Beech Bark Disease A Clear and Present Danger to Our Hardwood

Transcription

Beech Bark Disease A Clear and Present Danger to Our Hardwood
Beech Bark Disease
A Clear and Present Danger to Our
Hardwood Forests
Barry Davidson R.P.F.
Forest Manager
Westwind Forest Stewardship Inc.
Westwind Forest Stewardship Inc.
What is
Beech Bark Disease?
A disease associated with two non-native causal agents:
beech scale (Cryptococcus fagisuga)
&
Neonectria faginata
And pathogen spores
Westwind Forest Stewardship Inc.
Westwind Forest Stewardship Inc.
Where did it come from?
History (origin)
 beech scale introduced from Europe to the
Halifax area ~1890
 by 1930s tree mortality from BBD was
observed in the Maritimes and Maine
 BBD in Quebec - 1965
first tree mortality north of Toronto in 1981
 Muskoka area confirmed 2010 – near
Vankoughnet/Baysville
 Currently a wide band from east of Dorset to Parry Sound
 First significant beech scale within/beside
Killbear/Arrowhead Provincial Parks – coincidence or
firewood??
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Epidemiology
(infection & spread)
The infection process – beech scale
The outer cells of the beech bark are altered by
the scale feeding in such a way as to make
them receptive for infection by the N. faginata.
 Reports of lag times between scale infestation
and appearance of fungal infection range from
~2 to 10 years. Likely closer to 2 yrs here!!

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Lifecycle of the beech scale
1.
2.
3.
4.
5.
Eggs hatch on beech tree (~mid-summer);
Nymph, or “crawler”, finds suitable location on tree and
forces its tubular mouthpart (“stylet”) into the bark, and
begins to feed;
Crawler then molts to immobile 2nd stage and produces
wooly wax protective covering;
Crawlers overwinter and molt to adult stage in the
spring;
Each mature adult scale (all are female parthenogenesis) lays 4-7 eggs in early summer.
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A predator of beech scale
The twice-stabbed lady beetle (Chilocorus stigma) is a native
species and a predator of beech scale. Both the adult and
larval stages feed on scale – control not significant
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Cold winters will kill them?
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Might have some immediate reductions in
scale but can survive below snow
Some trees killed by infections on stump/root
area
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Epidemiology
(infection & spread)
The infection process – fungal pathogen(s)
 N. faginata (or rarely Nectria galligena)
infects bark cells altered by scale feeding;
 Pathogen colonizes a portion of bark as
deep as the cambium, producing a canker;
 In fall the pathogen produces small, bright
red perithecia which erupt through the bark;
 Infective ascospores are released from the
perithecia during damp or rainy weather.
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Epidemiology
(infection & spread)
Spread (natural)
 tiny crawler stage can move from tree to
tree on wind currents;
 on birds, insects mammals?
Spread (assisted)
 on firewood & logs, especially during the
crawler stage (mid-summer to late fall)
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Stages of Spread
The Advancing Front
…is characterized by…

arrival and colonization of trees by scale
alone
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Westwind Forest Stewardship Inc.
Stages of Spread
The Killing Front
…is characterized by…
rapid build-up of scale infestation;
 abundant Neonectria infection and canker
development;



heavy levels of tree mortality.
short timeframe from advancing to killing in Muskoka area
Westwind Forest Stewardship Inc.
Westwind Forest Stewardship Inc.
Westwind Forest Stewardship Inc.
Westwind Forest Stewardship Inc.
Westwind Forest Stewardship Inc.
Stages of Spread
The Aftermath Zone
…is characterized by…
lower scale populations;
 residual, defective and declining trees;



perhaps a few resistant/ tolerant trees.
Not there yet except in pockets
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Beech Bark Disease Resistance
What about resistant trees?
A very small percentage resistant to scale 1%?
no scale
No Beech Bark Disease
Which one
would you
have picked?
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Westwind Forest Stewardship Inc.
Marked 2012, Cut 2014, dead and
dying 2015 with BBD
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Beech Scale movements, Disease Development, Dying Trees FAST
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Approach in French/Severn Forest
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Recently: Aggressive: 80%
clumps plus leave only
scattered individuals
After international workshop
this week: be even MORE
aggressive
Salvage material now, leave
some pockets for mast
production in short term
We will NEED to greatly
reduce beech regeneration
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X
Westwind Forest Stewardship Inc.
DID I MENTION WE MUST CONTROL BEECH REGENERATION??
$$$
Westwind Forest Stewardship Inc.
30-40 species
eat beechnuts
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Beechnuts
Acorns
Corn
Protein
11%
6%
11%
Fat
17%
14%
3%
Fibre
27%
18%
2%
Sow reproduction after Mast year: 80%
After non-Mast year: 22%
Good NEWS? More dead and dying trees, for down woody debris AND in future
years mast crops should recover from many small bad quality beech
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A more common sight?
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Best Management Practices
Trees in urban and recreational areas
1. Trees with BBD often become hazard trees due to “beech
snap” resulting from secondary decay fungi invading
cankered areas. Removal is advised.
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2. High-value trees can be protected
from scale by:
Physical control – removal of scale
from accessible portions of the tree
by high-pressure water wash;
Oils – Application of dormant oil.
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Why is this forester not smiling for the camera?
Westwind Forest Stewardship Inc.
Our Future Beech?
Westwind Forest Stewardship Inc.