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SILVICULTURAL TREATMENT 



KIND OF CUTTING 

 Cleaning 



Liberation cutting . . . 

 Thinning 



Improvement cutting 



Salvage cutting 



Pruning 



TIME OF APPLICATION 



First to approximately the 

 twentieth year 



First to approximately the 

 twentieth year 



Early life to beginning of 

 period of regeneration 



Twentieth year to begin- 

 ning of period of regen- 

 eration 



Twentieth year to begin- 

 ning of period of regen- 

 eration 



First quarter or half of the 

 rotation 



REMARKS 

 Frequently unnecessary 



Frequently unnecessary 



Needed in all fully stocked 

 stands 



Usually required in mixed 

 stands previously un- 

 managed 



Used only in case of in- 

 jury to the stand 



Advisable only in special 



FIG. 73. Thinning and pruning a stand of Scotch pine in Pennsylvania. The 

 poorly formed, suppressed, weak, diseased and insect infested trees are removed 

 and the crown space left for the better specimens. All dead or green branches up 

 to a given height are cut off flush with the trunk to improve the quality of lum- 

 ber produced from the trees when cut. Several million acres of Federal and 

 State Forests have been thinned by the Civilian Conservation Corps in this way. 



The most extensive thinnings have been conducted by the Civilian 

 Conservation Corps, especially in the National Forests of the Lake 



