Circular No, 143. issued January 27, 1912. 



United States Department of Agriculture, 



BUREAU OF ENTOMOLOGY. 

 L. O. HOWARD, Entomologist and Chief of Bureau. 



INSECT DAMAGE TO STANDING TIMBER IN THE 

 NATIONAL PARKS. ' 



By A. D. Hopkins, 

 In Charge of Forest Insect Investigations. 



CHARACTER OF THE DAMAGE. 



The damage by insects to the living trees of the forests and orna- 

 mental grounds of the national parks consists of injuries to the 

 foliage, branches, or the entire tree which mar or destroy their 

 attractive, educational, and historic features and diminish or destroy 

 their commercial value. 



Throughout the forests of the Rocky Mountains and Pacific slope, 

 including the national parks, a large percentage of the timber has 

 died during the past half century. The old standing and fallen dead 

 trees, the red foliage of those that died last year, and the fading 

 tops of those now dying bear evidence of the work of insects and 

 are conspicuous examples of a great waste of forest resources. In 

 some localities a few scattering trees die each year within a town- 

 ship or section; in others, clumps of trees or whole forests die during 

 a single year. 



The conifers, which are the predominating trees of this western 

 part of the country, are subject to a high death rate from insect 

 attacks. The pines, the spruces, the Douglas fir, the balsam firs, 

 the hemlocks, the cedars, and the Sequoias (redwoods) have each at 

 least one destructive enem3\ 



In the fall, spring, and early sunmier the dying and recently dead 

 trees are conspicuous on account of their fading, yellowish-red, and 

 reddish-brown foilage, as if injured by fire. "UHien they are in 

 large patches, or extend over a considerable area, their death is 

 often attributed by the casual observer to forest fires. 



iThis paper was read by the author at a conference of national park superintendents 

 held under the auspices of the Secretary of the Interior, September 11-12, 1911, and 

 is embodied in the proceedings of the meeting issued by the Interior Department. 



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