completed and a report submitted during the year. 

 In the Rogue River area, about 48,000 acres near 

 Ashland, Oregon, the western pine beetle in 191-4 

 caused the death of 346,000 board feet of pine timber. 

 In 1915, 1.615.000 board feet were killed; 1,383,000 

 feet in 1916; and 608.000 in 1917. A count of the 

 young and matured stages of the beetles that develop- 

 ed in an average foot of bark, and also of the number 

 of exit holes through which the beetles emerged to 

 attack other trees, showed that there was a notable 

 decrease in numbers during the development of the 

 broods each year in the infested trees on account of 

 the increase of natural enemies and other disturbing 

 factors. This helps explain why these beetle epidemics 

 rise and fall within a limited period of years, and it 

 explains how the western forests of yellow pine are 

 naturally protected from total destruction. These 

 facts are especially significant in connection with the 

 application of the percentage principles of control, as 

 by aiding the natural forces which work against the 

 abnormal increase and spread of the beetles complete 

 control may be gained. The history of this epidemic- 

 shows the importance of prompt recognition and 

 prompt treatment of a threatened outbreak in order 

 to prevent the great loss of timber which would occur 

 before natural control became operative. 



"Another special study was made of the number 

 of all stages of the western pine beetle in 330 square 

 feet of infested bark selected from 67 trees, which 

 represented an average infestation within an area of 

 approximately 36 square miles. It was shown that 

 there is a large perecentage of mortality between the 



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