Data from: Geographic variation in forest composition and precipitation predict the synchrony of forest insect outbreaks

Datasets include 1) a spatiotemporal record of gypsy moth defoliation in the Northeastern United States from 1975 to 2014 and 2) summary data on host tree composition from the Forest Inventory & Analysis (FIA) Program, USDA Forest Service. The defoliation data were obtained from USDA Forest Service archives of annual aerial survey maps, which were digitized as sequential raster maps in a geographic information system. The data include the proportion of forest defoliated within 32 × 32 km quadrats and the coordinates of the quadrats. The coordinates (in meters) are derived from the azimuthal equidistant projection. Quadrats where defoliation was detected < 5 years are not included in this dataset, nor are plots with < 10 FIA plots. For more methodological detail, see the following publications: Liebhold, A.M., K.W. Gottschalk, E.R. Luzader, D.A. Mason, R. Bush, and D.B. Twardus. 1997. Gypsy moth in the United States: An Atlas. USDAForest Service General Technical Report NE-233.