GOVERNMENT FOREST WORK IN UTAH 13 



with less favorable growing conditions is dependent upon that 

 manipulation of grazing which will afford the native forage plants 

 an opportunity to mature seed and revegetate themselves. 



An experiment on range where shrubs, principally oak brush, make 

 up approximately 80 per cent of the vegetation, showed that such 

 range should be grazed only to a degree that will permit the increase 

 and perpetuation of the more palatable browse species and grasses 

 and weeds of approximately equal palatability, even though these 

 last species make up considerably less than half the total vegetation 

 and even though such grazing results in the nonuse of the bulk of 

 the less palatable shrubby vegetation. 



It is important to be able to recognize and correct overgrazing in 

 its early stages. On many summer ranges in Utah the wheat grasses 

 constitute the highest type of vegetation. If this cover is weakened 

 by overgrazing, such plants as yellow brush, lupine, mountain sun- 

 flower, sneezeweed, yarrow, sweet sage, and pentstemon take the 

 range and more or less erosion of the soil takes place. If overgrazing 

 is continued, these perennial weeds sooner or later are replaced by 

 annual plants of little forage value. Finally even these give way, 

 leaving the area denuded and subject to heavy erosion, and eventually 

 the fertile mountain slope is reduced to a barren waste. By learning 

 what plants come in as the desirable type of plants begin to give way, 

 it is possible to recognize overgrazing in its early stages, and to apply 

 remedial measures. 



Since one of the chief objects of Utah forest-land use is to provide 

 a continuous supply of timber, it is important to so manage grazing 

 that it will not interfere with timber reproduction. Investigations 

 have shown that injury to timber production by grazing in Utah, 

 regardless of the class of stock, varies with the intensity of use of a 

 range. It has been found that on cut-over aspen lands, sheep and 

 goats should be entirely excluded for at least three years in order 

 to give the young sprouts time to extend their leaders beyond the 

 height at which sheep browse. On cattle range light grazing is sel- 

 dom injurious to the aspen sprouts. Where young conifer or ever- 

 green species are being established, light grazing and open herding 

 are essential. 



Poisonous plants are one of the principal causes of losses of live- 

 stock on range lands. Experiments have shown that many of these 

 poisonous plants may be economically eradicated either by cutting 

 or grubbing. In the case of larkspur for example, if the cutting 

 method is used, the plants should be cut twice the first two seasons 

 and once the third year for complete eradication. If grubbing is 

 applied, the plants are at once destroyed, provided the roots are 

 grubbed to a depth of 8 or 9 inches. Usually a light regrubbing 

 is necessary in the second year. 



The water supply for irrigation, hydroelectric power, and domestic 

 use is the most important resource derived from mountain lands in 

 the West. An experiment has been under way at the Intermountain 

 Forest and Range Experiment Station since 1915 to determine the 

 effect of grazing on the herbaceous plant cover in relation to stream 

 flow and erosion. Its object is to determine the kind and degree of 

 grazing that may be practiced without adversely affecting the water 



