— 168 — 



3°. for a stand with " c " grgde. 



Equation: Probable % Diff. 



26.6524 



r, = 10.12e * ± 6.8% 



48.2452 



r2=43.47e ^ ± 4.8% 



The following diagrams (Plate XX) show a comparison of the theoretical 

 and the given results. 



Again, discussing the variations of the coefficients and constants in 

 the equation v=t:'J~—\j + t\ with regard to age, we may readily see from 

 the graphical study that the general trend of both t\ and r'a may be ex- 

 pressed by the formula: 



a'j^ _ &'j__ 



T\=a'e and t- =b'e 



The results are as follows: 



1°. for a stand with "a" grade. 



Equation: Probable % Diff. 



_ 1293551^ 

 T',=4.672e ^ ±39.9% 



_ 148.9388 

 r',=3.I91e * ± 9.9% 



2°. for a stand with " b " grade. 

 _ 99.2377 

 T', = 3.995e ^ ±11.1% 



_ 119.5731 

 r',=2.l76e ^ ± 3.9% 



3°. for a stand with " c " grade. 

 _ 115.1846 

 r',-6.09le ^ ± 5.27, 



_ I18.0828_ 

 r',2.= 786e ^ ± 6.7'/;- 



The following diagrams (Plate XXI) show the comparison of the 

 theoretical and the given results: 



We have thus investigated the elementary factors of the growth of 



