Post on 05-Apr-2018
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The Decline of Old Growth:A Comparison of Unmanagedand Managed Ponderosa Pine
Forests
Service Learning Project,Jacinda Thomas
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Biodiversity
Unmanaged
young trees crowd area
fierce competition
fewer numbers of and smaller shrubs, herbs, andgrasses
lower biodiversity
High biodiversity
strong indicator of health
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Comparison of Biodiversity Between Managed and
Unmanaged Old-Growth Ponderosa Pine Forests
13.50
0.602.03
0.87
8.198.75
0.511.95
0.82
7.54
0
2
4
6
810
12
14
16
Species Richness Pileou's Evenness
Index
Shannon-Wiener
Diversity Index
Simpson Index of
Diversity
Simpson
Reciprocal Index
number
Managed
Unmanaged
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Comparison of Importance Values Between Managed andUnmanaged Old-Growth Stands
(These represent the top 5 of 68 species of plant recorded)
2.8 3.1
8.19.1
6.8
2.9
16.7
2.3
9.5
3.6
0
5
10
15
20
ABICON ARNCOR FRAVIR PINPON POANER
re
lativeimportance
(%)
Managed
Unmanaged
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Density
Crowded stands
Tree density high
Trees compete
Canopy dense
Hinders smaller plants and brush to produce food
Death takes away the nitrogen-rich material
Stand weakens, disease sets in
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Duff Layers
Duff is the decomposing plant material onthe forest floor
Provides nitrogen for vegetation
Holds soil moisture
Blocks the sun
Cools the soil
Blocks raindrop erosion
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Comparison of Relative Cover Under Managed andUnmanaged Ponderosa Pine Forests
41.8
6.1
27.3 25.1
61.1
9.5
21.9
5.7
0
10
20
30
40
50
60
70
Duff/Litter Rel Cover DWD Rel Cover Tree Rel Cover Plant Rel Cover
relativecover(%)
Managed
Unmanaged
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Growth Rings
Indicate amount of yearly growth
Healthier tree
Less rings More growth occurs
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Comparison of soil moisture, tree growth rates and disease
frequency between managed and unmanaged old growth ponderosa
pine stands in Coffeepot Flat on the Fremont Winema NationalForest
17.95
2.18 2.6
9.33
2.77
32.5
0
5
10
15
20
25
30
35
40
soil moisture (%) growth rate (rngs/cm) disease frequency (%)
Managed
Unmanaged
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Basal Area 264, TPA 55, Canopy Cover 44%
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Basal Area 507, TPA 293, Canopy Cover 75%
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Results
Lower tree density
Higher percent soil moisture
Higher biodiversity Faster growth (fewer growth rings/cm)
Lower rates of disease
Less duff
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Conclusion
Old growth forests falling apartFire suppression
high densities
disease and insect damage
Possible solution thin understory (historic fire effects)
Concerns remain, should be considered