174 



CONSTRUCTION OF STANDARD VOLUME TABLES 



Irregularities in spacing the first set of curves are now shown by 

 this second set as similar distortions of each curve where they inter- 

 sect the same ordinate. This is shown in Fig. 29.^ 



Volumes read from this second and final set of curves increase with 

 both diameter and height according to the true laws of variation appli- 

 cable to each dimension. In this way Standard Volume Tables are 

 secured, which may be applied to a species throughout its range, unless 

 it is convincingl}^ shown that there are consistent differences in form 

 and volume not due to either height or diameter, which can be cor- 

 related with age or site, and call for separate standard table. 



TABLE XXX 



Standard Volume Table Read from Curves of Volume on Height for 

 Different Diameter Classes 



142. Local Volume Tables — Their Construction and Use. In the 



absence of a standard table, or when for any reason the available tables 

 are not reliable and there is no time to construct a table for all heights 



' Based on the law of variation between volume and height, this set of curves 

 (in rectangular co-ordinates the term "curve" apphes to any hne, curved or straight, 

 which follows a regular law and can be expressed by a formula) consists of lines which 

 are nearly straight, but not parallel, since the difference in volume increases with 

 each diameter class representing a single curve. 



