ROESER, JACOB, JR. (See Bates and Roeser, 

 1924; 1928) 



RONCO, FRANK. 1961. Bibliography of Engel- 

 mann spruce and subalpine fir. U.S. Forest 

 Serv. , Rocky Mountain Forest and Range Expt. 

 Sta. Paper 57, 58 pp. 



Includes 512 references and a subject index. 



RONCO, FRANK. 1961. Planting in beetle- 

 killed spruce stands. U.S. Forest Serv., 

 Rocky Mountain Forest and Range Expt. Sta. 

 Res . Note 60, 6 pp. 



ROTHERT, E. E. 1934. Density of stand in 

 different forest types in Estes and Rocky 

 Mountain National Parks. Jour. Colo.-Wyo. 

 Acad. Sci. 1(6): 46. (Abstract.) 



Discusses reproduction of Engelmann spruce 

 and subalpine fir. 



ROWAN, SAMUEL J. 1960. The susceptibility 

 of twenty-three tree species to black root 

 rot. Plant Dis. Rptr. 44: 646-647. 



ROWE,J. S. 1959. Forest regions of Canada. 

 Canada Dept. North. Affairs and Natl. Re- 

 sources, Forestry Branch Bui. 123, 71 pp. 

 (Revision of Bui. 89, "A forest classification 

 for Canada," by W. E. D. Halliday, 1937.) 



Includes distribution of Engelmann spruce and 

 community classification. 



RUDOLF, P. O. 1952. Low temperature seed 

 storage for western conifers. U.S. Forest 

 Serv., Lake States Forest Expt. Sta. Misc. 

 Rpt. 20, 8 pp. 



RYDBERG, P. A. 1915. Phytogeographical 

 notes on the Rocky Mountain region IV. 

 Forests of the subalpine and montane zones. 

 TorreyBot. Club Bui. 42: 11-25. 



RYDBERG, P. A. 1916. Phytogeographical 

 notes on the Rocky Mountain region VI. 

 Distribution of the subalpine plants. 

 Torrey Bot. Club Bui. 43: 343-364. 



RYDBERG, P. A. 1916. Vegetative life zones 

 of the Rocky Mountain region. N. Y. Bot. 

 Gard. Mem. 6: 477-499. 



Community description. 



RYDBERG, P. A. 1917. Phytogeographical 

 notes on the Rocky Mountain region VII. 



Formations in the subalpine zone . Torrey 

 Bot. Club Bui. 44: 431-454. 



RYDBERG, P. A. 1919. Phytogeographical 

 notes on the Rocky Mountain region VIII. 

 Distribution of the montane plants . Torrey 

 Bot. Club Bui. 46: 295-327. 



RYDBERG, P. A. 1920. Phytogeographical 

 notes on the Rocky Mountain region IX. 

 Wooded formations of the montane zone of 

 the southern Rockies. Torrey Bot. Club Bui. 

 47: 441-454. 



RYDBERG, P. A. 1922. Flora of the Rocky 

 Mountains and adjacent plains. 2d ed. 1143 

 pp. Pub. by author, New York. 



SAEMUNDSEN, E. G. (See Bjarnason and 

 Saemundsen. 1949) 



SAMPSON, ARTHUR W. 1918. Climate and 

 plant growth in certain vegetative associa- 

 tions. U.S. Dept. Agr. Bui. 700, 72 pp. 



SAMPSON, ARTHUR W. 1925. The foothill- 

 montane -alpine flora and its environment. 

 IN: Tidestrom, Ivar, Flora of Utah and 

 Nevada. U.S. Nat. Herb. Contrib. 25: 24-31. 



Includes climatic data and community 

 description. 



SAMPSON, ARTHUR W. , and HARRY E. 



MALMSTER. 1926. Grazing periods and 

 forage production on the National Forests. 

 U.S. Dept. Agr. Dept. Bui. 1405, 54 pp. 



Includes community description and pheno- 

 logical observations. 



S ANT AMOUR, F. S. , JR. 1960. New chromo- 

 some counts in Pinus and Picea. Silvae 

 Genetica 9: 87-88. 



n = 12 for Engelmann spruce. 



SARGENT, CHARLES SPRAGUE. 1884. Report 

 on the forests of North America (exclusive of 

 Mexico). 612 pp. U.S. Census, 10th. 1880. 

 Vol. 9. • 



SARGENT, C. S. 1890. The silva of North 

 America, vol. 12. New York: Houghton 

 Mifflin Co. 



SARGENT, C. S. 1922. Manual of the trees of 

 North America (exclusive of Mexico). 2d ed. 

 910 pp. Boston and New York: Houghton 

 Mifflin Co. 



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