. Hazard-rating systems in forest insect pest management : symposium proceedings, Athens, Georgia, July 31-August 1, 1980. Forest insects Biological control United States Congresses; Forest insects United States Analysis; Forest insects United States Management. dieted values obtained using equations developed in central Idaho. It should be noted that the predicted values are gener- ally lower than the observed values, sug- gesting regional differences in the rela- tionships. This is supported by a test of the variance about the slopes and inter- cepts estimated for equation [1] from the Idaho
. Hazard-rating systems in forest insect pest management : symposium proceedings, Athens, Georgia, July 31-August 1, 1980. Forest insects Biological control United States Congresses; Forest insects United States Analysis; Forest insects United States Management. dieted values obtained using equations developed in central Idaho. It should be noted that the predicted values are gener- ally lower than the observed values, sug- gesting regional differences in the rela- tionships. This is supported by a test of the variance about the slopes and inter- cepts estimated for equation [1] from the Idaho and Montana data sets. There was no significant difference between the slopes, but the intercepts were signifi- cantly different. Thus, for a given haz- ard value, central Idaho had a greater percent of trees killed than Montana. However, the proportionate increase in mortality for increasing hazard values was similar for both areas. Regional dif- ferences are not unexpected and can be accounted for by analytical procedures. The general approach to the hazard rating seems applicable to both geographic areas, though. Table levels of lodgepole pine mor- tality by mountain pine beetle in western Montana v. mortality levels predicted by equation (2) developed from central Idaho data (fig. 1). Stand hazard Percent basal area killed rating Observed Predicted 49 76 60 61 37 37 35 34 61 27 32 0 2 -3 9 -7 5 -8 18 -11 %BAK. STAND HAZARD RATING Figure values for 10 western Montana lodgepole pine stands; a test of the risk classification method of Schenk et al. (1980). Problems Encountered This hazard rating is similar to that developed for the fir engraver in that both are based on only stand (tree) char- acteristics and can therefore be subject to the same problems. A more important problem encountered in developing a hazard rating for the lodgepole pine-mountain pine beetle interaction was the scarcity of manag
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