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NATURALIST'S GUIDE TO THE AMERICAS 



trees (broadleaf sclerophyll) origi- 

 nally occurred in rather dense stands. 

 Farther south this type of vegetation 

 is found at a higher altitude. About 

 San Diego the country is commonly 

 classed as semi-desert. Farther back 

 the live oaks occur at higher altitudes. 

 The southeastern desert portion of 

 California includes the Mohave and 

 Colorado deserts, the former including 

 Death Valley. Here are some of the 

 most arid areas in the West, charac- 

 terized by moving sand dunes, almost 

 barren tracts covered largely with 

 creosote bush (Covillea tridentata) and 

 with only occasional watering places. 

 Characteristic trees of the various 

 timber belts of the Sierra are a.s follows: 1 



1. Foothill belt, 500 to 3000 ft.: digger 



pine (Pinus sabiniana), blue oak 

 (Quercus douglasii), interior live 

 oak (Quercus wislizenii). 



2. Main timber belt, 3000 to 6500 ft.: 



yellow pine (Pinus ponderosa), 

 black oak (Quercus kelloggii), sugar 

 pine (Pinus lamb erti ana) , white fir 

 (Abies concolor), incense cedar 

 (Libocedrus decurrens), big tree 

 (Sequoia gigantea}. 



3. Upper portion of main timber belt, 



6500 to 9000 ft.: red fir (Abies 

 magnified], tamarac pine (Pinus 

 murrayana}, Jeffrey pine (Pinus 

 Jeffrey i). 



4. Timber-line belt, 9000 to 11,000 ft.: 



white-bark pine (Pinus albicaulis), 

 Sierra juniper (Juniperus occiden- 

 talis), mountain hemlock (Tsuga 

 mertensiana) , tamarac pine, foxtail 

 pine (Pinus balfouriapia) . 



The southern and eastern portion of 

 California is geographically separated 

 from the northern two-thirds by differ- 

 ences in climate and location of moun- 

 tains. This area includes the semi- 

 desert low country south of Bakersfield, 

 the Mohave Desert, and Death Valley, 

 and the Colorado Desert (including 

 Coachella Valley and Imperial Valley) 

 and the low mountains which separate 

 the two areas. These mountains are 

 characterized by the broad leaf sclero- 

 phyll type of vegetation in the upper 



1 From Jepson, W. L., 1909, The Trees of Cali- 

 fornia (Cunningham, Curtis and Welch, S. F.), 

 228 pp. 



reach of the western slopes and conifers 

 on their highest peaks. Numerous 

 valleys, very nearly enclosed, with a 

 flat floor covered with scattered live 

 oaks and characterized by grasslands, 

 are common in the foothills. The 

 east slope of the mountains is quite 

 different in the character of the vegeta- 

 tion and these differences have been 

 used by Shreve to suggest the inade- 

 quacy of the theory of temperature 

 control and distribution. 



2. Fauna, especially larger vertebrates* 



The broken topography, lofty eleva- 

 tions, and the long coast line extending 

 from the latitude of Sitka, to the lower 

 latitudes of Lower California, constitute 

 some of the important factors which 

 lead to great diversification locally in 

 temperature and humidity. Within the 

 single state of California the effects of 

 this climatic diversity on the animal 

 life are abundantly illustrated. Terres- 

 trial vertebrate animals at home within 

 the boundaries of the state are represen- 

 tative of the life of the far North and 

 of that of portions of Mexico. Marine 

 life, of both cold and warm waters, is also 

 abundantly represented. The result is a 

 very large number of species and higher 

 groups in proportion to the size of the 

 area. Within this state alone there 

 have been detected up to 1915 a total of 

 361 species of mammals, 539 of birds, 76 

 of reptiles, and 24 species of amphibians. 

 It may be stated with confidence that no 

 other state in the Union, or even a 

 contiguous pair of states, possesses so 

 many species as California, unless Texas 

 proves more prolific than present knowl- 

 edge indicates. 



Dr. Grinnell states that the plants, 

 most of the birds and some of the mam- 

 mals which are found restricted to the 

 chaparral belt "are of relatively ancient 

 origin and that they are quite certainly 

 indigenous." He continues: 



Among these are to be counted the 

 huge grizzly bear of California, now 

 exterminated, and the nearly extinct 

 condor. Of the smaller mammals pecu- 

 liar to the same belt we may mention the 

 diminutive brush rabbit, the parasitic 

 white-footed mouse, . . . and cer- 



1 From Grinnell, Joseph, 1915, "The vertebrate 

 fauna of the Pacific Coast," (pp. 104-112) in Nature 

 and Science on the Pacific Coast (Paul Elder & Co., 

 S. F.), 302 pp. 



