Wednesday, December 13, 2006

Updating SPBMODEL for the 21st century

Marita P. Lih, mplih@charter.net1, Andrew Birt, abirt@tamu.edu2, Robert N. Coulson, r-coulson@tamu.edu2, James D. Smith, jdsmith@fs.fed.us3, James M. Guldin, jguldin@fs.fed.us4, and Fred M. Stephen, fstephen@uark.edu1. (1) University of Arkansas, Department of Entomology, 319 Agriculture Building, Fayetteville, AR, (2) Texas A&M University, Knowledge Engineering Laboratory, Department of Entomology, College Station, TX, (3) USDA Forest Service, Forest Health Protection, 2500 Shreveport Hwy, Pineville, LA, (4) USDA Forest Service, Southern Research Station, P.O. Box 1270, Hot Springs, AR

SPBMODEL, a southern pine beetle (SPB) (Dendroctonus frontalis) population dynamics simulation model, has been a primary tool for forest pest managers to assess short-term growth and impact of existing SPB infestations. Data collection needed to run the model has been kept to a minimum, and both model input and output are expressed in terms of numbers of trees, rather than in terms of beetle populations. Model predictions had an average absolute error of less than 17% for cumulative numbers of dead trees over a 92-day prediction period for 70 infested spots, and met the criteria that the model should predict with less than 30% error 70% of the time at 30 days into the prediction period for 27 spots in the Gulf Coastal Plain.

In order to make the model available to a wider audience through the Internet, it has now been translated from FORTRAN to C++. Current and future work will focus on validation of model performance over a broad range of conditions, analyses of model structure and function, refinements to incorporate available research data and to broaden the accepted input parameters, modifications to expand the modelís responsiveness to changing forest health conditions and the dynamic role of natural enemies and competitors, revisions to explore the effects of disturbance events, forest structure and stand configuration on SPB population dynamics, and enhancements to provide alternative input and output formats. The updated model will be a component of risk assessment models that examine factors influencing forest susceptibility to SPB.

Species 1: Coleoptera Curculionidae Dendroctonus frontalis (southern pine beetle)