340 Forestry Quarterly 



There is now obtainable a 2><-chain tape having the last J^< 

 chain graduated for the per cent slope. The person watching the 

 tape lets the 3-chain point run by, "snubbing" the tape at the 

 figure corresponding to the per cent slope. The distance is then 

 just 2 chains on the horizontal. Obviously the use of this tape 

 renders the table of slope corrections unnecessary. The per cent 

 graduations are the more desirable. The scale should run to at 

 least 125 per cent for very steep country. 



The forest survey crew can be run as a two-man crew, or as a 

 three-man crew. On the two-man crew the compassman and 

 mapper pulls the tape while the other man watches the rear end 

 of it. On the three-man crew the division of work is quite 

 different. Generally the best arrangement is for one man to run 

 compass, one to map, and one to estimate the timber or do the 

 other special work of the crew. The compassman pulls the tape, 

 as on the two-man crew. The mapper stays at the rear end of the 

 tape, thus permitting the third man to go ahead at his pleasure. 

 The mapper in using the hand level sights ahead on compass 

 line parallel to the slope or picks out a definite object above the 

 ground on or near compass line and allows for its height above 

 it when he gets up to it, or sights on the man at one end of the 

 tape, he himself being at the other end. The last is the more 

 nearly accurate. 



The following illustration indicates the procedure, with a two- 

 man crew, estimating timber. Let us suppose that the elevation 

 of the control point at which the crew is to begin work is 3250 

 feet. The compassman takes a hasty sight on line and finds that 

 the slope is about 35 per cent. He calls out "35" to the esti- 

 mator, and goes ahead. The latter stops him at 2 chains plus 

 the distance additional for a 35 per cent slope. The compassman 

 must now determine accurately the elevation of his present po- 

 sition. He turns around, takes a careful sight on the estimator, 

 signals the latter to come ahead, then reads the Abney. It reads 

 -f-34 per cent. The compassman then refers to his table of dif- 

 ference of elevation, finds that 3-i per cent for 2 chains is 45 

 feet, adds that to 3250 feet, and has 3295 feet as the elevation of 

 the new point. He plots the point and maps up to that point 

 using actual contours. The estimator comes ahead while the 

 compassman is figuring and mapping. 



The notes can be kept in several forms. Probably the simplest 



