440 Forestry Quarterly 



General Land Office public survey and by the Geological Survey 

 small scale topographic quadrangles, so that no primary control 

 had to be executed. On this same project, over 500 miles of strip 

 surveys were run with an average elevation closure of 10 feet to 

 the mile. The minimimi error on such lines was one foot to the 

 mile, while the maximum allowed was 30 feet. 



The errors of closure for alignment and distance on the strip 

 surveys each averaged one-half chain to the mile. Mapping was 

 done on a 4-inch to the mile scale, using a 50-foot contour interval. 

 It is readily apparent, therefore, that the errors of closure resulting 

 can be readily adjusted so as to be almost negligible on the scale 

 of the map. 



The cost of the work, including the control, mapping, timber 

 estimating, etc., was approximately 12 cents an acre. The results 

 of this project furnish an average example of what is being accom- 

 plished on a large amount of similar work. In less rugged and 

 more open timber, as in the Yellow pine and Lodgepole pine 

 stands, for example, closing errors and costs are more favorable. 



