98 



MISC. PUBLICATION 273, U.S. DEPT. OF AGRICULTURE 



ties, Oreg., and Grays Harbor County, Wash., was destroyed. 

 From 1911 to 1914 the hemlock looper killed much hemlock in 

 Stanley Park, Vancouver, B. C. Another major outbreak occurred 

 again in Tillamook County in 1918-21, when several townships 

 were affected and 500 million board feet of hemlock and Douglas 

 fir were reported to have been killed. A severe outbreak occurred 

 in Pacific and Grays Harbor Counties, Wash., from 1929 to 1932, 

 when 50,000 acres were involved and about 200 million board feet 

 of hemlock timber was destroyed. Losses in Pacific County were 

 reduced in 1931 through the first airplane dusting experiment at- 

 tempted against a forest defoliator in the western part of the 

 United States. Again, between 1943 and 1945 there was another 

 outbreak in Clatsop County, Oreg., covering some 12,000 acres, 



Figure 40. — Western hemlock defoliated and killed by the hemlock looper in 

 Clatsop County, Oregon, in 1945. 



