CONIFER HEALTH CLASSIFICATION OF COLORADO By Christopher J. Cole, Suzanne M. Noble, Steven L. Blauer, Beverly A. Friesen, Stacy E. Curry, and Mark A. Bauer Scientific Investigations Map 3103 2010 ABSTRACT: There is a lack of appropriate data regarding conifer forest health within Colorado at the landscape level.The State 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. Medium-resolution Landsat 5 Thematic Mapper imagery were collected statewide, and converted to at-sensor reflectance to reduce inter-scene variability due to differences in solar elevation and acquisition date. Cloud cover-affected Landsat pixels were identified and replaced with most recent, best available cloud-free data, and were normalized via linear regression based upon pseudo-invariant features (PIFS), whose spectral values should not appreciably change by scene date. 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. The National Landcover Database 2001 (NLCD 2001) was updated to account for current conifer forested cover within Colorado. A supervised maximum likelihood classification was performed using the Landsat multispectral bands, the NDVI, the RDII, and 30-m USGS 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. This assessment was performed using similar sampling and classification schema and methodologies as the statewide effort. Without the inclusion of this classification, a significantly larger portion of the State assessment would have been derived using pre-2008 imagery due to persistent cloud cover affecting this area of interest. USGS work within Grand County has confirmed significant vegetation mortality which would not have been captured using earlier data. 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 the State of Colorado. Classification uncertainty exists between healthy/unhealthy Ponderosa Pine, Piņon, and Juniper 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. However, we feel a repeatable, landscape-level assessment of coniferous forest health statewide was produced from these data. It is believed that high- to moderate-resolution multispectral imagery, coupled with field data, could significantly reduce the uncertainty rates. This will be investigated and used for subsequent sampling, analysis, and validation efforts. NOTE: The lines that may be visible in the on-screen version of the PDF are an artifact of the export methods used to create this file. The file should be viewed at 150 percent zoom or greater for optimum viewing. DISCLAIMERS: Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also contains copyrighted materials as noted in the text. Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein. These data have been created as a result of the need for having geospatial data immediately available and easily accessible to enhance the capability of Federal, State, and local land managers. Users should be aware that changes in forest health have undoubtedly occurred since this dataset was created and some parts of these data may no longer represent actual forest conditions. Users should not use these data for critical applications without a full awareness of these limitations. This database, identified as SIM 3103, has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore,it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use. CONTENTS: SIM3103_map.pdf SIM3103_pamphlet.pdf 00README.txt Geodata and other files are as follows: accuracy_points acc_pts.shp (.dbf/ .prj/ .sbn/ .sbx/ .shp.xml/ .shx/ and e00) Image files: co_conifer_health_classification.tfw co_conifer_health_classification.tif Metadata files: SIM3102_acc_pts.met SIM3103_image.met Vector_Data (from U.S. Census Bureau): co_bnd (.shp/.prj/.sbn/.sbx/.dbf/.shp.xml/.shx/ and e00) co_cntys (.shp/.prj/.sbn/.sbx/.dbf/.shp.xml/.shx/ and e00) co_hwy (.shp/.prj/.sbn/.sbx/.dbf/.shp.xml/.shx/ and e00) VI. INSTRUCTIONS AND DOCUMENTATION FOR U.S. GEOLOGICAL SURVEY SCIENTIFIC INVESTIGATIONS REPORT 3103 To access the data: The data files can be downloaded via the web from http://pubs.usgs.gov/sim/3103. The main product is a Portable Document Format (.pdf) map and pamphlet which requires Adobe Acrobat for viewing. Acrobat software runs on a variety of systems, and is available for download free of charge from Adobe at http://www.adobe.com. Software Required: Adobe Acrobat (6.x, 7.x, or 8.x), or Adobe Acrobat Pro (6.x, 7.x, or 8.x), or The free Adobe Reader (6.x, 7.x, or 8.x), 8.x is preferred. ArcGIS 9.1 or later preferred, older versions may also work.