[CANUFNET] Seeking advice for Birch Crotch pooling water

[C. Kavassalis]

Hello CANUFNET

I received the following inquiry to the Master Gardener of Ontario FB page
regarding a birch tree with a branch crotch with a deep hole. It  is
pooling considerable water (1 to 2 litres), and showing signs of rot,  "started
to swell / split the bark." The owner asks:

"Anything I can do to help it? I was thinking about drilling a small hole
through to let it drain, but then I thought I might be doing more harm than
good."  He notes the tree appears otherwise healthy.


My feeling was drilling a hole would introduce the core to pathogens, but
wondered what techniques are recommended for this. This appears to me to be
a situation where there are codominant stems and that would add some
complexity to the problem as I have read that pathogen protection is
reduced in such instances, (Farrell, 2003).


I have recommended an arborist visit, but would like to know what options
are recommended are sound with such occurrences.


Thank you

Catherine Kavassalis

MGOI.ca

https://www.facebook.com/groups/MasterGardenersofOntario/


Ref:

"Crotches have unique anatomical features that help to limit the movement
of water and some pathogens between the trunk and branch. The branch base
serves as a protection zone to stop the spread of pathogens from infected
or decaying limbs into the trunk (Shigo 1985). Decay-resistant substances
are concentrated in the swollen areas at the base and sides of the limb
(branch collar) where it joins the trunk. Differentiation in the vascular
system within the crotch reduces hydraulic conductivity and again acts to
limit transport between the branch and the trunk (Lev-Yadun and Aloni
1990). It is the combination of decay-resistant materials and the unique
vessel anatomy at the branch base that increases the ability of the crotch
to resist the spread of decay pathogens into the trunk (Eisner et al.
2002). This protection zone exists in branch-trunk unions but not in the
junction of codominant stems."
(Farrell, R. 2003. Structural Features Related to Tree Crotch Strength, MS
Thesis. Virginia Polytechnic Institute and State University.
https://vtechworks.lib.vt.edu/.../Farrellthesis0610.pdf...
<https://vtechworks.lib.vt.edu/bitstream/handle/10919/32619/Farrellthesis0610.pdf?sequence=1&fbclid=IwAR2lKHVp7bn0xs95gRuNeJsXwibKgJCPdvAiCN8VX0dLPNByM40ZFkwZocM>
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