CLUSTER ANALYSIS 

 77 79 



REVEGETATED AND UNTREATED AREAS 



U - Untreated (11 Tubes) 

 R - Revegetated (21 Tubes) 



16 34 29 1 8 3 37 39 24 14 38 42 21 4 12 13 32 6 40 7 22 33 30 35 25 41 10 26 28 36 31 17 

 RU RRRRUURRUUR RRRURUR RURU RU RRRURR 



Figure 2.— Dendrogram of soil-water samplers on the revegetated and untreated areas, 1977-79. 



Cophenetic correlation = 0.95. 



Untreated 1 974-75 vs. Untreated 

 1977-79 



The dendrogram using the samplers on the 

 untreated area only for both sample periods Indi- 

 cates a tendency for sampler grouping by samp- 

 ling period (fig. 3). 



Since the same samplers are shown twice in 

 figure 3, once for 1974-75. once for 1977-79, an 

 even split within dendrogram groups by years 

 would indicate no difference in the water quality 

 from 1974-75 to 1977-79. However, that is prob- 

 ably not the case. If the tree is cut at 0.70, seven 



groups of similar soil-water quality emerge (table 

 3.) Most of the 1977-79 samplers are contained 

 within the first group and are represented twice as 

 often as would happen by chance. Groups 4, 5, 6, 

 and 7 contain more of the 1 974-75 samplers than 

 would be expected by chance. In this case there is 

 a tendency for 1 974-75 results to group, and for 

 1977-79 results to group. In other words, the 

 1 977-79 samplers are more similar to each other 

 than they are to the 1974-75 samplers. 



Based on the evidence in figure 3 and table 1, 

 we conclude there is a difference in the soil-water 

 quality from 1 974-75 to 1 977-79. The concentra- 

 tion of copper, iron, and sulfate has decreased. 



5 



