— 167 — 



Now, turning to the. tables given above, we see that the probable per- 

 centage differences of the stand with "a" grade at the age of 32 is greater 

 than any other one, and that the probable percentage differences of each 

 stand diminishes with the age and the grade. The first fact is due to 

 the variability of the dimension of trees and the second to the increase 

 of the grade of homogenity (as to the grade of homogenity we have 

 already explained it in previous parts). Thus, we do not hesitate to state 

 that the equations above given for the height curve and the volume curve 

 of test trees are almost probable ones to be accepted. 



Kopezky proposed that the height curve accords with the formula: 



where «, and ^, are the constants, respectively and that the volume curve 

 accords with the formula: 



where a and ^ are constants. According to our investigations, it will be 

 readily seen that Kopezky's formula is only roughly approximate and 

 that in practical application it is inadequate. 



Now if we turn to discuss the variations of the coefficients and 

 constants in the equation h=v/-^-i\+t^ with regard to age, we may 

 readily see that the general trend of both Ti and z^ may be represented by 

 the formula: 



_ g, &L 



Ti=ae and T2— &e 



The results are as follows: 



1°. for a stand with " a " grade. 



Equation. Probable % Diff. 



6.5596 



T,=4.158e * ±16.9% 



55.8323 



T,=45.29e * ± 3.6% 



2°. for a stand with " b " grade. 



41.5207 



ti-11.57e ^ ±13.6% 



44.2921 



t 



r.,=36.48e ^ ± 4.2% 



