| Weights of Evidence (WofE) spatial analysis was used to predict the probability of Southern Pine Beetle (SPB) infestation in Angelina, Nacogdoches, San Augustine and Shelby Co., Tx. Thematic spatial data derived from LandSat imagery (1974--2002 LandSat 1--7) were used in the analysis. Data layers included: forest covertype, forest age, forest patch size and percent slope. WofE predicted infestation probabilities were significantly higher at actual infestation locations, over locations chosen at random (p < 0.0001). Significantly more infestations occurred in the higher probability areas (p = 0.002). Infestation size was not significantly correlated with probability (p = 0.0528). Significant correlations were found between WofE probability and traditional SPB hazard rating using the Mason (1981) system (p < 0.0001). WofE probability maps were used to produce current SPB three and five-class hazard rating maps for the study area. |
