142 BULLETIN 1105, U. S. DEPARTMENT OF AGRICULTURE. 



LITERATURE CITED. 



1. Bates, Caklos G. Windbreaks. U. S. Dept. Agr., Forest Service. BuL 



86. 1911. 



2. Bbiggs, Lyman J., and H. L. Shantz.' The wilting coefficient of different 



plants and its indirect determination. U. S. Dept. Agr., Bur. Plant 

 Ind. Bui. 230. 1912. 



3. Buckingham, E. Studies in the movement of soil moisture. U. S. Dept. 



Agr., Bur. Soils. Bui. 38. 1907. 



4. Chapman, Herman H. Unpublished reports, U. S. Forest Service, 1918, 



1919. 



5. Gkegoey, Herbert F. The Navajo Country, U. S. Geol. Surv., W. S. P. 



380. 1916. 



6. Haasis, Ferdinand W. Frost heaving of western yellow pine seedlings. 



(Submitted for pulication in Ecology.) 1921. 



7. . Relation between soil type and root form of western yellow pine 



seedlings. Ecology, vol. ii, No. 4. 1921. 



8. Hartley, Carl, T. C. Merrill, and Arthttb S. Rhoads. Seedling diseases 



of conifers. Jour. Agr. Res., vol. xv, No. 10. 1918. 



9. Hatton, John H. Livestock grazing as a factor in fire protection on the 



National Forests. U. S. Dept. of Agr. Cir. 134. 



10. Hesselm;an, Henkik. Studier over Salpeterbildningen i naturliga Jord- 



maner ock dess Betydelse i vaxtekologiskt Avseende. Meddel. fr. 

 Statens Skogsforsoksanstalt. Haft 13-14. 1916-1917. Also Skog^- 

 vardsforeningens Tidskrift, Haft 1. 1918. 



11. Hill, Robert R. Effects of grazing upon western yellow pine reproduction 



in the National Forests of Arizona and New Mexico. U. S. Dept. 

 Agr. Bui. 580, 1917. 



12. HoFMANN, J. V. Natural reproduction from seed stored in the forest floor. 



Jour. Agr. Vol. XI, No. 1. 1917. 



13. Jaenicke, Alexander J., and Max H. Foerster. The influence of a west- 



ern yellow pine forest on the accumulation and melting of snow. 

 Monthly Weather Review, 43 pp. 115-126. 1915. 



14. Leiberg, John B., Theodore P. Rixon, and Arthur Dodwell. Forest 



conditions in the San Francisco Mountains Forest Reserve, Arizona. 

 U. S. Geol. Surv. Prof. Pap. 22, 1904. 



15. Pearson, G. A. Reproduction of western yellow pine in the Southwest. 



U. S. Dept. Agr., Forest Sei-vice Circ. 174. 1909. 



16. . The influence of age and condition of the tree upon seed produc- 

 tion of western yellow pine. U. S. Dept. Agr. Circ. 196. 1912. 



17. . A meteorological study of parks and timbered areas in the west- 

 ern yellow pine forests of Arizona and New Mexico. U. S. Weather 

 Review, 41, pp. 1615-1629. 1914. 



18. . Yield and reproduction of western yellow pine. Jour. Forestry, 



March, 1918. 



19. . Factors controlling the distribution of forest types. Ecology, vol. 



1, Nos. 3 and 4, 1920, 



20. Plummer, F. G., Theodore P. Rixon, and Arthur Dodwell. Forest con- 



ditions in the Black Mesa Forest Reserve, Arizona. U. S. Geol. 

 Surv., Prof. Pap. 23. 1904. 



21. Robinson, Henry Hollister. The San Franciscan volcani.c field, Arizona. 



U. S. Geol. Surv., Prof. Pap. 76. 1913. 



