NATURAL AREAS AND RECIONS 



557 



1. UTAH 

 By C. F. Korstian 



Utah is situated near the center of the 

 western United States on the great 

 Intermountain Plateau. The main Wa- 

 satch Mountain Range extends north 

 and south practically the entire length 

 of the state; while the Uinta Mountains 

 extend eastward from the Wasatch 

 Range paralleling the Wyoming state 

 line. By far the greater part of the 

 state lies above an elevation of 4000 ft. 

 The main summits of the mountains 

 attain altitudes of 10,000 to 13,000 ft. 

 A number of isolated mountain masses 

 occur in practically every part of the 

 state. Situated, as it is, in the interior 

 of the continent and to the leeward 

 of the great Sierra Nevada Mountain 

 Range all of the state, with the exception 

 of the higher mountains, has a distinctly 

 arid climate. The annual rainfall varies 

 from 5 to 15 in. throughout the lower- 

 lying portions, while on the mountains 

 the precipitation is 20 to 30 in. per year. 



All the country west of the summit 

 of the Wasatch Range drains into the 

 Great Basin. The largest bodj^ of water 

 in the state is the Great Salt Lake, 

 the "water of which is so salty that a small 

 shrimp is practically the only form of 

 life found in it. This lake is the present 

 daj' remnant of the ancient Lake Bonne- 

 ville which formerly occupied an 

 extremely large area in this region. 

 The old shore-line ma}^ be traced along 

 the western foothills of the Wasatch 

 Range all the way from Provo to a point 

 some 30 mi. north of Ogden. 



Practically all of the valleys and the 

 plateau country between the mountain 

 ranges were originally a sagebrush 

 desert, the dominant species being 

 sagebrush {Arlemisia tridenlata) asso- 

 ciated with other small-leafed shrubs. 

 Greasewood (Sarcobatus vermicnlaius), 

 andshadscale (i'l/np^cxsp.) are the domi- 

 nant species on extensive areas of alkali 

 flats in the arid valleys. A distinctly 

 halophytic association of vegetation is 

 found on the salt flats adjacent to the 



Great Salt Luke. On the coarser soils 

 of the fnotliilis the junipcni (JuniperuM 

 utdhmsis -iJid J. ■ 



in tiic soiitlierii jtart . . , , .. ;, 



{Pinus c(luHs) form o|)on park-like wood- 

 iand.s. (Tiie foroKoinK tyi)Cfl of vcgcta- 

 tion fall witliin the Upfjcr Sonoran 

 Life Zone.) 



A small area of extreme dc»crl con- 

 ditions occurs aloHR the \'irKin Uivor 

 in soutliwcstcrn Utali. TIiIh i- -'■ — 

 acterized as a small-lcafcd shrui 

 in which the creosote Iniflh {Cortttra 

 Iridcntalfi) is the dominant 

 (Lower Sonoran Life Zonej. W .... 

 mammals except small burrowinR forma 

 occur naturally in this area, reptiles 

 are very abundant. 



The mountains were oriRinally clothed 

 with a coniferous forest which is often 

 regarded as a southward extension of 

 the northern evergreen forest. In the 

 southern part of the state western 

 yellow pine {Pinus jwndcroaa scopulo- 

 rum) is most abundant. In the cen'- ' 

 and northern part of the state t ..- 

 species is largely replaced by a brush 

 cover composed of various species of 

 shrubs and small trees (Transition Life 

 Zone). The next higher tyi>e altitudi- 

 nally is that in which Douglas fir {Pseu- 

 dolsvga taxifolia) and white fir (.1' '• 

 concolor) are dominant (Canadian I •<- 

 Zone). In the Uinta Mountains loii^. 

 pole pine {Pinus contorta) also forms 

 rather extensive stamls. On tin ' ' - 

 mountains above 0000 ft. Kn;, 

 spruce {Picca engelmanni) and alpine 

 fir {Abies lasiocarpa) are the char- 

 acteristic species (Hudsonian Liff' '^ 



The forest conditions are tl< 

 more fully by Baker and Ixicke in con- 

 nection with the in of the 



National Forests in i urni" "■' n 



Region.* Succulent plants arc i 

 principally to the higher mountain 

 slopes. 



The following animals have lx^cn 

 reported as inhabiting the Bftgrbruiih 

 desert: pronghorn 

 caprn amtrtcatui), r<'_>"n ■ ■...■.• -j-j- , 



> This volume. ptkK* •'*■ 



