MEASURING THE FOREST CROP 111 



pers. From time to time the heights of trees of different 

 diameters are measured by an instrument called a 

 "hypsometer" and with the diameters and average 

 heights known the contents of each strip may be obtained 

 by consulting a table of average contents called a 

 "volume table." Since there are ten square chains to 

 an acre and the strip is one chain (sixty-six feet) wide, 

 every ten chains advance means that one acre has been 

 measured. 



Ordinarily the making of a valuation survey of this 

 kind takes a party of four men. The compass man 

 runs the course, keeps track of the distance, either by 

 counting his paces or by means of a surveyor's chain 

 dragging from his belt. He makes note of the character 

 and condition of the timber and makes a map of the 

 country indicating the slopes, benches, mountaintops, as 

 well as lakes, rivers, roads or any other features bearing 

 on the logging of the tract. 



The two caliper men measure the trees with calipers 

 or a Biltmore stick. By practice they know about how 

 far to measure out from the chain or compass lines; if 

 they are not experienced it may be necessary for them 

 to pace in from time to time, for a large error in the 

 width of the strip would mean an error in the estimate. 

 Such errors as they do make generally average up 

 pretty well. Now they may get a tree which is too far 

 out but in a few minutes they miss one that is within 

 the two-rod strip each man is supposed to measure. 

 With care, the day's work will turn out quite well. 

 The fourth member of the crew is called the tally man. 

 He carries a note book in which he puts a dot for each 

 tree of a given species and diameter. He generally walks 

 along behind the compass man and between the caliper 

 man and checks the measurement of the trees. The 



