The effects of sanitation-salvage cutting on insect-caused mortality at Blacks Mountain Experimental Forest, 1938-1959 effectsofsanitat66wick Year: 1962 Figure 1. âThe experimental forest lies in the background, extending from Blacks Mountain on the left to Patterson Mountain on the right. INSECT PROBLEMS The insect problems of Blacks Mountain are typical of east side pine. The two most destructive insect species are the vestern pine beetle (Dendroc- tonus brevicomis Lec. ) in ponderosa pine, and the Jeffrey pine beetle (D. jeffreyi Eopk. )~in Jeffrey pine. In California, ponderosa pine is
The effects of sanitation-salvage cutting on insect-caused mortality at Blacks Mountain Experimental Forest, 1938-1959 effectsofsanitat66wick Year: 1962 Figure 1. âThe experimental forest lies in the background, extending from Blacks Mountain on the left to Patterson Mountain on the right. INSECT PROBLEMS The insect problems of Blacks Mountain are typical of east side pine. The two most destructive insect species are the vestern pine beetle (Dendroc- tonus brevicomis Lec. ) in ponderosa pine, and the Jeffrey pine beetle (D. jeffreyi Eopk. )~in Jeffrey pine. In California, ponderosa pine is about five times as abundant as Jeffrey pine, so that the vestern pine beetle is a much greater pest of eastside pine stands than is the Jeffrey pine beetle. Other injurious insects include the California flatheaded borer (Melanophila californica Van Dyke), various species of Ips, and the red tur- pentine beetle (Dendroctonus valens Lec). All of these beetles alone, or more often in combination with each other, attack both hosts. They all occur on the experimental forest. The mountain pine beetle (D. monticolae Hopk.) occasionally kills ponderosa pine, but more often it destroys in combination â with other bark beetles. Evidence of insect damage had become plentiful by 1933 when the resource inventory was started, and an epidemic of bark beetles was killing many ponderosa and Jeffrey pine trees throughout northern California. The magnitude of this damage is indicated by a survey in 1937 in which all of the trees killed on the experimental forest during the years 1933-1936 were measured (Anonymous, 1938). According to the results, insect-caused pine mortality during this period averaged 202 board feet per acre per year. These excessive losses occurred despite the fell-peel-burn control work done in 193^ (fig* 3), aimed at reducing the high bark beetle-caused losses. The mortality in 1937 averaged about 70 board feet per acre -k-
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