FOREST AND RANGE RESOURCES OF UTAH 25 



to assure plant vigor. Then when a bad year comes, a full utiliza- 

 tion of the forage can carry the stock. The surplus foliage of 

 the unusually favorable years gives to the heavily worked plants a 

 chance for recuperation that is much needed. 



METHODS OF DETERMINING CARRYING CAPACITY AND RANGE STOCKING 



Range carrying capacity is the maximum number of stock which 

 the unit will support each season over a period of years without 

 injury to the range or tree growth, or watershed, and without un- 

 warranted interference with game or recreation. 



In order to tell whether a range has too many or too few stock, 

 one must know whether it is improving or deteriorating from year 

 to year. When it is definitely known, however, that a range is 

 understocked or overstocked, the increase or decrease necessary to 

 stock the range properly can not always be determined easily. As 

 a help in determining how many stock to place on an area, range 

 surveys are made on the national forests by especially qualified men 

 who know the plants well, know the habits -of livestock on the range, 

 and know the value of the various plants for forage. These men 

 determine the density of the plant cover, that is, the proportion of 

 the ground that is covered by forage plants and the average palat- 

 ability of these plants. By multiplying the percentage of ground 

 covered by plants (density figure) by the average palatability figure, 

 a factor is determined which is multiplied by the total number of 

 acres, to give the number of forage acres. A forage acre is an acre 

 of ground entirely covered with plants wholly palatable to livestock. 

 An acre of dense bluegrass lawn might be called a forage acre. 

 Forage acres give a more or less definite measuring stick for dis- 

 tributing the stock on the range in proportion to the amount of 

 forage on the various units. 



The most satisfactory and surest way of determining how many 

 stock a range unit can carry is to keep accurate records of the num- 

 ber of stock, the length of time they graze, their condition at the end 

 of the grazing season, and the amount of forage that is left. 



Quadrats are sometimes established, representing average condi- 

 tions on the range. A plot of ground 40 inches square is marked 

 off into 100 four-inch squares by means of cross straps. The loca- 

 tion of each plant is then mapped. Remapping after several years 

 have elapsed will show whether the plant cover has increased or 

 decreased and whether good forage species are increasing or de- 

 creasing, thus giving an index to what is happening on the entire 

 unit. (Fig. 9.) 



As another help in studying what changes are taking place on the 

 ranges, and what the range is capable of producing, a 1-rod or 

 2-rod square is fenced. The plants in this inclosure have a chance 

 to grow and reproduce unmolested, thus showing what the range is 

 capable of producing, and offering a comparison between grazed 

 and ungrazed range. Often, abandoned but closed corrals, or 

 patches of range protected from grazing, may afford comparisons 

 with the grazed portion of the range. (Fig. 10.) 



Usually those responsible for the management of national-forest 

 ranges make frequent trips to study the use stock are making of the 

 range, the condition of the stock, and the condition of the range. If 



