Several change detection techniques, which use co-registered satellite images acquired at different time periods, are useful for this study. Change detection images such as the preliminary image shown below can provide additional information on the extent and patterns of change.

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Complex changes in forest patterns in the GYA are caused by natural and human disturbances. In the change detection image above, the effects of varying management practices on spatial patterns of forest change are readily apparent. Distinct changes in vegetation, visible from space, mark the western boundary of Yellowstone National Park. Vegetation changes caused by forest clearcuts that occurred between 1972 and 1986 are shown in light blue. Yellow polygons show clearcuts between 1986 and 1992. Vegetation changes following the 1988 Yellowstone fires (orange) also show changes in spectral reflectance.