Southwestern ecosystems embrace a range of

landscapes from tundra to grasslands. Drought

and fire are dominant influences. Only 4 percent

of the land in the Southwest is riparian. These

ribbons of green are highly valued and sometimes

contested by competing interests.


The province contains six landscape character

types. From California to Texas, these share the

characteristics of vast skies, long vistas, and a

strong horizontal line. The land forms are

plateaus, mountains, valleys, plains, and canyons.

Vegetation creates washes of color varying from

olive-drab scrublands to gray-green woodlands.

Geology adds grays and the deep reds of

dramatic sandstone formations. Landscape

character types include:


The Mexican Highlands, a vast area of Arizona

and New Mexico, roughly is divided into one-third

mountains and two-thirds plains and grasslands.

Drained by V-shaped ravines, the mountains of

the Mexican Highlands feature bold escarpments

and outcrops. Dry washes called arroyos drain

the plains. Vegetation varies from coniferous

forests at higher elevation, to woodland, to

desert shrub.


The Sonoran Desert dominates southwest

Arizona. Like the Mexican Highlands, the area

combines mountains with canyons and plains

drained by arroyos. The Colorado River is the

principal waterway. Mountains are relatively low

and barren with many exposed rocks. The plains

are relatively barren. Areas with no ground cover

plantings are justly called “desert pavement.”

But places where Saguaro cactus grows host

a rich complement of palo verde, mesquite, and

prickly pear.


The Tonto makes a transition between the desert

floor and the Colorado Plateau. This is a landscape

of coniferous forests, deciduous woodlands, desert

shrub, chaparral grasslands, palo verde, and cholla

cactus. Geology is epitomized by the dramatic

red-rock formations of Sedona, Arizona. The

principal rivers are the Verde and Salt rivers with

dry washes draining the foothills.


In California, the Southwest Mountain and Valley

is crossed by earthquake faults and dominated

by chaparral grasses that can grow 10 feet

tall. The province stretches from San Luis Obispo

County to the north to the Mexican border

and from the undulating coastal plains to

three rugged mountain ranges: the Transverse,

the Peninsular, and the Southern Coastal.

National forests comprise about

one-third of these lands.


This landscape generally is semiarid with forested

stands limited to higher elevations. It is

dissected by canyons and riparian areas.


The Desert and Desert Mountain includes

southeastern California from the Mexican border

and Nevada to the eastern base of the Sierra

Nevada, Peninsular, and Transverse mountain

ranges. Parts of the Colorado and Mohave

deserts fall within this province. Elevations range

from below sea level in Death Valley to 14,242 feet

on White Mountain Peak. This landscape character

type is typified by long views across sagebrush

and shadscale or creosote bush. Alkali flats and

bare peaks may be visible in the distance. Open

stands of Joshua trees are common. Pinyonjuniper

woodlands cover the foothills and lower

mountain slopes. Bristlecone pines grow at

elevations above 10,000 feet.


Figure of Desert and Desert Mountain

Figure of Sonoran Desert

Figure of Tonto


The Sierra Foothills and Low Coastal Mountains

include low hills at the base of the Sierra Nevada

and Cascade ranges as well as a major portion of

the Coastal Range. The Sierra foothills and

eastern Coastal Mountains are typified by oak

woodlands, rounded hills, and chaparral-covered

slopes. Trees range from 15 to 70 feet tall.

Several major rivers and canyons bisect the

province. The green hills of winter turn gold with

fields of poppy and lupine in summer. The western

Coastal Range rises to 5,000 feet with dense

forests of pine, fir, and oak. Madrone cover northand

east-facing slopes, and chaparral grasses

cover west- and south-facing slopes.


Figure of Sierra Foothills/Low Coastal Mountains



Native American: Early Native Americans in

Arizona, New Mexico, and southwestern Colorado

built the province’s first permanent structures—

modified caves and rock shelters. Eventually the

Anasazi groups built surface dwellings such as

pit houses. Between 700 and 900 A.D., they

developed above-ground masonry dwellings that

eventually were joined to form small villages.

Anasazi architecture reached its peak between

1150 and 1350 in the great multistoried pueblos

such as those in the Four Corners area. Perhaps

due to droughts, the Anasazi dispersed. Their

descendants built plaza-centered pueblos of

stone or puddled adobe. The Taos, Acoma, Zuni,

and Hopi pueblos date to this period.


Spanish Colonial: The first permanent Spanish

colonists occupied an abandoned pueblo near the

Rio Grande River and modified it with Spanishtype

doors and windows. In 1610, Governor Don

Pedro de Peralta established Santa Fe under a

town plan that followed a mandate called the Law

of the Indies. The code dictated that all Spanish

colonial towns contain a central plaza with public,

commercial, and institutional buildings (such as

churches) facing the plaza. Residences were built

along a grid pattern of streets extending from

the plaza.


The Pueblo Indian Revolt of 1680 forced the

Spanish to flee to the El Paso valley. When the

Spanish returned, they fortified buildings and

churches against further Indian attack. For

example, they built enclosed complexes with

smooth windowless exterior walls. Their buildings

included such defensive features as parapets,

troneras (gun ports), and torreones (lookout



Mission Style: Spanish Colonial missions and

churches were a continuing influence on later

Southwest design. Unlike the adobe structures

of the pueblos, these missions were built of

stone. Their construction derived almost entirely

from European designs.


Territorial Style: After the Gold Rush of 1849,

Americans surged into California on overland

routes like the Santa Fe Trail. The new settlers

adopted methods that served the Spanish well in

the arid Southwest, but they added decorative

elements from “back East.” Milled woodwork

added to flat-roofed adobe houses spawned the

Territorial style, so named because Arizona and

New Mexico, where this trend predominated,

remained territories into the 20th century.


CCC-Rustic: During the 1930’s, the WPA, CCC,

and other Federal relief programs built civic

buildings and public works throughout the

country. In the Southwest, WPA-era buildings

adopted Spanish Colonial, Pueblo, and Territorial

Revival styles. They used domes, curvilinear

parapets, vigas, canales, and stucco. The “rustic”

idiom was evident in parks, forests, and outdoor

recreational areas.


Materials: Adobe was not the only indigenous

building material. Clay beds along the lower Rio

Grande provided raw material for local brickmaking

operations from the 1860’s to the present.

Generations of Mexican and Mexican-American

artisans have built distinctive brick dwellings,

churches, and commercial buildings on both sides

of the Rio Grande from Laredo to Brownsville.




Chapter 4.8 Table of Contents

Reader’s Guide