A Multi-Criteria Framework for Producing Local, Regional, and National Insect and Disease Risk Maps

Frank J. Krist Jr.

USDA Forest Service Forest Health Technology Enterprise Team

The construction of the 2005 – 06 National Insect and Disease Risk map, compiled by the USDA Forest Service, State and Private Forestry Area, Forest Health Protection Unit, resulted in the development of a common GIS-based multi-criteria approach that can account for regional variations in forest health concerns. This framework, utilized by all nine Forest Service regions and 49 states, provides a consistent, repeatable, transparent process through which dynamic spatial and temporal risk assessments can be conducted at various levels to aid in decision making. The national framework consists of a five step process which can be a highly iterative process utilizing input from subject area experts:

1. Identify a list of risk agents and target host species.

2. Identify, rank, and weight criteria that determine the susceptibility (risk of introduction and establishment) and vulnerability (risk of mortality if an agent is established) to each risk agent. In some cases susceptibility to a pest approximates vulnerability and therefore represents risk of tree mortality. This is true for pests such as emerald ash borer and oak wilt.

3. Standardize risk agent criteria values and combine the resultant maps using a weighted overlay(s).

4. Convert modeled values for each risk agent to predicted Basal Area (BA) loss over a 15 year period.

5. Identify regions at risk of encountering a 25% or greater loss of total basal area or volume in the next 15 years. This potentially dynamic threshold was set by the National Risk Map Oversight team for the national risk map product.

Following these five steps models are individually run and dynamically assembled into a National Map on a central server located at the Forest Health Technology Enterprise Team (FHTET) in Fort Collins, Colorado. Regional GIS specialists upload and or build individual models on the FHTET server and reference standard data layers also located in the server environment. Separating data layers from the models that are dependant on them forages an environment that; 1) encourages separate critique and understanding of risk models from input data, 2) allows for continuous improvement of the final map by substituting more rigorously vetted data layers and 3) cultures continuous quality improvement of individual models.

This paper will briefly outline the risk map framework demonstrating how risk maps can be easily constructed at both the local, regional, and national levels using Southern Pine Beetle as an example. Model validation and updating are discussed along with a new ArcGIS toolset that has been developed to allow seamless transfer of GIS technology to resource managers engaged in risk assessments. Lastly, an internet based geospatial portal will be demonstrated which places dynamic risk map products directly in the hands of state, private, and federal resource managers.

Thursday Morning Plenary

corresponding author:

Frank J. Krist, Jr.
USDA Forest Service
Forest Health Technology Enterprise Team
2150 Centre Avenue, Bldg. A., Suite 331
Fort Collins, CO 80526-1891
970-295-5845
fkrist@fs.fed.us