RANGE PRESERVATION AND EROSION CONTROL. 35 
greater and shows itself in decrease in carrying capacity of the 
lands. 
3. While topography, climate, and soil are the primary factors in 
determining erosion, the combination of these factors on the lands 
under consideration is such that erosion is slight where the native 
ground cover has not been greatly disturbed. The seriousness of 
the erosion, therefore, is largely determined by the extent to which 
the ground cover is maintained. 
4. Serious erosion on western range lands is due chiefly to the 
destruction of the vegetation as a result of overgrazing and mis- 
management of live stock. 
5. The sum of conditions favoring destructive run-off and erosion 
is most pronounced in the fan-shaped drainage basins of the spruce- 
fir type (on the Manti National Forest between 9,000 and 10,500 
feet), where the ground cover is naturally rather sparse, where there 
is a characteristic sparseness of tree growth, and where the most 
desirable summer sheep ranges are located. 
6. To maintain an effective vegetative cover, overgrazing and too 
early cropping of the herbage must be avoided, deferred and ro- 
tation grazing should be applied, and stock should be properly con- 
trolled and distributed at all times in the season. 
7. In the case of incipient erosion, only slight changes in the use of 
the lands are generally necessary, and these changes do not neces- 
sarily imply even a temporary financial loss. 
8. Where erosion has had full play for a number of years, the 
reestablishment of the ground cover, even though grazing is dis- 
continued, does not always afford adequate protection. In such in- 
stances, which fortunately are relatively rare in this country, a 
combination of terracing and planting or, in exceptional cases, the 
construction of dams is justified. 
ADDITIONAL COPIES 
OF THIS PUBLICATION MAY BE PROCURED FROM 
THE SUPERINTENDENT OF DOCUMENTS 
GOVERNMENT PRINTING OFFICE 
WASHINGTON, D. C. 
AT 
10 CENTS PER COPY 
V 
