MPB and climate Flashcards
What is the key concept of fossil fuel burning
Fossil fuels are a result of millions of years of stored carbon dioxide. When we burn it, we are creating a massive imbalance
What limits the current range of mpb?
Climate not host. Jack pine is at risk as well. Cold winters will regulate the beetle.
What are the critical climate factors?
Winter -20C / -40C
Summer (warm and dry)
Ideal heat sum (accumulated warmth above minimum threshold temp for egg maturation)
What is heat sum
Accumulated warmth for the year
What is a degree day or heat sum
Each degree above a given threshold is considered 1 degree day.
If minimum is 5.5 and temp is 6.5 you get 1 degree day.
Does not develop backwards when cold
What are the 2 critical heat sums
Sufficient for hatch : > 305 degree days between peak flight and 50% hatch
Sufficient warmth to get to l3 l4 by winter: > 833 degree days from August 1 to July 31
What temp kills
-40 C under bark gives full kill
Why is dry good for beetle
Crappy fliers and can’t fly in rain
Tree resistance impeded due to reduced soil moisture.
What are the climate categories?
Are any of the regions growing ?
Inhospitable
Benign
Favourable (big outbreaks)
Favourable and benign are growing
Very warm summer can trigger..
Bivoltinism: many beetles will be in the wrong life stage to overwinter
But some beetles that are used to the warmth can just migrate north to the available food
Factors in climate change
Sun
Orbit
Albedo
Ocean currents (el Nino La Niña)
Atmosphere additions
What are the 4 main insects that are a problem due to climate change?
MPB, spruce beetle, western spruce budworm, forest tent caterpillar
Bivoltinism? What?
2 generations per year due to high temperatures. Many beetles will be at the wrong stage for overwintering.
If southern pops move north, this will no longer be an advantage as they have proper synchrony.
