In recent years, forested areas along the foothills of the Colorado Front Range have been subject to parasite infestations and drought conditions that have stressed these systems. The focus of this study are the Ponderosa Pines (Pinus ponderosa) of the Jefferson County Parks and Open Space, which show the accumulated effects of infestation by Dwarf Mistletoe (Arceuthobium vaginatum cryptopodum), Mountain Pine Beetle (Dendroctonus ponderosae), and drought conditions that began in the Fall of 2011. Numerous studies have demonstrated the effectiveness of satellite imagery analysis for the monitoring of parasite infestations and general forest health. We have examined WorldView-2 satellite imagery from 2010-2013, confirmed by ground truth provided by Jefferson County Parks and Open Space for White Ranch Park and Elk Meadow Park. The research approach included the examination of data optimization methods for spectral identification of affected trees using 8-band data (e.g., normalized band ratios, principal component analysis, maximum noise fraction, and statistical validation), decision tree land cover classification methods, and change detection. The results of supervised classification analysis of Ponderosa Pine health have an accuracy of > 90% and a precision of 0.89 (Kappa Statistic). High accuracy land cover mapping is critical for parasite mitigation, and efforts to minimize future infestations. This project is part of an ongoing a partnership between Jefferson County Parks and Open Space and DigitalGlobe, monitoring vegetation health, invasive species and parasite activity for the purpose of long-range remediation planning.

1. Monitoring Ponderosa Pine
Health Using Satellite Imagery
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2. Monitoring Ponderosa Pine Health Using
Satellite Imagery
Team Participants:
• Kathleen
Johnson*
• Greg Hammann
• Rachana Ravi
• Keith Bol
• Barbara Morey
*kathleen.johnson@digitalglobe.com
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3. Goals & Objectives
• To Demonstrate the capabilities of WV02 8-bands for
vegetation health/stress assessments
• Document the extent of tree stress from 2010 through
2013 in the White Ranch Park Area, using satellite
imagery.
• Test Case for DG classification system applied to
vegetative health studies
• Look for evidence of new Mountain Pine Beetle Activity
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4. World View-2
TABLE 1: WorldView -2 Bands
Band
#
1
Coastal
Wavelength
(nm)
400-450
2
Blue
450-510
3
Green
510-580
4
Yellow
585-625
5
Red
630-690
6
Red Edge
705-745
7
NIR1
770-895
8
NIR2
860-1040
PAN
Panchromatic
450-800
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Name
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5. Jefferson County Preliminary Study:
Elk Meadow Park
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6. Elk Meadow:
Dwarf Mistletoe Damage
JUNE 2010
JUNE 2012
False Color:
Healthy Trees are Bright Red
Natural Color:
Damage is Visible
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7. Jefferson County Research Site:
White Ranch Park
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8. Ground Truth Assumptions:
• Ground Truth for Dwarf Mistletoe acquired
December 2010 (Rawhide and Sawmill Ridges)
• Treatment for mistletoe control started after
ground truth acquisition (Spring 2011-Present)
• Mountain Pine Beetle was discovered during the
Winter Survey in 2010, and treatment began at
that time.
