X 
M Chemical plant 
Dot 
.. 
map of damaged trees 
condition class 2 
condition class 3 
condition class 4 
oz 
X= 
y X 2 Isopollutes ($ of damaged trees 
per ha) 
3a Linear trend surface (2=0.22 + 0.26X - 0.02Y R= 0.32) 
b Residuals from 3a (number of damaged trees/ha) 
42a Non-linear surface using Krumbein's expected-value 
p 
method (number of damaged trees/ha) 
b Residuals from 4a 
5 Potential surface (isopotentials : number of damaged 
trees/ha/km) 
  
  
Further explanation see text. 0 Ten 
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