U.S. Forest Service 

 Research Paper INT -38 

 1967 



SPIRAL GRAIN--A CAUSE OF POLE TWISTING 



by 



Charles A. Wellner and David P. Lowery 



INTERMOUNTAIN FOREST AND RANGE EXPERIMENT STATION 



Forest Service 

 U.S. Department of Agriculture 

 Ogden, Utah 84401 

 Joseph F . Pechanec , Director 



