Effect of Fire on Soil ability to Sustain Plant Life Becca Gentile and Erica Garroutte.
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Transcript of Effect of Fire on Soil ability to Sustain Plant Life Becca Gentile and Erica Garroutte.
Effect of Effect of FireFire on Soil on Soil ability to Sustain ability to Sustain PlantPlant
LifeLifeBecca Gentile and Erica
Garroutte
Figure 1—The wildfires of the Northern Rocky Mountains in 1910 burned over 3.1 million acres, destroying valuable timber resources
Figure 2—Over one-third of
Wallace, ID, burned during
the wildfires of 1910.
More than 1,700 starts!
19531944 1975
Forest Fires are a natural part of many habitats!
Why are fires good?
Clear out undergrowth
Fire-dependent seed germination
Increase soil nutrients
Increase diversity of forest composition and structure
June 8, 2002 – June 28, 2002
One start
138,000 acres in 20 days
Areas of severe burn
Wagle/Kitchen Study:
Soils in unburned sites are low in phosphorus and nitrogen
Available nitrogen and phosphorus levels increase with burn intensity
Water and nutrient availability in the soil both affect the germination and growth of plants
Debano/Conrad Study:
Organic plant material burned = nutrients returned to soil
Nutrients were burned off or leeched by runoff water and erosion
Temperature during fire = 340º - 370 º, which means accelerated evaporation
Loss of organic nutrients increases with burn severity
Question: How did the Hayman Fire affect the soil in areas of differing burn severity with regards to sustaining plant life? How does water availability play a role?
Hypothesis: Plants will grow most in soil from unburned areas with high water availability. Plants will grow least in soil from high burn areas with low water availability.
Site Description
Application rate: 2,000 lb per acre
1)Evidence of Aerial Mulching -Cereal Rye Grass (Lolium Multiflorium)
2)Parent Rock Material: Pikes Peak Granite
3)Elevation : 7,500-8,000ft
4) Same slope- West facing
K. Watenmaker http://www.uppersouthplatte.org/photos_fire/index.htm
Burn Site CriterionNo Burn Moderate Burn High Burn
- Rye Grass
-no black bark
-green branches
-West- facing
-12 trees in Quadrant
-scarce ground vegetation
-Lowest elevation
-slope: 24%
-Rye Grass
-partial black burned bark
-green branches at top
-West-facing
-13 trees in Quadrant
-scarce ground vegetation
-Highest elevation
-slope: 19%
- animal grazing
-Rye Grass
-completely black burned bark
-no green on trees
-West-facing
-25 trees in Quadrant
-Scarce ground vegetation
-Medium elevation
-Slope: 15%
-Animal grazing
http://www.uppersouthplatte.org/photos_fire/index.htm
6/12 unknown
http://www.uppersouthplatte.org/photos_fire/index.htm
E. Andrieska 6/13
http://www.uppersouthplatte.org/photos_fire/index.htm
S.Zufall 6/9
30ft
50 ft
N
Field Method : Quadrants
Tree Density:
11-25 trees
Slope: 15-24%
12 plants in each transect
Additional Measurements
-Moisture in soil - Dried all 3 soil types to determine grams of water present
-Animal evidence
--Potential disturbances
-Surrounding environment
Laboratory Method:Treatments
High Burn Area
Moderate Burn Area
No Burn Area
High Water Content(1oz everyday)
high burn, high water
moderate burn, high water
no burn, high water
Low Water Content(1oz every 4th day)
high burn, low water
moderate burn, low water
no burn, low water
*Temperature : Day 75 F Night 70 F
Corn Oats
Repetition:
6 plants for each treatment
Total: 36 plants
Repetition:
12 seeds for each treatment
Total: 72 seeds
Expected Results:Growth of Oats/Corn in Burn Area Soils
0
2
4
6
8
10
12
No Burn Moderate Burn High Burn
Sh
oo
t/R
oo
t G
row
th (
cm)
High Water
Low Water
Figure 1: (Note: measurements on the y-axis are meant to show a general trend, not specific values)
Height of Rye Grass in Burn Area Soils
0
0.5
1
1.5
2
2.5
No Burn Moderate Burn High Burn
Hei
gh
t (f
t)
Figure 2: (Note: measurements on the y-axis are meant to show a general trend, not specific values)
Most Growth: No Burn
Least Growth: High Burn
-Water is Limiting Factor
Results: Water in Soils
Soil Moisture
0
5
10
15
20
25
No Burn Moderate Burn High Burn
So
il M
ois
ture
(%
)
Field Results
Field Measurements of Rye Grass Height
010203040506070
No Burn Moderate Burn High Burn
Hei
gh
t (cm
)
No Significant Difference
Shoot Growth of Oat Seeds
-5
0
5
10
15
20
25
No Burn Moderate Burn High Burn
Gro
wth
(cm
)
High Water
Low w ater
Results: Oat Seed Growth
-more difference in No burn ( allocation to roots)
-no sig difference in Mod and High burn
What factor is causing the Moderate and High burn to grow?
