Assessing the Potential Risk of Assessing the Potential Risk of Emerald Ash Borer Emerald Ash Borer

Establishment and Spread using Establishment and Spread using GISGIS

Michael P. Strager

Jacquelyn M. Strager

William D. Ayersman

West Virginia University

OverviewOverview

• Background on EAB in North America

• Mapping risk factors

• Modeling probability of spread

• Desired outcomes

Emerald Ash Borer (EAB)Emerald Ash Borer (EAB)

• Native to Asia

• First detected in Detroit, Michigan (2002)

• Highly destructive to native ash species

Ash species in North America Ash species in North America

• Importance in the ecosystem

• Urban and developed areas– 25 million+ trees affected to date – High removal and replacement

costs in the billions $$– Loss of trees leads to reduced

property values

Ash Tree and EAB populationsAsh Tree and EAB populations

Cooperative EAB projectCooperative EAB project

APHISJan 2009

Project: Project: EAB in the mid-Atlantic regionEAB in the mid-Atlantic region

• EAB is not yet fully established in the study region

• Opportunity to focus monitoring and outreach

Quarantined Counties

Mapping risk factorsMapping risk factors

• Focused on mapping anthropogenic factors related to introduction/spread of EAB:– Movement of trees (nursery stock)– Movement of wood and wood products

Risk factors: Hardwood firewoodRisk factors: Hardwood firewood

• Parks and picnic areas

• Public and private campgrounds

• Vacation homes

• Retail sales of firewood

EAB infested firewood, Troy Kimoto, CFIA

Mapping firewood usageMapping firewood usage

• Campgrounds

Risk factors: SawmillsRisk factors: Sawmills

• Timber industry, particularly sawmills

• Wood haulers

WV sawmill, Appalachian Hardwood Center photo

Mapping sawmillsMapping sawmills

Risk factors: NurseriesRisk factors: Nurseries

• Ash species are valuable nursery crop

• Estimated 2 million ash trees / year

• Spread to Maryland was through nursery stock

WV Division of Forestry tree nursery

Mapping nurseriesMapping nurseries

• Nurseries

• Home and garden suppliers

Other factorsOther factors

• Population centers

• New home construction

• Interstate commerce

• Shipping

Data refinementsData refinements

• Campgrounds– Size, type of facility– Origin of visitors

• Nurseries, sawmills– Size of facility– Materials handled– Source of materials

Maximum entropy approachMaximum entropy approach

• A Bayesian technique• Useful for making predictions from incomplete

information – presence only• Robust to colinearity between explanatory

variables• Stable distribution with limited training data• Evaluates relative variable importance

Desired outcomesDesired outcomes

• Target monitoring

• Public outreach and education

Benefits / technology transferBenefits / technology transfer

This project will assist federal and state agencies by

• Mapping and modeling locations with high potential for insect introductions through the movements of wood and wood-based materials.

• Using a GIS-based approach, a risk prioritization framework is being developed to assess and rank various mapped risk factors for EAB introduction and spread.

• Data will be useful for other pests