2 BULLETIN 1405, U. S. DEPARTMENT OF AGRICULTURE 



to be able to determine (1) when the range is ready for grazing, 

 (2) the degree, or intensity, and frequency of grazing that may 

 be allowed, (3) how to handle the stock in order to begin at the 

 right time and to regulate intensity and frequency of grazing, and 

 (4) the natural re vegetation of the range that may be relied on in 

 making plans for handling the stock. How this may be done is 

 indicated in this bulletin on the basis of observations made over 

 an extensive region, but particularly at the Great Basin Experi- 

 ment Station and in other parts of the Wasatch Mountains of Utah. 



MAJOR FORAGE TYPES OF THE WASATCH MOUNTAINS 



The forage cover in the major portion of the Wasatch Mountain 

 Range may be classified into three major types or zones, the bound- 

 aries of which are largely determined by climate. These types are 

 designated according to the characteristic tree species, as oak-brush, 

 aspen-fir, and spruce-fir. 



OAK-BRUSH TYPE 



The oak-brush type, the lowest of the three, occurs between eleva- 

 tions of about 6,500 and 8,000 feet, or in what is often termed " the 

 foothills." Limited rainfall and comparatively high temperatures 

 are characteristic. The brush species are often comparatively 

 dense, the perennial herbaceous species ordinarily occurring in a 

 scattered stand as an understory of the brush, partly as a result 

 of too early grazing and of overgrazing in the past. 



Gambel oak (Quercus gambelii) predominates throughout this 

 type. The principal browse species associated with it are snow- 

 berry (SymphoHcarpos oreophilus), sagebrush (Artemisia tri- 

 dentala), service berry (Amelanchier alnifolia), birch-leaf mahog- 

 any (Cerocarpus montanus), chokecherry (Prunus demissa), 

 squaw apple (Peraphyllum ramosissimum) , and bitter brush 

 (Purshia tridentata). The principal herbaceous vegetation is com- 

 posed of one or more species of the following genera : Blue grasses 

 (Poa), wheat grasses (Agropyron) , fescues (Festuca), needle grasses 

 (Stipa), mountain rice (Oryzopsis hymenoides), June grass (Koe- 

 Jeria cristata), butterweed (Senecio), bluebell (Mertensia). and 

 yarrow (Achillea lanulosa). 



ASPEN-FIR TYPE 



The aspen-fir type is highly valuable for grazing. It lies between 

 elevations of about 7,500 and 9,500 feet, the lower boundary adjoin- 

 ing the oak-brush type and the upper merging into the spruce-fir 

 type. Aspen (Populus tremuloides) 1 occurs over extensive areas, 

 and where overgrazing has not destroyed the forage the aspen type 

 supports a dense stand of valuable plants. Douglas fir (Pseudo- 

 isuga taxi folia) and white fir (Abies concolor) occur as individual 

 scattered trees in the aspen t}^pe and on rather steep north exposures 

 join with Engelmann spruce (Picea engelmannii) and Colorado 

 spruce (P. pungens) to form small areas of a distinct timber type 



1 Tidestrom maintains that the western aspen is a distinct species, and employs the 

 name Populus aurea therefor. 



