It is estimated that there are 50,000 infested trees within the National Park boundaries and an additional 115,000 infested trees within a ten-mile zone surrounding the Park. But most of this infestation is either endemic or weakly epidemic in old beetle swept areas, so that only the real epidemic centers would appear to be possible sources of migration and need to be considered in any control plans.
Keen still did not recognize that the beetle outbreak was about as irresistible as the ocean tides. As long as extensive, over-mature stands of lodgepole pine were present, the beetle was sure to follow. The fact that the park and surrounding Forest Service lands contained thousands of acres of such susceptible forests made the control policy pursued for 6 years of questionable effectiveness.
In 1931, the Park Service treated 15,767 trees at a cost of $11,027. The recommendation for 1932 was to treat about 23,370 trees in the park and an additional 21,400 trees on surrounding National Forest lands (see footnote 35). This was gaining ground in retrograde and reminds one of military predictions made by generals during the Vietnam and other wars.
Keen’s rationale for the increased numbers of trees treated each year follows (see footnote 35):
This project is a splendid example of what can be accomplished in beetle control under what might be called the “local unit” clean-up plan as contrasted with the “extensive area” or “isolated unit” plan of control. No one questions but what the treatment of all the infestation which might reinfest an area to be protected is the safest course to pursue but at the same time the most costly, as the work in the Yellowstone Park region so very well illustrates, The question then arises as to whether anything less than a complete clean-up of all the infestation in the surrounding country will bring about satisfactory results.
The work on Crater Lake National Park was started in 1925 to determine this point—the feasibility of “local unit” control. Some very satisfactory results were secured but there was evidence of some reinfestation filtering back into the controlled areas each year and in 1926 a concentrated migration from north of the lake into the cleaned Munson plateau unit which completely wiped out the results of the work in that area. Thus control work under this plan prevented the building up of an epidemic in treated units but did not prevent heavy migrations. The net result has been that the protected areas south of the lake have been largely saved from the fate of the unprotected stands even though losing considerable timber through repeated light infestations and control work.
Since 1929 the threat of heavy migrations has been much less as the beetle epidemic waned on the unprotected areas. Then the plan was adopted of going out and mopping up all epidemic centers within the Park and on nearby National Forest lands that threatened the protected areas. With the extension of this program the control results on the protected areas improved; showed little more infestation than might be accounted for from local sources; but in no year have all the outlying epidemic areas been reached. This change in program increased the number of trees treated annually from about 3700 trees before 1929 to an average of 16,800 trees annually Since then. This does not mean that the epidemic has been increasing in spite of the control work, but simply that the area has been expanded each year to take in more of the threatening outlying areas.
Keen’s statements were blatant rationalizing and partially true, but the fact was that, sooner or later, the beetles attacked every mature stand of lodgepole pine in the park, whether controlled in the “local unit” plan or not.
I remember my own experiences battling mountain pine beetle in Yosemite National Park during a concurrent lodgepole pine needleminer (Coleotechnites milleri) out break in 1953 to 1958. In 1953, I surveyed a small area of mountain pine beetle outbreak in Conness Basin that contained about 2,050 infested lodgepole pine on 500 acres. [36] For the next 4 years the Park Service, with my misguided technical assistance, attempted to control the outbreak on an ever increasing area until thousands of acres and more than 10 times the number of trees were involved. Because most of the trees were over mature and all were weakened by lodgepole needle miner defoliation, it was a losing battle for the managers and the beetles eventually won.
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