METHODS 



Description of the Study Aiea 



Study-site selection was guided by the following criteria: 



1 . --Variation in slope and aspect would be minimal among treatments within one 

 replication; 



2. --Replications would be on such harsh-site conditions as the south or west 

 aspects of steep slopes with little or no vegetative cover; 



3. --Some variation in slope and aspect could be tolerated among replications, but 

 major variations would be avoided; 



4. --Fill slopes would be large enough to accommodate at least one replication of 

 contiguous treatments at a single location. 



A suitable study site was found on a large fill slope on the Deadwood River road, 

 Emmett Ranger District, Boise National Forest. The area is at an elevation of 4,700 

 feet on a steep, southwest- facing slope about 300 feet above the Deadwood River 

 (fig. 1) . A Pseudotsuga menziesii/Physooavpus malvaoeus habitat type existed on the 

 slope prior to road construction. (Habitat nomenclature from work by Robert D. Pfister, 

 Robert Steele, and others in unpublished reports available at the Forestry Sciences 

 Laboratory, Boise, Idaho.) 



Specifications for the study site actually exceeded the criteria outlined above 

 because the fill slope surface was uniform and averaged about 200 feet in length. This 

 uniformity made it possible to install all three replications at the same location, 

 under apparently similar site conditions, thus minimizing site contributions to experi- 

 mental error (fig. 2) . The road fill had a southwest aspect and a slope gradient rang- 

 ing from 70 to 75 percent. The fill was constructed in 1957, about 11 years prior to 

 the installation of this study. The area studied had been unsuccessfully seeded with 

 grass at least twice prior to study installation. Failures may have been due to 

 (1) excessive deposition of material resulting from road maintenance operations and 

 from reconstruction of nearby portions of the road following an 11-day storm in 

 December 1964; (2) surface erosion on the road fill; and (3) big game use. All plot 

 surfaces were essentially bare at the time of study installation. 



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