[CANUFNET] hybrid poplar tree hazard

[Mead, Mark]

Here in the Pacific Northwest, cottonwood are notorious for summer limb drop or as I call it "limb popoff". Examination of the branch collar at the site of popoff has an odd ball and socket appearance. We have been doing closer examinations of the cottonwood and removing branches that have branch unions that are perpendicular to the trunk and exhibit a large branch collar.
Nothing gets your attention like a large (14") diameter branch popping off a cottonwood from 60' feet up in the middle of the hottest day of the year at one of our well used beaches.

From: canufnet-bounces at list.web.net [mailto:canufnet-bounces at list.web.net] On Behalf Of Menounos, Kim
Sent: Wednesday, June 16, 2010 11:23 AM
To: 'Canadian Urban Forest Network'
Subject: Re: [CANUFNET] hybrid poplar tree hazard

We are constantly in the same philosophical debate about Cottonwood trees in a local park. The trees are very large (same latitude as Thunder Bay!) and old.  There are no residents close by, so it's a much lower risk.

The reason I am weighing in is just to mention that these trees appear to get to a point/age when their limbs become a hazard from falling. It isn't predictable, ie. only after a windstorm, and they are huge! We can manage this risk because their benefit to the local riparian ecosystem is important and the visitors to the park are less frequent. However, I personally would not want to bear the risk of one of these trees on my private property for this very reason! The context has to be part of the discussion. Is the property/tree owner going to be able to predict when a large limb is going to fall (and they will continue to fall because of the species) and be able to mitigate the hazard by having an arborist in in time to keep someone from being hurt?

Kim Menounos, RPF
City of Prince George

From: canufnet-bounces at list.web.net [mailto:canufnet-bounces at list.web.net] On Behalf Of Stephen Smith
Sent: June 16, 2010 9:28 AM
To: Canadian Urban Forest Network
Subject: Re: [CANUFNET] hybrid poplar tree hazard

I wouldn't condemn a tree just because of risk that something might/will happen sometime in the future based on species alone. It has to demonstrate an imminent risk of failure now.

That said, I wouldn't recommend planting them if I know of these characteristics, subject to other goals for planting that might be more important at the time.

If I want to remove one because of species, say a large Manitoba maple because it's an invasive species, I will remove it on that basis not future presumed risk, even if it has future risk of failure too but isn't imminent now. If your municipality doesn't make allowances for invasive species or other reasons for removal than imminent hazard, then it might get more complicated.

Stephen Smith
Urban Forest Associates Inc.
Urban Forestry and Ecological Restoration
www.ufora.ca<http://www.ufora.ca>
----- Original Message -----
From: Vince Rutter<mailto:vince at rutterurbanforestry.ca>
To: Canadian Urban Forest Network<mailto:canufnet at list.web.net>
Sent: Wednesday, June 16, 2010 9:52 AM
Subject: [CANUFNET] hybrid poplar tree hazard


A client's neighbour owns two large hybrid poplar (similar to cottonwood) trees that overhang his property.  They are healthy vigourous trees, both with many codominant stems and are quite large (2 metre DBH).  That's pretty big for here in Thunder Bay!  Over the past several years there have been many occasions where branches have snapped and fallen which is typical of the species.  The branches are anywhere from 2 inches to 5 or 6 in diameter.  They are truly concerned about the tree and would like to compel the owners to take action.
At best, we could clean the crown, reduce long branches and support included branch connections by cabling but I don't feel that would greatly reduce the risk of occasional limb breakage.  That said, have any of you condemned a tree based on its species characteristics like these poplars?
This problem comes up fairly frequently here and it usually leads to tree removal but in this case all parties involved can't come to an agreement.

Any insight would be greatly appreciated.
--
Vince Rutter, RPF
ISA Certified Arborist
www.rutterurbanforestry.ca<http://www.rutterurbanforestry.ca>
807-627-6201
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