Skip to main content

Landscape Characterization of Forest Susceptibility to Gypsy Moth Defoliation

Buy Article:

$29.50 plus tax (Refund Policy)


This paper seeks to relate defoliation by the gypsy moth, Lymantria dispar (L.), to components of the landscape in order to elucidate processes operating at the regional scale. Aerial sketch maps of gypsy moth-caused defoliation in Pennsylvania from 1969-1989 were assembled in a raster-based geographical information system (GIS). These images were manipulated using Boolean algebra to determine the total defoliation frequency for each 2 X 2 km grid cell over the 21-yr study period. Because the gypsy moth became established in different parts of Pennsylvania at different times, the defoliation frequency for each cell was corrected by dividing the raw frequency by the total number of years at risk to defoliation. The number of years at risk to defoliation was calculated as the number of years each area was considered within the generally infested area minus a constant lag term, to correct for the period in years between first designation of quarantine until first defoliation. For Pennsylvania the lag was estimated as 5 yr. Average defoliation frequencies were calculated for each of six major forest type groups occurring in Pennsylvania. Pine, oak-pine, and oak-hickory type groups were the most susceptible to defoliation; maple-birch-beech, aspen-birch, and nonforest-type groups were the least susceptible. The high defoliation frequency in pine types reflects heavy feeding on oaks in these areas since gypsy moth larvae rarely feed on most pine species. Forest type group areas were further cross-tabulated by elevation classes. The three most susceptible forest type groups exhibited decreased susceptibility at elevations lower than 200 m. For. Sci. 40(1):18-29.

Keywords: Geographical Information System; Lepidoptera; Lymantria dispar; Lymantriidae

Document Type: Journal Article

Affiliations: Pennsylvania Department of Environmental Resources, 34 Airport Dr., Middletown, PA 17057

Publication date: 1994-02-01

More about this publication?
  • Forest Science is a peer-reviewed journal publishing fundamental and applied research that explores all aspects of natural and social sciences as they apply to the function and management of the forested ecosystems of the world. Topics include silviculture, forest management, biometrics, economics, entomology & pathology, fire & fuels management, forest ecology, genetics & tree improvement, geospatial technologies, harvesting & utilization, landscape ecology, operations research, forest policy, physiology, recreation, social sciences, soils & hydrology, and wildlife management.
    Forest Science is published bimonthly in February, April, June, August, October, and December.

    2015 Impact Factor: 1.702
    Ranking: 16 of 66 in forestry

    Also published by SAF:
    Journal of Forestry
    Other SAF Publications
  • Submit a Paper
  • Membership Information
  • Author Guidelines
  • Podcasts
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free ContentFree content
  • Partial Free ContentPartial Free content
  • New ContentNew content
  • Open Access ContentOpen access content
  • Partial Open Access ContentPartial Open access content
  • Subscribed ContentSubscribed content
  • Partial Subscribed ContentPartial Subscribed content
  • Free Trial ContentFree trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more