Figvo'e 1. — Croun oharaateristias of ponderosa pine trees symbolizing each of the four 

 ratings of the Ponderosa Vine Risk Rating System and the relative risk^ or suscepti- 

 bility j, of trees in each rating to attacks by the western pine beetle: A, Risk 1 

 (law risk) ; Bj Risk 2 (moderate risk); C_3 Risk S (high risk) ; and 0, Risk 4 (very 

 high risk) . 



2 



