These conclusions do not require any substantial 

 change in handling control work on National Forests. They 

 indicate the need for a more comprehensive conception of an 

 infestation unit and of the total timber values endangered 

 by the infestation; and they may modify the plan of attack 

 on an infestation unit, or the order of attack -where a unit 

 can be treated only in several years because of lack of 

 funds. They would reduce the amount of clean-up work dur- 

 ing the second and subsequent years, and in some cesas might 

 eliminate its necessity altogether. A certain number of 

 unimportant individual trees which have heretofore been 

 treated would be left standing. 



There is no doubt that the experience of the For- 

 est Service in insect control work will help in demonstrating 

 the principles herein given. I", is exceedingly desirable 

 to study the results of our work in the light of these prin- 

 ciples and to bear there in mind in laying out new projects. 

 The method of partial cutting should be thoroughly tried out 

 in accordance with plans developed in advance, in order that 

 the principles of selecting trees may be developed as rapid- 

 ly as possible and adapted to local conditions in various 

 ~arts of the District, Supervisors should bear this in min<? 

 in preparing working plane for control projects, 



( ; i gne d ) C OERT DUE 013, 



District Forester. 



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