BIBLIOGRAPHY 215 



Sampson, Arthur W., and Dayton, William A. Relation of Grazing to 

 Timber Reproduction, Shasta National Forest. U. S. Dept. of 

 Agr., Forest Service, Review of Forest Service Investigations, 

 Vol. 2, 1913. 



Sparhawk, W. N. Effect of Grazing upon Western Yellow Pine Reproduc- 

 tion in Central Idaho. U. S. Dept. of Agr. Bui. 738, 1918. 



