[NatureNS] Trees and Fungus

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Date: Wed, 20 Dec 2006 09:04:48 -0800 (PST)
From: Paul MacDonald <paulrita2001@yahoo.com>
To: naturens@chebucto.ns.ca
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&gt;On 19-Dec-0
Hi Dave and All
Some woods - birch for example - if cut green, junked
in stove length and left in a moist spot will develop
fungus quite quickly. Well within a year. This will be
on the cut ends of the stick.
I suspect the fungus feed on the sap in the green wood
but soon start a decaying action.
Some of it is quite pretty - almost like coral that is
seen in the water. Various shades of red or purple.
I don't know if the spores of these fungus are air
borne or prehaps are on or under the bark. 
The other day I removed the bark from a piece of
spruce that was in the wood pile. A damp piece I might
add - under was crawling with larvea - little wonder
woodpeckers feed well on dead trees.
Enjoy the winter
Paul


--- David & Alison Webster <dwebster@glinx.com> wrote:

> Hi Peter & All,            Dec 19, 2006
>     That is a many sided question. There may be some
> anti-fungal agents 
> present in some bark. Some barks for example are rot
> resistant and used 
> for mulch or remain more or less intact for many
> years in forest litter. 
> But the primary barrier to invasion via bark is
> likely physical. The 
> outer bark is dead, as you supposed, and until the
> outer bark starts to 
> erode has as many annual rings as there are on the
> wood side. Only these 
> tissues are dense with almost no intercellular
> spaces (except in 
> lenticels), walls are suberized or thickened and
> firmly glued together, etc.
> 
>     In contrast, a common mode of entry for
> wood-rotting fungi is 
> through wounds; broken tops, broken branches, torn
> bark, insect holes 
> and pruning cuts. This invasion usually (always ?)
> happens when the 
> trees are live and may eventually lead to death but
> it is not uncommon 
> to see e.g. large hollow but partly living hardwood
> trees.
> 
>     In many trees there is a collar at the base of
> branches where the 
> wood of any one year of trunk and branch merge as a
> contorted bulge or 
> collar. When pruning is done with hand powered saws
> it is natural to 
> prune beyond this collar. But with chain saws, some
> are tempted to do a 
> 'good' job  and cut at the base of the collar rather
> than beyond it. 
> This increases the chance of fungal invasion because
> cutting at the base 
> of the collar exposes the wood of the trunk as much
> as a deep notch would.
>  
>     An additional barrier to direct invasion of
> intact above-ground bark 
> is moisture. Even dead bark on a standing dead tree
> usually rots from 
> the inside out; the outside is dry too much of the
> time. The outside of 
> bark, of a similar dead tree lying on the ground
> such that the bark 
> remains moist will soon develop a flame of fungal
> hyphae.
> 
>     I suspect that many fungal infections of
> heartwood are via broken 
> roots, especially roots near the surface, but do not
> know this for a fact.
> 
> Yours truly, Dave Webster, Kentville  
> 
> Peter Payzant wrote:
> 
> > Here's a question for the plant biologists: A dead
> tree soon develops 
> > a garden of various kinds of fungi on its bark.
> This doesn't happen to 
> > living trees, as far as I know (although lichens,
> liverworts etc. do 
> > attach to them).
> >
> >  
> >
> > The outer surface of the bark of a tree appears to
> be made up of dead 
> > tissue. How is the tree able to fight off
> infection by external fungi 
> > when it is more or less surrounded by dead
> material? Is it perhaps a 
> > matter of attacking the fungal "roots" when they
> penetrate the park to 
> > the living tissue?
> >
> >  
> >
> > Peter Payzant
> >
> >  
> >
> >  
> >
> 
> 
> 
> 


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