Mapping insect‐induced tree defoliation and mortality using coarse spatial resolution satellite imagery

Abstract

Insect‐induced defoliation causes significant timber and carbon losses in many forested countries. The purpose of this investigation was to examine the potential use of coarse spatial resolution satellite imagery for mapping tree defoliation and mortality caused by a large insect infestation. We examined 1 km multi‐temporal SPOT Vegetation (VGT) data over a coniferous forest region in Quebec, Canada that was severely defoliated during 1998–2000 by the eastern hemlock looper. A logistic regression model based on satellite change metrics was developed to map defoliation and mortality. The results suggest that coarse imagery is effective for mapping large‐scale conifer forest mortality caused by insects, and could also be useful for near real‐time monitoring of severe defoliation, although with 2–3 times greater errors of commission.

Acknowledgments

Michel Chabot of the Quebec Ministry of Natural Resources generously provided the defoliation and mortality survey data. We thank Richard Fernandes and Michel Chabot for their valuable input to the study and Abdelgadir Abuelgasim for commenting on an earlier version of the manuscript.