. Insect and disease conditions in the United States, 1979-83 : what else is growing in our forests?. Forest insects United States; Trees Diseases and pests United States; Plants Disease and pest resistance. Mountain Pine Beetle. Figure 3, Beetle- infested lodgepole pine dying on the Flathead National Forest, MT. in the phloem and xylem tissues and interrupt the flow of water and nutrients. When beetles are present in sufficient numbers, they overcome the tree. As a tree dies, its needles first turn a pale green, then light orange, and finally a bright orange red (fig. 3). This orange-red colo
. Insect and disease conditions in the United States, 1979-83 : what else is growing in our forests?. Forest insects United States; Trees Diseases and pests United States; Plants Disease and pest resistance. Mountain Pine Beetle. Figure 3, Beetle- infested lodgepole pine dying on the Flathead National Forest, MT. in the phloem and xylem tissues and interrupt the flow of water and nutrients. When beetles are present in sufficient numbers, they overcome the tree. As a tree dies, its needles first turn a pale green, then light orange, and finally a bright orange red (fig. 3). This orange-red color attracts the at- tention of forest visitors, especial- ly when trees are dying over millions of acres (fig. 4). Historical Perspective This insect has always been present in the Western United States but was not considered a serious pest until about 1900. Only as sawmills were built to produce the lumber for houses, farms, and industry did the early settlers discover that they were in competition with the beetle for the trees. The conflict between people and the mountain pine beetle has not been resolved to this day. Since 1975, the beetle has killed an estimated 440,000 cubic feet (12,460 m3) per year (Safranyik 1978). In the Intermountain States, a small infestation was discovered in 1953 on the north slope of the F-705635 Unita Mountains in Utah. By 1958, the infestation had developed into a full-scale out- break. Control efforts began in 1958 and continued for 10 years. But by 1965, most of the lodgepole forests in northern Utah, southern Idaho, and western Wyoming were experien- cing massive outbreaks. These outbreaks continued to spread northward, sweeping through Yellowstone National Park and in- to the Gallatin National Forest in Montana. In Montana and Idaho, infestations now extend over million acres ( million ha). In the Pacific Northwest, most of the damage has occurred east of the Cascade Mountains. From 1955 through 1966, 836,110 acres (338,369 ha) of lod
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