The Pacific Coast States

THE RANGE IN CALIFORNIA

M. W. Talbot, A. W. Sampson

ABOUT HALF of the 60 million acres in California that lie west of the Sierra Nevada Divide can be used for grazing. Despite the extent of this forage area, however, more meat and livestock are consumed than produced in the State, and as the population grows and demands on range lands get heavier, the need for sound management of these lands becomes more acute.

The grasslands lying west of the Sierra Nevada differ conspicuously from those in other western regions in climate, vegetation, and utility.

A long, interior trough, the Central Valley, lies between the Sierra Nevada range on the east and the Coast Range or, the west. These mountains and the Pacific Ocean contribute to a highly diversified climate. Soil conditions also vary widely and sometimes change abruptly. Precipitation generally is greater and temperature is lower with increase in altitude and latitude. The marine influence moderates temperatures along the coast and intermittently in the Central Valley. Summers are hot and dry. Most of the precipitation occurs from October to June.

Great changes have occurred here since Mission days. Intensive cultivation has replaced much of the grazing. Croplands and city lands now total approximately one-fifth of the Pacific slope. Native perennial bunchgrasses have decreased and introduced annuals have increased over large areas of the lower elevations.

The original cover evidently contained many native annual grasses and forbs; the degree to which these have changed in population is unknown. But the magnitude of the invasion of alien annuals is indicated by surveys that show that these plant immigrants now compose more than half of the herbaceous cover over vast foothill areas-60 percent, indeed, on the San Joaquin Experimental Range in the central Sierra foothills. Brush fields appear to occupy greater acreage now than formerly because of burnings and other disturbances in forest areas.

On some good timber-growing land, the acreage of available forage in fairly open stands of timber has been considerably reduced, as the thickening new stands of young trees gradually shade out the forage plants. Such forage loss is temporarily offset, at least in part, as timber stands open up with greater age, or as openings are made by logging. Conifers often have invaded mountain meadows.

The cover of vegetation on the Pacific slope comprises four provinces, arranged roughly by altitudinal zones: Open grassland, grass-woodland, chaparral, and timber-grass-brush.

Much of the Central Valley and large sections of the middle and south Coast Ranges are open grasslands, with many local exceptions where tree or shrub areas occur in intermingled patterns. The main body of comparatively treeless grassland, totaling approximately 9 3/4 million acres, is found from sea level to about 1,500 feet.

Lower elevations receive from 5 to 30 inches of precipitation, mostly in the form of rain, the amount increasing locally to as much as 40 inches in the north coast section. Summer temperatures go up to 105 F.

An unusually rich mixture of annual and perennial grass and forbs is a distinctive feature of the zone. The annual-grass areas are extensively grazed at all seasons, but their greatest value is as winter and spring ranges. Used in conjunction with the lower portion of the adjoining woodland, the open grassland province is the basis for the livestock industry of the State. Proximity to irrigated pastures, to the summer grazing lands of the mountains, to sources of supplemental feeds including crop residues, and to markets, makes it and the grass-woodland province the best situated for maximum flexibility in management.

Grass-Woodland

The increasing abundance of shrubs and trees in the vegetative cover set this zone apart from the adjoining open grasslands. The lower part of this belt has an orchardlike appearance because of the scattered stands of trees and shrubs of which Digger pine, live oak, blue oak, and California buckeye are locally most abundant.

As in the open grassland, hundreds of species of grasses and other herbs are common, but most of the forage comes from comparatively few species. For example, on the San Joaquin Experimental Range of this province, the three most important species soft chess, foxtail fescue, and broadleaf filaree provide fully two-thirds of the forage in pastures from which 225 different species have been identified.

Broadly considered, the grazing capacities are greatest along the lower margin. Higher up, the stand of trees and shrubs thickens, the period of availability for grazing shortens, and the acreage requirements per animal increase. The grazing value of the grass-woodland province as a whole is therefore intermediate between that of the lower grassland and the higher chaparral and the timber-grass-brush province.

Chaparral and Brush

From the northern mountains to Mexico, interrupted strips of shrubby growth lie largely below the timber-brush-grass province. The dense, shrubby growth is called "chaparral"; its province is usually termed "brush" land by stockmen.

Chaparral occupies some 11 million acres, or about 18 percent' of the Pacific-slope grasslands. It includes also a large acreage of woodland and of cut-over timber that has reverted to various brush species. True chaparral seems chiefly to be limited to areas where the temperature does not exceed 100 F. for long periods and where average annual precipitation is 10 to 35 inches.

Growing on steep, rugged terrain, the denser chaparral stands are found on north and east slopes, and more drought-resistant species occupy the south and west slopes of thinner, drier, and rockier soils. Most of the chaparral species are broadleaved, like manzanita, and ceanothus, but the most common and widely distributed species chamiza has narrow, needle-like foliage.

The food plants are primarily important because they supply most of the forage on fresh burns, and on glades within the brush association. Sprout, twig, leaf growth of some of the shrubs is browsed in winter and through the spring. Sprouts are most palatable up to about midsummer.

The limited seasonal pasturage furnished on the average chaparral cover is poor because the brush is of low palatability, and the understory vegetation is sparse and largely inaccessible.

Maximum usefulness of the brush-land forage is obtained in late winter, spring, and early summer, when nutritional constituents of the forage are high. After this, feed values decline.

Usually referred to as the coniferous forest zone, the timber-grass-brush province occupies about 28 percent of the area reported upon, and blankets the north Coast Ranges and the Sierra Nevada and Cascades. This province also includes in its steep and rugged terrain extensive areas of open, rocky grassland above the timber line in the high Sierra Nevada.

Except in the redwood region, this timber and grass zone lies in the snow belt. Most of the precipitation falls in winter and ranges roughly from 40 to 50 inches on the western slopes of the Sierra to as much as 50 to 80 inches in the redwoods.

Range land on the forested western slopes consists largely of timber and brushland on ridges and steep slopes, interspersed with openings and small bottomlands of open character. Browse and a small amount of grass and forbs furnish the major forage. In the fir stands of the higher elevations and the dense Douglas-fir and redwood forests of the northwestern part of the State, grazing is confined mainly to glades, burns, and small clearings.