Root Growth of Oat Seeds
0
5
10
15
20
25
30
35
No Burn Moderate Burn High Burn
Gro
wth
(c
m)
Low Water
High Water
-amt of water in No burn-more difference in High burn-error bars show no sig difference
High Burn No Burn
Oat growth
No burn
Low water
Oat Root Growth
No burn
High water
Mod burn
Low water
Mod burn
High water
High burn
Low water
High Burn
Low water
Results: Corn
-most difference in no burn
-no overall sig difference
-all receiving same amount of light
Note: roots were broken in moderate burn during measurement
-more difference in Mod and high
-no overall sig difference
Root Growth of Corn
-6
-4
-2
0
2
4
6
8
10
12
No Burn Moderate Burn High Burn
Gro
wth
(cm
)
Low Water
High Water
Shoot Growth of Corn
-2
-1
0
1
2
3
4
No Burn Moderate Burn High Burn
Gro
wth
(cm
)
Low Water
High Water
Corn Growth
Corn Root Growth
No burn
Low water
No burn
High water
Mod burn
Low water
Mod burn
High water
High burn
Low water
High Burn
Low water
Factors affecting Results:-Animal grazing
-Site differences (light, soils, etc.)
-Tearing of roots in measurements
-Species of plants
-Small growth time
-Transplant shock
-Human error (measurement, etc.)
Does not support hypothesis:
There was no significant growth difference in No Burn , Moderate Burn, and High Burn sites
There was no significant growth difference in High Water and Low Water treatments
Discussion:
Why less water in Moderate and High Burn sites?
-Hydrophobic layer
- evaporation (Debano/Conrad study)
Why are plants in No Burn and High Burn sites growing at same rate with a significant difference soil moisture?
-Water limiting to some extent- then nutrients
-Water brings in nutrients
What are the effects of Rye grass?
-stop erosion
-competition
-bring in animals
-is it really sterile?
Improvements:
-More repetitions
-More variation in water treatments
- Use same species in lab and field
-Use more variety and less plastic plants
-Allow for longer growth time
Why does this study matter?
-Multiple Factors (nutrients + water)
-Water retained does not necessarily predict root/shoot growth
-More research is needed
-Could affect fire prevention and fire fighting policies
-When should humans get involved?
-Do humans really understand what is best for the environment?
Http://www.fs.fed.us/rm/hayman_fire/
Debano, L.F; Conrad, C.E. “The Effect of Fire on Nutrients in a Chapparal Ecosystem.”Ecology, Vol. 59, No. 3 (1978):489-497
Ricklefs, Robert E. The Economy of Nature. 5th ed. St. Louis: University of Missouri,2001
Wagle, R.F.; Kitchen, J.H. “Influence of Fire on Soil Nutrients in a Ponderosa Pine Type.”Ecology, Vol.53, No.1(Jan.,1972):118-
125
Works Cited