Prioritizing locations for managing forest disease in complex landscapes

Abstract

Prioritizing locations for managing forest disease in complex landscapes Anna V. Klevtcova a,b,d, Devon A. Gaydosa,b,d, Vaclav Petrasa,c,d, Ross K. Meentemeyera,b,d

a Center for Geospatial Analytics, North Carolina State University, Raleigh, NC b Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC c Department of Marine, Earth and Atmospheric Science, North Carolina State University, Raleigh, NC

Abstract Management of invasive plant pathogens in natural ecosystems is often challenging in complex landscapes comprised of significant social and ecological heterogeneity. Phytophthora ramorum is an example of an invasive pathogen, responsible for the emerging forest disease sudden oak death (SOD), killing millions trees along the Pacific Coast. The tanoak tree, one of the most vulnerable hosts in northern California is considered a valuable species for ecosystem functioning and local tribes’ culture. Disease outbreaks in this region are expected to cause substantial tree mortality and therefore a robust disease management plan is vital. However, expensive treatment costs and budget constraints in conjunction with a remote geographic area and a variety of legal considerations present obstacles for effective management. To help overcome these challenges and assist stakeholders and policy makers with strategic planning, we developed geospatial models to prioritize locations for disease management, using Humboldt County as a case study. We considered three control strategies currently utilized to manage SOD: (1) clear cutting, (2) mechanical tree removal, and (3) prescribed fire. We prioritized potential management areas based on 1) site accessibility (proximity to roads) and 2) site conditions, such as vegetation density and slope. Using multicriteria decision analysis we quantified different combinations of site factors and produced management suitability maps for each control strategy. This research provides a tool to evaluate where management option are most cost-effective and may serve as an initial step in SOD management planning.