GRAZING AND FORAGE PRODUCTION ON NATIONAL FORESTS 21 



summer this dries up and it becomes necessary to move the stock to 

 other areas. 



Because of the desirability or necesity of grazing the spring-range 

 zone for a period in the fall, it is often essential to leave a certain 

 amount of forage for this use at the close of the spring period. 

 Occasionally the character of forage and the soil and climatic condi- 

 tions are such that the feed necessary for the fall period is produced 

 after the close of the early season, while the livestock are on the 

 summer range. 



The closing of the grazing period on summer and fall ranges is 

 governed largely by (1) proper utilization of the forage, (2) weather 

 conditions and the trampling of wet soil, (3) the condition of the 

 livestock, (4) the availability of late fall and winter forage else- 

 where, and (5) the availability of water. 



Proper utilization may be defined as that degree of grazing which 

 utilizes the largest quantity of forage possible without threatening 

 the future productivity of the type, or which allows the type to 

 recuperate if it is depleted. It is generally conceded that if from 

 10 to 25 per cent of the herbage of the more important palatable 

 species remains in the fall proper utilization has been affected. 

 When proper utilization has been attained, irrespective of the other 

 factors mentioned, the livestock should be removed from the range. 

 It is never good practice on any type to crop the forage in the fall 

 so closely that the animals merely survive. Furthermore, such close 

 cropping often results in the exposure of the crown and buds of the 

 plant, a condition which is responsible for much winter-killing and 

 loss of plants by frost upheaval. 



In some years weather conditions determine the proper time for 

 the close of the grazing period on fall ranges. Frequently heavy 

 snowfall early in the season makes it necessary to remove the live- 

 stock from the range earlier than would otherwise have been neces- 

 sary. If the fall is exceptionally wet, they should be removed 

 early to prevent damage to the range by trampling and loss in 

 weight of the animals. It is especially undesirable to hold beef 

 cattle overlong on the fall range, for at that season they usually 

 lose in weight and finish. The availability of good feed elsewhere 

 is not uncommonly a determining factor as to the time when the 

 animals may be removed in the fall. 



Livestock should be removed from winter range early enough 

 in the spring to allow time for the forage plants on this range to 

 make a satisfactory new growth. The date of such removal is 

 largely determined by the character of the vegetation and the pre- 

 vailing moisture conditions. Where it is necessary to remove the 

 livestock from the winter range before the spring range is ready, 

 supplemental feed must be provided for the interval. 



GRAZING PERIODS IN EACH VEGETATIVE TYPE 



The following grazing periods are those which give the best 

 results on each of the three major types of the Ephraim Canyon 

 watershed, where the detailed studies were made : 



Oak-brush type (6,500 to 8,000 feet elevation) : Spring to 

 early summer, and late fall; May 20 to June 9, and Octo- 

 ber 1 to October 15. 



