16 BULLETIN 790, U. S. DEPARTMEITT OF AGKICULTUEE. 



Sampson. Arthur W. Climate and Plant Growth m Certain Vegetative Asso- 

 ciations. U. S. Department of Agriculture, Bulletin 700, 1918. 



Chapline, W. R. Production of Goats on Far Western Ranges. U. S. Depart- 

 ment of Agriculture, Bulletin 749, 1919. 



Sampson, Arthur W. Plant Succession in Relation to Range Management. 

 U. S. Department of Agriculture, Bulletin 791, 1919. 



GRAZING CAPACITY. 



Grazing capacity, as used here, means the number of stock of a 

 given class or classes wliicli a range unit will support for the period 

 of grazing allowed. The ideal sought is the maximum number of 

 stock which the unit will support each season over a period of years 

 without injury to the range, tree growth, or watershed, or unwar- 

 ranted interference with game and recreation. If this ideal is to be 

 realized, both overgrazing and unnecessary undergrazing must be 

 avoided. 



OVERGRAZING. 



Overgrazing may be defined as grazing which when continued 

 one or mor^ j^ears, reduces the forage crop or results in an undesir- 

 able change in the kind of forage. Such grazing may exist over an 

 entire forest, but this is not likely with regulated range use. It may 

 exist over an entire large unit of cattle range or sheep range, but 

 seldom does. It occasionally exists over small cattle units or indi- 

 vidual sheep allotments, as a whole. Most often, however, overgraz- 

 ing occurs locally on parts of cattle range or sheep range because of 

 poor distribution of the stock or improper handling, or both. 



It is apparent, therefore, that an overgrazed spot on an allotment 

 does not mean that the allotment, as a whole, is overgrazed. Nor 

 does overgrazing on a few allotments mean that the forest as a whole 

 is overgrazed. On the other hand, the fact that the forest, as a whole, 

 or a range allotment, as a whole, is not overgrazed does not mean 

 that portions of either or both are not, even seriously, overgrazed. 

 Usually the difficulty can be remedied by more uniform distribution 

 of range by units, better distribution of stock on each unit, and better 

 handling of the stock. To get results, however, the man on the 

 ground must be able to recognize both overgrazing and undergrazing 

 and the causes and remedies for each. 



In determining whether a range is overstocked for any current 

 year to a point where overgrazing will result, both the condition of 

 the range and the condition of the stock at the close of the grazing 

 season must be carefully observed ; also the period during which the 

 range is grazed is important. If a range, for example, is not grazed 

 or is only lightly grazed during the main growing season of the 

 principal forage plants, but is heavily grazed later in the season, the 

 forage suitable for stock may be entirely consumed without damage 

 to the range. The same intensity of grazing during the growing 



