| Abstract: | Colorado has undergone substantial changes in forests due to urbanization, wildfires, insect-caused tree mortality, and other human and environmental factors. The U.S. Geological Survey Rocky Mountain Geographic Science Center evaluated and developed a methodology for applying remotely-sensed imagery for assessing conifer health in Colorado. Two classes were identified for the purposes of this study: healthy and unhealthy (for example, an area the size of a 30- x 30-m pixel with 20 percent or greater visibly dead trees was defined as ?unhealthy?).
Medium-resolution Landsat 5 Thematic Mapper imagery were collected. The normalized, reflectance-converted, cloud-filled Landsat scenes were merged to form a statewide image mosaic, and a Normalized Difference Vegetation Index (NDVI) and Renormalized Difference Infrared Index (RDII) were derived.
A supervised maximum likelihood classification was done using the Landsat multispectral bands, the NDVI, the RDII, and 30-m U.S. Geological Survey National Elevation Dataset (NED). The classification was constrained to pixels identified in the updated landcover dataset as coniferous or mixed coniferous/deciduous vegetation. The statewide results were merged with a separate health assessment of Grand County, Colo., produced in late 2008.
Sampling and validation was done by collecting field data and high-resolution imagery. The 86 percent overall classification accuracy attained in this study suggests that the data and methods used successfully characterized conifer conditions within Colorado. Although forest conditions for Lodgepole Pine (Pinus contorta) are easily characterized, classification uncertainty exists between healthy/unhealthy Ponderosa Pine (Pinus ponderosa), Pi?on (Pinus edulis), and Juniper (Juniperus sp.) vegetation. Some underestimation of conifer mortality in Summit County is likely, where recent (2008) cloud-free imagery was unavailable. These classification uncertainties are primarily due to the spatial and temporal resolution of Landsat, and of the NLCD derived from this sensor. It is believed that high- to moderate-resolution multispectral imagery, coupled with field data, could significantly reduce the uncertainty rates. The USGS produced a four-county follow-up conifer health assessment using high-resolution RapidEye remotely sensed imagery and field data collected in 2009. |
| Genre: | USGS Numbered Series |
| ProdID: | 98711 |
| Citation Author: | Cole, Christopher J.; Noble, Suzanne M.; Blauer, Steven L.; Friesen, Beverly A.; Curry, Stacy E.; Bauer, Mark A. |
| Citation Contributing Office: | Rocky Mountain Geographic Science Center |
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| Citation Edition: | - |
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| Citation Language: | ENGLISH |
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| Citation LatN: | 0410000 |
| Citation LatS: | 0370000 |
| Citation LonE: | -1020000 |
| Citation LonW: | -1090000 |
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| Citation Phsyical Description: | iv, 11 p.; |
| Citation Projection: | Albers Conical Equal Area Projection |
| Citation Public Comments: | |
| Citation Publisher: | U.S. Geological Survey |
| Citation Series: | Scientific Investigations Map |
| Citation Series Code: | SIM |
| Citation Series Number: | 3103 |
| Citation Search Results Text: | Conifer health classification for Colorado, 2008; 2010; SIM; 3103; Cole, Christopher J.; Noble, Suzanne M.; Blauer, Steven L.; Friesen, Beverly A.; Curry, Stacy E.; Bauer, Mark A. |
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| Citation Year: | 2010 |
| Type: | citation/reference |
| Text: | Conifer health classification for Colorado, 2008; 2010; SIM; 3103; Cole, Christopher J.; Noble, Suzanne M.; Blauer, Steven L.; Friesen, Beverly A.; Curry, Stacy E.; Bauer, Mark A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/sim_3103.jpg |
| URL (INDEX PAGE): | http://pubs.usgs.gov/sim/3103/ |
| Date Other: | Fri, 17 Sep 2010 00:00 -0500 |
| Publisher: | U.S. Geological Survey |
