K are highly variable. The coefficients of 

 variation, i.e., 100 a/m, where tr is the stand 

 ard deviation and m the means are: 



A K 



Trees 21.46 28.49 



Shrubs 18.46 28.03 



Trees and shrubs . . . 20.20 28.27 



Herbs 23.46 25.33 



Our problem is to determine whether 

 higher values of K are associated with higher 

 values of A, or whether within each of these 

 growth forms 2 these two constants of the solu 

 tion are essentially independent. 



Determining the correlation coefficients by 

 the usual product moment method we have 

 the following measures of relationship be 

 tween the magnitudes of K and A in the 

 various series. 



For trees, # = 19, r = + 0.127 .152 



For shrubs, N = 3Q, r = 0.079 =fc .112 



For trees and 



shrubs, N = 55, r = -f 0.022 =fc .091 



For herbs, N = 162, r = + 0.150 .052 



For ligneous plants the correlations be 

 tween A and K are low and statistically in 

 significant in comparison with their probable 

 errors. The coefficient for shrubs is actually 

 negative in sign. That for trees and shrubs 

 together is sensibly zero. The coefficient for 

 herbaceous plants is also low but may indicate 

 a slight relationship between the two con 

 stants, higher values of A being associated 

 with higher values of K and vice versa. 



2 It is necessary to separate the growth forms, 

 since, as shown in detail elsewhere (Harris, Gort- 

 ner and Lawrence, loc. cit.) } the growth forms are 

 highly differentiated with respect to both A and K. 

 The actual means are: 



A Ky. io 



Trees 1.292 11,213 



Shrubs 1.177 10,770 



Trees and shrubs . . 1.217 10,923 



Herbs 0.846 14,308 



