CO 



sz 



X 



<D 



■o 



c 



c 

 o 



"■£! 



o 



3 

 ■D 

 O 



O 



O) 



CO 



o 



UL 



<1> 



E 

 E 



c/) 



600 



500 



1960 



1965 1970 1975 



Year 



1980 



1985 



Figure 3 . 9 



An index of summer forage production (kg/ha) for 

 forbs and shrubs at selected sites on the 

 Missouri River Breaks study area as determined 

 by clipping and regression analysis. 



July-April ) ]. This index indicated that 1961, 1980, and 

 1985 were years of extremely poor forage production on the 

 study area, while 1959, 1965, 1975, 1978, and 1979 were 

 characterized by forage production more than 1 standard 

 deviation above the mean. Although production in other years, 

 such as 1963, 1967, 1968, 1973, 1974, 1982, and 1986, was 

 indicated to be less than 1 standard deviation above the mean, 

 all stand out in field notes, general observations, or other 

 data as years of above-average forage production. 



Forage Abundance 



in 



2 

 g. 



Forage production was directly measured on only 4 sites 



vegetation types (Table 3.4), but a variety of data 



, Tables 3.2 and 3.3) were available to estimate the 



63 