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9. White Ranch Park: Ground Truth
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10. Parasites:
Dwarf Mistletoe
(Arceuthobium vaginatum)
Mountain Pine Beetle
(Dendroctonus ponderosae)
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11. Pre-Processing:
• Imagery Selection (4):
- 10JUNE24, 11AUGUST23, 12MAY24, 13AUGUST14
• Bundle Adjustment
- Orthorectification (30 m DEM)
- Co-registration
• Atmospheric Correction (DG-ACOMP)
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12. Vegetative Indices
Normalized Difference Vegetation Index (NDVI)
NDVI = (rNIR – rRED)/(rNIR + rRED)
Brightness = Health
TABLE 4. Summary of Vegetative Indices applied to the JCOS Forestry Problem
Index
Formula
Normalized Difference
(NIR1 - Red)/(NIR1 + Red)
Vegetative Index NIR1 NDVI-1
Bands
7-5
Reference
Rouse et al. (1974)
Shamsodinni et al. (2010)
Normalized Difference
(NIR2 - Red)/(NIR2 + Red)
Vegetative Index NIR2 NDVI-2
8-5
Rouse et al. (1974)
Shamsodinni et al. (2010)
Red Edge NDVI
6-5
Filchev (2010)
DigitalGlobe
(Red Edge - Red)/(Red Edge + Red)
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13. NDVI Results & Change Detection
JUNE 2010
AUGUST 2013
CHANGE
Table 7. Change Detection Color Codes
BLUE
Negative Change:
YELLOW
Neutral/Positive Change:
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14. Classification Model:
• DG Classification-Supervised
• Decision Tree Classifiers:
Robust to outliers
• Applies the same rule at each Node
• Compares well to Non-linear Classifiers
• Random Forest – Ensemble Tree Method
•
• (Random Forest: Breiman 2001)
• Use WEKA Scorer to Evaluate Models
• http://www.cs.waikato.ac.nz/ml/weka/
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15. Random Forest – 20 Trees:
• A stable model builder with little data
preprocessing
• Does not require a normal distribution
• Relies upon balanced class sample size
• Ensemble decision tree method (employs multiple
trees)
• Most robust decision tree method for outliers
• Competitive with nonlinear classifiers such as
neural networks
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16. Classification Results: Accuracy and Precision
Imagery
Accuracy
Kappa Statistic
10JUNE24
93.17
0.92
11AUG23
93.47
0.92
12MAY24
93.88
0.93
13AUG14
89.69
0.88
95% Confidence Interval
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17. Ponderosa Health:
Random Forest-20
10JUNE24
DigitalGlobe
11AUGUST23
Table 8. Classification Codes
ORANGE
Unhealthy/Stressed
GREEN
Healthy
Yellow-Green
Broadleaf
12MAY24
13AUGUST14
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18. Ponderosa Health:
Random Forest-20
10JUNE24
DigitalGlobe
Table 8. Classification Codes
ORANGE
Unhealthy/Stressed
GREEN
Healthy
Yellow-Green
Broadleaf
11AUGUST23
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19. Ponderosa Health:
Random Forest-20
12MAY24
DigitalGlobe
Table 8. Classification Codes
ORANGE
Unhealthy/Stressed
GREEN
Healthy
Yellow-Green
Broadleaf
13AUGUST14
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20. Ponderosa Health:
Pine Beetle Treatment
10JUNE24
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Table 8. Classification Codes
ORANGE
Unhealthy/Stressed
GREEN
Healthy
Yellow-Green
Broadleaf
11AUGUST23
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21. Ponderosa Health:
Pine Beetle Treatment
12MAY24
DigitalGlobe
Table 8. Classification Codes
ORANGE
Unhealthy/Stressed
GREEN
Healthy
Yellow-Green
Broadleaf
13AUGUST14
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22. Summary of Classification Results
10JUNE24
DigitalGlobe
11AUGUST23
12MAY241
3AUGUST14
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23. Conclusions:
•
Ponderosa Pines within White Ranch Park have shown signs of
accumulated stress:
Mistletoe,
Pine Beetle
Drought (Fa11 2011-Spring 2013)
Tree stress was severe enough to be visible in natural color imagery in many
instances.
- Through time, the total number of trees has been reduced by remediation
activities
-
•
DG Classification results were more reliable than NDVI Change
Detection:
- Performed at > 90% accuracy except in the case of the 2013, where some of
the ground truth had been removed by mistletoe remediation.
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24. Conclusions:
•
This Study lays the foundation for continuing forestry studies across
the Foot Hills region, using satellite imagery:
- Identify additional areas to be examined for mistletoe infestation and
remediation
- Can identify potential Pine Beetle attacks early IF we can capture imagery
during the proper stages of the Life Cycle (need March snow free imagery)
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25. Acknowledgments:
JCOS: Keith Bol, Barbara Morey
• Project Sponsor: Kumar Navulur, NGP Director
• My Manager: Giovanni Marchisio, Data Mining Director
• DG Classification Training: Rachana Ravi, Kris Koperski
• Data Pre-Processing: Chuck Chaapel, Donnie Marino
•
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26. Thank You
Questions/Discussion
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