood by flex or weight bearing capability of the upper 
portion. This then becomes a race between the pathogen/decayer and how quick 
the tree is able to grow additional new annual rings to support against total 
collapse. Unlike Brown Decay deterioration of cellulose there tends to be 
little outward body language and can subsequently fail catastrophically with 
little warning. This to my simple mind makes good sense (which is why I can 
recall it now). Anyhow interesting discussion.
Hi Dave,

‘Brown rot doesn't really stop a tree from flexing any more than white rot 
makes it flex more.’ Not clear on what this sentence is actually suggesting.
My prior understanding with ‘bottle butt’ has been associated with outward 
expression of enhanced root flare thought to signify slow deterioration of 
main stem lignin providing opportunity for the tree to react, stimulating 
growth of reaction wood by flex or weight bearing capability of the upper 
portion. This then becomes a race between the pathogen/decayer and how quick 
the tree is able to grow additional new annual rings to support against total 
collapse. Unlike Brown Decay deterioration of cellulose there tends to be 
little outward body language and can subsequently fail catastrophically with 
little warning. This to my simple mind makes good sense (which is why I can 
recall it now). Anyhow interesting discussion.

From: uktc-request@xxxxxx.tree-care.info <uktc-request@xxxxxx.tree-care.info> 
On Behalf Of David Evans
Sent: 02 August 2021 17:55
To: UK Tree Care <uktc@xxxxxx.tree-care.info>
Subject: RE: Ganoderma resinaceum

Hi Jerry

Sorry for the delayed reply. I missed this.

<<So the selective loss of lignin from a tree does not lead to a greater 
tendency to flex under wind loading, thereby stimulating buttress growth; and 
'bottle butt' and the 'Eiffel tower' effect are all
imaginary...(?)>>

One of the problem with the Mattheck drawings we've all grown up with is he's 
been applying the strength-loss characteristics of inner decay on to outer 
soundwood.

The central parts of mature trees that are decayed aren't carrying much wind 
load and don't affect the load bearing capacity significantly because they're 
close to the neutral plane. The outer parts of the tree that aren't decayed 
are what's carrying the most load in tension and compression because they're 
furthest from the neutral plane. How are the material properties of the 
highly loaded outermost soundwood of the tree being significantly affected by 
the lightly loaded strength-loss characteristics of the central decay?

Brown rot doesn't really stop a tree from flexing any more than white rot 
makes it flex more.

<<However much one might deplore the fact, tree risk assessment always 
contains an element of assessing the risk to the assessor...>>

Nicely put but I'd emphasise it more. My research suggests its likely the 
crucial element. Arborists are trained to see red (what increases the 
likelihood of failure) and pay a lot less attention to the green (what 
reduces the likelihood of failure).

<<(As a matter of interest, do you still actively assess tree professionally? 
)>>

Yes. Even when I'm doing it for fun ;-)

Cheers

Acer Ventura
NPS
 From: uktc-request@xxxxxx.tree-care.info 
<uktc-request@xxxxxx.tree-care.info> On Behalf Of David Evans
Sent: 02 August 2021 17:55
To: UK Tree Care <uktc@xxxxxx.tree-care.info>
Subject: RE: Ganoderma resinaceum

Hi Jerry

Sorry for the delayed reply. I missed this.

<<So the selective loss of lignin from a tree does not lead to a greater 
tendency to flex under wind loading, thereby stimulating buttress growth; and 
'bottle butt' and the 'Eiffel tower' effect are all
imaginary...(?)>>

One of the problem with the Mattheck drawings we've all grown up with is he's 
been applying the strength-loss characteristics of inner decay on to outer 
soundwood.

The central parts of mature trees that are decayed aren't carrying much wind 
load and don't affect the load bearing capacity significantly because they're 
close to the neutral plane. The outer parts of the tree that aren't decayed 
are what's carrying the most load in tension and compression because they're 
furthest from the neutral plane. How are the material properties of the 
highly loaded outermost soundwood of the tree being significantly affected by 
the lightly loaded strength-loss characteristics of the central decay?

Brown rot doesn't really stop a tree from flexing any more than white rot 
makes it flex more.

<<However much one might deplore the fact, tree risk assessment always 
contains an element of assessing the risk to the assessor...>>

Nicely put but I'd emphasise it more. My research suggests its likely the 
crucial element. Arborists are trained to see red (what increases the 
likelihood of failure) and pay a lot less attention to the green (what 
reduces the likelihood of failure).

<<(As a matter of interest, do you still actively assess tree professionally? 
)>>

Yes. Even when I'm doing it for fun ;-)

Cheers

Acer Ventura



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