Apr. 12,1924 Vegetation in the Semiarid Portion of the United States 115 
other species. Under the shrubs there is usually a good stand of grasses and 
weeds. This type is restricted to the mountain and foothill areas of the Rocky 
Mountains, about 6,000 feet elevation. With the exception of sagebrush, all 
the species are very good browse for cattle and sheep. Areas that can be culti¬ 
vated are usually small and although lands of this character could be used for 
crop production their position and distribution are such that only small garden 
patches can be developed. The soil is usually dark and rich, but the growing 
season is sometimes too short to mature grains. The carrying capacity of this 
type is about 25 to 50 head of cattle per section. 
(92) Mountain Mahogany ( Cercocarpus parvifolius Nutt.).—Included in 
this type are all brush lands where mountain mahogany or closely related species 
predominate. It may be associated with oak brush, shadblow, river hawthorn, 
and mormon-tea. This type occupies drier soils than the preceding type. The 
stand of herbaceous vegetation under the shrubs is rather scattering. It occurs 
in rather low mountains and on foothills in Colorado, Utah and New Mexico. 
It is nonagricultural owing to the broken and rocky character of the surface but 
forms good browse for cattle and sheep, having a carrying capacity of 20 to 40 
head of cattle per section. 
(93) Chaparral ( Ceanothus velutinus Dougl.).—This is a very common brush 
type on burned-over timber lands, representing one of the stages of reproduction, 
where it often occurs in dense stands. It is also found on foothills associated 
with sagebrush, chokecherry, shadblow, aspen, or manzanita. It is a very 
common type above 6,000 feet in all the Western States except New Mexico and 
Arizona. It usually occupies lands too rough to be used for growing crops and 
it is also worthless for grazing. 
(94) Manzanita Brush Type. —This type includes all brush land where 
manzanitas (Arctostaphylos manzanita Parry, A. pungens H. B. K., A. nevadensis 
Parry) are the predominant shrubs. This type is very common in the mountain 
and foothill lands of Oregon and California, growing most commonly on southern 
slopes. In Oregon the manzanitas comprise 75 to 95 per cent of the shrubs in 
the type, while the remaining 5 to 25 per cent is made up of white oak ( Quercus 
garryana Hook.), Ceanothus cuneatuSj California laurel {Arbutus menziesii 
Pursh.) and black oak {Quercus californica (Torr.) Coop.). This type comes in 
on burned areas and is most frequently found in dense patches. Its agricultural 
possibilities are similar to the preceding type, and its carrying capacity is very 
low. 
(95) Southwest Mountain Brush Type. —This is a mixed mountain and 
foothill brush type found in New Mexico and Arizona containing a predominance 
of one or all of the following shrubs: Catsclaw {Acacia greggii A. Gray), Baccharis 
pteronioides DC., small mesquite {Mimosa biuncifera Benth.), Apache plum 
{Fallugia paradoxa (D.Don) Endl.), mormon-tea (Ephedra), cliffrose, and shad¬ 
blow {Amelanchier sp.). The last two species are usually found above 7,000 
feet, while the others are found below this elevation. The lower species may 
have a scattering of scrub oak and mesquite. This is nonagricultural due to the 
broken and rocky character of the lands occupied by this type. It has a carry¬ 
ing capacity of 15 to 25 head of cattle per section. 
(96) Oak Brush. —Classified under this type are all brush lands where oak 
brush or other closely related species predominate. This is a foothill type and 
is common in Utah, Colorado, New Mexico, and Arizona, where the oak brush 
consists mainly of Quercus utahensis (A.DC.) Rydb., and Q. arizonica Sarg. 
The latter species is restricted largely to Arizona and New Mexico. Associated 
with the oaks are the shrubs listed in Types (91) and (92) for Utah and Colorado 
and Type (95) for New Mexico and Arizona. In the coast region of northern 
California the oak brush type consists of a mixture of live oaks {Quercus chrys - 
2 
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