Beyond the Beetle: Modeling Change in a Post-Attack Subalpine Forest Ecosystem

Satellite imagery of bark beetle infestation. Credit: DEVELOP

Credit: DEVELOP

Authors: Bill Zawacki, Kelli Groy, Carl Reeder, Anthony Vorster

Mentors/Advisers (affiliation): Jeffrey Morisette (U.S. Geological Survey), Paul Evangelista (Natural Resource Ecology Lab)

Team Location: North Central Climate Science Center, Fort Collins, Colorado

Abstract: Mountain pine beetle (Dendroctonus ponderosae) has infested 3.4 million acres of forest in Colorado alone since the first outbreak in 1996 and continues to spread across western North America. This project studied forest structure before (2002) and after (2011) the mountain pine beetle outbreak in Fraser Experimental Forest (Grand County, Colorado) to develop a decision-support tool for partner agencies. Landsat 5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+) imagery combined with biologically relevant ancillary datasets were used with Software for Assisted Habitat Modeling (SAHM) to improve previous models of forest cover classification. These models were validated with field calibration methods and ArcGIS Spatial Analyst. Pre- and post-beetle forest classifications were compared to better understand the mountain pine beetle epidemic by identifying changes and similarities in forest cover abundance by species. The impacts of mountain pine beetle on forest structure need to be better understood to address influences on fire dynamics, habitats, aesthetics, recreation, watersheds, erosion, and safety. Results assisted in local management decisions, restoration efforts, and future research. This work was in collaboration with the U.S. Geological Survey, U.S. Forest Service, the Natural Resource Ecology Laboratory of Colorado State University, and the North Central Climate Science Center.