It appears likely that forests of mature ponderosa pine will be present for many 

 years; some will include remnants, perhaps, of today's old-growth pine stands. Young 

 pine stands will continue to mature, most assuredly, under increasingly intensive 

 management. Segments of today's mature ponderosa pine stands are being placed in more 

 or less reserved status in some multiple use zones as a result of the pressures exerted 

 by a growing outdoor recreation-oriented public. These pressures are already forcing 

 consideration of more selective cutting practices that tend to delay harvest cuttings 

 in commercial ponderosa pine stands (Curtis and Wilson 1958). 



The threat of bark beetle outbreaks in western Montana's existing forests of mature 

 ponderosa pine is already indicated by appreciable numbers and volumes of high risk pine 

 trees. The possibility exists that even more high risk trees might develop in some 

 stands as the pine overstory competes for soil nutrients and moisture with increasing 

 numbers of dense understory stands of more tolerant species (fig. 3) . 



As to the second question, even the meager data produced by the risk rating study 

 point to a recognizable ability of the risk rating system to identify pine trees various- 

 ly susceptible to lethal attacks of bark beetles in western Montana, if not generally 

 throughout the northern Rocky Mountains. Assuming this capability, the rating system 

 can do here what it has done elsewhere: 



1. Identify individual pine trees susceptible or resistant in varying degrees to 

 beetle attack. 



2. Assess the risk, or hazard, of whole pine stands from the threat of beetle- 

 caused depletion, or from the likelihood of these stands serving as breeding habitats 

 that may support rapidly expanding beetle populations (Johnson 1949, 1951). 



3. Assist forest managers to formulate plans to counter the threat of beetle 

 depredations by giving priority for harvest cuttings or stand improvement treatments to 

 stands with the highest beetle hazard. 



4. Provide the detailed basis for sanitation-salvage cuttings to beetleproof pine 

 stands suspected of being unusually susceptible to damage from bark beetle outbreaks 

 (Johnson 1968) . 



The study has provided information on the abundance of high risk trees in a variety 

 of pine stands. For example, it has shown that most of the stands sampled had 15 percent 

 or more of their volume in high risk trees. From results of this study and experience 

 gained elsewhere, we believe that this percentage figure represents an arbitrary but 

 realistic demarcation between ponderosa pine stands that are either resistant to serious 

 beetle attacks (those with less than 15 percent of their volumes in high risk trees) or 

 acutely susceptible to them (stands with more than 15 percent of their volumes in high 

 risk trees) . 



Like those of other similar studies, the results of this study should allay the fears 

 of some foresters and timber operators that sanitation-salvage cuttings are universally 

 uneconomical. Finally, economic- oriented studies have shown that harvesting of only high 

 risk trees can be profitable and that the quality of timber removed is as good or better 

 than that of the stand as a whole. It can be argued, of course, that some sanitation- 

 salvage cuttings would not be economical. 



In conclusion, we believe the study has provided foresters in this region with a 

 workable basis for coping with a potentially serious insect problem--a basis soundly 

 rooted in good si Ivi cultural practice and responsive to the public's growing concern 

 for operating techniques that exhibit full consideration for the total forest 

 environment . 



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