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  • From: david.maxwell@dal.ca
  • To: North American Fruit Explorers <nafex@lists.ibiblio.org>
  • Subject: Re: [NAFEX] Dying tree
  • Date: Sun, 24 Jul 2011 14:43:08 -0300

I am most grateful to all those who have offerred advice and comments. But I
don't think we
have this nailed down yet. Michelle, I do not think it is "Brown Line
Decline" I sectioned the
trunk starting at ground level. At this point the wood is clean and white.
The bark is quite a
bright orange, and i am a little uncertain whether this represents disease.
Starting about 8
cm above ground level there is a little discoluration of the wood and an area
of blackening of
the bark. As one proceeds up the trunk the discolouration in the wood
becomes more and
more prominent and obvious, giving a mottled appearance. The bark at these
levels has a
clear area of necrosis, with a blackened appearance under the bark, which is
separating. The
maximum staining of the wood occurs between 24 and 30 cm., and above this,
the bark is
slightly darker in a small area, and only the heartwood is discoloured. The
graft union is at
about 40 cm and here there is only a minimal staining of the heartwood, but
persistence of
the small area of darker bark. Above the graft union the Gideon cultivar
looks absolutely
clean, with green cambium and intact bark.
My analysis is that whatever this is penetrated the bark at about 24 cm above
ground level,
and spread a little down, and up as far as the graft union, but not beyond
it. Judging by the
staining of the wood, it has been present for a number of years. (The tree
was grafted in
2001). The interesting thing is the absence of external evidence of cankers
or anything to
suggest what was going on under the bark.




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