Defoliation in the Wenatchee

A sizable portion of the Wenatchee National Forest, Washington shows less vegetational vigor than it did at its peak of the last decade. While such declines in NDVI often result from tree death due to wildfires in the west, no large fire has occurred here as is shown by the distribution of MODIS hotspots (shown as white triangles) between 2000 and 2011. Much of this reduction through September 13, 2011 may have been caused by the cumulative effects of defoliating insects on tree mortality, particularly from spruce budworm. The current year’s MODIS hotspots are available on the FCAV and they can be downloaded for GIS applications from the USDA Forest Service’s Remote Sensing Applications Center (RSAC) website here: http://activefiremaps.fs.fed.us/gisdata.php