Figure 5.4 



Condition of Shrublands and Grasslands in the Contiguous States, 1976 



MM. Acres 



All Rangeland 

 (650) 



Shrublands 

 (358) 



Grasslands 

 (292) 



Effect of condition on forage supply. — Each eco- 

 system has its inherent natural potential productivity 

 or ability to produce herbage and browse. The natu- 

 ral potential production is the average annual pro- 

 duction that could be expected from an ecosystem 

 without irrigation or fertilization if that ecosystem 

 were in good condition. Thus the two largest range- 

 land ecosystems, plains grasslands and sagebrush, 

 containing 175 and 130 million acres respectively, 

 each have a potential to produce an average of a little 

 over one-half ton per acre annually. Wet grasslands 

 have the highest potential, over 5,100 pounds; and the 

 desert shrub the lowest, about 250 pounds (table 2.6). 

 Natural potential of deserts for forage is virtually nil. 



Since rangeland in fair, poor, or very poor condi- 

 tion produces less than its natural potential, any 

 improvement in range condition can usually be 

 expected to increase the supply of forage produced. 

 Conversely, any downward departure from good 

 condition will usually have a negative effect upon the 

 supply. Thus, the actual production of rangelands is a 

 function of present condition and the inherent pro- 

 duction of the ecosystem. 



Figure 5.5 shows the present production of the 

 rangelands in the contiguous States. The rangelands 

 having the highest production of herbage and browse 

 are the grasslands in the Central Plains and in the 

 coastal and near coastal Southern and Pacific South- 

 west areas. The sagebrush lands of the Intermountain 

 and Pacific Northwest also are significant contribu- 

 tors of herbage and browse. Although areas to the 

 east of the Great Plains have the water and soil 

 requirements for high forage growth, plant succession 



has resulted in their being covered with forests rather 

 than with rangeland plant communities. In the 

 Pacific Northwest, the heavily timbered zones are 

 similarly high in timber growth but low in forage 

 output, while the arid lands of the Southwest repre- 

 sent the least productive areas for forage under his- 

 torical management for reasons noted previously. 

 Should range conditions of higher herbage and 

 browse producing areas be improved, significant in- 

 creases in forage production can be expected. 



Grazing Use Of Range 



Use by livestock. — Livestock grazing is the major 

 use of the range. In 1976, almost two-thirds of the 

 1,207 million acres of forests and rangelands, or 789 

 million acres, were grazed in the contiguous States. 

 Most of the grazed range is in the 17 traditional range 

 States west of the Mississippi River. Here the forests 

 and rangelands are characterized by large acreages of 

 palatable and nutritious forage plants and have been 

 grazed by livestock ever since settlement by the early 

 pioneers and before that by large wild herbivores. 

 These States have about 70 percent of the forests and 

 rangelands in the 48 States, but they provide some 

 720 million acres of range grazing, or 91 percent of 

 the range grazed in the 48 States (table 5.3). 



The 31 States east of the Mississippi River supply 

 some 69 million acres of grazed range, only 9 percent 

 of the total grazed in the contiguous States. The 

 range grazing in the East reported here relates mostly 

 to livestock grazing in forest lands under varying lev- 

 els of management. Most livestock grazing in the East 



161 



