Assessing the Impact of Extreme Climatic Events on ASpen Defoliation Using MODIS Imagery
Recent studies document the decline of quaking aspen across large geographic areas of North America.Extreme climatic events are possible contributors to the decline, and drought is often cited as an important driver of aspen phenology. Little is known, however, about the effects of spring freeze events on aspenphenology, even though such events are projected to occur more frequently in future. This study usesmoderate resolution imaging spectrometer (MODIS) imagery to assess the spatial pattern and magnitude of damage to aspen forests during spring freeze and summer drought events that occurred in Utah in 2007. The analysis finds above normal Normalized Difference Vegetation Index (NDVI) in early spring, and below normal NDVI following the freeze event and during the summer drought. Aspen damage is concentrated in certain terrain classes, depending on the type of extreme climatic event. These findings suggest there are predictable patterns of aspen defoliation that identify aspen stands vulnerable to extreme climatic events.
Currit, Nate and Clair, Samuel B. St. 2009. Assessing the impact of extreme climatic events on aspen defoliation using MODIS imagery. Geocarto International. 25(2):133-147.