ECOLOGICAL CROSS-SECTION OF BOULDER 

 PARK (TOLLAND, COLORADO)^ 



By Francis Ramaley and Louis A. Mitchell 



The following ecological observations were made in Boulder 

 Park, Colorado, during the late spring and part of the summer of 

 1909. There have been so few studies of this kind recorded that 

 it has seemed worth while to put the material into shape for pub- 

 lication. An examination of the records of the few stations will 

 give the reader some idea of environmental conditions in the mid- 

 mountain districts (montane zone) of Colorado. Being selected 

 so as to represent different plant associations, they should be rather 

 generally useful. Various authors, among whom may be mentioned 

 Mrs. Clements,^ Shantz,^ Pool,'' Young,s Schneider^ and one^ of us, 

 have made determinations of soil moisture and temperature in 

 Colorado, but most of the studies have been in the plains area or in 

 the foothill region. 



Boulder Park is situated in Gilpin County in the north-central 

 part of Colorado at an altitude of about 9,000 ft. It is really a moun- 

 tain valley which extends two miles east and west, and is three- 

 quarters of a mile wide. Mountains rise abruptly on either side; 

 the valley narrows into a canyon at each end. The low morainal 

 hills in the middle of the park and perched boulders on the canyon- 



' Publication of the Colorado Biological Survey, No. 4. 



' Clements, Edith S. "The Relation of Leaf Structure to Physical Factors," Trans. Amer. Micr. Soc, 

 pp. 19-102 (no date). 



3 Shantz, H. L., "A Study of the Vegetation of the Mesa Region East of Pike's Peak," Bot. Gazette, 

 Vol. XLII, pp. 16-47 and 179-207, 1906. 



« Pool, Raymond J., "Histological Studies in the Artemisia Formation," University Studies (Nebraska) 

 Vol. Vni, pp. 411-38, 1908. 



5 Young, Robert J., "Forest Formations of Boulder County, Colorado," Bot. Gazette, Vol. XLVI, pp^ 

 321-52, 1907. 



« Schneider, Edward C, "The Succession of Plant Life on the Gravel Slides in the Vicinity of Pike's 

 Peak," Colorado College Publication, Science Series, Vol. XII, pp. 289-311, 1911. 



' Ramaley, Francis, " Remarks on Some Northern Colorado Plant Communities with Special Reference 

 to Boulder Park (Tolland, Colorado)," University oj Colorado Studies, Vol. VII, pp. 223-36, 1910. 



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