— 171 — 



may say that such a conclusion is very questionable, and that the both 

 heights are nearly equal to one another. 



For convenience of comparison of fluctuation of the two sorts of 

 heights, if we calculate the index number and draw the diagrams, then we 

 may conclude that the fluctuation of the two sorts of heights are precisely 

 the same. 



Thus the fluctuation of the average height may be represented by 

 the equation: 



B.=ke * 

 Applying the equation to the given data, we find: 



for a stand with " a " grade ; 



40.6837 



„ ooo. t Probable % Diff. ±5.9% 



Ha=33.34e 



for a stand with "b" grade; 



35.3762 



H6=30.80e * Probable % Diff. ±4.3% 



for a stand with " c " grade ; 



38.8214 



H,-=36.29e * Probable % Diff. ±4.7% 



The following diagrams (Plate XXIII) show the comparison between 

 observed and calculated results for each stand. 



(e) On the Average Volume. 



In the preceding part, we have investigated the volume curve of test 

 trees in a stand and stated that the volume curve may be represented by 

 the formula: 



Hence if we put x=D, then we get 



_^> 



This last equation shows that the trend of the volume of a test tree 



