[CANUFNET] Seeking advice for Birch Crotch pooling water

Mon Jul 27 10:17:27 EDT 2020

Catherine,

I would advise to do nothing about the water. From my perspective when a cavity is holding water it is an indication that for now the tree seems to be walling off the affected area from further decay, which is a good thing that we should not interfere with. Drilling would be the worst option…

I think it would be good to have an arborist look at the tree and that specific branch. Hard to figure everything out from your pictures. 

The maybe more concerning import of the cavity is that it is located at the base of a large branch and may be making the branch more prone to failure. Reduction pruning to reduce the loading may be one recommendation and maybe a small cable to support the branch could be another. Or let Mother nature do her work if there is no significant target under the branch…

Birch are short lived and poor at defending themselves from decay. If this one is doing that, best to just leave it alone.

Cheers,

Philip van Wassenaer, B.SC., MFC

Urban Forest Innovations Inc.

1331 Northaven Drive

Mississauga ON L5G 4E8

Tel:  (905) 274-1022

Cell: (647) 221-3046

Fax: (905) 274-2170

www.urbanforestinnovations.com <http://www.urbanforestinnovations.com/> 

From: CANUFNET <canufnet-bounces at list.web.net> On Behalf Of C. Kavassalis via CANUFNET
Sent: July 27, 2020 9:00 AM
To: Canadian Urban Forest Network <canufnet at list.web.net>
Cc: C. Kavassalis <c.kavassalis at gmail.com>
Subject: [CANUFNET] Seeking advice for Birch Crotch pooling water

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/bitstream/handle/10919/32619/Farrellthesis0610.pdf?sequence=1&fbclid=IwAR2lKHVp7bn0xs95gRuNeJsXwibKgJCPdvAiCN8VX0dLPNByM40ZFkwZocM> https://vtechworks.lib.vt.edu/.../Farrellthesis0610.pdf...

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