work 



timber is very valuable this method may be varied to an 

 actual count of every tree. Usually in such latter instances the 

 subdivisions are smaller than the square mile, the forty acre 

 tract being perhaps the standard. As in any other expendi- 

 ture for knowledge the degree of expense must vary with 

 the value of the principal about which information is sought, 

 and the higher the intrinsic value of that principal the 

 more refined can be the methods of determining facts about it. 



These results are tabulated on specially prepared sheets. 

 Calipering work is done in order to obtain a sample acre of tree 

 facts for the tract or one of its subdivisions. 



There are many ways of doing this field work. One way which Methods 

 has been found especially satisfactory in fairly dense growth is to of field 

 measure the trees in quarter-acre circles, a radius of 59 feet. An 

 assistant does the calipering, runs out the tape to check distance, 

 and sometimes tallies 

 the diameters called off. 

 But each tract of land 

 will call for certain 

 methods, and no general 

 rule can be laid down as 

 to what the best method 

 may be. The method 

 chosen is influenced, not 

 only by the land itself, 

 but by the results that 

 are desired, the need of 

 quick work, and other 

 incidental things. But 

 accurate measurements 

 must be insisted upon in 

 all methods used if the 

 work is to be correct. 



The information ob- 

 tained by the survey 

 and the exploration 

 usually covers the fol- 

 lowing points: 



Tract lines are marked 



on the ground and The bark wou]d not strip f ro m this dry 

 tract areas are known. cedar post. 



21 



