Periodical Literature. 205 



permit their use for single stems, since they represent only aver- 

 ages. To permit closer approximation to single stem volumes the 

 form quotient should be introduced when tapering as well as 

 cylindrical stems may be determined more accurately. 



To avoid making the tables too cumbersome, the author does 

 not give the form factor for each form quotient. 



A comparison of form factors for spruce and pine shows that 

 the form factors in the same form class approach each other 

 closely. For heights from 30 feet upward the differences are at 

 most 2%. Hence, since an error of 2% in estimating may be 

 neglected, the volume tables for pine may also be used for spruce. 



A comparison with the form factors established for pine and 

 spruce in Austria by Schiffel brings out the interesting fact of a 

 remarkable similarity, so that, if the form quotient is taken care 

 of, it is not necessary to recognize growth regions. Such volume 

 tables may be employed for extensive areas. 



The results of the author show that age does not have a definite 

 influence on form ; nor does a regular rise or fall of the form 

 factor occur with rising b. h. d. ; but the form factor sinks or 

 rises with the form quotient; and in each form class the form 

 factors decrease with increasing height (contrary to Fricke's 

 opinion, see Quarterly, Vol. VI, p. 303). For instance, for pine: 



Form Class. Average Height. 



.65 16.8 m 



.70 14. s " 



•75 13-8 " 



.80 12.5 " 



Since a higher stem is mostly older and stouter than a lower, 

 it follows that the form quotient sinks with rising age and 

 diameter. 



The form quotients for pine and spruce move mainly between 

 .575 and .825. 



In using the volume tables diameters are measured, height and 

 form class estimated, the latter from the relation between breast 

 high and middle diameter, which relation is given in a special 

 table. Other relations are discussed. 



A small series of measurements shows that the bark alone 

 shows for pine from 18 to 10% of the total volume with bark, 



