Table 2. — The significance of seasonal means for extractive content as 



determined by Duncan's New Multiple Range Test 



Date of 

 sampling 



Code for 

 sample 





Samples having significant difference 

 (P = 0.05) in mean extractive content 





Leaves 



iviean 



Stems 



Mean 



10/26/66 



A 



BCDEFGH 



11.34 



DEFH 



8.29 



12/22/66 



B 



ACDEFGH 



11.24 



DEFH 



6.65 



3/ 2/67 



C 



ABE 



9.66 



DEH 



5.94 



4/27/67 



D 



AB 



8.80 



ABCGH 



4.54 



6/21/67 



E 



ABCFH 



8.44 



ABCFGH 



4.33 



7/12/67 



F 



ABE 



9.57 



ABEH 



5.19 



8/12/67 



G 



AB 



8.72 



DEH 



5.83 



12/28/67 



H 



ABE 



9.72 



ABCDEFG 



8.29 



Percen t dry weigh t, ash free. 



The regression between extractive content 

 and heat content of the total fuel, ash free, 

 was determined by using data from two out 

 of the six samples per sample date. These sub- 

 samples were picked randomly; data for these 

 are presented in table 3. A portion of the 

 1963 data is also included in this analysis. Fig- 

 ures 6 and 7 show the relationships for leaves 

 and stems. The coefficient of determination. 



r" , is 0.72 for leaves and 0.58 for stems. The 

 equations for the lines are 



Leaves: Y = 8.000 + 169X 



Stems: Y = 8,800 + 101X 



where Y = high heat content 



(B.t.u./lb., ash free) 



and X = ether extractive content 

 (percent dry weight, ash free). 



8 5 9.0 9 5 10 10 5 110 



ETHER EXTRACTIVES (Percent dry weight) 



= 9400 



4.0 5.0 6.0 7.0 8.0 



ETHER EXTRACTIVES (Percent dry weight) 



Figure 6. — The relationship between the extractive 

 content of the leaves and total ash-free 

 heat content. 



Figure 7. — The relationship between the extractive 

 content of the stems and total ash-free 

 heat content. 



6 



