THE GENUS DENDROCTONCJS. 



99 



but that it is necessary to reduce its numbers beyond the power of 

 doing harm. 



The removal of the infested bark from at least the lower half of 

 the standing trees offers many advantages over felling the trees for 

 the purpose of barking all of the trunk. More insects can be destroyed 

 in the standing trees within a given time and the barked standing 

 timber may be left standing until suitable facilities can be provided 

 for its utilization; thus, if necessary, all of the specified time for the 

 destruction of the in- 

 sects may be devoted 

 exclusively to the re- 

 moval of the bark. 



The barking of newly 

 attacked trees in Au- 

 gust and September is 

 not to be recommended 

 for this species. Trap 

 trees are of little or no 

 service in combating it 

 and continued timber- 

 cutting operations ap- 

 pear to have little or 

 no influence in check- 

 ing its ravages on liv- 

 ing timber. 



Recent reports of 

 conditions in the vicin- 

 ity of Colorado Springs, 

 where a large percent- 

 age of the infested tim- 

 ber was barked in 1905 

 and during the winter 

 and spring of 1906, in- 

 dicate most successful 

 and satisfactory re- 

 sults. (See also other references to successful control, pp. 36-38.) 



The depredations in the Black Hills have been so extensive that 

 little or nothing has been accomplished toward the control of the 

 beetle, owing to lack of. sufficient funds and other facilities for adopt- 

 ing the radical measures necessary to accomplish anything of im- 

 portance. 



(For additional information, see Bulletin No. 56, Bureau of Ento- 

 mology, of which the above is a partial revision.) 





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Fig. 58.— Removing bark from base of trunk of standing tree with 

 special barking tool, to destroy broods of the Black Hills beetle. 

 (Original.) 



