Volume differences 

 0.175+ * 



0.425 



-1.025+ * 



----+---•+----+----+----+-- 



Frequency 

 Each * may represent up to three trees 



Figure 1 .—Frequency distribution (stem-and-leaf plot) 

 between Huber's volume formula and Newton's volume for- 

 mula applied to the destructive sample data. Volumes for 

 each tree were computed by the two formulas and the 

 difference of Huber's minus Newton's is plotted. 



Frequency 



2 



1 



6 

 38 

 107 

 63 

 25 

 19 



7 



9 



3 



8 



2 



2 



3 



1 



3 



1 



303 



Table 1. — Comparison between wood and bark volume computed by Huber's formula minus vol- 

 ume computed by Newton's formula for destructive sampled trees 



Median 



Diameter Number volume 



class Species of trees Mean volume difference difference 



DRC inches 







Ft^ 



Percent^ 



Ft^ 



3- 6.9 



Juniper 



23 



-0.05 



-10 



-0.01 





Pinyon 



53 



-.07 



-11 



-.05 





Pinyon and juniper 



76 



-.07 



-12 



-.04 



7-10.9 



Juniper 



51 



-.08 



-4 



-.03 





Pinyon 



60 



-.12 



-3 



-.05 





Pinyon and juniper 



111 



-.10 



-3 



-.04 



11-14.9 



Juniper 



35 



-.07 



-1 



-.03 





Pinyon 



32 



-.15 



-1 



-.09 





Pinyon and juniper 



67 



-.11 



-1 



-.06 



15-18.9 



Juniper 



19 



-.03 







-.01 





Pinyon 



16 



-.15 







-.06 





Pinyon and juniper 



35 



-.08 



-1 



-.04 



>19 



Juniper 



11 



-.05 







-.01 





Pinyon 



3 



-.10 







-.03 





Pinyon and juniper 



14 



-.06 







-.01 



Total 



Juniper 



139 



-.06 



-1 



-.02 





Pinyon 



164 



-.11 



-2 



-.05 





Pinyon and juniper 



303 



-.09 



-2 



-.04 



^Mean percent difference is the mean volume difference divided by ttie mean volume computed by 

 Newton's formula. 



3 



