Potential of MODIS forest change products for estimating percent forest mortality from mountain pine beetle outbreaks: comparison of MODIS and aerial data products for an area in the Colorado Rockies
PARTNERS: Leidos Innovations, Inc.; USDA Forest Service Western Wildland Environmental Threat Assessment Center, Forest Health Technology Enterprise Team, Remote Sensing Applications Center, and Rocky Mountain Research Station; University of Idaho
SUMMARY: Bark beetle outbreaks and the resulting forest mortality have become widespread in the western United States and therefore a matter of national and regional concern. Such events can represent significant threats to adjacent living forests both in terms of continued direct attacks and also by potentially increasing the risk of wildfires. Moderate Resolution Imaging Spectroradiometer (MODIS) forest change products show spatio-temporal gradients of forest disturbances in the multiple areas of the West that have been affected by regionally evident, persistent bark beetle attacks, along with multiple large extensive wildfires that collectively have occurred in areas across the West during the MODIS data collection era of 2000 to present. Such disturbances have affected a variety of forest types across the West, ranging from closed canopy lodgepole pine forests to semi-open canopy ponderosa pine forests to semi-open pinion-juniper woodlands.
The goal of the Colorado mountain pine beetle remote sensing project is to perform a test case study to evaluate MODIS-based forest disturbance detection products for western U.S. areas subjected to multiyear mountain pine beetle outbreaks during the MODIS era. The primary objective is to quantify, assess, and report accuracy of MODIS-based forest disturbance detection products compared to available relevant higher spatial resolution satellite, aerial, and ground reference data.
EFETAC'S ROLE: This project is supported by Eastern Threat Center funding and collaborative research.
PROGRESS: Year 1 Progress: NASA and Threat Center researchers actively collaborated on a study to compare ForWarn results (i.e., MODIS-based forest change products using ForWarn data as inputs) to a percent forest mortality map derived from high resolution aerial data. This work will help assess ForWarn products for their ability to detect regionally evident disturbances in areas affected by mountain pine beetle outbreaks. Researchers completed a case study in the Meadow Creek reservoir area in the Colorado Rockies, with promising initial results. NASA and Threat Center researchers will complete quantitative analysis and prepare a scientific manuscript describing this work. Next, researchers will begin geospatial and statistical examination of ground-based data from the Frasier Experimental Forest (FEF), a new mountain pine beetle-impacted location. Finally, NASA researchers will begin applying comparison techniques developed during these two studies to mortality events in other western U.S. forest ecosystems of concern (e.g., more open-canopy forest woodlands consisting of ponderosa pines).
Year 2 Progress: Over the past year, researchers derived alternative MODIS-based product indicators of forest mortality, employing trend analysis of MODIS NDVI (vegetation "greenness") time series data for 2000-2011. Researchers computed such products for forests as a singular type, as well as separately for broadly defined conifer and deciduous broadleaved forest types. Some of these products were then contributed to ForWarn’s Forest Change Assessment Viewer and were also provided to the Forest Service FHTET group for use in development of National Insect and Disease Risk Maps. These MODIS-based NDVI indicator maps included depictions of: 1) declining deciduous hardwood forest; 2) thriving deciduous hardwood forests; 3) declining conifer forests; and 4) thriving conifer forests. Researchers further applied some of these products to assist assessments of conifer (e.g. hemlock) and hardwood (e.g., aspen) declines. In addition, researchers outreached these results in part through presentations on the ForWarn system given at multiple professional meetings.
Other efforts included: 1) the additional processing of MODIS data in an effort to improve upon early work to derive correlations between MODIS NDVI change products and aerial-based percent forest mortality map for a Colorado area severely damaged by mountain pine beetle; 2) the acquisition and additional processing of ortho-rectified QuickBird data for the Fraser Experimental Forest (FEF) as a precursor to generating high spatial resolution percent mortality maps; 3) a meeting with collaborator Rob Hubbard at the Forest Service Rocky Mountain Research Station to discuss and plan future work involving the development and testing of products for aiding Forest Service research at the FEF; and 4) preparation of a draft manuscript that discusses apparent correlations between MODIS-based forest change products and conifer forest mortality maps derived from aerial multispectral imagery.
CONTACT: Bill Hargrove, Eastern Threat Center Ecologist, firstname.lastname@example.org or 828-257-4846
Updated August 2018