Mountain Pine Beetle
Natural Disaster
or
Natural Consequence?
Presentation Overview
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Meet the Mountain Pine Beetle (MPB)
Importance of Lodgepole Pine in BC
Life Cycle of the bug
Green – Red – Gray Attack
Population Dynamics
Pine – Beetle – Fire Ecology
Management Tactics
Meet the MPB
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MPB - a small beetle, the size of a grain of rice
Range western N.A. (and is now expanding)
MPB is an important part of the ecosystem
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but it can have dramatic effects
Preferred host is lodgepole pine
Importance of Lodgepole Pine in BC
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BC – has a vast amount of lodgepole pine
Some figures:
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95 million ha (hectares) – size of BC
60 million ha – forested land
25 million ha – “operational forests”
15 million ha – lodgepole pine forest (~25% of BC’s forest)
13.5 million ha – MPB outbreak
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0.2 million ha harvested per year
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When the outbreak is finished …
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80% of the mature lodgepole pine in BC will be dead
The Outbreak !!
Videos – Ministry of Forests
Cumulative Damage –of current outbreak (from 1999)
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Life Cycle
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Typical 4 stages of an insect (with complete metamorphosis):
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Adult
Egg
Larva
Pupa
Adult
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Adults emerge from under
the bark in late summer
Need to fly!
Female seeks out a suitable
host
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Larger (older) pine is
preferred (kairomones)
Once suitable host is found
… pheromones female-perfume &
males-cologne (=party time!)
Mating pair then tunnels
into the cambial zone
Inoculate tree with blue
stain fungus
“No vacancy” pheromone
once tree is fully occupied
Egg
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Parents bore a gallery
in the inner bark /
cambial region
Gallery is vertical
Eggs are laid
alternately along the
sides of the gallery
Larva
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Larva hatch after 1-2
weeks
Larva create feeding
tunnels at right angles
Inner bark (phloem) is
full of sugar!
Larva overwinter under
the bark …
… and continue feeding
next spring
Pupa
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Pupal stage occurs the
following year
Takes about 2-4 weeks
to change from a larva
to an adult
Life Cycle Review
4) Next Summer (next generation of adults emerge)
1) Summer (adults emerge & attack)
3) Next Spring (larva continue feeding, then pupate)
2) Over winter
(as larva under the bark)
Blue Stain Fungus
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Ceratocystis spp. (Ophiostoma)
Ascomycetes (not a decay fungus)
Brought in with the beetle
Fungus infects sapwood
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Blocks water flow
Reduces ability to ‘pitch out’ beetle
Retains moisture – good for beetle brood
Provides critical nutrition for young adults
Green – Red – Gray Attack
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In the year a pine tree
is attacked (summer) it
remains green
The following year it
dies … and turns bright
red (but beetles are gone)
After that the foliage
turns gray and falls off
Only the green attack
trees contain beetles
Susceptible Stands
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Susceptibility increases with
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Age (>80 years are at highest risk)
Size (> 25 cm diameter @ breast ht.)
Stand composition (higher % of pine, higher risk)
Stand density (750 – 1,500 trees/ha)
Temperature (lower latitude/elevation, higher risk)
Population Dynamics (4 Stages)
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4 Stages:
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Factors favoring the outbreak
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Abundant food source (Pl forest)
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Drought stress (late ’90’s and 2003)
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Endemic – “normal” level – natural thinning agent
Incipient – building phase
Epidemic – outbreak! – stand replacing agent
Collapse (back to endemic)
Nice weather for beetle flight (summer)
Mild winters
Collapse Factors
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Lack of food
Cold weather
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-40C ‘spike’, -30C prolonged, -20C in shoulder season
Reminder
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This outbreak is the
largest in BC recorded
history
After it is done … ~80%
of the lodgepole pine
will be dead
Reasons for outbreak:
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Abundance of pine
Mild winters
Warm summers
MPB – Fire – Lodgepole Pine
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Fire & the MPB play a complex role in regenerating
lodgepole pine (video)
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you will have the option to download a video from the Canadian Forest Service (CFS) web site; video is about 5 minutes and VERY good
after viewing the video, when you hit the “back” button to return to this presentation, you may see a window that asks whether you want to open,
save or cancel – select open to return to this slide
Low intensity fires act as a thinning agent
High intensity fires act as a stand replacing agent
We fight fires … so we now have denser (more
stressed) stands AND we have more area with older
lodgepole pine than ever before (3 x’s)
Natural fires ~500,000 ha … now ~23,000 ha fire
Remember the MPB likes older, stressed lodgepole
pine
Management Options – aimed at MPB
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Annual Monitoring
(aerial/ground surveys, pheromone traps)
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Mass Trapping
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“Go after the beetle”
– often with other trtmts
(with pheromones, ineffective in epidemic)
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Sanitation Logging – a control tactic
(get the green attack before beetle flight)
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Spot Treatment – for isolated patches
(insecticide (MSMA) or fall & burn, before flight)
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Broadcast Fire - mimic nature
(with control measures)
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Hauling Restrictions
– no hauling during beetle flight (less of an issue in vast epidemic)
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Salvage Logging – not a control tactic
(get the red/gray attacked trees)
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Abandon – for out of control epidemic
(just “walk away”)
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Protective Insecticide
– for urban setting
(Carbaryl (Sevin) on trunk before flight)
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Pheromone Repellant
- verbenone, looks promising
(“no vacancy” scent)
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Trunk Screen
- fiberglass wrapped around trunk – urban setting
Management – Aimed at Pine
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Log most susceptible
stands first (80+ yr, 25+ cm dbh, etc.)
Create an age class mosaic
within a watershed
Utilize a shorter rotation
(harvest) age
Promote mixed species
(planting & spacing)
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Remove pine from mixed
stands (during outbreak)
(speed succession)
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“Beetle proof” pine stands
reduce density <500 sph
(light/temp, wind, vigour)
Summary
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Outbreaks result from an abundant food
source and favourable weather (warm
summers & mild winters)
In spite of best efforts, outbreaks will occur …
they are natural
Best time for action is at the incipient stage
Long term management should focus on
lodgepole pine, not the MPB
This presentation was brought to by… the
Tree Doctor
That’s all folks!