Forest canopy greenness decline in portions of Montmorency, Alpena, Alcona, and Oscoda counties of Michigan
ForWarn’s ability to accurately map defoliation comes from the high temporal frequency of the source imagery (MODIS). With any change detection, multiple disturbances are often at work in the same landscape at the same time, so careful assessment requires consideration of other stressors or disturbances.
In the Boise National Forest, defoliation from the spruce budworm and large wildfire have been recurring every year. Recently, a periodic eruption of the Douglas fir tussock moth has begun, and drought is episodic.
Emmett Ranger District
"Area was hit hard by gypsy moth caterpillar defoliation for the third year in a row. We mapped it during this years aerial survey and ground truthed the area last week to confirm gypsy moth as the primary defoliation agent".