March 1997

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(Zip file with shapefile for each year)


The Department of Conservation and Recreation insect infestation data layers indicate the areas that have been defoliated by insects, diseases, or natural weather events on a year to year basis. Data are available for each year from 1934 through 1946 (with no defoliation in 1942 and 1943) and from 1961 to 1997 (with the exception of 1979).

The DCR, Bureau of Forestry, Forest Health Program uses this information to follow various forest stress factors which might be causing a decline of the forest resource.

The layers are named BUGS<yy>_POLY, where <yy> represents a 2-digit year.


Each year the entire state is flown by trained observers at an altitude of approximately 2000 feet above the forest canopy. All areas which look abnormal are sketched on to USGS topographic maps. These areas are then visited on the ground to document the cause of the problem. All polygons are labeled as to the cause of the problem and digitized into GIS.

From 1962 to the present 1:24,000 or 1:25,000 scale maps are used. Prior to 1961 the 1:62,500 were used.


Each polygon layer has some or all of the following attributes:
COMMONNAME Common Name of the Insect
ACRES Approximate area defoliated
TOWN Town Name
FIPS_STCO FIPS ID (State and County code)


Development of the layer is currently on hold.

Last Updated 1/8/2013