We examined attributes of piÃ±on pine (Pinus edulis) associated with the probability of infestation by piÃ±on ips (Ips confuses) in an outbreak in the Coconino National Forest, Arizona. We used data collected from 87 plots, 59 infested and 28 uninfested, and a logistic regression approach to estimate the probability of infestation based on plot and tree-level attributes. PiÃ±on pine stand density index was a good predictor of the likelihood of infestation by piÃ±on ips at the plot level, and a cross-validation analysis confirmed that the model correctly classified 82% of the cases. Diameter at root collar and piÃ±on dwarf mistletoe infestation level were good predictors of individual tree infestation, and a cross-validation analysis indicated that the model correctly classified 72% of the cases. Results suggest that the occurrence of piÃ±on ips infestations may be related to stress factors associated with increased stocking and piÃ±on dwarf mistletoe infestations.
Negrón, José F. and Wilson, Jill L.
"Attributes associated with probability of infestation by the piñon ips, Ips confusus (Coleoptera: Scolytidae), in piñon pine, Pinus edulis,"
Western North American Naturalist: Vol. 63
, Article 4.
Available at: http://scholarsarchive.byu.edu/wnan/vol63/iss4/4