Kim Tarde
Vegetation Ecology
Summer 2014
Mountain Research Station, University of Colorado, Boulder
Ponderosa Pine
 Most widely distributed
species in North America
(Little, 1971)
 Characterized by open
grassland interspersed with
widely spaced trees
 Several species have an
association with Ponderosa
Pines
 Spike Fescue, Needle-and-
Thread (Alexander, 1988)
Grass Species
 Spike Fescue
 Native, indicator of community
climax with wind dispersal (Bradley
et. al., 1992)
 Needle-and-Thread
 Native, mid-successional species
with wind dispersal
 Cheat Grass
 Invasive, originally from Europe and
parts of Asia
 The number and size of infestations
increased dramatically over twenty
years (Mosely et. al., 1999)
 Smooth Brome
 Invasive, originally from Eurasia
 Highly adaptable
Orientation
 There is a correlation with the orientation of aspen
and kinnikinnik surrounding Ponderosa when looking
at the roots of the species (Berndt et. al., 1954)
 Microhabitats for grass species have a suggested
pattern in regions with foraging hens (Rumble et. al.,
1996)
Question
What is the orientation of grass species around
Ponderosa Pines and how may canopy cover affect these
species?
Null Hypothesis: There is no pattern within the grass
species orientation or canopy cover of a Ponderosa Pine.
Alternative Hypothesis: There is a pattern within the
grass species orientation and canopy cover of a
Ponderosa Pine.
Plot Set-up
Cover Classes:
Class 1: 0-5%
Class 2: 5-25%
Class 3: 25-50%
Class 4: 50-75%
Class 5: 75-95%
Class 6: 95-100%
 Randomly chose
Ponderosas
 Pseudoreplication
 Three trees in the
same area
10m diameter
Orientation: Spike Fescue and Needle-andThread
• Significant relationship between spike fescue and a N+NE orientation
• Indication of a relationship between needle-and-thread and a S+SW
orientation
Frequency of Cover Class
Frequency of Cover for Native Species
9
8
7
6
5
4
3
2
1
0
Spike Fescue
Needle and Thread
0
1
2
0
NNE
1
SSW
Cover Class
2
P-Values
• Spike Fescue:
0.043
• Needle-andThread: 0.115
Orientation: Native vs. Invasive
Species
 Compared the two
native species (spike
fescue and needleand-thread) with two
invasive species
(Cheat Grass and
Smooth Brome)
P-value: 0.713
NNE: N+NE
SSW: S+SW
Canopy Cover: Cheat Grass
Species Cover Class
Canopy Cover
<50% >50%
0
2
1
1
2
4
2
3
5
3
1
4
4
2
0
P-value: 0.765
• Present in most plots
• No statistically significant difference in
orientation around Ponderosa Pines
Orientation and Canopy Cover:
Open Ground
Ground Cover Class
Plot Orientation
NNE
SSW
2
7
2-4 7
2
0-1
P-value: 0.018
• Significant relationship
with more open ground
to the N+NE
Ground Cover
Class
Canopy Cover
0-30% 70-100%
0
0
4
1-2
0
7
3-4
2
1
P-value: 0.014
• Significant relationship
showing less open
ground with more
canopy cover
Discussion
 Spike Fescue and Needle-and-Thread appear to have opposite
orientations
 Needle-and-Thread adapted to drier conditions, Spike Fescue is not
 No difference in the distribution between native and invasive
species
 Native species are found on separate sides of the tree, invasive
species are found on all sides
 Cheat grass has no relationship with orientation or canopy cover
 Able to grow in many different conditions, almost impossible to get
rid of
 Open ground was more likely to be found in plots with less
canopy cover
 More sunlight, less moisture
Conclusions
 There could be a relationship between spike fescue,
needle-and-thread, and orientation; and open ground
and canopy cover
 For future research, you would need larger sample
sizes and true replication
Sources Cited
 Alexander, Robert R. 1988. Forest vegetation on National Forests in the Rocky Mountain
and Intermountain Regions: habitat and community types. Gen. Tech. Rep. RM-162. Fort
Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and
Range Experiment Station. 47 p.
 Berndt, H. W., & Gibbons, R. D. 1958. Root distribution of some native trees and
understory plants growing on three sites within ponderosa pine watersheds in Colorado.
Rocky Mountain Forest and Range Experiment Station.
 Bradley, Anne F.; Noste, Nonan V.; Fischer, William C. 1992. Fire ecology of forests and
woodlands of Utah. Gen. Tech. Rep. INT-287. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain Research Station. 128 p.
 Frederick, B. A.; Klein, D. A. 1994. Nitrogen effects on rhizosphere processes of range
grasses from different successional seres. Plant and Soil. 161(2): 241-250.
 Little, Elbert L., Jr. 1971. Atlas of the United States trees. Volume 1. Conifers and
important hardwoods. Misc. Publ. 1146. Washington, DC: U.S. Department of
Agriculture, Forest Service. 320 p.
 Mosely, Jeffrey C.; Bunting, Stephen C.; Manoukian, Mark E. 1999. Cheatgrass. In: Sheley,
Roger L.; Petroff, Janet K., eds. Biology and management of noxious rangeland weeds.
Corvallis, OR: Oregon State University Press: 175-188.
 Rumble, M. A., & Anderson, S. H. 1996. Variation in selection of microhabitats by
Merriam's turkey brood hens. USDA Forest Service/UNL Faculty Publications, 90.