18 



sliiiped and not very large trees the measurement o£ a single 

 diameter rnay suffice,' especially if, as tree after tree is gauged, 

 the diameters of two successive trees are measured in different 

 directions, more or less at right-angles to one another. Although 

 a matter of petty detail, it is necessary to say that the callipers 

 should be applied to the trunks of the trees properly, and the 

 diameter or girth read off iefore they are removed. The diameters 

 should be all measured at breast-height, and on hillsides this 

 heigbt should be taken on the upper side of the slope. Breast- 

 height has been assumed to be 4j feet; but as the boles of 

 trees do not taper either regularly or very rapidly, it is not 

 necessary that this height sbould be exactly measured on the tree 

 before the calliper is applied. Sufficient accuracy is attained if the 

 measurer is careful to hold tbe calliper at the height of his chest 

 and the diameter is measured at any height between 4| and 5 feet. 

 When a tree divides into two or three main stems near the point 

 at which the calliper should be applied, each stem should be mea- 

 sured separately. 



The enumeration survey should be effected over successive nar- 

 row strips, each strip being gone over once and in a direction 

 opposite to that in whjch the immediately preceding strip has 

 been surveyed. On steep slopes it is convenient to run the strips 

 horizontally and to begin at the bottom of the slope. The mea- 

 surers, furnished with callipers, gauge the diameter of the trees 

 and call out the figures read, which are at once noted in a pro- 

 perly-ruled field-book by the recorder, who is usually himself the 

 surveyor in charge of the party. The number of measurers that 

 can keep one recorder fully employed depends on the density of 

 the forest, on the nature of the ground, on whether he is also in 

 charge of the party, and on whether all or only certain classes of 

 the trees composing the crop are to be measured. The number of 

 measurers may thus, according to circumstances, range from 2 to 

 6, and even 7 and 8. 



As the survey progresses the trees measured are immediately 

 marked with a clearly visible blaze, which should not, however, be 

 deep enough to expose the wood. In order to make the blaze, each 

 measurer should be provided with a light short-handled axe. The 

 blaze should be made on the side opposite the area still remainino- 

 to be surveyed, so that when the next strip is being surveyed the 



