[CANUFNET] Beech Bark Disease

Mon Feb 27 10:29:58 EST 2012

Hello

I am passing on this note from Dr John McLaughlin

Barb Boysen

---------------

Hi Barb,

   I am working on a BBD publication with an Ontario focus, which we hope will be published by this summer. Because BBD has been in Ontario for less time than in the Maritimes or New England, some of the information and observations from those areas need to be adjusted to reflect the Ontario situation. 

   In Ontario we are currently focussed on defining the limit of the spread of the scale (the "Advancing Front"), the fungal infections that cause the cankering and tree decline/death (the "Killing Front"), and on identifying putatively resistant trees, i.e. trees which do not become infested with scale, and therefore do not become infected by the pathogen. BTW, in Ontario I only consider Neonectria faginata important in BBD. The native N. ditissima (syn. Nectria galligena) is rarely found associated with infections, and even then at insignificant levels.

   Retention of trees without scale infestation among trees with abundant scale and/or cankers is essential; these are the beech of the future, similar to the situation with butternut. What we have also observed, and are beginning to study is possible "disease tolerance", i.e., trees that became infected as the first wave of scale and fungal infection moved through, but which survived with only superficial damage. We have seen cases where the infections (cankers) look really bad, but they don't penetrate all the way to the cambium, and even become contained by tree defence mechanisms. These trees may remain in a vigorous condition even though they look bad.  We don't know how long, and under what conditions this disease tolerance will last; we have seen trees that suffered a second, fatal wave of infection. If you don't suspect that the trees are showing much disease tolerance, and decline and death looks like it will be quick and widespread it is probably best to remove heavily infected trees, which will rapidly become hazard trees, and also to reduce the inoculum load (i.e. the abundance of infective N. faginata spores) in the immediate area.

   Another observation is that trees along the south-western advancing front seem to survive longer than trees along the northern advancing front. This may be because of environmental factors contributing to greater tree vigour in the southwest.

   On the topic of BBD workshops, Richard Wilson and I are interested in holding more workshops this year. Norfolk County and Simcoe County have already expressed interest, but no dates or locations have been chosen. The best time for such workshops is probably early fall, when both the scale and Neonectria fruiting bodies are best observed.

   Finally, I can't miss an opportunity to say this - always advise people to be careful when moving firewood (or don't do it!). We have satellite BBD locations far in advance of known areas of either scale or disease which can only have been introduced by human vectors, probably on firewood.

Bye for now,

John

John A. McLaughlin, PhD

Forest Research Pathologist

Ontario Forest Research Institute

1235 Queen St. E.

Sault Ste. Marie, ON

Canada

P6A 2E5

tel: +1 705-946-7419

John.McLaughlin at ontario.ca

http://ontario.ca/ofri <https://webmail.ontario.ca/exchweb/bin/redir.asp?URL=http://ontario.ca/ofri> 

________________________________

From: canufnet-bounces at list.web.net on behalf of Boysen, Barb (MNR)
Sent: Sun 26/02/2012 4:25 PM
To: forestreecare at nexicom.net; Canadian Urban Forest Network; Canadian Urban Forest Network
Cc: McLaughlin, John (MNR); Wilson, Richard (MNR)
Subject: Re: [CANUFNET] Beech Bark Disease

Hello

Ed & Bohdan are correct.  I've attached a one page document with some general genetic guidelines for forest managers. Two of those apply here:

- Retain trees exhibiting resistance to insect and disease problems.

- Reduce or delay removal of large trees with good growth, form and resistance until regeneration is established.

This has been important in the recovery programs for chestnut, white pine, elm, butternut and now beech and ash.  It is also important to keep enough living trees, even less vigorous ones that are not hazaards, in any one population to allow them to continue to cross pollinate and maintain genetic diversity in the species, as checks and balances for these new pests and pathogens species evolve in and with our forest communities.

MNR's Dr Richard Wilson and Dr John McLaughlin have held workshops recently in southern Ontario to help people understand the rationale for this with beech.  I have copied them here

Barb Boysen

Forest Gene Conservation Association

barb.boysen at ontario.ca

www.fgca.net

________________________________

From: canufnet-bounces at list.web.net on behalf of forestreecare at nexicom.net
Sent: Sat 25/02/2012 6:28 AM
To: Canadian Urban Forest Network
Subject: Re: [CANUFNET] Beech Bark Disease

Bowdan is correct. Never recommend the removal of a putitively resistant, or resilient tree to any disease or insect attack. There are always some trees (<5%) in a population that will pass on genetic resistance to the next generation. Saying all this, we must consider that the larger beech trees will not 'canker' similar to the regenerating trees which will be more deformed. Older, larger >60 cm dbh trees will likely have the initial population of beech scale when they first invade the area. That population of scale will subside over time and the two Nectria fungi responsible for bbd will then kill the trees over a number of years. The whole process is 10+ years or more.
There is lots of information on bbd out there.
Ed Czerwinski
Forestree Care
Sent on the TELUS Mobility network with BlackBerry
________________________________

From: "Koskinen, Jennifer" <Jennifer.Koskinen at stantec.com>
Sender: canufnet-bounces at list.web.net
Date: Fri, 24 Feb 2012 13:34:36 -0700
To: canufnet at list.web.net<canufnet at list.web.net>
ReplyTo: Canadian Urban Forest Network <canufnet at list.web.net>
Subject: [CANUFNET] Beech Bark Disease

Good day,

To cut or not to cut?  Beech Bark Disease (scale and fungus = canker) is destroying our beech trees.  I have observed cankering on many American Beech (Fagus grandifolia) trees in forests throughout Southern Ontario.  I would definitely recommend a tree (located in/adjacent to a public/residential area) in poor condition with this canker to be removed.  But what about removing trees that appear to be in good condition, minimal to no deadwood in crown, no observed rot on the stem, But with minimal signs of infection on the bark?  Without knowing how long these 'good condition' trees with small patches of infection will survive should we go ahead and remove them to be proactive?  Or retain them and possibly have them die in one or two years becoming a hazard tree?

What do you guys think?  Are there any pathology tree experts out there?

-jk

Jennifer Koskinen, HBESfcon
ISA Certified Arborist ON-1234A
Stantec

49 Frederick Street
Kitchener ON N2H 6M7
Ph: (519) 585-7442
Fx: (519) 579-8664
jennifer.koskinen at stantec.com

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

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