A Landscape Scale GIS Tool to Assess Eastern Hemlock Susceptibility to Hemlock Wooly Adelgid Infestation

Jennifer Pontius, Richard Hallett, Mary Martin, and Lucie Plourde

USDA Forest Service Northeastern Research Station (1-2) and University of New Hampshire Complex Systems Research Center (3-4)

Hemlock woolly adelgid (Adelges tsugae Annand) (HWA) is an invasive insect pest that is causing widespread mortality of eastern hemlock. However, some stands remain living more than a decade after infestation. Susceptibility models were created from variables including soil and foliar chemistry and landscape position, and were validated against detailed, yearly, post-infestation decline measurements (including pre-visual symptoms). The most effective model was used to predict hemlock susceptibility to HWA infestation (post infestation rate of decline) at a landscape scale using variables derived from hyperspectral remote sensing imagery and digital elevation models (DEM). Our previous work has shown that hyperspectral remote sensing technology can be used to map the location of the host resource (hemlock abundance), hemlock health, and foliar chemistry (Nitrogen) and create continuous, spatially accurate, landscape scale coverages of these variables. We demonstrate this modeling technique by integrating these data layers into ARC GIS and creating a landscape scale model to map relative hemlock susceptibility to HWA in the Catskills region of NY. These techniques are applicable to HWA infestation across the Northeastern U.S. and will provide a basis for forest land management agencies to focus biological control efforts and make management decisions as HWA continues to spread.

Exotic Pests Session - Tuesday Afternoon

corresponding author:

Jennifer Pontius
USDA Forest Service
Northeastern Research Station
P.O. Box 640
Durham, NH 03824
603-868-7739
Jennifer.Pontius@unh.edu