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Monitoring Aspen Using Remote Sensing
Randy Hamilton, Eric Nielsen, USDA Forest Service, Salt Lake City, UT, and Dale Bartos, USDA Forest Service, Logan, UT
Large acreages of aspen (Populus tremuloides) are and continuing to disappear from western forests due to successional decline and sudden aspen decline (SAD). Land managers, anxious to restore aspen ecosystems, are often hampered in their efforts by limited budgets and by a lack of defensible information on the location and condition of aspen. Modern remote sensing technologies can provide cost effective monitoring methods to obtain the needed information about aspen populations at multiple scales. For example, a computer automated technique which compares historic Landsat satellite imagery with current imagery shows resource managers areas of the greatest aspen decline. This procedure was implemented for a study area located on Cedar Mountain, southeast of Cedar City, Utah. The map produced by this technique will help land managers identify and prioritize areas for potential treatments. Strata formed by the map allow resource managers to efficiently sample the area with field or photo-interpreted plots to derive defensible information about the change that has occurred. Similar techniques can also be applied to track the response of aspen to treatments. In addition to monitoring change in aspen abundance, remote sensing also provides an efficient way to map and quantify existing aspen, providing defensible information to support restoration activities and establishing a baseline for future monitoring.