Dudley Fire Ecology

Question 1

summarize our general knowledge of climate change

Answer 1

its already happening, its going to get worse, its going to cost us dearly, we can still do something about it

Question 2

fire ecology

Answer 2

fire is common, fire is good, plants have adaptations to fire, humans have used fire to adapt their habitats, fire interacts with the global climate

Question 3

has the number of wildfires increased or decreased

Answer 3

decreased

Question 4

has the severity and number of acres destroyed by fires increased or decreased and why

Answer 4

increased due to hotter driver conditions that make blazes harder to contain

Question 5

does fire destroy wilderness?

Answer 5

no, destroyed is the wrong word, burned does not mean destroyed, fire is healthy for ecosystems

Question 6

components of fire

Answer 6

fuel, O2, ignition source

Question 7

fire:

Answer 7

a rapid chemical oxidative reaction that generates light and heat and produces a variety of chemical products

Question 8

why is dry cellulose better for burning

Answer 8

water evaporation is cooling

Question 9

is a forest fire more similar to a candle or a bunsen burner

Answer 9

candle, only the exterior of the flame burns because it requires oxygen to diffuse from the atmosphere unlike a Bunsen burner which has oxygen mixed in the fuel

Question 10

process of a forest fire:

Answer 10

1. evaporation of highly volatile compounds
2. more evaporation of highly volute compounds
3. volatiles enter flame and burn at the interface of the atmosphere and flame or enter the lower oxygen interior
4. pyrolysis of cellulose into volatiles and solid char
5. products of vaporization and pyrolysis miss the flame and move directly into the atmosphere

Question 11

pyrolysis

Answer 11

decomposition caused by high temperatures

Question 12

simplified process of a forest fire

Answer 12

1 Pyrolysis of plant materials in the absence of oxygen producing solid biochar and volatiles
2 Combustion of volatile gases when they mix with oxygen

Question 13

what are the dominant predictors of a wild fire

Answer 13

amount of fuel

dryness of fuel

Question 14

where are fires most common

Answer 14

areas with medium productivity and dry seasons

Question 15

how often do fires occur naturally

Answer 15

every 2-200 years depending on location and conditions

Question 16

surface fire

Answer 16

burning of forest floor, burning shrubs bottoms of trees ex. prairie grassland fire

Question 17

crown fire

Answer 17

aerial fuels, tops of trees burning, lots of biomass, takes more to get it burning but once it starts it is intense ex. lodgepole pine tree forest fire in canada

Question 18

consequences of crown fires

Answer 18

intense fire creates its own weather systems, convection columns 10-12 km high, fire whirls, 10-12 times the amount of wind, forward bursts can be 30m wide and shoot 100m

Question 19

pyrocumulus clouds

Answer 19

evaporating water from fire condenses into clouds, can produce rain and extinguished fire, can produce lightning and start more fire, can cause downdrafts causing the fire to unpredictably change direction

Question 20

ground fire

Answer 20

slowest but most destructive fire, actual ground is on fire, biomass in the soil is burning, can last months and spread unnoticed ex. peatland fire in drained lakebed

Question 21

patchy effect of real fires

Answer 21

a large scale fire may have a mosaic of ground, crown, and surface fires

Question 22

C3 plants

Answer 22

C3 plants do normal photosynthesis. all plants have C3 photosynthesis

Question 23

C4 plants

Answer 23

C4 plants do C3 and C4, C4 refers to the number of carbons in the intermediate sites of photosynthesis. C4 is a mechanism for concentrating carbon in the leaves by increasing carbon dioxide level near the leaves, C4 are very productive plants and are usually warm plants

Question 24

C3 Vs C4

Answer 24

C3 wins at low temperatures and shade but C4 wins at high temperatures and high light

Question 25

what vegetation is fire prone

Answer 25

grasslands, mediterranean scrublands, boreal forests (c4 and gymnosperm primarily)

Question 26

what vegetation is NOT fire prone

Answer 26

broadleaf forest and tundra (C3 and angiosperms primarily)

Question 27

what if there were no fires

Answer 27

less grassland, less C4, less boreal forest, no mediterranean shrub-land, more broadleaf forest, very different vegetation and biodiversity

Question 28

what is the role of volatile compounds in fire

Answer 28

volatile gases are the fuel that burns; some volatile gases are produced by heat decomposition of cellulose

Question 29

when is a fire called a ground fire

Answer 29

the organic soil burns

Question 30

how are grasslands maintained

Answer 30

periodic burning maintains grassland, without fire they would not stay grassland, other vegetation would grow

Question 31

do fires kill plants

Answer 31

cooler fires allow resprouting from undamaged plants, hot fires kill vegetation but create favourable seedbeds, the longer the plant is in a fire the more tissues will heat up and be killed

Question 32

how do different parts of plants survive fire

Answer 32

leaves die quickly aboveground stems and trunks may not die depending on insulation, thickness, water content below ground plant material may not die unless the fire is very hot or lasts a long time

Question 33

3 types of pine fire adaptations

Answer 33

fire tolerators: individuals survive fire fire embracers: individual dies but seeds are dispersed and prosper fire avoiders: not adapted to fire

Question 34

serotiny

Answer 34

seed cones that don't open until a fire heats them

Question 35

grass stage of pine

Answer 35

meristems are low and more protected from surface fires

Question 36

self pruning

Answer 36

fire tolerators lose lower branches to survive fire better

Question 37

fire evolution

Answer 37

evolution of traits in response to fire frequency

Question 38

in North America, policy has been to suppress fires. what is the predicted effect of fire suppression

Answer 38

fires that occur are hotter and more likely to be canopy fires

Question 39

if we could totally suppress fire worldwide, the result would be a large increase in

Answer 39

broadleaf forest

Question 40

in california, damage from fire was photographed showing melted cars sitting below undamaged trees. explain this

Answer 40

a surface fire occurred which burned hot and low burning matter on the surface including the cars but not burning the tops of trees