Forest Insect and Disease Newsletter

Aerial Survey Results 2011

image: Aerial photo of Eastern larch beetle deforestationSince the early 1950's, aerial survey has been a valuable tool for monitoring the activities of forest insects and pathogens across the 16 million acres of forest land in Minnesota. For the past fourteen years, these surveys have been accomplished through the collaboration of DNR Forest Health and Resource Assessment Units and USFS, State and Private Forestry. The Forest Health staff plans the scope, timing and intensity of the surveys, trains Resource Assessment staff, provides ground-truthing, analysis and dissemination of survey data. Resource Assessment staff conducts the aerial sketch-mapping, digitizes the data and produces digital shape files. In addition to being used in Minnesota, the survey results are incorporated into the USFS's national database since our procedures and products comply with national standards.

image: Forest tent caterpillar caused defoliation  2011 map

Due to a three week State of Minnesota government shutdown, the state portion of the aerial survey was delayed this year. Normally the aerial survey would start by mid-June and finish by in late July. In 2011 the survey did not begin until June 26th and was not completed until Sept 5th. This made it more difficult to map some of the early season events such as defoliation by forest tent caterpillar and oak wilt mortality. As a result of this, comparing results of previous years' surveys with this year survey is more difficult. For example, the reduced acres of defoliation by forest tent caterpillar mapped in 2011 compared to 2010 does not necessarily mean we had less forest tent caterpillar this year.

In addition to the lateness of the survey, we also dropped 5 quads from the survey in order to complete it as early as we did. The polygons dropped were: Fosston, Grygla, Hallock, Angle Inlet and Oak Island, all of which are in the north west portion of MN.

In an effort to help us complete the survey, Marc Roberts flew and mapped two additional polygons (Sandstone and Mille Lacs Lake) in the central part of the state. This also served as aerial sketch map training for a DNR employee, Gentry Carlson, who manages the shapefile and is being trained as a aerial survey sketchmapper.

Thanks to Mike Hoppus and Gentry Carlson, Resource Assessment's sketch-map team, who accomplished this year's aerial survey and data processing. Thanks also to Marc Roberts, USFS-S&PF, for mapping the federal lands and helping us out during the government shutdown. Thanks to Quinn Chavez, USFS-S&PF, for post-flight map rectification and the final review meeting.


Full report PDF