. 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. THE CALIFORNIA PINE RISK-RATING SYSTEM: ITS DEVELOPMENT, USE, AND RELATIONSHIP TO OTHER SYSTEMS Richard H. Smith, Boyd E. Wickman, Ralph C. Hall, Clarence J. DeMars, and George T. Ferrell1 Abstract. --The California Pine Risk- Rating System provides a method for rating current probability of tree mortality caused largely by western and
. 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. THE CALIFORNIA PINE RISK-RATING SYSTEM: ITS DEVELOPMENT, USE, AND RELATIONSHIP TO OTHER SYSTEMS Richard H. Smith, Boyd E. Wickman, Ralph C. Hall, Clarence J. DeMars, and George T. Ferrell1 Abstract. --The California Pine Risk- Rating System provides a method for rating current probability of tree mortality caused largely by western and Jeffrey pine beetle. It was formulated in stands of old-growth, eastside ponderosa and Jeffrey pine in California. Individual trees are risk-rated on easily recognized and classi- fied crown characteristics. When applied to selective logging, it is called sanita- tion/salvage. Remdval of high-risk trees, generally about 15 percent of the stand, recovers the value of trees that would otherwise be lost to insects, and has sig- nificantly reduced beetle activity in the area by 80 percent for more than 20 years. In the mid-1920's efforts were made to find host conditions that cause suscep- tibility to western pine beetle. No de- cisive or easily recognized condition was found until Salman turned to crown charac- teristics of eastside ponderosa pine in the mid-1930's. The California System re- sulted from this effort. It has become a silvicultural principle for eastside pon- derosa and Jeffrey pine in California and Oregon and is applicable to other regions in the West. Keen Tree Classes preceded and are related to the California System. A pen- alty system quantifying crown and stem characteristics is a refinement to assist field application of the System. Deriva- tives of California System include a stand hazard classification for ponderosa and Jeffrey pine in northeastern California and risk-rating systems for red and white fir in northern California. INTRODUCTION This paper trac
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