198 



THE FORM OF TREES AND TAPER TABLES 

 TABLE XXXIII 



Form or Taper for White Ash Trees of Different Diameters under 75 

 Years of Age, Giving Diameters inside Bark at Different Heights 



ABOVE THE GrOUND 



90-foot Trees 



Original Curves, Tapers Based on Heights above Stump} In the 

 form shown, these average tapers or upper diameters may be insufficient 

 to bring out the true average form for large numbers of trees. The 

 irregularities of form, occasioned by the variation in form of individual 

 trees and lack of sufficient number of trees to secure a true average by 

 arithmetical means, are best shown by plotting the forms of the result- 

 ant average trees. For this operation, height above stump is taken 

 as the independent variable i)lotted on the horizontal scale while upper 

 diameter is the dependent variable plotted on the vertical scale. A 

 separate curve is required for trees in each D.B.H. class. 



1 The details of constructing taper curves are fully discussed by W. B. Barrows, 

 Proc. Soc. Am. Foresters, Vol. X, 1915, p. 32. 



