Prevent at ive Measures . 



Destructive forest insects are always present in 

 our forests. They breed and increase enormously in freshly 

 cut material such as results from the building of roads and 

 trails, telephone lines, cabins, rangers' and supervisors' 

 sales, clearings for lookout stations, clearing of fields 

 for administrative use, etc. Since epidemics start from any 

 of the above causes, great care should be taken to pile and 

 burn slash during the field season in which it is cut before 

 the insects spread to the surrounding standing timber. 



The principle to be followed is not to destroy the 

 material before infestation, but after it is infested and 

 before the insects escape. Two purposes are thus servad: 

 (1) To prevent the broods from escaping to the adjoining 

 forest, and (2) To provide trap material for the reduction 

 of the injurious forest insects already e^istin-* in the vi- 

 cinity. As many of these insects are two -brooded, one brood 

 emerging in the spring and one in the fall months, this metho 

 cannot always be followed out. Therefore, all material re- 

 sulting from any improvement work in the early spring should 

 be burned, if possible, before the opening of the fire season 

 Every ranger should aim to have all brush on his district 

 disposed of by April 1. All material resulting from improve 

 merit v/orl: during the fire season should be burned immediate] 



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