UKTC Archive

RE: Ganoderma resinaceum

Subject: RE: Ganoderma resinaceum
From: David Evans
Date: Aug 02 2021 16:55:21
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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