Distrubance Effects on Boreal Forest Structure

Question 1

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-
-

Answer 1

disturbance

flooding
fire
insect outbreaks
timber harvest

Question 2

___ bark is least resistant to dire, __ ___ bark is most resistant

Answer 2

birch
jack pine

Question 3

Explain non-serotinous vs serotinous seeds

Answer 3

Non-serotinous= not fire resistant seeds (they’re open)

Serotinous= fire resistant (closed, and open with fire) older trees can make these

Question 4

most disturbances lead back to ___ ___ dominance because most things favor its ___

Answer 4

black spruce
recovery

Question 5

ground fire vs crowing fire:

Answer 5

ground fire= burns shrubs etc, not the trees

crowning fire= burns the entire tree

Question 6

the fire cycling is increasing in ___

Answer 6

frequency

Question 7

relay succession=

Answer 7

the sequential replacement of species (plant & animal) in an ecosystem recovering from a disturbance

Question 8

-
-

-
-

Answer 8

Intolerant=
- jack pine
- red pine
- aspen

Tolerant
- spruce
- balsam fir
- cedar

Question 9

Why isn’t legacy soil recovering?

Answer 9

deciduous trees dominate early on in succession, and they store C in surface

positive feedback of fires= fire frequency is increasing, legacy carbon doesn’t have a chance to replenish

Question 10

high severity burns have lower initial ___ but increase over time

biomass of deciduous ____ over time in high severity burns, but low severity burns have ___ deciduous over time

Answer 10

biomass

increase

declining

Question 11

2 fire intensity determinants:

Answer 11

• biomass accumulation (load) –> depends on time since last fire and ecosystem producivity
• water budget

Question 12

2 fire intensity determinants:

Answer 12

• biomass accumulation (load) –> depends on time since last fire and ecosystem productivity
• water budget

Question 13

___ trees are most susceptible to insect outbreaks

Answer 13

stressed/ unhealthy

Question 14

___ ___ is one of the most damaging insects in the eastern boreal forest

Answer 14

spruce budworm

Question 15

spruce budworms eat ___ ___ and ___ ___, and their ___ stage is the most damaging

Answer 15

balsam fir (prefers)
white spruce
larval

Question 16

Insect outbreaks have 4 stages:

Answer 16

1. Release- no more natural control
2. Peak- exponential increase
3. Decline- sharp decline
4. Post-decline- continuing slow decline (goal is to keep this)

Question 17

spruce budworm outbreaks have increased recently, due to ___ use, ____ practices, ___ suppression, and ___ variation

Answer 17

pesticide use (kills their predators)

logging
fire
climate

Question 18

after a high-severity burn, deciduous trees will dominate, and they store 5x more carbon than black spruce after 100 years. Why?

Answer 18

higher nitrogen use ecosystem efficiency

rapid transfer from soils in deciduous stands

Question 19

feedback of C and fires is ___ because of the emergence of ___ tree stands, which ___ more carbon

Answer 19

negative!
deciduous
store