326 FORAGE ESTIMATES 



Comparative Value of a Forage Acre of Different Types. — One 

 of the most puzzling and complicated features experienced by 

 the apprentice grazing examiner is the practical application of 

 the forage acre. This is due to the fact that a forage acre of one 

 type of range does not necessarily have the same pasture value 

 as does a forage acre of quite a different type. Yet this is not 

 an unsurmountable complication among experienced range 

 technicians. However, grazing reconnaissance would be more 

 directly applicable in estimating the grazing capacity of an area 

 which supports various types of vegetation if a forage acre of one 

 type had the same grazing value as that of any other type. 



In grazing reconnaissance the use of the term forage acre is 

 comparable to that of a ton of roughage; it is merely a standard 

 measure of comparison. Nobody would argue that a ton of 

 alfalfa hay contains the same feeding value or fattening quahties 

 as does a ton of timothy. Indeed, nobody would contend that 

 a ton of alfalfa hay has the same food value for the different 

 classes of foraging animals. For similar reasons stockmen and 

 pasture experts would not contend that a forage acre of succulent 

 broad-leaved herbs (" weeds "), for example, would furnish as 

 much feed for cattle or horses as for sheep in numbers equivalent 

 to cattle or horses in forage requirement. However, a forage 

 acre of a given type in a given region, like a ton of alfalfa hay, 

 has practically the same forage value for a given class of stock as 

 has the same type of forage acre no matter how remotely lo- 

 cated within that region. 



To determine the relative grazing capacity of the different 

 types a large number of practical grazing tests with the different 

 classes of stock has been made by the United States Forest 

 Service, and the relative grazing value of a forage acre of many 

 of the important types has been determined with considerable 

 accuracy. Although this work is in its infancy, it is nevertheless 

 possible to estimate somewhat closely on a forage-acre basis the 

 grazing capacity of any portion of the range or of the range as a 

 whole. Thus the actual carrying capacity of a forage acre of a 

 given type takes the place of such a chemical analysis or food- 

 value test, for instance, as has been determined for a ton of 

 alfalfa hay. 



